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Biogeography and conservation of viperids from North-West Africa: an application of Ecological Niche-Based Models and GIS
... Five species of vipers with partially overlapping distributions are found in southwestern Morocco (Bons and Geniez, 1996;Brito et al., 2011;Martínez del Mármol et al., 2019a). In this region, some of the species coexist in broad sympatry and even in syntopy, which is usually facilitated by man-made structures, such as water cisterns or roads (Brito et al., 2011;Martínez-Freiría et al., 2016;García-Cardenete et al., 2017;Martínez del Mármol et al., 2019b). ...
... Five species of vipers with partially overlapping distributions are found in southwestern Morocco (Bons and Geniez, 1996;Brito et al., 2011;Martínez del Mármol et al., 2019a). In this region, some of the species coexist in broad sympatry and even in syntopy, which is usually facilitated by man-made structures, such as water cisterns or roads (Brito et al., 2011;Martínez-Freiría et al., 2016;García-Cardenete et al., 2017;Martínez del Mármol et al., 2019b). As these are venomous and the possibility of snakebite exists, their specific distributions are of considerable interest. ...
... The overall geographic distribution of these two vipers is known to overlap in the coastal area between Agadir and Laayoune (Bons and Geniez, 1996;Martínez-Freiría et al., 2017a;Martínez del Mármol et al., 2019a, b), and it appears to be the only area in the range of the genera Bitis and Daboia where both coexist (Wallach et al., 2014). Sympatry between these two species has been reported along the Plage Blanche road (Sites 2 and 4 in the current study), at distances between 14 and 40 km from Site 1, as well as around Oued Chbika, a distance of 120 km from Site 1 (Brito et al., 2011;Martínez del Mármol et al., 2019b). Cerastes cerastes has also been found relatively close to Plage Blanche (Brito et al., 2011;Martínez del Mármol et al., 2019a) and syntopy between this species and D. mauritanica has been reported previously from Aouinet Lahna (Martínez-Freiría et al., 2016), close to Site 9 in the current study. ...
Amphibians and reptiles were surveyed at ten sites in southwestern Morocco from 13–22 October 2019 and a total of 24 species (two frogs, one turtle, 11 lizards, ten snakes) were recorded. We describe a possible natural case of syntopy between two viper species, Bitis arietans and Daboia mauritanica. We also provide additional localities for 11 species: Tarentola boehmei, Tropiocolotes algericus, Mesalina guttulata, Myriopholis algeriensis, Lytorhynchus diadema, Macroprotodon brevis, Spalerosophis dolichospilus, Psammophis schokari, B. arietans, Cerastes cerastes, and D. mauritanica. These additional records provide valuable information about the distribution of these species and provide a baseline for their conservation.
... This assemblage consists of species with major allopatric distributions, resulting from distinct biogeographical affinities (i.e. Palearctic, including three Mediterranean and two Saharan species; and Afrotropical, with one Sahelian and one Afrotropical generalist species) and ecological requirements (Bons & Geniez, 1996;Brito et al., 2011;Sindaco et al., 2013). However, some species can be found in adjacent areas and similar habitats (e.g., Bitis arietans, Cerastes cerastes and Daboia mauritanica in South Western Morocco; see Brito et al., 2011). ...
... Palearctic, including three Mediterranean and two Saharan species; and Afrotropical, with one Sahelian and one Afrotropical generalist species) and ecological requirements (Bons & Geniez, 1996;Brito et al., 2011;Sindaco et al., 2013). However, some species can be found in adjacent areas and similar habitats (e.g., Bitis arietans, Cerastes cerastes and Daboia mauritanica in South Western Morocco; see Brito et al., 2011). In fact, by applying ecological niche-based models, potential sympatry for five of these species was found in an area of environmental transition located between the southern slopes of the Anti-Atlas to the As Saquia Al Hamra river valley (South Western Morocco; Brito et al., 2011). ...
... However, some species can be found in adjacent areas and similar habitats (e.g., Bitis arietans, Cerastes cerastes and Daboia mauritanica in South Western Morocco; see Brito et al., 2011). In fact, by applying ecological niche-based models, potential sympatry for five of these species was found in an area of environmental transition located between the southern slopes of the Anti-Atlas to the As Saquia Al Hamra river valley (South Western Morocco; Brito et al., 2011). Landscape transformation in this region is still reduced but there is a high proliferation of water cisterns for watering livestock which act as death traps for vertebrate fauna (see García-Cardenete et al., 2014). ...
Morocco has seven species of vipers, with allopatric distributions, for which coexistence has never been cited. However, an area of potential sympatry has been identified between
five of these species in the southwest region of the country. In this note we present a case of sytopia between a Saharan species, Cerastes cerastes, and another Mediterranean, Daboia mauritanica, that were trapped in the decantation chamber of a cistern. The observation occurred in the lower Drâa, southwest of Morocco; it is an environmental transition zone, where the two species must meet in sympathy and probably also with a third species of afro-tropical origin, Echis pyramidum leucogaster.
... Three sets of environmental factors, or ecogeographical variables (hereafter EGV) were used for building ecological niche-based models (Supplementary material Appendix 1, Table A.3). These EGVs were selected for the ecological models according to their meaning to the ecology and distribution of biodiversity in arid regions (e.g., Brito et al., 2011;Vale et al., 2014). The sets include: 1) one topographical grid that was used to derive the variable Slope (Worldclim; www.worldclim.org); ...
... To convert the categorical land-cover EGV into a continuous variable, one binary grid was created for each land-cover type and the Euclidean distance of each grid cell to the closest land-cover type was calculated for each individual land-cover grid. Converting categorical (presence/absence of a land-cover type) into continuous variables (distance to a land-cover type) has been widely used in species distribution modelling in drylands (Brito et al., 2011;Vale et al., 2014). Only land-cover classes that covered more than 5% of each continent were considered for these analyses (Supplementary material Appendix 1, Table A.4). Overall, most variables were correlated at r < 0.75 with some exceptions (Table A.5). ...
... The selected threshold maximizes both the sensitivity and specificity of models, i.e., maximizes the correct classification rate of both observed presence and absence data (Liu et al., 2013). Finally, both total species richness and species richness of each functional group for each dryland site were estimated by adding the individual predictions of species presence/absence in each grid cell (Brito et al., 2011). ...
Remotely sensed estimates represent relevant tools for assessing biodiversity distribution, yet their relationships with functional groups across drylands have never been evaluated. We assessed relationship between bio-indicators derived by the ESA Diversity II project and distribution of terrestrial vertebrates in five drylands. Twenty seven bio-indicators were derived from MERIS data, including averages and inter-annual variability of seasonally aggregated proxies for net primary production, rainfall, soil moisture, rain use efficiency, and soil moisture use efficiency. For each dryland, the functional strategy of 739 terrestrial vertebrates was summarized into functional groups and predicted functional species richness was related with bio-indicators. Water availability was better related with functional species richness than net primary production estimates, suggesting water availability as a critical aspect shaping vertebrate distribution in drylands. Body size appeared as an important functional trait influencing vertebrate distribution across drylands, especially in small-sized species associated with water availability. Selected functional traits, quality of species presence data, and ecological modelling approaches affected analyses relating bio-indicators to vertebrate distribution. The 27 bio-indicators showed potential for biodiversity distribution assessments, and may be taken into consideration in future studies with appropriate model adaptations. The followed methodological approach could be applied to other drylands and even other ecosystems.
... The species has been recorded further down the Drȃa valley, south of Tiglit (Aymerich et al., 2004), suggesting that its distribution embraces the lower course of the Drȃa river. This region is found within an area of high occurrence probability as predicted by niche modelling analysis (Escoriza et al., 2009;Brito et al., 2011). North of Assa, the closest locality in which the species has been recorded is Tata at 200 km (Martinez del Marmol and Rebollo Fernandez, 2012), which is halfway from the populations situated west of Agdz (Fig. 2). ...
... Genetic analyses have indicated that Moroccan Echis are very closely related to those found in southern Mauritania, suggesting that these populations either have a continuous distribution or have been separated in recent times (Escoriza et al., 2009). A better knowledge of the distribution of E. leucogaster in Morocco is required for predicting factors that may negatively impact the survival of its populations under scenarios of climatic and environmental changes (Brito et al., 2011). ...
... One factor that may influence the distribution of E. leucogaster in Morocco is the interaction with other viperids (see for example Herrmann et al., 2000). The southwestern part of Morocco in which Echis has been found is an environmental transition zone with potential sympatry of five distinct species of vipers (Brito et al., 2011). Indeed, Cerastes cerastes has been found (e.g. two adult individuals observed by M. Sassoe in May 2017) at sites near Aouinet Lahna where Echis has also been recorded. ...
... Other key areas include North Africa (e.g., Brito JC, 2011, on viperid snakes [54]) and Southwestern USA (e.g., West AM, 2016, on cheatgrass [55]). These areas are often chosen due to their biodiversity, ecological significance, and the increasing threats they face from environmental changes. ...
... Table S1: The table describes the details associated with 99 of the most influential publication selected papers in SDM. References [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60]71, are cited in the Supplementary Materials. ...
Species distribution modeling (SDM) is a vital tool for ecological and biogeographical research, allowing precise predictions of species distributions based on environmental variables. This study reviews the evolution of SDM techniques from 1985 to 2023, focusing on model development and applications in conservation, climate change adaptation, and invasive species management. We employed a mixed review with bibliometric and systematic element approaches using the Scopus database, analyzing 982 documents from 275 sources. The MaxEnt model emerged as the most frequently used technique, applied in 85% of the studies due to its adaptability and accuracy. Our findings highlight the increasing trend in international collaboration, particularly between China, the United Kingdom, and Brazil. The study reveals a significant annual growth rate of 11.99%, driven by technological advancements and the urgency to address biodiversity loss. Our analysis also shows that while MaxEnt remains dominant, deep learning and other advanced computational techniques are gaining traction, reflecting a shift toward integrating AI in ecological modeling. The results emphasize the importance of global cooperation and the continued evolution of SDM methodologies, projecting further integration of real-time data sources like UAVs and satellite imagery to enhance model precision and applicability in future conservation efforts.
... They comprise a monophyletic group of four species (Mochales-Riaño et al., 2024), typically found in sandy environments and adapted to extreme aridity (Sindaco et al., 2013). As ectotherms, their distribution and demography are highly mediated by climatic gradients and fluctuations (Brito et al., 2011;Martínez-Freiría et al., 2017, implying that they were affected by past dry/humid shifts. Within the group, the Saharan horned viper, Cerastes cerastes, is widely distributed across the Sahara and also inhabits the south-western Arabian Peninsula. ...
... For Ecological Niche Models (ENMs), we compiled occurrence records at 5 arc-minute resolution (~10 × 10 km) from distinct sources, including fieldwork performed by the authors and collaborators (see Acknowledgements), distribution atlases and other publications (e.g. Werner et al., 1999;Brito et al., 2011;Sow et al., 2014), and the Global Biodiversity Information Facility repository (GBIF, 2023). The GBIF dataset was carefully examined to delete records that were potentially erroneous, as those falling outside the species range determined by IUCN (Wagner et al., 2021). ...
Hyperarid habitats comprise the most dominant and harsh portion of the Sahara Desert, yet how local biotas have responded to paleoclimatic shifts and landscape heterogeneity remains unclear. Here, we assess the historical biogeography of Cerastes cerastes, a conspicuous but poorly known vertebrate inhabiting the hyperarid Sahara, to understand the links between intermittent and stable climatic suitability and patterns of genetic diversity and differentiation in these extreme environments. We combine phylogeographic and ecological modelling tools using a comprehensive species dataset, which includes DNA samples (n = 62) and occurrence records (n = 557) covering most of its range. We show that paleoclimatic oscillations were major evolutionary and biogeographic drivers in C. cerastes, which exhibits different levels of intra-specific diversity and allopatric lineage structuration across the desert. High lineage richness in the northwestern Sahara contrasts with an overall lack of genetic diversity throughout the central and eastern Sahara. Climatic refugia along the desert's periphery and around mountain patches harbour single endemic lineages, stressing the links between stable climatic conditions and population isolation and divergence. Increasing climatic suitability during historical arid phases prompted widespread connectivity across the desert. This study lays the groundwork for better understanding the historical dynamics of the hyperarid Sahara.
... As this drying of north-eastern Africa continued, the moist climatic and vegetational zones retreated further and further south, taking with them the Afro-tropical species previously found in Egypt. The effects of these significant climatic changes and particularly the mid-Holocene aridification are likely to have been particularly significant for ectotherms like snakes (Barlow et al. 2013;Brito et al. 2011;Martínez-Freiría, Velo-Antón, and Brito 2015;. These range shifts, coupled with the possibility of relictual populations in mesic enclaves, might explain why the authors of the Brooklyn Papyrus recorded a herpetofauna in Ancient Egypt that may have differed significantly from that seen in the present. ...
... Most snakes are thought to be highly climatedependent (Barlow et al. 2013;Brito et al. 2011;Martínez-Freiría, Velo-Antón, and Brito 2015;, but other factors are presumably also important. Our present-day models, for instance, suggested that our African and Levantine species are sensitive to water levels (see Supplemental Information 2). ...
The Brooklyn Papyrus is a medical treatise from Ancient Egypt (∼660-330 BCE) focusing on snakebite. Herpetologists have proposed identifications for many of the animals it describes, but some remain uncertain partly because the species no longer live in Egypt. This paper uses niche modelling to predict the palaeodistributions of ten of these snake species, to test some proposed identifications. Occurrence records and environmental variables were used to generate maximum entropy models for each species in the present day and the mid-Holocene (∼4,000 BCE). Our models performed very well, generating AUC scores ≥0.867 and successfully predicting species' current ranges. Nine species' predicted palaeodistributions included areas within Ancient Egypt, and four (Bitis arietans, Dolichophis jugularis, Macrovipera lebetina and Daboia mauritanica) were within modern Egypt. Daboia palaestinae was also predicted to occupy a patch of suitable habitat inside modern Egypt, but separate from the species' core range. The tenth species, Causus rhombeatus, would have been present in kingdoms that were the Ancient Egyptians' regular trading partners. We therefore conclude that all ten species modelled in this study could have bitten Ancient Egyptian people. Our study demonstrates the usefulness of niche modelling in informing debates about the species ancient cultures may have interacted with. ARTICLE HISTORY
... All variables were processed and dimensioned according to the study area using DIVA-GIS software v.7.5 (Hijmans et al., 2012). Principal components analysis (PCA) was used to summarize the environmental variability of the study area (Brito et al., 2011). A set of 3,000 random points based on the narrowrange reptiles was used to extract the values of the 37 environmental variables using DIVA-GIS. ...
... Considering the available data for this study, the growing degreedays in the Pampas grassland and surrounding areas are strongly correlated with eight climatic variables, none of them employed in our study to model the geographic distribution (BIO1, BIO10, BIO11, CTI, MCT, MTC, MTW, and PETcol; see Table 1). Together or separately, they reflect environmental characteristics determining the potential distribution of several species of reptiles (e.g., Urbina-Cardona and Flores-Villela, 2010;Brito et al., 2011;Corbalán et al., 2011;Rivera et al., 2011;Debandi et al., 2012;Nori et al., 2013a, b;Minoli and Avila, 2017;Di Pietro et al., 2018;Sarquis et al., 2018;Andrade-Díaz et al., 2019;Minoli et al., 2019). Similarly, three temperature-related variables, annual potential evapotranspiration, mean annual temperature, and growing degree-days, were identified as the most predictive variables for birds in North America (Barbet-Massin and Jetz, 2014), and particularly, growing degree-days below 0℃ for grassland birds (Wilsey et al., 2019). ...
... The mean percentage contribution to the model of each climatic variable was considered to assess the variable's importance in explaining the species' distribution. Univariate response curve profiles for the most important variables were examined to understand the relation between species occurrence and specific predictors, e.g., [15,54]. ...
... Standard deviation was used as an indication of prediction uncertainty, e.g., [15,54]. The effect of model extrapolation on predictor variables lying outside of the training range was assessed using a multivariate environmental similarity surface (MESS) map [55]. ...
Phylogeographic and paleoclimatic modelling studies have been combined to infer the role of Pleistocene climatic oscillations as drivers of the genetic structure and distribution of Mediterranean taxa. For the European whip snake, Hierophis viridiflavus, previous studies based on paleoclimatic modelling have depicted a low reliability in the pattern of past climatic suitability across the central Mediterranean Basin, which barely fits the species’ genetic structure. In this study, we combined phylogeographic and paleoclimatic modelling tools to improve our understanding of the biogeographic history of H. viridiflavus, particularly extending the sampling and phylogeographic inferences to previously under-sampled regions. Phylogeographic analyses recovered two major clades that diverged at the beginning of the Pleistocene and had diversified in different ways by the late Pleistocene: the east clade (composed of three subclades) and the west clade (with no further structure). Paleoclimatic models highlighted the temperate character of H. viridiflavus, indicating range contractions during both the last inter-glacial and last glacial maximum periods. Range expansions from southern-located climatic refugia likely occurred in the Bølling–Allerød and Middle Holocene periods, which are supported by signals of demographic growth in the west clade and South–East–North subclade. Overall, this work improves our understanding of the historical biogeography of H. viridiflavus, providing further insights into the evolutionary processes that occurred in the Mediterranean Basin hotspot.
... Therefore, various studies have evaluated and predicted the distribution of reptile species under various climate change scenarios focusing on biogeography and conservation biology for conserving biodiversity (Gibbons et al., 2000;Brito et al., 2011a;Rugiero et al., 2013;Caten et al., 2017). It is critical to identify major factors affected by global warming and to predict the distribution range to establish a successful species conservation strategy (Bombi et al., 2011;Brito et al., 2011b;Martínez-Freiría, 2015;Lourenço-de-Moraes et al., 2019). ...
... Only using appearance data, it can predict species distribution with a small sample size (Hernandez et al., 2006;Wisz et al., 2008). This prediction method has been used in various studies of other viper species (e.g., Brito et al., 2008Brito et al., , 2011aBrito et al., , 2011bBombi et al., 2011;Martínez-Freiría, 2015). The species distribution model was constructed by using the appearance data of three pit vipers species as dependent variables and ten environmental variables (Table 3) as independent variables. ...
Climate change can pose severe threats to wildlife populations causing population declines and destroying their habitats. Particularly, pit vipers belonging to reptiles, poikilotherm, are vulnerable to climate change due to their narrow movement range and low dispersal capability. This study aimed to identify pit viper species vulnerable to climate change using their predicted geographical habitat range based on the current and future Korean pit viper species distribution model. The results of this study showed that three major environmental factors related to altitude and temperature (BIO4 and BIO5) influenced the habitat distribution of three pit viper species. These factors showed significant variation between increased, maintained, and decreased habitat areas of the species due to climate change. It was also predicted that the habitat of Korean pit vipers would decrease by more than 80% under the RCP 8.5 scenario. Especially, Central Asian pit viper was predicted to lose 98.52% of its habitat, indicating that it would be the most vulnerable species to climate change. Although we confirmed that forest areas around the Taebaek Mountains, known as current major distribution areas of pit vipers, would provide maintained or even increased habitat areas to these species along climate change, habitable space for the vipers was still predicted to be very narrow. Therefore, it is critical to protect the forest areas around the Taebaek Mountains to minimize the impact of climate change on Korean pit vipers. Moreover, since some populations of Central Asian pit viper, most vulnerable to climate change, are geographically isolated, it will be necessary to establish systematic conservation measures by determining the protection priority of populations through studying genetic diversity between populations. We believe that the results of this study will provide an important basis for establishing management measures in designating the habitat of a threatened population due to climate change as a protected area.
... Viperine envenomation is a deadly disease and many Moroccans remain at risk. Due to reporting standards, many cases are not officially documented [3][4][5]. Bites occur mainly in summers with a peak in August, as in our patient's case. A previous study reported an envenomation rate of 80% in cases of viperine syndrome, which is considerably higher than the 30-50% envenomation rate reported in the literature [6]. ...
... The regions of Souss Massa Daraa, Guelmim Es-Smara, and Marrakech Tensift El Haouz are particularly at risk with high lethality rates. This can be explained by the geographical distribution of the Heurping viper and the Atlas viper [2][3][4]. Clinically, there are local signs with inflammation (constant), bite marks (inconsistent), hemorrhagic signs, compartment syndrome, and necrosis. In addition, there are general signs of hemorrhagic syndrome and shock which may be vagal, anaphylactic, or cardiogenic [7]. ...
In Morocco, envenomations caused by viper bites and scorpion stings are frequent and associated with high lethality. It occurs mainly during the summer season with a peak between June and August. It is a medical emergency requiring intensive care. It is a life-threatening disease mainly due to the systemic hemorrhagic syndrome. Here, we present the clinical course of a patient in his 50s who suffered a snakebite and describe the neurological sequelae. The patient was admitted to the emergency room in a state of unconsciousness with gangrene on the right foot. An emergency brain scan showed meningeal hemorrhage and intracerebral hematomas. The biological assessment revealed disseminated intravascular coagulation. The evolution of the clinical course was rapidly unfavorable and the patient died within 24 hours of admission.
... A second individual of this species (Fig. 2E) was removed from a water hole during the late afternoon in the surroundings of Tilemsoune at survey site six on 24 October 2018. This record is within the high to mediumprobability of occurrence of the range predicted by Brito et al. (2011) however further west than any other live specimens of this species reported from Morocco (Herrmann et al., 2000;Herrmann and Herrmann, 2003;Geniez et al., 2004). ...
... Garcia-Cardenete et al., 2014). Considering the records of E. leucogaster in the present work along with that reported by Hermann and Hermann (1999), combined with the rapid increase of known locations for this species in recent years (Koleska et al., 2018), it seems likely that this species may be found along much of the length of the Oued Drâa where it passes through suitable climatic zones (Brito et al., 2011). With future field work in this region a greater area of occurrence than is presently understood in Morocco may well be revealed. ...
The present work provides new records, including range extensions for Ptyodactylus oudrii, Macroprotodon brevis and Echis leucogaster, as well as the first observations of P. oudrii south of the proposed biogeographical barrier formed by the Djebel Ouarkziz mountain range and the westernmost record of Echis leucogaster in Morocco. Data presented herein shows that at least two species of reptile thought geographically-limited by this chain of mountains, or previously not known from a particular ecoregion in the country, have ranges encompassing a greater portion of these areas than was formerly known. This new knowledge highlights the importance of faunal surveys in regions where fieldwork is often difficult, as well as the need for further surveys in such environments to help improve knowledge of species’ distributional ranges.
... Spatial biases in sampling effort can negatively influence ENMs by producing over-fitting problems in areas with high numbers of presences (see Merow et al., 2013;Radosavljevic and Anderson, 2014). To reduce biases caused by sampling effort, we evaluated the level of spatial clustering within presence datasets for each species using the Nearest Neighbour Index (NNI; see Brito et al., 2009Brito et al., , 2011. Presence records for the caracal, the cheetah and the sand cat presented a random distribution (NNI<1.06), ...
... When two or more species exhibited high values of contribution for a given variable, similar profiles for this variable were taken as an indication of parallel relationships between the occurrence of these species and the range of variation of the variable (e.g. (Martínez-Freiría et al., 2008;Brito et al., 2009Brito et al., , 2011. This indicates also the possible occurrence of sympatry and eventual competition within the range of values of the variable equally selected by species. ...
Mammalian carnivores play a fundamental role in ecosystem structure and function. Arid ecosystems of the Central Iranian plateau host a high diversity of carnivore species for which patterns of habitat selection and coexistence are poorly understood. We evaluated habitat correlates and segregation for five felid species in a mountainous arid region in central Iran: the sand cat, wildcat, caracal, Asiatic cheetah and Persian leopard. We produced ecological niche models (ENMs) and metrics of niche overlap to identify the most important drivers of habitat selection and patterns of species coexistence within the felids guild. We found three distinct patterns of habitat use, implying niche partitioning among the five felid species: (1) specialised use of sand dunes and desert woodlands by sand cat; (2) specialised use of flat and foothills desert areas in the case of the cheetah; and (3) broad, more generalised use of numerous habitat types in wildcat, caracal, and leopard. Together, these results indicate that mountains within vast, flat deserts (a.k.a. sky islandss) are a cornerstone for maintaining ecological communities and predator-prey dynamics in southwestern Asia. By increasing our understanding of coexistence in an understudied carnivore guild, our work provides critical information for the conservation of arid ecosystems. Powered by TCPDF (www.tcpdf.org) Explanation letter Dear Dr Wauters, I am sending the revised version of our manuscript titled "USING ECOLOGICAL MODELS TO EXPLORE HABITAT PARTIONING WITHIN A GUILD OF DESERT FELIDS". As you had suggested we accepted all the editorial corrections, cross-checked the references and reduced the number of citation (17 references were removed). We hope that the manuscript is now suitable for publication. Best regards Mahmoud-Reza Hemami Download source file (7.87 MB) 2 ABSTRACT-Mammalian carnivores play a fundamental role in ecosystem structure 30 and function. Arid ecosystems of the Central Iranian plateau host a high diversity of 31 carnivore species for which patterns of habitat selection and coexistence are poorly 32 understood. We evaluated habitat correlates and segregation for five felid species in a 33 mountainous arid region in central Iran: the sand cat, wildcat, caracal, Asiatic cheetah 34 and Persian leopard. We produced ecological niche models (ENMs) and metrics of 35 niche overlap to identify the most important drivers of habitat selection and patterns of 36 species coexistence within the felids guild. We found three distinct patterns of habitat 37 use, implying niche partitioning among the five felid species: (1) specialised use of sand 38 dunes and desert woodlands by sand cat; (2) specialised use of flat and foothills desert 39 areas in the case of the cheetah; and (3) broad, more generalised use of numerous 40 habitat types in wildcat, caracal, and leopard. Together, these results indicate that 41 mountains within vast, flat deserts (a.k.a. 'sky islands') are a cornerstone for 42 maintaining ecological communities and predator-prey dynamics in southwestern Asia. 43 By increasing our understanding of coexistence in an understudied carnivore guild, our 44 work provides critical information for the conservation of arid ecosystems. 45 "Manuscript no 12397" 46
... Despite the global range of these snakes is relatively well known, there is a knowledge gap about local distribution, suitable habitats and the contribution of environmental variables derived from distribution models. In this sense, the use of high-resolution data for the development of local distribution models is crucial to improve future conservation planning (Brito et al., 2011;Vale et al., 2016). In addition, distribution and habitat models are important tools for assessing the conservation status of snakes, considering that habitat loss and fragmentation are the main causes of their worldwide decline (Gibbons et al., 2000;Reading et al., 2010). ...
... All variables were processed and dimensioned according to the study area (latitude, -38.8791 to -36.8375; longitude, -63.4541 to -60.5875; Fig. 1) using DIVA-GIS software version 7.5 (Hijmans, Guarino, & Mathur, 2012). Principal Component Analysis (PCA) was used to summarize the environmental variability of the study area (Brito et al., 2011). A set of 1000 random points based on the snake assemblage was used to extract the values of the 22 environmental variables using DIVA-GIS. ...
We analyzed the spatial distribution of a snake assemblage from the Sierras de Ventania mountain range, a rich endemism area in east-central Argentina. We used field-collected and museum specimens combined with high-resolution environmental variables to identify common distributional patterns, estimate the suitable habitat for each species, and develop a conservation proposal related to the Protected Natural Areas (PNAs) system. Distributional models diverged into two opposite patterns: suitable habitats for most species at relatively high altitude in the hills, and suitable habitats for Bothrops ammodytoides and Lygophis anomalus at relatively low altitude in the surrounding hill plain. We assessed two proposals based on different conservation algorithms: the additive benefit function (ABF), which favours hilly environments, prioritizing areas with high specific richness, and the core-area zonation (CAZ), which prioritizes the distribution of all species, further indicating areas with low richness in the surrounding plain. Regardless of the algorithm used, our results indicated that the existing PNAs are not effective in protecting the snake assemblage. Protecting at least 5% of the highest species richness areas (ABF) or 5% of the distribution core areas of all species (CAZ), the existing PNAs only represented 2.2% of these priority areas. Our findings are largely consistent with previous work, highlighting that a widespread area needs to be assigned for conservation purposes. Thus, protection of the snake assemblage should take place both inside and outside the PNAs.
... All variables were processed and dimensioned according to the study area using DIVA-GIS software version 7.5 (Hijmans et al., 2012). Principal component analysis (PCA) was used to summarise the environmental variability of the study area of each species (Brito et al., 2011;Vale et al., 2016). We estimated the study area, or the accessible area "M" (Barve et al., 2011), by considering the ecological features, environmental traits and potential historical distribution to generate an extent for each species (e.g. ...
Climate change is one of the main causes of biodiversity loss worldwide. However, detailed knowledge about the impacts of climate change on most species in the Neotropical region is incipient, and the herpetofauna from Pampas grassland is no exception. In this frame, we model the suitable habitats of nine endemic amphibian and reptile species that inhabit the Pampas grassland of Argentina, under current climatic conditions and future climate change scenarios, with the general objective of prioritising conservation and management strategies. To model the suitable habitat of each species we used the Maxent algorithm, while the complementary spatial analyses were carried out with DIVA-GIS. We found a significant loss in both suitable habitat surfaces and known populations in most studied species. The relationship between these two parameters provided a ranking of species for long-term conservation and monitoring. Finally, based on the conservation priorities obtained for each species, we identified and discussed the main management strategies to mitigate the impacts of climate change. Our results were consistent with previous reports in the Neotropical region, highlighting the negative climate change impacts on herpetofauna species, and the urgent need for management strategies to mitigate it. In conclusion, our results establish the bases to develop monitoring, conservation and management strategies to face the predicted changes in the suitable habitats of the endemic and threatened herpetofauna from Pampas grassland. Keywords: biodiversity, conservation, habitat loss, management, population loss
... This reflects the dispersal ability of taxonomic groups, with birds dispersing better than mammals, and mammals better than fishes (Keates and Reid, 2024, Chapter 19). Few biogeographic studies focus on aquatic organisms (e.g., Brito et al., 2011;Penner et al., 2011) other than fish in West Africa (Hugueny and Lévêque, 1994;Husemann et al., 2014). Different results are seen in studies of aquatic birds, which is expected due to their independence from watershed connections for migration (De Klerk et al., 2002). ...
The West Africa is characterized by varied climatic zones and habitat types, which include the dry Sahel, grassland, and savannah. Related to these habitat types is the highly variable rainfall patterns, which contribute significantly to the region's river dynamics. The large and permanent rivers are found south of the Sahel region. Many of the major rivers of this region such as the Senegal, Gambia, Niger, Volta, and Chad Rivers support rich diversity of plant and animal life. They are transboundary and provide ecosystem services across different countries. This chapter provides a brief review of West African rivers, paying close attention to their associated climate, physiography, biogeography, as well as their geomorphology and hydrology. The chapter finishes by discussing the major threats to rivers of West Africa and some of the conservation initiatives undertaken by different nations and organizations in an effort to ameliorate the threats faced by these rivers. Most of these conservation interventions are focused on large rivers, and it will appear that smaller rivers are not being extended the same attention.
... Wallach et al. (2014) mentioned the occurrence of D. mauritanica in El Oued and Ouargla, but they did not provide specific location data. The existence of the species in these two provinces is questionable and requires further confirmation considering the absence of suitable habitat, specifically mountain units (Brito et al. 2011;Geniez 2015) and the lack of sightings of the species despite intensive surveys in the region (personal observation; Mouane et al. 2013Mouane et al. , 2021b. ...
Daboia mauritanica (Gray, 1849), Moorish Viper, is native to North Africa. We update the distribution map for this species in Algeria, providing 19 new locality records, filling distribution gaps and significantly expanding the species’ known range. Our updated distribution map reveals a widespread presence of the species in northern Algeria, extending south into the northern Sahara. We note that some historical records in certain provinces remain unconfirmed and/or questionable, indicating the need for further investigation. Our findings underscore the importance of collaboration between researchers and citizen scientists in Algeria.
... Indeed, the basic genetic assessment performed in this study allowed to assign the viper found in Tamda'n Oughmar to the V. m. monticola subspecies (Fig. 1B). The presence of V. monticola in this area was previously reported by F. Cruzin (observation collected by P. Geniez; in Brito et al., 2011a), and trekking field guides also warned about the presence of "adders" at the campsites (Brown, 2012). Other than this information, there was no detailed information about whether this population belonged to the central (V. ...
Morocco comprises most of the geographic range extent of Vipera monticolaand the three subspe-cies described within this taxon. However, the distribution of this species is likely underestimated due to its low detectability. In this note, we use data collected through recent fieldwork campaigns and citizen science to update the distribution of V. monticola in Morocco, considering the distribu-tion of the three described subspecies. We provide records for 45 vipers corresponding to 15 UTM 10x10 km cells (six new UTM 10x10 km cells), increasing by 8.8% the range of V. monticola in the country. Remarkable range increases occur for the subspecies V. monticola atlanticaand V. monti-cola monticola, the latter confirmed by genetic assessment, as well as for V. monticola saintgironsi with a new record in Jbel Bou Naceur. We note the occurrence of habitat degradation across the species range, likely promoted by anthropogenic factors as deforestation, aridification and overgrazing. We also indicate Jbel Oukaimeden as a potential area to develop population-monitoring studies.
Key words: Atlas; habitat degradation; Maghreb; Mediterranean relict; range extensions; Rif; Vi-peridae.
... MaxEnt models probability of a species being present based on spatially defined variables, such as vegetation cover and land use, which might determine the habitat of that species. MaxEnt has consistently performed well in comparison to other methods 18 and as presence data are common although they vary in accuracy 19 . The application of spatially explicit presence-only habitat models to real world situations has been shown to be useful within Asian ecosystems. ...
Crop raiding are an increasing concern in wildlife conservation. This study identified the environmental factors that cause wild Asian elephants (Elephas maximus) to enter sub-urban and rural areas and share resources with humans in the Eastern Economic Corridor (EEC) in the eastern part of Thailand. The snowball method was used to interview villagers that had crop raiding experienced in seven provinces of the EEC and adjacent provinces in the eastern part of Thailand in 2020, and data from 183 households indicated that crop raiding had increased continuously from 2000 to 2020, especially in Chonburi, Chachoengsao, and Prachinburi provinces, which have seen increases in damaged agricultural areas. MaxEnt analysis showed an increase in incidents of crop raiding, while the elephants distribution area decreased from 9534 km² in 2000 to 5199 km² in 2010 and 4850 km² in 2020. The study area has had land use changes in the low elevations from croplands of cassava and sugar cane to eucalyptus, para rubber, and fruits. These mixed crop plantations provide a pseudo-habitat for wild Asian elephants. The results from this study provide evidence that changes in land use and reduction of suitable habitat are factors that influenced the movement of wild Asian elephants to the rural agricultural areas and increased the incidents of crop raiding.
... Maximum entropy (MAXENT) is a species distribution model that combines presence only data with selected environmental variables to predict species distribution. Studies have shown that MAXENT in comparison with other methods performed better and has been widely used for ecological niche modeling of many species (Elith et al., 2006, Brito et al., 2011. Incorporating GIS technology and ecological modelling therefore will aid in African forest elephant management in terms of habitat selection, anthropogenic threats and their protection (Reza et al., 2013;McNulty, 2013;Sanare et al., 2015). ...
Maximum entropy (MAXENT) algorithm was used to explore how environmental variables influence habitat of African forest elephant in Omo forest reserve. The occurrence data and the predictor variables were processed using Geographic Information system software. The survey was conducted for both wet and dry season. Result shows that distance to river, mean diurnal range, distance to farmland, distance to road, and NDVI contributed mostly to predicting the habitat suitability for both dry and rainy seasons. There were several streams that flows within the forest reserve which reflects in elephant movement pattern towards riverine areas. Suitable habitat within the study area were found to be areas with dense vegetation. Elephant frequent movement around agricultural and cultivated areas within the reserve resulted in crop raiding and destruction. The model combined result for the study area suitability shows a suitable area of 332.90km2, moderate area of 434.47km2 and unsuitable area of 529.65km2. The performance ratings of AUC values (area under receiver operating curves) were 0.779 and 0.781 for dry and rainy seasons respectively. Due to increasing anthropogenic activities, elephants’ activities were greater in the northwestern part of the forest reserve which provides suitable habitat that meets food, water and vegetation cover requirement for the species.
... Most snakebites (95%) occur in rural areas, leading to up to 125,000 deaths annually and three times as many amputations and permanent disabilities [1][2][3]. In Africa alone, over 1 million snakebites are recorded annually, resulting in over 100,000 envenomations and over 10,000 fatalities [4][5][6]. Among the venomous snakes in the region, cobras (Naja sp.) are common and capable of delivering deadly venom. ...
... Most snakebites (95%) occur in rural areas, leading to up to 125,000 deaths annually and three times as many amputations and permanent disabilities [1][2][3]. In Africa alone, over 1 million snakebites are recorded annually, resulting in over 100,000 envenomations and over 10,000 fatalities [4][5][6]. Among the venomous snakes in the region, cobras (Naja sp.) are common and capable of delivering deadly venom. ...
In Morocco, eight species of venomous snakes belonging to the Viperidae and Elapidae families are responsible for severe envenomation cases. The species from the Elapidae family is only represented by the medically relevant cobra Naja haje, which is widely distributed in North Africa. However, there is little information on the systemic effects of Moroccan cobra venom on vital organs due to regional variations. It has been demonstrated that the venom of Naja haje from Egypt causes hemorrhage, while the venom of the Moroccan cobra is neurotoxic and devoid of systemic bleeding. This variability is known to significantly influence treatment efficacy against Naja haje cobra bites in the Middle East. In this study, we examined the pathophysiological mechanisms responsible for the lethality induced by Naja haje venom, as well as the evaluation of the neutralizing capacity of two antivenoms; the monospecific antivenom made for Naja haje only and the antivenom marketed in the Middle East and North Africa. We first determined the toxicity of Naja haje venom by LD50 test, then compared the neutralizing capacity of the two antivenoms studied by determining the ED50. We also performed histological analysis on Swiss mice envenomed and treated with these antivenoms to observe signs of cobra venom envenomation and the degree of reduction of induced systemic alterations. The results showed significant differences between both antivenoms in terms of neutralization. The monospecific antivenom was four times more effective than the marketed antivenom. These results were confirmed by a histological study, which showed that monospecific antivenoms neutralized severe signs of mortality, such as congestion of blood vessels in the heart and kidneys, pulmonary and renal edema, cytoplasmic vacuolization of hepatocytes in the liver, and infiltration of inflammatory cells in the brain and spleen. However, the polyvalent antivenom failed to protect all severe lesions induced by Naja haje venom in mice. These findings highlight the negative impact of geographic variation on the effectiveness of conventional antivenom therapy and confirm the need for a specific Naja haje antivenom for the effective treatment of cobra envenomation in Morocco.
... Furthermore, Oukkache's study [44] showed the toxic activity of the venom of Moroccan vipers D. mauritanica, C. cerastes and B. arietans, matching our results, since the LD50 (i.p injection, male Swiss mice) of B. arietans venom (1.627 µg/g) was higher than that of C. cerastes (0.3788 µg/g) and D. mauritanica (0.29 µg/g). All these results prove that the intraspecific variation in snake venom is a ubiquitous phenomenon, particularly evident in species with a wide range of distribution, especially for the C. cerastes viper, which is more widespread compared to D. mauritanica and B. arietans in North Africa [45][46][47]. Of note, several factors such as sex, age, diet, genetic strain and animal health seem to be involved. ...
Morocco is one of the richest countries in biodiversity in the Mediterranean region, especially in its ophidian fauna. In total, there are eight species of venomous snakes, with seven belonging to the Viperidae family, responsible for 67.2% of severe envenomation cases in the country. Cerastes cerastes, Daboia mauritanica and Bitis arietans are considered among the most venomous vipers whose bites cause high levels of morbidity, disability or mortality. Despite their wide distribution in the kingdom, the incidence of these snakebites remains poorly understood and largely underestimated. Moreover, intraspecific variations in the venom composition significantly affect the effectiveness of antivenoms. Due to the unavailability of locally produced antivenoms, we evaluated the efficacy of Inoserp-MENA, the only available antivenom in Morocco, against C. cerastes, D. mauritanica and B. arietans. First, we conducted a comprehensive characterization of these venoms, including an LD50 test to examine their toxicity and SDS-PAGE as a technique to analyze the enzymes responsible for biological activities, such as hemorrhagic and edematous activities and myotoxicity, which generate physiopathological effects in the skin, paws and muscles of envenomed mice. Then, we assessed the ability of Inoserp-MENA antivenom to neutralize the toxic activities of Moroccan vipers. Our results indicate that the venom of C. cerastes, D. mauritanica and B. arietans are toxic, causing severe alterations such as edema, myotoxicity, myonecrosis and significant hemorrhages with the formation of hemorrhagic foci. C. cerastes venom is more dangerous in terms of lethality and hemorrhages, while B. arietans venom is more edematous. The effects of C. cerastes venom were effectively neutralized, but Inoserp-MENA antivenom failed to protect mice against the toxic effects induced by B. arietans and D. mauritanica venom. The study reveals alarming shortcomings in the effectiveness of the current commercially available antivenom’s dosage and neutralization capabilities, highlighting the urgent need to develop a region-specific viper envenomation therapy.
... From a northern hemisphere viewpoint, north latitudinal range limits could imply incompatibility with cold. The south-western Moroccan population of the B. arietans complex is found mainly in warm and humid coastal and savannah environments, with moderate annual temperature range, south of~32°N (Brito et al., 2011). Qafzeh Cave is located around the same latitude (32. ...
We studied Viperidae remains from Qafzeh Cave, Israel, to understand past dispersal timing and range expansion of Afro-Arabian taxa to the Southern Levant during the early Late Pleistocene (Marine Isotope Stage 5). A total of 62 African adder (Bitis) snake remains were retrieved from multiple layers at Qafzeh Cave, alongside five non-Bitis 'Oriental viper' taxa vertebrae. These are the only available specimens of Bitis ever reported in the Southern Levant. The morphology of the maxilla and vertebrae corresponds well to that of the Bitis arietans complex. Qafzeh Cave thus becomes the northernmost boundary of the B. arietans complex expansion ever recorded outside Africa. The unprecedented occurrence of Bitis at Qafzeh Cave, in conjunction with other archaeozoological evidence at the site, attest to exceptional climatic and environmental conditions in the surroundings of the cave during the Mousterian Homo sapiens occupations. It reinforces previous evidence for taxa expanding from sub-Saharan Africa to the Mediterranean biome of the Southern Levant through the now hyper-arid Saharo-Arabian desert belt. The environmental conditions following deposition of the early Late Pleistocene layers were probably not favourable for the establishment of the snake, and eventually the B. arietans complex became locally extirpated.
... Therefore, animals living on dunes are adapted to either moving on the sand or through it (Attum et al., 2007;McLachlan, 1991). Most ecological research in desert dunes in the Sahara, Sinai, and Negev deserts focused on small rodents, such as heteromyids and gerbils (Kotler, Ayal, & Subach, 1994;Kotler & Brown, 1988;Shenbrot et al., 2012) and some viper (Cerastes) species (Brito et al., 2011;Dorfman et al., 2023;Subach et al., 2009Subach et al., , 2022. Other dune animals have been studied to a lesser extent. ...
Compared with other desert habitats, desert dunes are relatively rich in species, some of which are unique to such habitats. To better understand the interspecific interactions among species in the dunes, their ecology, and their behavior, we studied the habitat use of Stenodactylus petrii . This species is common in desert dunes in Israel and North Africa, and it is a mesopredator, interacting with both its predators and prey, thus affecting populations of both higher and lower trophic levels. We performed an experiment to see whether these animals spend more time in vegetated or open habitats. Our experiment demonstrated that S. petrii individuals moved twice faster out of open dune areas than out of microhabitats simulating desert vegetation. Yet, observations of the gecko's tracks suggest that it is similarly present in open areas and around bushes, necessitating further studies. We also reveal that this nocturnal species is more active earlier in the night than later, and more active in late summer (August) than earlier (June–July). We examined which other co‐occurring animals are active together with the studied gecko in time or space. The spatial and temporal activity patterns of S. petrii are negatively correlated with the activity patterns of gerbils, suggesting that their activity time and microhabitat preference differ. The spatial activity pattern of S. petrii is positively correlated with Tenebrionid ground beetles, suggesting a shared microhabitat preference. However, neither the temporal nor the spatial activity of the gecko is correlated with that of vipers, which are its potential predators. Future studies of S. petrii 's natural history are important to understand how expected habitat change (e.g. dune stabilization) should affect it.
... It uses as baseline climatic information data from 1960 to 1990 taken from weather stations and estimate values to areas not covered between stations. Climatic variables were selected based on the results of a pilot modelling study in combination with natural history data (Angetter et al., 2011;Brito et al., 2011;Rodríguez-Cabrera et al., 2020). The pilot model was made to identify the group of variables that could best explain the patterns of distribution of the Cuban species. ...
Geographical ranges and physiological tolerances of species are correlated, and it can be expected that widespread species encounter higher climatic variation across their distributions than restricted species. Widespread species should consequently be more tolerant to extreme or variable weather conditions, and may have the ability to better conserve their current geographical ranges under future climate change scenarios. We tested this hypothesis by studying the relationship between the climatic variation experienced by restricted and widespread Anolis lizards from different ecomorphs and regions of Cuba and the distributional shifts induced by climate change. We selected seven bioclimatic variables from WorldClim to characterize the realized climatic niche of 12 Cuban anoles, where the coefficients of variation of each variable were taken as a measure of climatic variation. We used niche modeling to predict changes in suitable habitats under future climatic scenarios. We found that species from Eastern Cuba occupy areas with the highest climatic variation, likely related to the topography of the region. Crown giant anoles experienced habitats with lower climatic variation in comparison with species from other ecomorphs, which together with their tree canopy habitat and large body size may represent a disadvantage to face changing climates. All species will experience a severe decrease in their habitat suitability, with the Western species being predicted to lose a higher proportion of suitable habitat. Combining niche modeling with physiological data would better predict the effects of climate change on Cuban lizards and might allow taking management actions for species and habitats to mitigate the possible negative impacts of this phenomenon.
... Elevation was included as a predictor since E. leucogaster appears to prefer relatively low elevations (Geniez 2015). These variables have proved effective in predicting suitable areas for many ophidian taxa (Mizsei et al. 2016;Freitas et al. 2018;Bouam et al. 2019), inter alia, arid-adapted viperid snakes (Brito et al. 2011;Kane et al. 2019). ...
Knowledge of biodiversity distribution and how climate change may affect species across the Sahara-Sahel is scarce despite it harboring both high biodiversity and a high rate of endemism. As ectotherms, snakes are particularly vulnerable to climate change and susceptible to range shifts and demographic changes driven by climate change. Ecological niche models are a common method for predicting the probability of the occurrence of species and future range shifts induced by climate change. This study examines the probable gaps in the distribution of the white-bellied saw-scaled viper, Echis leucogaster, and the potential influence of climate change on its future geographic range in the western Sahara-Sahel. The currently predicted environmentally suitable areas fitted well with the known geographical range of the species showed relative congruence with the Sahara-Sahel ecoregion delineations and identified areas without known occurrences. In the future, the environmental conditions for the occurrence of E. leucogaster are predicted to increase, as the environmentally suitable areas will potentially experience an increase in their proportion. Future projections also showed that the potentially suitable areas might undergo moderate southward shifts during the late twenty-first century. The results of the present study significantly expand our knowledge on the potential distribution of E. leucogaster and provide valuable insights to guide future sampling efforts and conservation planning for the species.
... However, this similarity ultimately separates species geographically, and differentiates their ecological niche through interspecific competition (Martínez-Frei-ría et al., 2008;Metzger et al., 2009). Therefore, studies on the distribution of similar species coexisting in the same area are important to understand the relationship between ecological niches and habits in phylogenetically similar species (Wiens and Graham, 2005;Costa et al., 2008;Brito et al., 2011;Lee et al., 2014). ...
Studies on the distribution of species are important to understanding the interspecific ecological niche and habitat selection through geographic environmental information. Particularly, vipers in the same genus have been an important topic because they show differences in the preferred geographical environment, depending on the distance of the phylogenetic relationship. This study investigated the geographical environment of red-tongued pit vipers (Gloydius ussuriensis) and Central Asian pit vipers (Gloydius intermedius) in the mountainous area, Cheonmasan Mountain County Park, South Korea, from April 2012 to October 2014, to understand the relationships among their habitat characteristics and ecological niche. Red-tongued pit vipers mainly lived in low altitude, wet valley areas with a low solar reflectance, while Central Asian pit vipers inhabited high altitude, dry land with large amounts of sunshine. As a result, our study supports that the ecological niche of red-tongued pit vipers and Central Asian pit vipers, inhibiting in Cheonmasan Mountain was overlapped low according to the majority of geographical environmental variables. The differentiated diet preference might be took into consideration as one of the potential key factors to the ecological niche differentiation among two species.
... From a northern hemisphere viewpoint, north latitudinal range limits could imply incompatibility with cold. The south-western Moroccan population of the B. arietans complex is found mainly in warm and humid coastal and savannah environments, with moderate annual temperature range, south of~32°N (Brito et al., 2011). Qafzeh Cave is located around the same latitude (32. ...
We studied Viperidae remains from Qafzeh Cave, Israel, to understand past dispersal timing and range expansion of Afro-Arabian taxa to the Southern Levant during the early Late Pleistocene (Marine Isotope Stage 5). A total of 62 African adder (Bitis) snake remains were retrieved from multiple layers at Qafzeh Cave. These are the only available specimens of Bitis ever reported in the Southern Levant. The morphology of the maxilla and vertebrae corresponds well to that of the Bitis arietans complex. Qafzeh Cave thus becomes the northernmost boundary of the B. arietans complex expansion ever recorded outside Africa. The unprecedented occurrence of Bitis at Qafzeh Cave, in conjunction with other archaeozoological evidence at the site, attest to exceptional climatic and environmental conditions in the surroundings of the cave during the Mousterian Homo sapiens occupations. It reinforces previous evidence for taxa expanding from sub-Saharan Africa to the Mediterranean biome of the Southern Levant through the now hyper-arid Saharo-Arabian desert belt. The environmental conditions following deposition of the early Late Pleistocene layers were probably not favourable for the establishment of the snake, and eventually the B. arietans complex became locally extirpated.
... iv) How will landscape connectivity be affected under global change scenarios? Ecological niche-based models of species/community distribution are needed to relate EBV community composition and environmental variation and global change drivers (e.g., Brito et al. 2011b;Sow et al. 2014;Vale et al. 2014;Gonçalves et al. 2018). Ecological models need to be projected to past climatic conditions to infer areas of climatic stability across time and historical network connectivity. ...
Drylands range across more than half of the global terrestrial area and harbour about a quarter of continental vertebrate species, many of them endemic. However, this fauna is being increasingly threatened, in particular the one that inhabits deserts, one of the last biomes on earth. This work tracks the most relevant global change drivers acting on drylands, especially in deserts and arid regions, the conservation actions being developed, and the research needs for vertebrate conservation, following IUCN standar-dised classification schemes. Using the Sahara-Sahel wetlands as case study, it is provided a detailed examination of these aspects to support regional biodiversity conservation and human welfare. Deserts and arid regions are threatened by the synergistic effects of increasing development of urban areas, agriculture, energy production, mining, transportation and service corridors, resulting in pollution, invasive species, human intrusions and disturbance, biological resource overuse and in general, natural system modifications. In addition, climate change together with social underdevelopment of many desert-range countries places the mitigation of threat factors in a large and complex web of global-local societal challenges. Conservation actions targeting land/ water and species protection and management, as well as education, awareness, capacity building, and legislation measures to increase livelihood development, are being developed. Additional research efforts are need to enhance biodiversity conservation planning, monitoring biodiversity and land-degradation status (based on Essential Biodiversity Variables), and quantification of socioeconomic factors associated with sustainable use of natural resources and human development. Sahara-Sahel wetlands are important life-support systems for both humans and vertebrates, the last vulnerable to listed global threats. They offer framework scenario to revert current environmental and societal challenges in deserts. Long-term conservation of desert vertebrate biodiversity requires appropriate policy instruments to promote sustainable use of natural resources. Raising environmental alertness within local communities of uniqueness of desert biodiversity is needed to promote policy change.
... In both of these references, the authors collected their own chorological information and included many other partial works that have appeared in recent years, bringing a considerable advance to the knowledge on the distribution and biogeography of the Saharan herps (e.g. Beukema et al., 2013;Brito et al., 2011;Mediani et al., 2013 andQnimba et al., 2013;Crochet et al., 2015;Sánchez-Vialas & Aznar-González de Rueda, 2016). ...
Smara is a city inland of the Atlantic Sahara located next to the riverbed of the Saquia Al Hamra. This important basin, due to the tempering of climatic conditions, constitutes a corridor for the herps species present in the coastal strip, which enter more than 100 km in the hyper-arid continent. The list of reptiles cited in Smara is quite complete, although this is not the case with amphibians, of which there are no published records.
Observations of two species of amphibians, Bufotes boulengeri and Pelophylax, are presented here.
... Numa análise quantitativa a expedição totalizou 104 dias, foram percorridos um total (Boratyński et al. 2012Brito et al. 2005Brito et al. , 2008Brito et al. , 2011Fonseca et al. 2008Fonseca et al. , 2009Froufe et al. 2009Froufe et al. , 2013Gonçalves et al. 2012Gonçalves et al. , 2018aKapli et al. 2015;Koepfli et al. 2015;Lado et al. 2019;Leite et al. 2015;Lopes et al. 2015;Metallinou et al. 2015;Padial et al. 2013;Rato et al. 2007;Rebelo & Brito 2007;Sow et al. 2014aSow et al. ,b, 2017Tamar et al. 2017;Vale et al. 2012Vale et al. , 2015Vale et al. , 2016Vasconcelos et al. 2010;Velo-Antón et al. 2018, 2019) e de divulgação (Brito et al. 2006;Farinha 2005 Upwelling (biol.) -afloramento de nutrientes à superfície do mar devido a correntes oceânicas e ao relevo submarino. ...
Este diário relata as aventuras e desventuras vividas ao longo de quase 20 mil quilómetros e durante os três meses e meio que durou uma expedição ao Saara-Sael em 2004. Não se trata apenas de um diário de vivências. Os dados geográficos, etnográficos, geológicos e biológicos de precisão científica que entremeiam as aventuras pretendem, além de enquadrarem uma viagem inesquecível, dar uma visão o mais abrangente possível do Saara. E quem sabe, talvez despertar a curiosidade do leitor para um mergulho nesse imenso mar de areia. A reprodução desta publicação para fins educativos ou outros propósitos não comerciais é autorizada sem a permissão prévia dos autores, se devidamente citada e uma cópia do material reproduzido seja enviada aos autores. A reprodução desta publicação para revenda ou outros fins comerciais, bem como da fotografia de capa, é proibido sem a permissão dos autores.
... The distinction is also often unclear in published papers (e.g. Brito et al. 2011, Báez et al. 2019. Filtering is a procedure to reduce the clustering of species records (Boria et al. 2014) which frequently results from survey biases, as distribution data are collected more often from sites with easier access (Kadmon et al. 2004, Barbosa et al. 2010. ...
Ecological niche models (ENMs) are widely used statistical methods to estimate various types of species niches. After lecturing several editions of introductory courses on ENMs and reviewing numerous manuscripts on this subject, we frequently faced some recurrent mistakes: 1) presence-background modelling methods, such as Maxent or ENFA, are used as if they were pseudo-absence methods; 2) spatial autocorrelation is confused with clustering of species records; 3) environmental variables are used with a higher spatial resolution than species records; 4) correlations between variables are not taken into account; 5) machine-learning models are not replicated; 6) topographical variables are calculated from unprojected coordinate systems, and; 7) environmental variables are downscaled by resampling. Some of these mistakes correspond to student misunderstandings and are corrected before publication. However, other errors can be found in published papers. We explain here why these approaches are erroneous and we propose ways to improve them.
... The known distributional records of the Sahara sand viper in Morocco range from 0 to 850 m of elevation above sea level, and cover three main areas in the country's southern and south-eastern parts, namely Erg Chebbi, Ergs of M'hamid, and the sandy plateaus of the costal Atlantic Sahara (e.g., Khnifiss Lagoon) (Fig. 1). Ecological niche-based models showed that C. vipera can be found throughout most desertic Moroccan areas with less potentially suitable habitats further north (Brito et al., 2011). Herein, we report a new observation of C. vipera about 250 km to the north-east of the nearest known locality of this species in Morocco. ...
... Similarly, many studies do not provide information on the operations used for rescaling (i.e., statistical operation used to calculate new values such as average or maximum) their data or the interpolation method (e.g., nearest neighbour, bilinear, cubic) used to do so. Most often, only a statement about the decreasing or resampling of the resolution is provided (e.g., Brito et al., 2009Brito et al., , 2011Martínez-Gutiérrez et al., 2018;Rodríguez-Soto et al., 2011). This often goes hand in hand with missing information about the order in which the operations were performed (e.g., Convertino et al., 2012;Mateo-Tomás and Olea, 2015). ...
Terrain attributes (e.g., slope, rugosity) derived in Geographic Information Systems (GIS) from digital terrain
models (DTMs) are widely used in both terrestrial and marine ecological studies due to their potential to act as
surrogates of species distribution. However, the spatial resolution of DTMs is often altered to match the scale at
which species observations were collected. Here, we highlight the significance of adequately reporting the
methods used to derive terrain attributes from DTMs and the consequences of their incorrect reporting in
ecological studies. To ensure full repeatability of studies, they should report (i) the source and the resolution of
the original DTM; (ii) the algorithm used to calculate terrain attributes; (iii) the method used for rescaling (e.g.,
aggregating or resampling, using the mean or maximum values); and (iv) the order in which these operations
were performed. We contrast the effects of two common scale alteration approaches for the derivation of terrain
attributes from DTMs. These two scale alteration methods differ in the step at which the change is performed: (i)
the resolution alteration is performed after computing terrain attributes from the original DTM at the native
resolution, or (ii) the resolution alteration is performed on the native DTM before computing terrain attributes.
While these approaches conceptually do the same thing (i.e., change the resolution of the terrain attributes), we
demonstrate that they produce two distinct sets of variables that are not interchangeable and describe different
properties of the terrain. In a species distribution modelling (SDM) context, the first approach calculates terrain
attribute values within the cell where a species is found, while the second approach calculates terrain attribute
values with respect to neighbouring cells. A mutual substitution of the two approaches results in a decrease of
models' discrimination ability and in misleading spatial predictions of species probability of occurrence.
Regardless of the DTM-derived attribute, we argue that the choice of the approach should be carefully guided by
both the ecological scale relevant to the question being asked and the performance of pre-analyses. We emphasize
that selected methods be clearly described to encourage reproducibility and proper interpretation of
results, thus enabling a better understanding of the role of scale in ecology.
... Future suitability maps (Figures 1c-f and 2c-f) were generated by calculating the median and standard deviation of suitability values at each grid square from all 910 projections for each of the four combinations of emission scenario and future timeframe. Recent potential and future suitability maps show the probability of suitable environmental conditions on a scale from 0(least) to 1 (most), and regions of uncertainty (the standard deviation of models, which can range from 0 to 0.5;Brito et al., 2011;Johnson, Kotz, & Balakrishnan, 1996;Martínez-Freiría, Argaz, Fahd, & Brito, 2013). ...
Local and Indigenous Peoples play critical roles in safeguarding global biological and cultural diversity. However, species distribution modelling has yet to incorporate perspectives that assess threats to the linked biological and cultural systems of local and Indigenous Peoples.
Here, we provide the first example of integrating species distribution modelling with benefit‐relevant indicators. This novel approach assesses how human access to culturally important species may change over time.
Focusing on two culturally significant species used by the Indigenous Māori people of New Zealand, we first identified predictor variables relevant to the habitat of each species. We used species distribution models (SDMs) to estimate the recent (1961–1990) potential distribution for each species based on occurrence records and predictor variables, then generated future climate suitability maps.
Our models show that future suitability for one species shifts to the south, in line with changes in temperature and precipitation, while the second species range expands into higher latitudes, driven primarily by increased temperature. When we combined these models with knowledge of tribal boundaries and cultural practices, results indicated that these distributions might decrease access to culturally important plants. Future suitability for one species shifted substantially from where it is most valued for weaving, while the second species range expanded to include more of its primary medicinal users.
Climate change‐mediated shifts in the ranges of these species are likely to affect intergenerational human–environment relationships, sense of place, cultural identity and knowledge on a regional scale, as well as cultural identity and social cohesion on a national scale.
By interpreting SDMs within a socioecological framework, this research illustrates a new approach to assessment of vulnerabilities to climate change and identifies strategies for adaptation.
A plain language summary is available for this article.
... Information System; GIS)과 통계기법을 기반으로 종들 의 분포자료와 지리적 환경 자료들을 이용해 확인할 수 있으며, 다양한 분류군들을 대상으로 생태학과 생물지 리학, 보전학 분야에서 중요하게 다뤄지고 있다 (Brito et al. 2011;Lee et al. 2014). 더욱이 최근 10년 동안 지리 정보 시스템과 종 분포 모델링(Species Distribution Modeling; SDM) 기술을 적용하여 기후변화에 따른 서 식범위의 증감과 생물다양성이 높은 보전지역 예측에 대한 다양한 연구들이 수행되고 있다 (Santos et al. 2006;Garcia et al. 2014;도 2014 (Peterson et al. 1999;Metzger et al. 2009 (Bull 1991;Martínez-Freiría et al. 2008 (Fig. 5A). ...
It is important to recognize and evaluate the ecological niche and geographical habitat of species for
understanding the biogeographic distribution pattern of them. The objectives of this study were to identify the
spatial distribution and ecological niches of three brown frog species (Rana dybowskii, R. coreana, and R.
huanrensis) using geographic information system (GIS) and examine the habitat environment in the contact
zone of these species by predicting the geographic distribution based on a species distribution model. The results
of this study showed that the brown frog species showed different distribution range along Taebaek Mountains
and the altitude was an important variable affecting their distributions. Moreover, the altitude was significantly
correlated with the climate conditions of the region. Although the ecological niches of three species were highly
overlapped, the overlapped geographical area was very small compared to the entire study area. The brown frog
species showed a parapatric distribution pattern and the overlapping habitats were mainly forests and farmlands.
It was not possible to identify precise causal factors affecting the parapatric distribution among the species.
However, it is believed that it will be possible to find specific reasons why they showed a parapatric distribution
if more detailed analysis (grid size=500m or less) is performed for various environmental factors.
... These sources can be used to perform a baseline to study the changes and composition of biological communities or local extinctions (Grixti et al., 2009). Within this framework, the exponential growth of field work carried out both by researchers (Brito et al., 2011;Beukema et al., 2013;Sánchez & Escoriza, 2014;Martínez-Freiría et al., 2017;Rosado et al., 2017;Tamar et al., 2017) and by amateur people interested in herpetology and in nature of Morocco (as reflected by the development of web pages such as http://www.moroccoherps.com), provides a remarkable source of current information which, joined to scientific collections, could be useful to infer temporal changes in biological characteristics, to identify possible local extinctions and also to planning biodiversity conservation measures. ...
Se presenta el catálogo de los anfibios y reptiles de Marruecos conservados en el Museo Nacional de Ciencias Naturales de Madrid (MNCN-CSIC) y se destaca la especial relevancia de las contribuciones realizadas por dos expediciones históricas para el conocimiento herpetológico de la región. Ambas expediciones sumaron un total de 31 especies colectadas principalmente en las regiones de Essaouira, Tánger y Ketama. Se constata la presencia en la colección de los ejemplares que representaron las primeras citas de Cerastes vipera y Scincus albifasciatus en Marruecos. Asimismo, alberga las series tipo de Rana ridibunda riodeoroi, Psammodromus algirus ketamensis y Salamandra algira tingitana. Los especímenes colectados en tiempos históricos conservados en colecciones científicas ofrecen una valiosa información para identificar cambios sufridos por las comunidades biológicas y diseñar medidas de conservación de la biodiversidad.
... My effort represents the first comprehensive bioregion analysis focusing on tetrapod endemic species to the Afro- Arabian region. Previous attempts have either focused on small geographical regions (e.g. the Sahara or even parts of the Sahara) ( Brito et al. 2009Brito et al. , 2011Brito et al. , 2016 , I classified the Afro-Arabian region into four discrete bioregions for amphibi- ans and reptiles, and five discrete bioregions for birds and mammals. I expect this work to po- tentially help in the prioritisation of taxon specific conservation efforts in the Afro-Arabian re- gion. ...
In this study, distribution data and environmental information for predicting the potential habitat of amphibians and reptiles in South Korea were compiled. The distribution data of amphibians and reptiles include nationwide surveys conducted by the National Institute of Ecology (seven surveys) and the Korea National Park Service (one survey). The distribution data are based on 57,777 locations for 35 species. Environmental information related to the habitat of amphibians and reptiles was constructed from 19 bioclimatic variables related to climate and four spatial variables related to geographic factors, and 19 bioclimatic variables for the future (2020-2090) were constructed using the results of SSP scenarios. In addition, species distribution models (MaxEnt) were used to predict current and future potential habitat for 28 amphibian and reptile species with more than 50 survey sites. The model validation values for the 28 species ranged from 0.717 to 0.987. These data have the potential to inform conservation strategies in response to climate change by spatially identifying current and future potential habitat for amphibians and reptiles.
Habitat selection and use by species is determined by a variety of biotic and abiotic factors.
Abiotic features, such as plant cover, wind conditions, or the surface's inclination affect the
costs and benefits animals face when foraging, commuting, seeking mates, etc. These costs and
benefits, in turn, dictate where animals should be found and what activities they should perform
in different parts of the habitat. In this work, the Saharan horned viper's (Cerastes cerastes)
interactions with the abiotic features of its habitat – the dunes of the western Negev desert,
were studied. Additionally, as this is the first study concerning the ecology and behavior of the
viper in the field, I also report here the population size, average weight and length of the vipers
and the vipers' seasonal and daily activity patterns.
This work had two main goals: (1) To examine C. cerastes' basic ecology, as this species has
never been studied in detail in nature. Furthermore, in Israel it solely resides in threatened
habitats, thus these details can assist in conservation efforts. (2) To describe the species'
microhabitat preferences and study the reasons behind them, while generalizing the results to
contribute to our understanding of animal habitat use in general.
Dunes can be divided into three microhabitats according to their plant cover and stabilization
state: (1) stable microhabitat, (2) semi-stable, and (3) shifting sands. The vipers’ microhabitat
preferences were studied based on their occurrence – where are the vipers mostly found and
where do they travel more? And activity type – where do the vipers prefer to forage? The
effects of two of the dune's features – plant cover and slope, on the movement of C. cerastes,
were tested as possible explanations for these preferences. The microhabitat preferences of the
dune's rodents were tested as well as a proxy for the vipers' resource distribution.
Vipers moved for longer distances at the beginning of the active season. Males were more
likely to be found active at this time, while females became more active towards the season's
6
end. Additionally, vipers were more likely to engage in a sit-and-wait hunting strategy at the
end of the season, compared to the first few months. During each night, vipers were mostly
active in the first few hours after sunset, being less active while the night progressed. As for
microhabitat selection, no preference was detected while considering occurrence alone.
However, vipers set significantly more ambushes in the semi-stable microhabitat than in the
other two. Rodents preferred to forage in the shifting sands, closely followed by the semi-stable
microhabitat. The effect of plant cover on the vipers' movement was significant: vipers moved
~10 times faster in vegetation-free areas compared to densely vegetated areas. While the slope
only affected the vipers' stride length and not their speed. Furthermore, vipers have displayed
a surprisingly strong inclination to move up a slope – on 18 trials out of 20, vipers moved
straight up the slope when presented with the choice to go either way, while in the two other
trials, the vipers moved up and sideways but not down.
A possible explanation for these results is that while vipers hunt mainly in the semi-stable areas
of the dune, they use the shifting sand as 'highways' between ambush sites, and the tendency to
go up the slope (anti-gravitaxis) represents a behavioral adaptation (learned or innate) for
locating these areas. However, stable areas may be preferred when stealth is prioritized over
decreased movement costs in order to avoid detection by prey or predators.
These results can be formalized and even generalized to other animals by experimentally
establishing relationships between species and environmental variables in their habitat.
In conclusion, I describe here for the first time C. cerastes' activity patterns in the wild. The
vipers' microhabitat preferences are described and explained experimentally by abiotic and
biotic factors of the habitat. Finally, I propose to formalize these results and discuss the uses
of it. This work sheds light on the behavior of a scarcely studied nocturnal predator, and,
hopefully, will shed light on habitat use research in general
The desert vipers of the genus Cerastes are a small clade of medically important venomous snakes within the family Viperidae. According to published morphological and molecular studies, the group is comprised by four species: two morphologically similar and phylogenetically sister taxa, the African horned viper (Cerastes cerastes) and the Arabian horned viper (Cerastes gasperettii); a more distantly related species, the Saharan sand viper (Cerastes vipera), and the enigmatic Böhme’s sand viper
(Cerastes boehmei), only known from a single specimen in captivity allegedly captured in Central Tunisia. In this study, we sequenced one mitochondrial marker (COI) as well as genome-wide data (ddRAD sequencing) from 28 and 41 samples, respectively, covering the entire distribution range of
the genus to explore the population genomics, phylogenomic relationships and introgression patterns within the genus Cerastes. Additionally, and to provide insights into the mode of diversification of the group, we carried out niche overlap analyses considering climatic and habitat variables. Both nuclear phylogenomic reconstructions and population structure analyses have unveiled an unexpected evolutionary history for the genus Cerastes, which sharply contradicts the morphological similarities
and previously published mitochondrial approaches. Cerastes cerastes and C. vipera are recovered as sister taxa whilst C. gasperettii is a sister taxon to the clade formed by these two species. We found a relatively high niche overlap (OI > 0.7) in both climatic and habitat variables between C. cerastes and
C. vipera, contradicting a potential scenario of sympatric speciation. These results are in line with the introgression found between the northwestern African populations of C. cerastes and C. vipera. Finally, our genomic data confirms the existence of a lineage of C. cerastes in Arabia. All these results highlight
the importance of genome-wide data over few genetic markers to study the evolutionary history of species.
Using animals in sacrificial rituals and socio-religious ceremonies has a long history and is still practised in various cultures and religions worldwide. This phenomenon remains a complex issue, with deeply held cultural and religious beliefs on one side and concerns for animal welfare and ethical treatment on the other. This study aims to analyze the domestic and wild animals exploited for sacrificial practices and socio-religious purposes among the Moroccan and comprehend the symbolism of these practices. This fieldwork has been undertaken in various regions of Morocco, where we focused on visiting areas known to use animals in rituals. Ethnozoological data were gathered during field observations, visits to public markets, and our participation in ritual activities. A total of 128 wild and domestic animal species belonging to 62 zoological families were identified in this investigation as being used for various sacrificial rituals and socio-religious events. The documented animals were distributed among eight classes. It was demonstrated that the most frequently cited classes were Mammalia, with 40 species. The presence of local wildlife, cultural trends, and economic factors contribute to the sustainability and growth of the market for ritualistic animal products. However, the absence of effective monitoring and regulation poses a challenge from a conservationist standpoint. To conserve and responsibly utilize Morocco's fauna, it is crucial to possess comprehensive information about the animal species involved in sacrificial rituals and socio-religious events. By exploring folk knowledge and healthcare practices, we can gain deeper insights into human interactions with the surrounding ecosystem, leading to the development of suitable strategies for preserving natural resources.
Understanding the geographic distribution of species is crucial for establishing protected areas. This study aimed to identify the preferred habitat environment of South Korean herpetofauna using distribution point information, providing the information necessary to protect their habitat by establishing a species distribution model. We found that climate variables in the region where 19 amphibians and 20 reptiles were distributed correlated with the altitude, suggesting that altitude had a major influence on their distribution. The species distribution modeling indicated that 10–12 amphibian and 13–16 reptile species inhabit the Gangwon-do region, forming hotspot areas in the eastern and western regions around the Taebaek Mountains. Some of these hotspot areas occurred in the Demilitarized Zone and national parks, which are government-managed ecological conservation areas. However, some hotspot areas are vulnerable to habitat destruction due to development and deforestation as they are not designated conservation areas. Therefore, it is necessary to establish new conservation areas with a focus on herpetofauna after confirming the actual inhabitation of species through precise monitoring in predicted hotspot areas and designating them as protected areas. Our results can serve as important basic data for establishing protection measures and designating protected areas for herpetofauna species.
The desert horned viper occurs in the dunes of the northwestern Negev desert, Israel. We report on a 2 year study on the viper's behaviour and ecology in its natural habitat. We examined whether the vipers moved faster in a vegetation-dense microhabitat versus an open dune area and detected much slower movement in the former. We nevertheless detected no preference of the vipers for any of the dune areas. We suggest that the vipers trade-off the ease of movement on open areas with prey, which is probably more available in areas with denser vegetation. The activity was higher early in the season and the vipers were mostly active right after sunset, with a second smaller activity peak at sunrise, perhaps searching for burrows to spend the day. Fitting this explanation, movement at the track's end was less directional than at its beginning. We found inter-sexual and between-year differences. For example, females were larger than males in the second year of the study but not in the first one and the population seemed to be smaller in the second year of the study than in its first year. The information we provide on this viper may assist its conservation, as sand dunes are threatened habitats in Israel.
Understanding the geographic distribution of species is crucial for establishing protected areas. This study aimed to identify the preferred habitat environment of South Korean herpetofauna using distribution point information, providing the information necessary to protect their habitat by establishing a species distribution model. We found that climate variables in the region where 19 amphibians and 20 reptiles were distributed showed a correlation with altitude, suggesting altitude had a major influence on their distribution. The species distribution modeling indicated that 10–12 amphibian species and 13–16 reptile species inhabit the Gangwon-do region, forming hotspot areas in the eastern and western regions around the Taebaek Mountains. Some of these hotspot areas occurred in the Demilitarized Zone (DMZ) and national parks, which are government managed ecological conservation areas. However, some hotspot areas are vulnerable to habitat destruction due to development and deforestation as they are not designated conservation areas. Therefore, it is necessary to establish new conservation areas with a focus on herpetofauna, after confirming the actual inhabitation of species through precise monitoring in predicted hotspot areas, and designate them as protected areas. These results can serve as important basic data for establishing protection measures and designating protected areas for herpetofauna species.
Understanding species' habitat use is fundamental for conservation and management. However, quantifying habitat use for small cryptic species is limited by imperfect detection during field surveys and the lack of habitat data at meaningful spatial scales. Topographically-derived habitat variables from digital elevation models (DEMs) have the potential to overcome these limitations. Here we used DEM-derived topographic variables as fine-scale proxies for abiotic conditions to study site-occupancy patterns of the berg adder (Bitis atropos), a small-bodied cryptic viper. We carried out seven repeated field surveys across 219 hectares in a mountainous protected area in northeastern South Africa to estimate snake detection probability and occupancy using maximum likelihood methods. Although snakes occurred across a third of the surveyed habitat, they were only detected 40% of the time during the springtime when detection was highest. Results showed that these snakes preferred northwest facing, mid and upper slopes, which are exposed to afternoon sun and presumably higher ambient energy. Our results demonstrate the value of using DEM-derived topographic variables for ecological studies where habitat data are either unavailable or inappropriate, thereby providing valuable insights into habitat use of cryptic and difficult to detect species.
As a sedentary bird, the Caspian Snowcock is a typical high-mountain and alpine species. The bird is distributed in the mountainous regions of north, northwest and western parts of Iran. In this respect, in recent years, the populations of this species are declining due to habitat destruction, unregulated hunting, overgrazing, etc. Therefore, conserving the relatively large patches of habitat is very important in order to support the species’ vital requirements. In this study, the habitat suitability of Caspean Snowcock in Charmahal and Bakhtiari Province (as a region containing mountainous landscapes) has been investigated. According to the results, elevation (44.3%), annual precipitation (19%), slope (17.2%) and human footprint (8.5%) contributed the largest percents to the habitat suitability model. Potentially, the Caspian Snowcock can occurs in habitats with elevation of 1700 to 4150 m above sea level. However, only 0.81% of suitable habitats fell within elevation of 1700 to 2000 m. The estimated suitable habitats of the species cover approximately 19.4% of this province, but only about 15.8% of these areas are officially protected. On the other hand, human disturbances such as residential locations, roads, overgrazing and collecting of medicinal and aromatic plants could lead to accelerating the habitat degradation and fragmentation. To further assess the impacts of habitat fragmentation on the Caspian Snowcock, it is suggested to survey the dispersal capacity of this species as well. In addition, considering ecological niches, the Caspian Snowcock can be regarded as an umbrella or flagship species in the high altitude mountains of this area.
The Maghreb region (North Africa) constitutes a major component of the Mediterranean Basin biodiversity hotspot. During the last centuries, a consistent human population growth has led to an unprecedented rate of habitat transformation and loss in the region and thus, threatening its biodiversity. The Western Mediterranean viper Vipera latastei-monticola inhabits humid and subhumid areas in the main mountain ranges of the Maghreb, facing such threatening factors; however, its elusive character and rarity hindered data collection for distinct biological purposes. Here, we study the biogeographical patterns and conservation status of the Maghrebian V. latastei-monticola resulting from recent sampling campaigns in Morocco and Tunisia. We update species distribution, and integrate phylogeographic and ecological niche modelling analyses at both species and lineage level to identify suitable areas, and to evaluate the impact of anthropogenic transformation and level of protection of their suitable space. We identified four highly divergent mitochondrial lineages, including a new lineage endemic to the Western High Atlas, with allopatric distributions and restricted to mountain ranges, supporting the role of mountains as past climatic refugia. Despite the remoteness of suitable areas, we report widespread habitat degradation and identify the low effectiveness of the current protected areas system in preserving the species and lineages range. Our study shows the urgent need to apply management actions for the long-term conservation of this vulnerable species and suggests a revaluation of the specific status of V. monticola, as these populations likely represent an ecotype of V. latastei.
During the last 20 000 yrs, the mountains of Africa between the Mediterranean and the equator have experienced significant climatic changes with important consequences for the vegetation and resource potential. At about 18 000 BP present altitudinal belts were depressed and the zonation of climate and vegetation was changed considerably. In the Holocene, higher temperatures led not only to more humid conditions but also to an uplifting of altitudinal belts and transformation of climatic and ecological zones and to increased natural resource potential. The cumulative effects of natural and anthropogenic processes and impacts within the last 2000 yrs are also depicted. In particular, human impact on ecosystems formed under more favorable climatic conditions could result in irreversible degradation. -from Authors
Forty-two species of reptiles known to occur in The Gambia are listed together with notes on habitat and behavior. Two of the species in the list are for the first time recorded north of the rain forest limit in West Africa. Gallery forest in The Gambia acts as a faunal refuge for reptiles and other animals whose distribution otherwise is confined to tropical rainforest. -Author
INEICH I., 1997 - Les amphibiens et les reptiles du littoral mauritanien. In F. Colas (éd. scient.). Environnement et littoral mauritanien. Actes du colloque, 12-13 juin 1995, Nouakchott, Mauritanie. CIRAD, Montpellier, collection Colloques, pp. 93-99 (196 pages + XIV pl. hors texte).
A biogeographical classification of reptiles in the Riff region (northern Morocco, Africa) was carried out to look for shared distribution patterns, here termed chorotypes. Baroni-Urbani & Buser's similarity index was applied to the presence/absence data of reptiles in 1010 km UTM (Universal Transverse Mercator) squares, and then UPGMA (Unweighted Pair-Group Method using arithmetic average) was used to classify the species. A probabilistic method was employed to assess the statistical significance of the groups obtained. An ordination method, the Canonical Correspondence Analysis, was also used to study the distribution of the reptiles within a continuous framework. A gradual longitudinal replacement of reptile species was found throughout the Riff, with no sharp discontinuities for the distributions of most of the species. This may be due to the biogeographical northward movement of the Saharan boundaries, which have not yet reached biogeographical equilibrium. Thus, Saharan reptiles enter the Riff region from the east, through the lower basin of the River Moulouya. Seven reptile chorotypes were identified in the Riff, and these comprise Mediterranean species and others endemic to the Maghreb (the region that spans most of North-western Africa, excluding the Sahara). These chorotypes have a western distribution, and are segregated from one another according to altitude. Historical and ecological processes can account for the distributions shared by these species, which have inhabited the Riff for longer than eastern reptiles. Résumé Une classification biogéographique des reptiles a été réalisée dans la région du Riff, au nord du Maroc, pour étudier les schémas de distribution partagés, appelés ici chorotypes. On a appliqué l'index de Baroni-Urbani & Buser aux données sur la présence ou l'absence de reptiles dans des quadrilatères de 10 km/10 UTM (Universal Transverse Mercator), puis l'UPGMA (Unweighted Pair-Group Method using arithmetic Average) pour classifier chaque espèce. Une méthode de probabilité a été utilisée pour évaluer la signification statistique des groupes obtenus. Une méthode de classification, la Canonical Correspon-dence Analysis, fut aussi employée pour étudier la distribution des reptiles dans *Correspondence. 1997 East African Wild Life Society. un cadre continu. On a découvert un remplacement longitudinal graduel des espèces de reptiles le long du Riff, sans discontinuité abrupte dans la distribution de la plupart des espèces. Ceci peut être dû au mouvement biogéographique vers le nord des limites sahariennes, qui n'ont pas encore atteint un équilibre biogéographique. Donc, les reptiles sahariens pénètrent dans le Riff par l'est, par le bas du bassin de la rivière Moulouya. On a identifié dans le Riff un total de sept chorotypes, et ceux-ci comprennent des espèces méditerranéennes et d'autres qui sont endémiques au Maghreb (la région qui couvre la plus grande partie du nord-ouest africain, à l'exclusion du Sahara). Ces chorotypes ont une distri-bution occidentale et sont séparés l'un de l'autre en fonction de l'altitude. Des processus historiques et écologiques peuvent avoir influencé les distributions partagées par ces espèces qui ont occupé le Riff depuis plus longtemps que les reptiles orientaux.
Twenty-six Amphibia (plus two possible) and 45 Reptilia have been recorded in SE Senegal; 23 Amphibia (plus three probable) and 39 Reptilia (plus five probable) are listed for the Niokola-Koba National Park. New country records made in October 1996 were Amphibia: Kassina fusca Schiøtz 1967; and Reptilia: Agama sankaranica Chabanaud 1918, Cophoscincopus cf.greeri, Mabuya quinque-taeniata scharica Sternfeld 1917 and Chalcides thierryi pulchellus Mocquard 1906, with extended ranges for Bufo maculatus Hallowell 1854 and Phrynomantis microps Peters 1875. Cophoscincopus Mertens 1934 is a genus new to Senegal. Relative density of diurnal woodland lizards was nearly 4-fold that of bushland and thicket lizards of drier northern and western Senegal. Where riparian forest habitat formed within undifferentiated Sudanian woodland, reptile species differed and diversity was lower. Percentage frequency of woodland A. sankaranica was reduced by man-made road structures, while Agama agama Linnaeus 1758 and Hemidactylus brooki complex were only recorded with them. Geckos were not recorded inside the boundary of the Niokola-Koba National Park (baboons and patas monkeys abundant), and diversity was reduced; outside, reptile density was nearly 5-fold, with geckos (Tarentola parvicarinata Joger 1980 and H. brooki complex) predominant. Faunal overlap of lizards in SE Senegal with those of W Mali—the same area of endemism—was higher than with species in northern and western Senegal.
Growth, mortality and sexual size dimorphism of Vipera latastei were investigated in northern Portugal. Size structure ranged from 16–58 cm of snout–vent length (SVL), with peaks between 40–45 cm for males and 35–40 cm for females. Age structure ranged between 0 and 14 years, with peaks at 4 and 5 years for males and at 4–6 years for females. Longevity was 11 and 14 years for males and females, respectively. Sexual maturity was attained approximately at four years in males, and one year later in females, however, at a similar body size. Growth rates decreased with increasing SVL; males grew faster than females at all ages; and asymptotic body size was larger in males than in females. Mortality was higher in males than in females and increased after sexual maturity in both sexes. The sexual differences in mortality annulled an age-specific sexual size dimorphism in favor of males and produced a minor sexual size dimorphism in mean adult body size of V. latastei.
Abstract Although bioclimatic modelling is often used to estimate potential impacts of likely climate changes, little has been done to assess the reliability and variability of projections. Here, using four niche-based models, two methods to derive probability values from models into presence–absence data and five climate change scenarios, I project the future potential habitats of 1350 European plant species for 2050. All 40 different projections of species turnover across Europe suggested high potential species turnover (up to 70%) in response to climate change. However variability in the potential distributional changes of species across climate scenarios was obscured by a strong variability in projections arising from alternative, yet equally justifiable, niche-based models. Therefore, projections of future species distributions and derived community descriptors cannot be reliably discussed unless model uncertainty is quantified explicitly. I propose and test an alternative way to account for modelling variability when deriving estimates of species turnover (with and without dispersal) according to a range of climate change scenarios representing various socio-economic futures.
Aim To investigate the impact of past environmental changes on Cedrus atlantica and its current genetic diversity, and to predict its future distribution.
Location Morocco, Algeria and Tunisia.
Methods Eleven fossil pollen records from these three countries were used to locate putative glacial refugia and to reconstruct past climate changes. A mechanistic vegetation distribution model was used to simulate the distribution of C. atlantica in the year 2100. In addition, a genetic survey was carried out on modern Moroccan C. atlantica .
Results Pollen records indicate that Cedrus was present during the last glacial period, probably in scattered refugia, in Tunisia, Algeria and Morocco. In the Tunisian and Algerian sites, cedar expanded during the late glacial and the early Holocene, then disappeared after c . 8000 yr bp . Reconstructed mean annual precipitation and January temperature show that the last glacial period in Morocco was cooler by 10–15°C and drier by c . 300–400 mm year ⁻¹ than the climate today. Modern chloroplast microsatellites of 15 C. atlantica populations in Morocco confirm the presence of multiple refugia and indicate that cedar recolonized the Moroccan mountains fairly recently. Model simulation indicates that by the year 2100 the potential distribution of C. atlantica will be much restricted with a potential survival area located in the High Atlas.
Main conclusions Environmental changes in northern Africa since the last glacial period have had an impact on the geographical distribution of C. atlantica and on its modern genetic diversity. It is possible that by the end of this century C. atlantica may be unable to survive in its present‐day locations. To preserve the species, we suggest that seedlings from modern C. atlantica populations located in the High Atlas mountains, where a high genetic diversity is found, be transplanted into the western High Atlas.
En 1989 comenzamos a estudiar la comunidad de reptiles de esta región, entonces la menos conocida de Marruecos bajo el punto de vista herpetológico. Los muestreos se realizaron en la proximidad de localidades con información meteorológica (precipitación, temperatura media de las mínimas del mes más frío, temperatura media de las máximas del mes más cálido); además, se consideraron diversas variables geográficas y estructurales (altitud, pendiente del terreno, cobertura de piedras, tipo de substrato, altura de la vegetación, cobertura del estrato matorral y estrato arbóreo, biotopo). Aquí se presentan los resultados sobre la distribución y ecología de trece especies de anfisbenios y ofidios (Blanus tingitanus, Trogonophis wiegmanni,
Eryx jaculus, Coluber hippocrepis, Coronella girondica, Macroprotodon cucullatus, Malpolon monspessulanus,
Natrix maura, Natrix natrix, Spalerosophis dolichospilus, Psammophis schokari, Vipera latasti,
Macrovipera mauritanica). Zoogeográficamente, la fauna rifeña de reptiles muestra una alta diversidad específica;
las 43 especies presentes constituyen el 47.2% de la fauna de reptiles de Marruecos, y ello es 12 veces
superior a la proporción de terreno que representa el área de estudio con respecto a Marruecos. Cuatro factores
son los que mejor explican la presencia en el Rif de una proporción tan grande de la fauna de reptiles de
Marruecos y del Mediterráneo: i) su proximidad al continente europeo (y la existencia de puentes terrestres
durante el Mioceno), ii) el aislamiento paleogeográfico de la región, que favoreció el funcionamiento de mecanismos
de aislamiento (endemismos), iii) la penetración de algunas especies saharianas por el valle del Ued
Muluya, y iv) la fachada a la costa Atlántica, lo cual favorece la penetración de algunas especies magrebíes
occidentales.
Palabras clave: anfisbenios, ofidios, Marruecos, distribución, biogeografía.
JOORIS, R., and FOURMY, R. 1996. An analysis of scutellation in populations of Cerastes vipera (Linnaeus, 1758): scale characters co-vary with environmental temperature. Afr. J. Herpetol. 45(2): 59–67.Scutellation in populations of Cerastes vipera varies geographically. Specimens occurring in more southern and warmer regions are characterized by a higher number of ventrals, preventrals and lateral head scales. Some morphological characters (e.g. subcaudals and interoculars) are not correlated geographically with temperature profiles. Correlation of scale characters with temperature does not exclude a genetical basis. A possible genetic divergence between populations of the great sand dunes west of Chaanba-Tademait-Hoggar (with a high number of ventrals) and their northeastern Saharo-Mediterranean conspecifics (with a low number of ventrals) is postulated, but must be confirmed with supplementary genotypic methods.
Detecting individuals of amphibian and reptile species can be a daunting task. Detection can be hindered by various factors such as cryptic behavior, color patterns, or observer experience. These factors complicate the estimation of state variables of interest (e.g., abundance, occupancy, species richness) as well as the vital rates that induce changes in these state variables (e.g., survival probabilities for abundance; extinction probabilities for occupancy). Although ad hoc methods (e.g., counts uncorrected for detection, return rates) typically perform poorly in the face of no detection, they continue to be used extensively in various fields, including herpetology. However, formal approaches that estimate and account for the probability of detection, such as capture-mark-recapture (CMR) methods and distance sampling, are available. In this paper, we present classical approaches and recent advances in methods accounting for detectability that are particularly pertinent for herpetological data sets. Through examples, we illustrate the use of several methods, discuss their performance compared to that of ad hoc methods, and we suggest available software to perform these analyses. The methods we discuss control for imperfect detection and reduce bias in estimates of demographic parameters such as population size, survival, or, at other levels of biological organization, species occurrence. Among these methods, recently developed approaches that no longer require marked or resighted individuals should be particularly of interest to field herpetologists. We hope that our effort will encourage practitioners to implement some of the estimation methods presented herein instead of relying on ad hoc methods that make more limiting assumptions.
New quotes of two relict Palaearctic species: Vipera latastei and Emys orbicularis in the Tangier Peninsula.
In the framework of an environmental impact assessment related to a wind farm project in Jbel Haouch Ben Kre'aa (ca. 30 km south of Tangier) a field work (23-30 May 2009) was carried out in order to inventory the amphibians and reptiles of the region. During this work we recorded three amphibian species and twelve reptile species. Of these, two are Palaearctic relict species: the European pond turtle Emys orbicularis the Lataste's Viper Vipera latastei. For the former, this site remains the northernmost in Morocco, this is an extension of the species' known range in Morocco by almost 50 Km. For the last, this is only the fourth record of the species in Tangier Peninsula after those of Boettger (1883) and Bons (1967).
We assess the national conservation status of the amphibians and reptiles of Morocco by applying the IUCN Red List Criteria at the national level and assess its utility as a planning tool to establish regional priorities for conservation. We rely on the accessory data accompanying regional red lists, mainly distribution range and habitats used by, and threats affecting, species of conservation concern. We also correlated some natural history traits to examine the nature and causes of the risk of extinction. With 13 species of amphibians (31% regionally threatened) and 99 species of reptiles (14% regionally threatened), Morocco is one of the Mediterranean countries with the highest diversity of herpetofauna, mainly because of the high percentage of endemism (amphibians 31%, reptiles 24%). The relative frequencies of threatened species were found to be contingent on both taxonomic group and habitat. The overwhelming importance of the threats of small range and number of habitats used by species is different from the threats to the same species at the global level; this demonstrates the usefulness of national or regional analyses of conservation status for setting conservation priorities. The importance of regional assessment derives from the fact that the boundaries set for conservation management are mainly political rather than biogeographical.
Abstract Climate change effects on biodiversity are already manifested, and yet no predictive knowledge characterizes the likely nature of these effects. Previous studies suggested an influence of topography on these effects, a possibility tested herein. Bird species with distributions restricted to montane (26 species) and Great Plains (19 species) regions of central and western North America were modeled, and climate change effects on their distributions compared: in general, plains species were more heavily influenced by climate change, with drastic area reductions (mode 35% of distributional area lost under assumption of no dispersal) and dramatic spatial movements (0–400 km shift of range centroid under assumption of no dispersal) of appropriate habitats. These results suggest an important generality regarding climate change effects on biodiversity, and provide useful guidelines for conservation planning.
Transforming the results of species distribution modelling from probabilities of or suitabilities for species occurrence to presences/absences needs a specific threshold. Even though there are many approaches to determining thresholds, there is no comparative study. In this paper, twelve approaches were compared using two species in Europe and artificial neural networks, and the modelling results were assessed using four indices: sensitivity, specificity, overall prediction success and Cohen's kappa statistic. The results show that prevalence approach, average predicted probability/suitability approach, and three sensitivity-specificity-combined approaches, including sensitivity-specificity sum maximization approach, sensitivity-specificity equality approach and the approach based on the shortest distance to the top-left corner (0,1) in ROC plot, are the good ones. The commonly used kappa maximization approach is not as good as the afore-mentioned ones, and the fixed threshold approach is the worst one. We also recommend using datasets with prevalence of 50% to build models if possible since most optimization criteria might be satisfied or nearly satisfied at the same time, and therefore it's easier to find optimal thresholds in this situation.
Mediterranean vipers are ecologically very similar. When in contact, they constitute an exceptional model to study the effects of competitive interactions and niche segregation mechanisms. In High Ebro, distinct methodologies (random visual encounter, road sampling and radio-tracking surveys, captive maintenance, standardized transects and ad hoc field observations) were used to compare ecological traits (diet, micro-habitat, activity, reproductive and demographic) of V. aspis, V. latastei and hybrids among both species and determine competitive advantages of each form. Diet preferences were similar but few differences were found in feeding frequency and annual variation in diet consumption. Males of the three forms compete for areas with similar characteristics but differences were found mainly during summer. Significant differences in average movement rates and home range size were found among males. Fecundity and new-borns fitness were lower in V. aspis than in V. latastei, whereas hybrids had intermediate values. Male and female adult hybrids were more abundant than parental forms, whereas female and juvenile V. latastei and juvenile hybrids had high road-mortality. The three forms seem to be competing intensely for resources but the segregation on the spatial and temporal axes of their niches could be reducing interspecific competition and allowing coexistence. The use of different resources probably confers reproductive and demographic advantages for V. latastei and hybrids, respectively. Moreover, reproductive fitness of hybrids suggests the occurrence of endogenous selection. Comparative thermal and genetic studies are needed to clarify the limiting factors of vipers and to establish a model of the hybrid zone.
In northwest Africa some species from Sahelian origin appear with relict populations and apparently isolated by the extreme aridity of the Sahara desert. However very tolerant to aridity species could maintain continuous populations as might be the case for Echis leucogaster as indicated by results from genetic analysis and bioclimatic models. Resum: Al nord-oest d'àfrica apareixen un grup d'espècies d'origen sahelià en poblacions relictes i aparentment aïllades pel desert del Sàhara. No obstant això espècies molt tolerants a l"aridesa podrien mantenir poblacions contínues, com podria ser el cas de Echis leucogaster segons indiquen els resultats de l'anàlisi genètica i els models bioclimàtics.
Species distribution modelling has been widely applied in order to assess the potential impacts of climate change on biodiversity. Many methodological decisions, taken during the modelling process and forecasts, may, however, lead to a large variability in the assessment of future impacts. Using measures of species range change and turnover, the potential impacts of climate change on French stream fish species and assemblages were evaluated. Our main focus was to quantify the uncertainty in the projections of these impacts arising from four sources of uncertainty: initial datasets (Data), statistical methods [species distribution models (SDM)], general circulation models (GCM), and gas emission scenarios (GES). Several modalities of the aforementioned uncertainty sources were combined in an ensemble forecasting framework resulting in 8400 different projections. The variance explained by each source was then extracted from this whole ensemble of projections. Overall, SDM contributed to the largest variation in projections, followed by GCM, whose contribution increased over time equalling almost the proportion of variance explained by SDM in 2080. Data and GES had little influence on the variability in projections. Future projections of range change were more consistent for species with a large geographical extent (i.e., distribution along latitudinal or stream gradients) or with restricted environmental requirements (i.e., small thermal or elevation ranges). Variability in projections of turnover was spatially structured at the scale of France, indicating that certain particular geographical areas should be considered with care when projecting the potential impacts of climate change. The results of this study, therefore, emphasized that particular attention should be paid to the use of predictions ensembles resulting from the application of several statistical methods and climate models. Moreover, forecasted impacts of climate change should always be provided with an assessment of their uncertainty, so that management and conservation decisions can be taken in the full knowledge of their reliability.
Current climate change is a major threat to biodiversity. Species unable to adapt or move will face local or global extinction and this is more likely to happen to species with narrow climatic and habitat requirements and limited dispersal abilities, such as amphibians and reptiles. Biodiversity losses are likely to be greatest in global biodiversity hotspots where climate change is fast, such as the Iberian Peninsula. Here we assess the impact of climate change on 37 endemic and nearly endemic herptiles of the Iberian Peninsula by predicting species distributions for three different times into the future (2020, 2050 and 2080) using an ensemble of bioclimatic models and different combinations of species dispersal ability, emission levels and global circulation models. Our results show that species with Atlantic affinities that occur mainly in the North-western Iberian Peninsula have severely reduced future distributions. Up to 13 species may lose their entire potential distribution by 2080. Furthermore, our analysis indicates that the most critical period for the majority of these species will be the next decade. While there is considerable variability between the scenarios, we believe that our results provide a robust relative evaluation of climate change impacts among different species. Future evaluation of the vulnerability of individual species to climate change should account for their adaptive capacity to climate change, including factors such as physiological climate tolerance, geographical range size, local abundance, life cycle, behavioural and phenological adaptability, evolutionary potential and dispersal ability.
Aim Techniques that predict species potential distributions by combining observed occurrence records with environmental variables show much potential for application across a range of biogeographical analyses. Some of the most promising applications relate to species for which occurrence records are scarce, due to cryptic habits, locally restricted distributions or low sampling effort. However, the minimum sample sizes required to yield useful predictions remain difficult to determine. Here we developed and tested a novel jackknife validation approach to assess the ability to predict species occurrence when fewer than 25 occurrence records are available.
Location Madagascar.
Methods Models were developed and evaluated for 13 species of secretive leaf‐tailed geckos ( Uroplatus spp.) that are endemic to Madagascar, for which available sample sizes range from 4 to 23 occurrence localities (at 1 km ² grid resolution). Predictions were based on 20 environmental data layers and were generated using two modelling approaches: a method based on the principle of maximum entropy (Maxent) and a genetic algorithm (GARP).
Results We found high success rates and statistical significance in jackknife tests with sample sizes as low as five when the Maxent model was applied. Results for GARP at very low sample sizes (less than c. 10) were less good. When sample sizes were experimentally reduced for those species with the most records, variability among predictions using different combinations of localities demonstrated that models were greatly influenced by exactly which observations were included.
Main conclusions We emphasize that models developed using this approach with small sample sizes should be interpreted as identifying regions that have similar environmental conditions to where the species is known to occur, and not as predicting actual limits to the range of a species. The jackknife validation approach proposed here enables assessment of the predictive ability of models built using very small sample sizes, although use of this test with larger sample sizes may lead to overoptimistic estimates of predictive power. Our analyses demonstrate that geographical predictions developed from small numbers of occurrence records may be of great value, for example in targeting field surveys to accelerate the discovery of unknown populations and species.
Climate suitability models are used to make projections of species’ potential future distribution under climate change. When studying the species richness with such modeling methods, the extent of the study range is of particular importance, especially when the full range of occurrence is not considered for some species, often because of geographical or political limits. Here we examine biases induced by the use of range-restricted occurrence data on predicted changes in species richness and predicted extinction rates, at study area margins. We compared projections of future suitable climate space for 179 bird species breeding in Iberia and North Africa (27 of them breeding only in North Africa though potential colonizers in Europe), using occurrence data from the full Western Palaearctic (WP) species range and from the often-considered European-restricted range. Current and future suitable climatic spaces were modeled using an ensemble forecast technique applied to five general circulation models and three climate scenarios, with eight climatic variables and eight modeling techniques. The use of range-restricted compared to the full WP occurrence data of a species led to an underestimate of its suitable climatic space. The projected changes in species richness across the focus area (Iberia) varied considerably according to the occurrence data we used, with higher local extinction rates with European-restricted data (on average 38 vs 12% for WP data). Modeling results for species currently breeding only in North Africa revealed potential colonization of the Iberian Peninsula (from a climatic point of view), which highlights the necessity to consider species outside the focus area if interested in forecasted changes in species richness. Therefore, the modeling of current and future species richness can lead to misleading conclusions when data from a restricted range of occurrence is used. Consequently, climate suitability models should use occurrence data from the complete distribution range of species, or at least within biogeographical areas.
At least 33 anuran, 7 chelonian, 3 crocodilian, 42 lizard and 54 snake species have been recorded in or at the borders of Mali. Uromastyx maliensis, a new species found between the Niger River and the Tanezrouft desert, is described. New country records from recent collections and museum material comprise Bufo pentoni, B. maculatus, Ptychadena aequiplicata, Phrynobatrachus perpalmatus, Tomopterna sp., Afrixalus weidholzi, Trionyx triunguis, Hemidactylusmabouia, Agama paragama, Acanthodactylus guineensis, Mesalina pasteuri and Echis leucogaster (Tomopterna and Trionyx are genera new to Mali).
After defining the state of knowledge and reviewing national inventories, the author looks at the reasons which led him to study Mediterranean and Saharan Africa and to detail their biogeographical significance. For Mediterranean and Saharan Africa, the generic and specific richness, the richness of endemics, and the entire biogeographical range are first analyzed at the family level. In the second part, the various biogeographical elements which play a part in the formation of the floras at the generic and specific levels are defined; several examples are provided respectively for the Mesogean (Mediterranean, Saharo-Arabian and Irano-Turanian) and tropical elements. A third part is devoted to endemism: first generic and specific endemism, then the biogeographical significance of the endemic taxa. It appears that the flora of Mediterranean Africa is about three times richer than that of Saharan Africa and that endemism there is two times greater. Whereas the flora of Mediterranean Africa is for the most part made up of Mediterranean taxa, in Saharan Africa there is a nearly equal distribution of Mediterranean, Saharo-Arabian, and tropical elements. These characteristics are related to the hostile ecological conditions which govern the Sahara now, but also reflect the climatic disturbances which took place during the Pleistocene. A special chapter is devoted to a discussion of the historical interpretation of the flora of Mediterranean and Saharan Africa, taking into account the new data provided by paleoclimatology and paleobotany. It is concluded that the Mediterranean flora is relatively old and goes back at least as far as the middle Miocene, whereas the present Saharan flora is a reflection of intense climatic changes which have severely affected this region since the Pliocene. In each of these cases emphasis has been placed on the role elements of African origin played in the development of the present flora.
A wide range of modelling algorithms is used by ecologists, conservation practitioners, and others to predict species ranges from point locality data. Unfortunately, the amount of data available is limited for many taxa and regions, making it essential to quantify the sensitivity of these algorithms to sample size. This is the first study to address this need by rigorously evaluating a broad suite of algorithms with independent presence-absence data from multiple species and regions. We evaluated predictions from 12 algorithms for 46 species (from six different regions of the world) at three sample sizes (100, 30, and 10 records). We used data from natural history collections to run the models, and evaluated the quality of model predictions with area under the receiver operating characteristic curve (AUC). With decreasing sample size, model accuracy decreased and variability increased across species and between models. Novel modelling methods that incorporate both interactions between predictor variables and complex response shapes (i.e. GBM, MARS-INT, BRUTO) performed better than most methods at large sample sizes but not at the smallest sample sizes. Other algorithms were much less sensitive to sample size, including an algorithm based on maximum entropy (MAXENT) that had among the best predictive power across all sample sizes. Relative to other algorithms, a distance metric algorithm (DOMAIN) and a genetic algorithm (OM-GARP) had intermediate performance at the largest sample size and among the best performance at the lowest sample size. No algorithm predicted consistently well with small sample size (n < 30) and this should encourage highly conservative use of predictions based on small sample size and restrict their use to exploratory modelling.
Checkliste der Amphibien und Reptilien von Westsahara (Amphibia, Reptilia) PHILIPPE GÊNIEZ & JOSÉ-ANTONIO MATEO & JACQUES BONS KURZFASSUNG Die Liste der Amphibien und Reptilien von West Sahara umfaßt 46 definitiv nachgewiesene Arten (4 Am-phibien, 42 Reptilien). 13 weitere Arten, die für das Gebiet noch nicht bekannt sind, könnten hier noch gefunden wer-den. Tarentola boehmei wird aus der Faunenliste von West Sahara genommen und die Auswirkungen des Jbel Ouarkziz, einer biogeographischen Grenze, welche die herpetofaunistischen Elemente Marokkos (nördlich des Jbel Ouarkziz) von denen der West Sahara trennt, werden beschrieben. Die Zusammensetzung der Herpetofauna von West Sahara wird wie folgt beurteilt: 10 Arten zeigen mediterrane Affinitäten, 2 nord-saharische, 19 rein saharische und 7 sahelische; 4 sind tropische Relikte und 4 sind auf den ozeanischen Küstenstreifen beschränkt und können als "konti-nental-makaronesische Endemiten" bezeichnet werden. Danach ist die Herpetofauna von West Sahara im wesentlichen saharischen Ursprungs, doch stellt das Gebiet trotz der offensichtlich einförmigen Landschaft ein tiergeographisches Grenzgebiet für Amphibien und Reptilien dar. Dies kann auf die große Nord-Süd-Ausdehnung von West Sahara und den Klimakontrast zwischen dem ozeanisch beeinflußten, relativ feuchten und gemäßigten Küstengebiet und dem Landesinneren zurückgeführt werden, das dem trockenen Saharaklima mit seinen starken Temperaturschwankungen ausgesetzt ist. ABSTRACT The list of the amphibians and reptiles of Western Sahara includes 46 species (4 amphibians and 42 reptiles), while 13 further species unknown in this area could conceivably be discovered there. Among the important facts, we exclude Tarentola boehmei from the fauna of Western Sahara, and report on the effect of the Jbel Ouarkziz which acts as a biogeographical boundary, separating the herpetofaunal elements from Morocco (north of the Jbel Ouarkziz) and from Western Sahara. The herpetofauna of Western Sahara is composed as follows: 10 species can be considered as being of Mediterranean affinities, 2 as North Saharan, 19 as purely Saharan, 7 as being of Sahelian affinities, 4 are tropical relicts and 4 are limited to the oceanic fringe of the Sahara and can be considered as "continental Macaro-nesian endemics". This confirms that the herpetofauna of Western Sahara is mainly of Saharan origin but that this area is, in spite of its apparently uniform landscape, a biogeographical cross-roads for Amphibians and Reptiles. This can be related to the wide latitudinal amplitude of Western Sahara and by the climate contrast between the oceanic fringe, comparatively humid and temperate, and the remaining of the country, subject to a dry Saharan climate with strongly contrasted temperature.
Tropical African climate has oscillated between markedly wetter and drier conditions on all timescales in response to global climate disturbances. A step-like increase in aridity over the past 3 Ma has been primarily paced by orbital cycles coupled with the onset and amplification of high-latitude glacial cycles. On the 104–103-ka timescales, observed changes imply interactions between insolation, sea-surface conditions and vegetation. High-frequency variations could be linked to oscillations in major atmospheric circulation modes, in solar output, or to major volcanic events. To cite this article: F. Gasse, C. R. Palevol 5 (2006).
Aim Spatial modelling techniques are increasingly used in species distribution modelling. However, the implemented techniques differ in their modelling performance, and some consensus methods are needed to reduce the uncertainty of predictions. In this study, we tested the predictive accuracies of five consensus methods, namely Weighted Average (WA), Mean(All), Median(All), Median(PCA), and Best, for 28 threatened plant species.
Location North-eastern Finland, Europe.
Methods The spatial distributions of the plant species were forecasted using eight state-of-the-art single-modelling techniques providing an ensemble of predictions. The probability values of occurrence were then combined using five consensus algorithms. The predictive accuracies of the single-model and consensus methods were assessed by computing the area under the curve (AUC) of the receiver-operating characteristic plot.
Results The mean AUC values varied between 0.697 (classification tree analysis) and 0.813 (random forest) for the single-models, and from 0.757 to 0.850 for the consensus methods. WA and Mean(All) consensus methods provided significantly more robust predictions than all the single-models and the other consensus methods.
Main conclusions Consensus methods based on average function algorithms may increase significantly the accuracy of species distribution forecasts, and thus they show considerable promise for different conservation biological and biogeographical applications.
A cladistic biogeographic study of the western Mediterranean terrestrial fauna is made using taxon-area cladograms of ten groups of animals showing high levels of endemicity in the area. The groups analysed are the Nephrotoma flavescens group, the Tipula (Acutipula) maxima group, the T. (Lunatipula) bullata and falcata group, the subgenus T. (Mediotipula), the T. (Savtshenkia) goriziensis group, the T. (S) signata group (Insecta, Diptera, Tipulidae), the Protonemura corsicana group (Insecta, Plecoptera, Nemouridae), the genus Speonemadus (Insecta, Coleoptera, Cholevidae), and the subgenera Triturus (Palaeotriton) and Triturus (Triturus) (Urodela, Salamandridae). The groups contain a total of 123 species and subspecies. Detailed distribution maps of 94 species and subspecies of Tipulidae included in the study are given. Based on the distributions of 74 endemic species and subspecies, 13 areas of endemism in the Mediterranean are recognized. The geology of the western Mediterranean since the late Oligocene is discussed with reference to a number of maps showing kinematic reconstructions of the area. Five methods for cladistic biogeographic purposes were employed, viz. Brooks Parsimony Analysis, Component Compatibility Analysis, Component Analysis, Three-Area Statements Analysis, and Paralogy-free Subtree Analysis. General area cladograms produced by computer implementations of the five methods show low levels of congruence. Geological area cladograms are fully compatible with some of the results of Brooks Parsimony Analysis only.
The conservation status of the snake fauna of a given region or territory is often hard to estimate due the secretive habits of these animals, as well as of the lack of long-term demographic studies and generally low population densities. We examined the conservation status of the snakes from the Iberian Peninsula by applying two complementary methods. The first method, created by Filippi and Luiselli for a study of the Italian snakes conservation status, takes into account the ecological and non-ecological attributes which make species vulnerable to extinction. The second is a cartographic analysis which consists of calculating two indexes derived from the comparison of old and recent citations in UTM 10×10 km squares of Iberian snakes by means of extensive database sets. For each species, we calculated the percentage of recent citations, and the percentage of squares with both old and recent citations. Species with low proportion of recent citations and new squares appeared to be in decline. We found considerable coincidence between the two methods in the identification of the most threatened snake species: Vipera latastei, Coronella girondica, and Natrix natrix. We suspect that the ecological specialisation and the low reproductive output make C. girondica and V. latastei prone to extinction when faced with environmental changes (i.e. habitat loss). For N. natrix, we argue that this semi-aquatic snake experiences suboptimal environmental conditions in Mediterranean habitats. A combination of both methods proved adequate to detect vulnerability to extinction of snake species, hence revealing an effective tool for establishing conservation strategies in snakes and other secretive faunas.
The present study aimed to infer evolutionary scenarios for Vipera latastei and Vipera monticola in the Iberian Peninsula and the Maghreb through the identification of spatial patterns in morphological character variation and biogeographic patterns in morphological variability distribution. Ten morphological traits from 630 vipers were analysed with geostatistic and ecological niche modelling in a geographical information system. Interpolation by Kriging was used to generate surfaces of morphological variation, which were combined with spatial principal components analysis (SPCA). Putative morphological differentiated groups generated by SPCA maps were tested with discriminant function analysis (DFA). Maximum entropy modelling and nine environmental variables were used to identify factors limiting the distribution of groups and areas for their potential occurrence. Groups supported by DFA were: Western Iberia, Eastern Iberia, Rif plus Middle Atlas, Algeria, and High Atlas. Their distribution is influenced by common environmental factors such as precipitation. Areas of probable sympatry between Iberian groups matched the morphological clines observed by geostatistics tools. Geographic variation patterns in V. latastei-monticola are probably due to vicariant separation of Iberian and African populations during the opening of the Strait of Gibraltar, and population refugia during the Quaternary glaciations with secondary contact. The taxonomic status of northern Morocco and Algerian groups should be further investigated. We conclude that geostatistics and niche-modelling tools are adequate to infer morphological variability across wide geographic ranges of species.
Several life-history traits may increase vulnerability of species to extinction. Among snakes, ambush predation and dietary specialisation are factors that increase this vulnerability. European viper species, genus Vipera, display such traits and are categorised as endangered in several parts of its range. For their conservation management, a deeper knowledge of their ecology and habitat use is highly relevant. One of the species with less ecological data is the Lataste's viper Vipera latastei, a species which lives in the Iberian Peninsula and northwestern Africa. Here, we describe its diet based on the analysis of gut content of 435 museum specimens plus nine bibliographic data from the entire Iberian range. The species showed seasonal and ontogenetic shift in diet but no sexual variations. Feeding activity (percentage of vipers with prey) was low in accordance with its ambush predation tactics, being lower in spring than in summer and autumn. Prey spectrum included two main (reptiles and small mammals), and three sporadic, types of prey (arthropods, amphibians and birds). The consumption of reptiles and mammals was seasonal; the former decreased in occurrence from spring to autumn, whereas the latter showed an opposite pattern. There was an ontogenetic shift in the diet: juveniles fed mainly on reptiles and arthropods, whereas adult vipers progressively substitute this prey with insectivores, and the largest vipers primarily foraged on rodents and birds. Our results suggest that the seasonal variation in prey type was related to prey availability, whereas the ontogenetic shift was linked to gape limitation. The apparently wide prey spectrum of V. latastei must therefore be examined, taking into account that there are seasonal and ontogenetic dietary variations as well as geographic differences, the latter probably driven by climatic contrasts into the Iberian Peninsula. This new data of the endangered Iberian V. latastei can aid the effective conservation management of this species.
Geostatistics and geographical information system (GIS) procedures are novel techniques helpful for the identification of environmental correlates sustaining contact zones among subspecies or closely related species. In this paper, we tried to infer evolutionary scenarios for Vipera ammodytes across the European part of its distribution area using geostatistics and ecological niche-based models, hence trying to solve several biogeographical questions that remained unclear after the application of classical morphological tools and genetic analyses. Eleven morphological traits from 871 vipers were analysed with geostatistics and ecological niche-based modelling. Interpolation by kriging was used to generate surfaces of morphological variation, which were combined with spatial principal components analysis (SPCA). SPCA maps were used to test putative morphological differentiated groups with discriminant function analysis (DFA). Maximum entropy modelling and seven environmental variables were used to identify factors limiting the distribution of groups and areas for the potential occurrence of such groups. Three patterns of morphological variation were observed: a north-west/south-west cline, transition zones with steep clines of variation in a west–east arc, and particular character traits that disturbed the general cline. SPCA identified between three and nine putative population groups, of which three were supported by DFA. Areas of potential occurrence of these groups were coherent with the range of the three subspecies of V. ammodytes currently recognized. The distribution of all subspecies was mostly related to precipitation in the driest month. Areas of probable sympatry between subspecies are generally small and restricted. The main patterns of geographic variation of morphological characters for V. ammodytes were similar to the patterns obtained for Vipera latastei and Vipera monticola; the same environmental factors limit the distribution of differentiated groups of vipers in the Balkans and the Iberian Peninsula. The influence of humidity on the variation of morphological traits in spatially separated viper taxa from the two European peninsulas coincides with their phylogenetic relatedness. Geostatistics and GIS procedures were successful in the identification of environmental correlates sustaining contact zones among V. ammodytes subspecies in the Balkans. The same techniques should be applied for studying other parapatric forms and refugia regions. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 651–666.
Climate envelope models (CEMs) have been used to predict the distribution of species under current, past, and future climatic conditions by inferring a species' environmental requirements from localities where it is currently known to occur. CEMs can be evaluated for their ability to predict current species distributions but it is unclear whether models that are successful in predicting current distributions are equally successful in predicting distributions under different climates (i.e. different regions or time periods). We evaluated the ability of CEMs to predict species distributions under different climates by comparing their predictions with those obtained with a mechanistic model (MM). In an MM the distribution of a species is modeled based on knowledge of a species' physiology. The potential distributions of 100 plant species were modeled with an MM for current conditions, a past climate reconstruction (21 000 years before present) and a future climate projection (double preindustrial CO2 conditions). Point localities extracted from the currently suitable area according to the MM were used to predict current, future, and past distributions with four CEMs covering a broad range of statistical approaches: Bioclim (percentile distributions), Domain (distance metric), GAM (general additive modeling), and Maxent (maximum entropy). Domain performed very poorly, strongly underestimating range sizes for past or future conditions. Maxent and GAM performed as well under current climates as under past and future climates. Bioclim slightly underestimated range sizes but the predicted ranges overlapped more with the ranges predicted with the MM than those predicted with GAM did. Ranges predicted with Maxent overlapped most with those produced with the MMs, but compared with the ranges predicted with GAM they were more variable and sometimes much too large. Our results suggest that some CEMs can indeed be used to predict species distributions under climate change, but individual modeling approaches should be validated for this purpose, and model choice could be made dependent on the purpose of a particular study.
Aim Climatic factors are known to influence species distributions. However, elucidating the underlying mechanisms is challenging because direct and indirect effects of climatic and non‐climatic factors are correlated. In the absence of this covariation and at fine‐grain resolutions the direct effect of climate via physiological constraints should be stronger on the distributions of ectothermic organisms. So far, no comprehensive study has explicitly tested the influence of climate on species distributions by quantitatively comparing ectothermic and endothermic vertebrates.
Location Peninsular Spain.
Methods Presence–absence data of native terrestrial vertebrates in Peninsular Spain were modelled using generalized additive models to disentangle the influence of climate and other contemporary correlated factors (topography and plant cover). We performed partial regressions to partition the deviance explained by climatic and non‐climatic effects into independent and shared components. We compared the independent contributions of climatic and non‐climatic effects between ectothermic and endothermic vertebrates, and among mammals, birds, reptiles and amphibians.
Results After reducing the covariation with non‐climatic factors, climate explained a greater proportion of deviance in ectotherms than in endotherms. Also, the contribution of temperature was highest for reptiles, and the contribution of precipitation was highest for amphibians, after extracting their overlaps with precipitation and temperature, respectively. The contribution of topography and plant cover remained high for birds after extracting the overlap with climate.
Main conclusions Our results are consistent with the prediction that, at fine resolutions, the direct influence of climate (via physiological constraints) on range distributions is stronger in ectothermic vertebrates. Also, at least for birds, indirect effects of climate (via plant productivity) and other habitat characteristics remained relatively important once their covariation with climate was reduced. This study shows that controlling the direct effects of climate by their indirect effects and/or other correlated factors, combined with comparisons among functional groups, can be a useful approach to elucidate causal links with the spatial patterns of organisms.
Conservation planning is usually done within geopolitical units that tend to encompass only part of the geographic range of most species. Consequently, the relative rarity of a species within the study area considered does not necessarily reflect its relative global rarity or its conservation relevance. We investigated the implications of species' rarity in complementary reserve selection across geopolitical boundaries based on data on the distribution of birds in southern Africa. Our results demonstrate that restricted-range species have a disproportionate effect on the number and identity of the cells selected by complementarity. The most extreme situation occurs when species whose ranges occupy single cells impose the selection of those particular sites as irreplaceable cells. Not all restricted-range species are equally important. Some are “apparent rarities” in the study area because they are vagrants, occur very marginally to their range, or have been introduced, and these are mainly irrelevant to conservation planning in a region. Filtering rare nontarget species from the data before reserve selection results in a significant increase in the efficiency of minimum complementary sets. It is particularly recommended for taxa with high mobility, in which vagrancy is more likely. Dividing the study area into geopolitical units has a profound effect on the sites selected by complementarity. It results in loss of overall efficiency, in a tendency for selection of sites at the periphery of the units, and in some species receiving more protection at the edge of their ranges than at the center. Geopolitical coordination in conservation planning may not only result in improved overall efficiency but also a better allocation of resources that improves the long-term robustness of reserve networks.
The current range of European vipers is mostly parapatric but local-scale allopatric distribution is common and few cases of sympatry are known. In the High Course of Ebro River, northern Spain, there is a contact zone between Vipera aspis, V. latastei, and V. seoanei. Sympatry was detected between aspis and latastei and also specimens with intermediate morphological traits. Presence-data at a local scale (1 × 1 km) and ecological niche-based models manipulated in a GIS were used to (1) identify how environmental factors correlate with the distribution of the three vipers and with the location of the sympatry area, and (2) identify potential areas for viper occurrence and sympatry. Ensemble for casting with 10 Maximum Entropy models identified a mixture of topographical (altitude, slope), climatic (precipitation, evapotranspiration, and minimum and maximum temperature), and habitat factors (land cover) as predictors for viper occurrence. Similar predicted probabilities according to the variation of some environmental factors (indicating probable sympatry) were observed only for aspis-latastei and aspis-seoanei. In fact, areas of probable occurrence of vipers were generally allopatric but probable sympatry between vipers was identified for aspis-latastei in 76 UTM 1 × 1 km squares, for aspis-seoanei in 23 squares, and latastei-seoanei in two squares. Environmental factors correlate with the location of this contact zone by shaping the species range: some enhance spatial exclusion and constrain distribution to spatially non-overlapping ranges, while others allow contact between species. The distribution in the contact zone apparently results from the balance between the pressures exerted by the different environmental factors and in the sympatry area probably by interspecific competition. Further ecological and genetical data are needed to evaluate the dynamics of the probable hybrid zone. GIS and niche-modelling tools proved to be powerful tools to identify environmental factors sustaining the location of contact zones.
Species distribution models should provide conservation practioners with estimates of the spatial distributions of species requiring attention. These species are often rare and have limited known occurrences, posing challenges for creating accurate species distribution models. We tested four modeling methods (Bioclim, Domain, GARP, and Maxent) across 18 species with different levels of ecological specialization using six different sample size treatments and three different evaluation measures. Our assessment revealed that Maxent was the most capable of the four modeling methods in producing useful results with sample sizes as small as 5, 10 and 25 occurrences. The other methods compensated reasonably well (Domain and GARP) to poorly (Bioclim) when presented with datasets of small sample sizes. We show that multiple evaluation measures are necessary to determine accuracy of models produced with presence-only data. Further, we found that accuracy of models is greater for species with small geographic ranges and limited environmental tolerance, ecological characteristics of many rare species. Our results indicate that reasonable models can be made for some rare species, a result that should encourage conservationists to add distribution modeling to their toolbox.