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Forest cover change in the Los Tuxtlas Biosphere Reserve and its future: The contribution of the 1998 protected natural area decree
Abstract
The Los Tuxtlas mountain range harbors one of the last remnants of tropical rain forest on the coastal plain of the Gulf of Mexico. This volcanic range has a high degree of heterogeneity in its geology, climate and ecology, in addition to a very long history of human occupation. The original area covered by tropical forest has been drastically reduced by agricultural activities, and during the last four decades in particular, deforestation has been very intense. In order to protect the remaining forest, in 1998 the Mexican government created the Los Tuxtlas Biosphere Reserve (LTBR). While previous studies estimated deforestation rates and the amount of forest cover remaining in some areas of the LTBR, this is the first study to do so for the entire protected area. A retrospective analysis from 1986 to 2011 was conducted to assess the effect of the 1998 decree of the LTBR on deforestation rates, and to predict future changes in forest cover up to the year 2025 using Markov chains and cellular automata based on current deforestation patterns. The results show that shortly after the 1998 decree, deforestation rates in the LTBR not only decreased but reversed, however this trend did not continue. In recent years deforestation has again increased. Our projection shows that if current trends continue unchanged then by the year 2025 we might have lost close to 14% (ca. 9000 ha) of the forest cover that was present in 2011. The decree of the LTBR was part of the federal policy to protect biodiversity in Mexico and our results show that the strategy of establishing this protected area did work to protect tropical forest, at least temporarily in Los Tuxtlas. Also, our results show that it is not only possible to reverse forest loss within the ample buffer zone of the LTBR, it is also still relatively easy to achieve by promoting passive restoration.
... This study was carried out in the Los Tuxtlas Biosphere Reserve (RBLT), located in the coastal plain of the Gulf of Mexico, in the southeast of (18° 30′-18° 40′ N and 95° 03′-95° 10′ W), covering a total area of 155,122 ha (Von Thaden et al. 2018;Fig. 1). ...
... The region has a hot and humid climate; the average annual temperature is 24.5 °C, and the average annual rainfall is 3928 mm (Soto 2006;Hernández-Ruedas et al. 2018). The native vegetation is a tropical rainforest (Af, Am;Von Thaden et al. 2018). However, due to the expansion of agriculture and livestock, there was a process of forest loss and fragmentation until the 1998 federal decree of the Los Tuxtlas Biosphere Reserve (Mendoza et al. 2005;Hernández-Ruedas et al. 2018;Von Thaden et al. 2018). ...
... The native vegetation is a tropical rainforest (Af, Am;Von Thaden et al. 2018). However, due to the expansion of agriculture and livestock, there was a process of forest loss and fragmentation until the 1998 federal decree of the Los Tuxtlas Biosphere Reserve (Mendoza et al. 2005;Hernández-Ruedas et al. 2018;Von Thaden et al. 2018). Consequently, different isolated forest patches have been generated within a matrix dominated by grasslands (Mendoza et al. 2005;Hernández-Ruedas et al. 2018;Von Thaden et al. 2018). ...
Landscape changes in tropical environments result in long-lasting and complex changes in biodiversity that involve several biological responses (e.g., loss of species diversity and functional diversity). Both taxonomic and functional diversity might respond differently to land-use change, and this response might also vary depending on several factors, such as the taxonomic group or landscape context. Even though each level of diversity expresses different properties of the community structure, studies characterizing the species community in human-dominated landscapes have often only focused on patterns involving taxonomic diversity. Here, we evaluated different descriptors of taxonomic (i.e., richness, diversity, and dominance) and functional entropy (i.e., richness, diversity, and redundancy) and the taxonomic and functional composition of ants in a forest cover gradient (%) in 16 highly fragmented tropical humid forest landscapes in Mexico. We found that all descriptors of taxonomic diversity decreased along a gradient of forest loss. Furthermore, functional redundancy was the only component of functional diversity that was positively associated with forest cover (%). These findings suggest an ecological backup of functions provided by species in landscapes with higher forest cover, protecting these landscapes against habitat disturbance or species loss. We also observed that landscapes with larger forest cover were inhabited by ant species with larger interocular distances and smaller femurs, which could allow predator ants the exploitation of ground cracks and higher mobility in leaf-litter microhabitats. Our results highlight the importance of the primary forest as a reservoir of the taxonomic and functional diversity of ants in highly fragmented tropical rainforest landscapes.
... We conducted this study in the Los Tuxtlas Biosphere Reserve, located in the coastal plain of the Gulf of Mexico, in the southeast of the State of Veracruz (18°30′ to 18°40′N and 95°03′ to 95°10′W), covering a total area of 155,122 ha (Von Thaden et al. 2018). According to the Köppen climatic classification, the climate is humid and warm throughout the year (Af), with average annual precipitation of more than 4000 mm and average annual temperature of 27 °C (Soto 2006). ...
... According to the Köppen climatic classification, the climate is humid and warm throughout the year (Af), with average annual precipitation of more than 4000 mm and average annual temperature of 27 °C (Soto 2006). The dominant vegetation is tropical rainforest (Von Thaden et al. 2018). In the last decades, the original vegetation has been converted into agricultural fields and pastures, leaving native vegetation remnants in different conservation states immersed in an anthropogenic matrix (Vega-Vela et al. 2018;Von Thaden et al. 2018) (Fig. 1). ...
... The dominant vegetation is tropical rainforest (Von Thaden et al. 2018). In the last decades, the original vegetation has been converted into agricultural fields and pastures, leaving native vegetation remnants in different conservation states immersed in an anthropogenic matrix (Vega-Vela et al. 2018;Von Thaden et al. 2018) (Fig. 1). ...
Recent
studies have shown that several sources of variation can influence our ability to quantify biological responses to environmental variables, and that spatial scales are important in this process. For instance, sampling methods may differ in their efficiency or specificity, leading to different inferred relationships between community responses and landscape composition—i.e., forest cover (%), landscape heterogeneity, edge effects, and functional connectivity. Consequently, this can also influence the predictive power of the models when evaluating organisms as bioindicators of habitat loss and land use modification. Here, we evaluated how sampling methods (i.e., Winkler, pitfall, beating, and baits) influence our capacity to assess the scale of effect of two landscape composition metrics on ant diversity. We conducted ant sampling in 16 landscapes within a Mexican tropical rainforest and assessed the relationship between species richness and landscape composition metrics through buffers with 12 different spatial extents (from 50 to 1000 m). We found that the sampling method influenced the scale of effect when evaluating the relationships between ant species richness and forest cover and landscape heterogeneity. Combining all sampling methods, we found that the scales that best explained ant species richness were 700 m for forest cover and 900 m for landscape heterogeneity. Therefore, we highlight that our ability to detect ant-based diversity responses to environmental variables depends on the sampling method and spatial extent used in the study.
... The outermost transition zone connecting with the buffer zone is a region where people live, and a diversity of human activities such as infrastructure construction and agriculture are carried out (UNESCO 1996;Ishwaran et al. 2008;Price et al. 2010). Although BRs are widely regarded as "living laboratories" (Van Cuong et al. 2017, p. 13) and reservoirs of important biodiversity, they are vulnerable to human-induced environmental degradation (Taïta 2003;Li et al. 2005;Ortega-Huerta 2007;Kala 2015;Béliveau et al. 2017;Von Thaden et al. 2018). This is likely worsened given that the spatial zonation is delineated based on imaginary boundaries (except for the core zone) which cut across diverse preexisting land uses in the BR. ...
... This is likely worsened given that the spatial zonation is delineated based on imaginary boundaries (except for the core zone) which cut across diverse preexisting land uses in the BR. If uncontrolled, such environmental changes can jeopardize the long-term sustainability of BRs (Olah and Boltiziar 2009;Navarrete et al. 2011;Biswal et al. 2013;Saranya and Reddy 2016;Von Thaden et al. 2018). Globally, various studies have been conducted to investigate land cover characteristics in BRs, for example, in Asia (Li et al. 2005;Chowdhury 2006;Navarrete et al. 2011;Biswal et al. 2013;Satish et al. 2014;Dutta et al. 2016;Parsa et al. 2016;Sahana et al. 2016;Saranya and Reddy 2016;Sharma et al. 2016), North America (Ortega-Huerta 2007;Sánchez-Azofeifa et al. 2009;Navarrete et al. 2011;Manzo-Delgado et al. 2014;Béliveau et al. 2017;Von Thaden et al. 2018;Flores-Casas and Ortega-Huerta 2019), and Africa (Clerici et al. 2007;Coetzer et al. 2010;DeVries et al. 2012;Houessou et al. 2013;Evans 2017;Konko et al. 2018). ...
... If uncontrolled, such environmental changes can jeopardize the long-term sustainability of BRs (Olah and Boltiziar 2009;Navarrete et al. 2011;Biswal et al. 2013;Saranya and Reddy 2016;Von Thaden et al. 2018). Globally, various studies have been conducted to investigate land cover characteristics in BRs, for example, in Asia (Li et al. 2005;Chowdhury 2006;Navarrete et al. 2011;Biswal et al. 2013;Satish et al. 2014;Dutta et al. 2016;Parsa et al. 2016;Sahana et al. 2016;Saranya and Reddy 2016;Sharma et al. 2016), North America (Ortega-Huerta 2007;Sánchez-Azofeifa et al. 2009;Navarrete et al. 2011;Manzo-Delgado et al. 2014;Béliveau et al. 2017;Von Thaden et al. 2018;Flores-Casas and Ortega-Huerta 2019), and Africa (Clerici et al. 2007;Coetzer et al. 2010;DeVries et al. 2012;Houessou et al. 2013;Evans 2017;Konko et al. 2018). The findings stemming from these researches suggest that each BR possesses unique land cover change patterns. ...
Biosphere reserves (BRs) seek to reconcile a sustainable relationship between human welfare and environmental integrity by adopting a landscape model that distinguishes between three interdependent management zones (core, buffer, transition). Considering the increasing human influence on landscapes in BRs, the tracking land use–land cover (LULC) dynamics is crucial for the development and planning of efficient management strategies for specific management zone. This study aimed at (i) assessing biodiversity protection around the core zones to highlight the threats facing the core zones and (ii) tracking the effect of the proclamation of the Vhembe Biosphere Reserve (VBR) on the LULC dynamics in the management zones through spatio-temporal analysis using Landsat imagery acquired from1999 to 2018. Six LULC categories (water body, forest/bush, shrubs/grass, agricultural land, bare soil, and built-up/mines) were identified and mapped using the support vector machine (SVM) classification to address both objectives. Assessment of threats around the core zones using artificial buffers (0–5, 10–15, and 15–20 km radius) created around them showed agricultural activities in the most immediate buffers (0–5 km radius). The LULC dynamics showed vegetation increase in all the management zones evidenced by the reduction of bare soil as well shrub/grass lands, and by the corresponding increase in foliage-richer forest/bush lands since the proclamation of the reserve in 2009. The findings might signify a positive outcome of vegetation increase as a consequence of the proclamation of the VBR. However, firmer conservation measures must be adopted and priority must be given to the arrangement of the management zones to strengthen biodiversity protection in the core zone.
... In southeast Mexico, the Los Tuxtlas region represents the northernmost limit of tropical rainforests in the Americas, which has historically suffered high rates of deforestation, with a reduction by 84% between 1967and 1987(Dirzo and Garcia 1992. Although declared a Biosphere Reserve in 1998, Los Tuxtlas is still ongoing change in land use and deforestation, where most remaining old-growth forests are isolated fragments lying within a pasture matrix (Von Thaden et al. 2018). The deforestation and conversion of the natural vegetation to pasture areas eliminates most terrestrial, climbing, and epiphytic aroid species, many of which are shade-dependent (Mayo et al. 1997), and even secondary forests present a poor colonization by aroids (Barrancos et al. 2019). ...
... According to the Köppen climatic classification, the climate of the region is humid and warm throughout the year (Af), with an average annual rainfall of 4700 mm, with a relatively dry season from March to May and average annual temperature of 27 °C (Gutiérrez-García and Ricker 2011). The dominant vegetation is tropical rainforest (Von Thaden et al. 2018), characterized by a canopy of more than 30 m in height, highlighting species such as Ficus spp., Poulsenia armata, Nectandra ambigens, Brosimum alicastrum, among others, whereas the understory is dominated by palm trees (e.g., Astrocaryum mexicanum and Chamaedorea spp.) (Ibarra-Manríquez et al. 1997). Another important component of the physiognomy of this tropical rainforest is the Araceae species, which are present in the understory and epiphytic vegetation. ...
In nature, leaf rolls form during the expansion of young leaves of some plant species but their importance as shelter structures for arthropods is unknown. We examined the role of expanding rolled leaves of aroid species as shelter sites for arthropods and evaluated the effect of leaf size and environmental context (natural forest vs pastures) on the occupation of these leaves. In a Mexican tropical rainforest, arthropods were sampled from 25 fully expanded and 25 expanding rolled leaves of each of three aroid species (Rhodospatha wendlandii, Dieffenbachia oerstedii, and Spathiphyllum ortgiesii), that differ in the size of their leaves. In addition, for D. oerstedii we also collected leaves from a pasture area. We recorded 120 arthropods (44 in expanded and 76 in rolled leaves) from 53 unique morphospecies (21 and 38). Average arthropod abundance was greater in rolled leaves compared with expanded leaves. Average arthropod species richness and abundance, and colonization frequency were lower in the aroid species with smaller leaves (R. wendlandii). Although we found no significant effects of habitat type on arthropods in rolled leaves of D. oerstedii, 3.4 times more individuals (34) and 2.11 times more morphospecies (19) were found in the rolled leaves in the forest compared with those in pasture (10 and 9). This study demonstrates that expanding rolled leaves of aroids, despite being an ephemeral resource, represent suitable leaf shelters used by a diverse arthropod fauna, and that leaf size and environmental context are important factors that affect the colonization of these leaves by arthropods.
... Despite the encouraging news about their rediscovery and more records, the known geographical distribution of C. nelsoni is still less than 100 km² and restricted to small patches of cloud forest on the San Martín Tuxtla volcano. Unfortunately, there has been a continuous deterioration of habitats around the known localities of this shrew due to land-use changes, mainly involving logging, cattle grazing, and crops (Von Thaden et al. 2018). Therefore, it is listed as "critically endangered" by the International Union for the Conservation of Nature and Natural resources and "under special protection" by the Mexican government (Matson et al. 2018;Trujillo Segura 2019). ...
... Tuxtlas is a region of high species richness and endemism, containing flora and fauna that have experienced climatic oscillations across historical times, volcanic activity, and extreme weather events as a consequence of its proximity to the sea (Guevara and Laborde 2012). In the last century, land-use change has been the top threat in this region, destroying and fragmenting the vast majority of its original vegetation cover (Von Thaden et al. 2018). However, by the year 2050, the most pressing threat will be anthropogenic climate change (Esperon-rodriguez et al. 2019). ...
The Nelson’s small-eared shrew (Cryptotis nelsoni) is a mammal at high risk of extinction and endemic to the cloud forest in the mountains of Los Tuxtlas, an isolated volcanic field in eastern México. It is a little-known species that remained unrecorded for over a century. However, recent works have increased the number of museum specimens and tissue samples of C. nelsoni, which we studied here to improve our knowledge of their taxonomy and conservation status. We compared the morphology and DNA barcode sequences of C. nelsoni against its three most closely related species. We also evaluated the possible effect of anthropogenic climate change on this mountain species according to three general circulation models and two scenarios proposed for the year 2050. The results showed that the skull and postcranial variables could easily discriminate C. nelsoni from the other species in terms of body size, to which some distinctive qualitative characteristics related to the width of the snout and the curvature of the humerus also contribute. DNA barcoding also helped identify the shrew species accurately, with a genetic distance of more than 6% from its closest species. The morphological and genetic characteristics highlight the evolutionary distinctiveness of C. nelsoni. Unfortunately, warmer extremes and higher rainfall than today could pose a severe threat to the survival of this shrew for decades to come, even in the most optimistic scenarios.
... El establecimiento de un ANP, si bien puede entenderse como un logro de la conservación, no garantiza per se la protección. Como se ha demostrado en México por medio de estudios globales (ASF, 2006;Figueroa y Sánchez-Cordero, 2008;Figueroa et al., 2017) y particulares (Domínguez, 2013;Farfán et al., 2015;García-Frapolli et al., 2009;Von Thaden et al., 2018) aún persisten cambios de uso de suelo en las ANP, con la pérdida de miles de hectáreas de vegetación original, a causa de la expansión de la ganadería y de otras actividades agropecuarias. La Comisión Nacional de Áreas Naturales Protegidas (CONANP) en su Sistema de Información, Monitoreo y Evaluación para la Conservación, manifiesta la persistencia de otros problemas relacionados con la extracción de flora y fauna (tráfico de especies, sobrepesca y pesca furtiva, cacería ilegal, tala clandestina y explotación no planificada de los recursos forestales), la contaminación con residuos sólidos y aguas residuales, y los incendios forestales, frecuentemente provocados. ...
... Un estudio de la ONG Proyecto Sierra de Santa Marta A.C. (PSSM, 2011), financiado por la CONANP, reveló que solo entre 2007 y 2011 se perdieron 928 ha forestales, tasa mucho menor a la registrada previo a la declaración de la reserva, pero aun preocupante. De mantenerse así, llevaría a una pérdida del 14% de la cobertura forestal en el año 2025 (Von Thaden et al., 2018). En las entrevistas realizadas a 80 personas que viven y/o trabajan en la reserva (incluyendo representantes de instituciones del gobierno, ONG, empresas y autoridades locales), se evidenció que seguía habiendo importantes problemas de contaminación de los cuerpos de agua, y de tala y cacería ilegales. ...
A nivel global, México es de los países con mayor biodiversidad, pero también de los que soporta una destacada explotación de sus recursos naturales. La declaración de áreas naturales protegidas se ha convertido en una de las principales estrategias mexicanas para conservar la naturaleza. El artículo analiza los desafíos de esta herramienta de gestión territorial partiendo de la capacidad de gestión. Para alcanzar este fin, se realiza la oportuna revisión bibliográfica y el análisis de cuestionarios semiestructurados aplicados a actores clave de dos casos de estudio: las reservas de la biosfera Los Tuxtlas y Los Petenes. Los resultados demuestran que, si bien los espacios protegidas han contribuido a disminuir la destrucción del patrimonio natural, éste aún sigue sufriendo graves afectaciones a causa de los insuficientes recursos destinados a las políticas ambientales, lo que debilita la capacidad de gestión y, consiguientemente, dificulta alcanzar los objetivos de conservación.
... Therefore, conservation efforts should also include the strengthening of the quality of secondary forests in order to reduce the habitat-matrix contrast (Levey et al., 2021) and to promote landscape supplementation/ complementation dynamics (Dunning et al., 1992) for toucan and parrot populations. Fortunately, deforestation rates in Los Tuxtlas have decreased since the decree of the Los Tuxtlas Biosphere Reserve in 1998, with deforestation in the nucleus zones of the reserve halved since 1998-2011(Von Thaden et al., 2018 and reforestation efforts have taken place in the area (Von Thaden et al., 2020). Nevertheless, a substantial loss of forest cover is predicted by 2025, particularly in the buffer areas of the reserve (Von Thaden et al., 2018). ...
... Fortunately, deforestation rates in Los Tuxtlas have decreased since the decree of the Los Tuxtlas Biosphere Reserve in 1998, with deforestation in the nucleus zones of the reserve halved since 1998-2011(Von Thaden et al., 2018 and reforestation efforts have taken place in the area (Von Thaden et al., 2020). Nevertheless, a substantial loss of forest cover is predicted by 2025, particularly in the buffer areas of the reserve (Von Thaden et al., 2018). Additionally, a more recent and longterm monitoring of toucans and parrots in Los Tuxtlas is necessary to determine the actual status of populations of these birds. ...
Background and Research Aims: Habitat amount plays an important role in determining the presence and abundance of bird species in modified landscapes, whereas habitat fragmentation has shown little effects. Toucans (Ramphastidae) and parrots (Psittacidae) are large-bodied primary consumers and among the most representative birds in Neotropical forests. They are highly sensitive to habitat loss; nevertheless, their response to fragmentation has been poorly assessed leading to contradictory results. Here, we evaluate the influence of landscape structure on toucans and parrots in the tropical forest of Los Tuxtlas, Mexico. Methods: We censused birds in 12 landscapes of Los Tuxtlas and used a multi-scale landscape approach to assess the influence of landscape composition and configuration on the number of individuals of toucans and parrots. Results: We found that the most important and positive predictor of toucans and parrots was the amount of primary forest cover in the landscape. Forest fragmentation had positive effects on the number of toucan individuals, whereas parrots had negative responses to patch density but positive responses to edge density in the landscape. Conclusion: Our results suggest that primary forest loss is the main threat for toucans and parrots in Los Tuxtlas. Implications for conservation: Future conservation and land management must consider the protection of large and small remnants of primary forest and avoid additional forest loss in order to preserve toucan and parrots and their functional roles in human-modified Neotropical landscapes.
... The purpose was to conserve and study two contrasting tropical ecosystems present in the country: tropical rain or humid forests and tropical dry forests. In 1967 Los Tuxtlas Tropical Biology Station (EBTLT for its acronym in Spanish) was created in the south of Veracruz state on the Gulf of Mexico coast (Von Thaden et al., 2018) (Fig. 1). Previously in 1965, researchers from the Botanical Garden of UNAM made a request to the government for 800 hectares in a sparsely populated area. ...
... Unfortunately, in 1987 a tenure conflict with a rural settlement left the station with the 640 hectares that it covers today (Durand and Ruiz, 2009). Since the 70"s the region has been protected by different management laws (Laborde, 2006), and in 1998 the government established Los Tuxtlas Biosphere Reserve with 155,122 ha under its control (Diario Oficial de la Federación, 1998;Von Thaden et al., 2018). The EBTLT is within the boundary of the protected area. . ...
Tropical ecosystems have been transformed at alarming rates provoking their transformation mainly into agricultural and pasturelands for cattle. This has drastically modified landscapes, the provision of ecosystem services, and thus human livelihoods. As a response to the need to preserve and study tropical forests, the National Autonomous University of Mexico created two research field stations around 50 years ago. Los Tuxtlas Tropical Biology Station located in a tropical rain forest on the southern coast of the Gulf of Mexico, and the Chamela Biological Station established in a tropical dry forest on the central Pacific coast. A significant amount of research has been conducted in both areas although one question that arises pertains to the impact these stations have had on the areas in which they are located. The aim of this paper is to analyze the scientific production of the research field stations and their relation to local information needs and interests, as well as to document local people's perspectives regarding their presence in their regions. Research methods included interviews and surveys with local communities, as well as analysis of the stations' databases. Although our results are preliminary, they show that from the identification of information needs and interests of local communities at each site (52 and 28 respectively), around 40% were not covered by existing knowledge. Furthermore, those fully or partially covered would need to be transformed into products accessible to rural communities. In both sites, local people expressed an interest in the work of the stations and particularly, they acknowledge possible benefits for their regions. If the goal is to reverse the degradation of ecosystems and mitigate environmental problems, field stations can no longer work in isolation but become agents of social transformation. It is necessary to revise how biological, ecological, and socio-ecological knowledge can be shared with people so that it is meaningful and useful for them. A linkage process between scientific institutions and local people should be strengthened in order for scientific knowledge to have a local impact on the long-term maintenance of tropical socioecological systems.
... Sin embargo, a pesar de todas estas iniciativas, no se ha logrado detener por completo la deforestación en la zona, que entre 1967 y 1986 alcanzó tasas de superiores a 4% anual en los alrededores del volcán San Martín Tuxtla (Dirzo y García, 1992). Posteriormente al decreto de 1998, la tasa de deforestación en toda la RBLT no solo disminuyó, sino se revirtió, siendo mayor la superficie reforestada que la deforestada entre 1998 y 2003 con una tasa negativa de -1.8% anual; sin embargo, a partir del 2003 vuelve a incrementar la deforestación con tasas de 1.0% anual (Von Thaden et al., 2018). Por lo tanto, no sólo es prioritario el monitoreo de la deforestación y la estimación de los cambios en los usos del suelo, sino también el resaltar la importancia de estimar la superficie y distribución actual de la vegetación natural a la resolución más fina o detallada posible. ...
... La disminución en la tasa de deforestación encontrada en este estudio puede no estar vinculada a un cambio en un componente socioeconómico (Von Thaden et al., 2018), sino al hecho de que cada vez existe menos cobertura forestal que sea de fácil acceso o apta para las actividades agropecuarias; así como a que la superficie forestal que queda en pie se encuentra al interior de áreas restringidas o protegidas en la actualidad (por ejemplo, zonas núcleo u otro tipo de áreas de conservación). Tabla 4 Matriz de confusión entre clases para la imagen del 2016 (ver notación de los tipos de cobertura en la tabla 3). ...
La Reserva de la Biosfera Los Tuxtlas (RBLT) alberga los últimos remanentes de bosque tropical perennifolio (BTP) y bosque mesófilo de montaña (BMM) en la llanura costera del golfo de México. Sin embargo, en las últimas décadas ha perdido ~ 60% de su cobertura forestal. La información precisa y detallada sobre la dinámica del cambio de uso del suelo es fundamental para implementar planes de manejo/conservación pertinentes a la situación actual y futura de una región. El objetivo del trabajo fue determinar la dinámica reciente de los cambios espacio-temporales del uso del suelo y la cobertura vegetal, con un alto grado de precisión en la RBLT. Se evaluaron 3 imágenes satelitales (2006, 2011 y 2016) mediante fotointerpretación manual a escala fija de 1:5,000. Entre 2006 y 2016, la tasa de deforestación fue de 0.8% anual, siendo la vegetación arbórea de franjas ribereñas la categoría más deforestada (~ 1,300 ha). Se registró una transición de ~ 550 ha de pastizales a cultivos, sugiriendo un cambio de actividad económica en zonas de la reserva. Dada la importancia ecológica de las franjas ribereñas como elemento conector del paisaje, es urgente protegerlas particularmente en la zona de amortiguamiento. Las zonas núcleo han protegido el BTP y el BMM eficientemente.
... Empirical evidence indicates that PNAs represent restraints on forest conversion in Mexico (Deininger and Minten 2002;Figueroa and Sánchez-Cordero 2008;Sims and Alix-Garcia 2017;Miteva et al. 2019;Gallardo-Cruz et al. 2021;Figueroa et al. 2021). The establishment of new PNAs can potentially halt deforestation already in progress (Von Thaden et al. 2018). In short, new PNAs make deforestation more difficult by obstructing the free exploitation of frontier land, which effectively raises the cost of forest conversion, c. ...
In developing countries, especially in Latin America, two separate approaches to providing land to farmers have been widely implemented: (1) opening state-owned frontier areas to settlement, which potentially increases deforestation, and (2) redistributing existing farmland. This paper argues that, in some contexts, land redistribution might act as a substitute for agricultural frontier expansion. A theoretical model is developed, which demonstrates that factors discouraging frontier settlement make the redistribution of already cultivated farmland more likely. An empirical analysis of Mexico suggests that the creation of institutional impediments to deforestation on the frontier increases the probability of land redistribution.
... Dirzo and García (1992) reported high deforestation rates in the Los Tuxtlas region since 1967 with an important reduction of the forest area, mainly due to the agricultural use. In 1998, the area was designated as a biosphere reserve (Von Thaden et al., 2018) and hence there was a reduction in the tendency for deforestation from 1998 to . Unfortunately, Von Thaden et al. (2018 documented an increase in forest loss from 2007 to 2011. ...
Iron oxides can be produced in soils due to chemical weathering/pedogenesis and are related to climatic conditions and also anthropogenic alterations. In this research, four soil profiles (TAC1, TAC2, TAC3 and LV1) were analyzed in areas with different climatic conditions in two lake basins of volcanic environments: the Alberca de Tacámbaro (TAC) in the state of Michoacán, with a warm-subhumid climate and Lago Verde (LV) in the state of Veracruz with a warm-humid climate. The objective of this study was to generate preliminary information on the transformation of the landscape in the two lake basins, taking into account the site-specific pedogenic processes on a centennial-millennial time scale and the possible impact of recent anthropogenic activities on the soils of these lakes’ basins. Differences in the degree of pedogenesis in soils were analyzed from magnetic mineralogy studies that were complemented and compared with studies of micromorphology, bulk rock mineralogy, clay identification, color, and texture of soil horizons. 14C dating was also obtained in organic matter from several of the horizons to, together with the micromorphological features, interpret the possible landscape changes in these basins due to anthropic impact. It was identified that in the TAC and LV soils, the pedogenetic processes were not sufficient to erase the magnetic signal of the volcanic minerals. The magnetic mineralogy in the profile is dominated by low coercivity ferrimagnetic minerals; magnetite and titanomagnetite in the case of the TAC profiles and also maghemite in the case of the LV1 profile. The characteristics of the LV1 profile, such as the presence of a Bt-type horizon, clay illuviation, and the presence of Fe oxides, suggest a more advanced pedogenic development than in the TAC profiles. In both the TAC and LV profiles, the reworking of the edaphic material and several cycles of soil formation related to the possible anthropic impact were observed. In profiles TAC1 and TAC2, the above was evidenced by the presence of charcoal fragments and the ages of the BC horizons of 1955 cal AD, while in profile TAC3, three cycles of sedimentation and soil formation were observed. In profile LV1, at a depth of 90 cm, an age of 2007 cal AD was obtained for the 2Cb1 horizon, and the reworking of the edaphic material was observable by the presence of clay soil fragments and fresh minerals in the modern soil (Ah -AB-Bt). All the data obtained will help to establish soil-sediment relationships for paleoclimatic studies on lake sediments from the central region of Mexico.
... Despite the protected status of the LTBR (155 km 2 ), both primate species remain threatened. The LTBR was historically subject to different land uses, which resulted in the loss of approximately 60% of its forest cover, leaving populations of both species reduced and with howlers often in isolated forest patches (Estrada and Coates-Estrada, 1996;Laborde, 2004;Vega-Vela et al., 2018;Von Thaden et al., 2018). The case of spider monkeys is more concerning, as the once common species is now locally extinct in northern LTBR due to habitat loss and hunting (Cristóbal-Azkarate and Dunn, 2013). ...
Audiovisual media has become an integral part of conservation education strategies, with the potential not only to communicate information but also to impact on its viewers perceptions and attitudes towards a particular subject. Despite this potential, few studies have evaluated either the use of film for primate conservation initiatives or the wider impact of participatory film production. Our study evaluates the impact of a participatory documentary film about historic human-primate coexistence in the Los Tuxtlas region, Veracruz, Mexico, to improve people's knowledge, perception, and attitudes towards the local primate species, Alouatta palliata and Ateles geoffroyi. Our study took place in six rural localities, in four of which a participatory film-making process was undertaken, involving production workshops and public screenings; two localities were intentionally left out as control groups. People's knowledge, perception, and attitudes towards primates were assessed through randomized sampling using a questionnaire prior (n = 419) and following (n = 223) the presentation of the documentary. Results indicate a minimal but positive shift in participant's attitudes and perceptions, with statistically significant increases in primate knowledge scores. While the participatory approach offers promise, further exploration and refinement are essential for effective conservation education. The study highlights the need for diverse and locally based perspectives in developing conservation education materials and programs to foster meaningful engagement and drive primate conservation efforts forward.
... The climate in this area is warm and humid with mean temperatures ranging from 24 to 26°C and total precipitation ranging from 2000 to 4000 mm (Soto, 2004). The vegetation in this region includes evergreen tropical forest with a high level of fragmentation surrounded by an agricultural and cattle ranching landscape (Von Thaden et al., 2018). The ranch itself has cattle pastures, bordered by remnants of forests ( Figure S1). ...
Consideration of plant phylogenetic diversity in ecological restoration carries substantial potential, as communities with a greater diversity of lineages with older evolutionary histories can increase the diversity of niches and thus are likely to recover larger species networks than communities clustered in specific clades with reduced variation in functional traits. In this study, we experimentally assessed how arthropod communities were affected by the phylogenetic diversity of a set of tropical tree species. We established 12 experimental restoration plots with either high or low plant phylogenetic diversity while maintaining constant the number of plant species. After 1 and 3 years, arthropods with different feeding habits (herbivores, predators, pollinators, and detritivores) were collected and identified as morphospecies or operational taxonomic units using metabarcoding techniques. We provide insights on the influence of plant phylogenetic diversity on arthropod abundance and species diversity, particularly among predator, pollinator, and detritivore common and dominant species, which increased with plant phylogenetic diversity. The trend, however, was the opposite for the diversity of herbivore common and dominant species, which decreased as plant phylogenetic diversity increased. These findings highlight the importance of considering plant species richness when designing restoration strategies, but also their evolutionary histories, as the same number of plant species can produce different outcomes for higher trophic levels, as a function of their phylogenetic relationships.
Abstract in Spanish is available with online material.
... Among the related techniques , an important role is played by the Markov model (Brown et al. 2004;. The universality of the model is confirmed by its applicability to various landscapes, ranging from urban areas , to natural protected areas (Jose Von Thaden et al. 2018) or deserts . The strength of the model also relies in its ability to be integrated with other approaches, such as cellular automata (Mansour et al. 2020) or machine learning methodologies (Gomez-Chova et al. 2015). ...
The aim of the paper is to introduce appropriate tools for quantifying the changes occurred at edge level when analyzing land cover changes. The research is conducted in two directions. Firstly, the binary change index at edge level is introduced and its relationship to the already existing binary change edge (computed at pixel level) is studied. It is proved that a certain inequality between the values of the two indices holds. The theoretical part is completed with real-world examples. The second direction investigated in the paper is the possibility of applying Markov type models, a basic tool in land cover change analysis, in quantifying the changes occurred at edge level. This combined approach is illustrated by a case study and it is shown that it provides complementary information related to the spatial extension of the land cover types and to their distribution. Thus, this type of analysis can improve the methodology of measuring the extent and the implications of land cover changes.
... The results indicate that extensive timber harvesting, agribusiness, and formal recognition of indigenous territories are important factors in reducing and accelerating primary habitat conversion throughout the Amazon. José Von Thaden et al. (2018), studied forest cover change in Los Taxlas Biosphere Reserve and its future prediction. The results illustrated that deforestation has increased in recent years and it is predicted that if the current trend continues unchanged, nearly 14% of the forest cover may be destroyed by 2025. ...
... Conversely, the other species could be more vulnerable to environmental changes, particularly the narrowly distributed D. colorata, but further studies are necessary to assess this. Tropical rainforests have been facing accelerated deforestation for decades (Martínez-Ramos 2006, von Thaden et al. 2018, von Thaden et al. 2020. Habitat loss is one of the main extinction threats for D. ambigens, D. gentlei, and D. salicifolia; thus, it is a serious concern that the current population sizes and trends of these species are still unknown (de Kok 2020a, b, c). ...
... Therefore, it is necessary to evaluate the downscaling results. Meanwhile, with the continuous development of remote sensing technology, the research on land use change has gradually changed from land evaluation research to land use model and prediction research, involving studies on land use patterns, ecological environments, dynamic mechanisms, and many other aspects [19][20][21]. The study of simulation and prediction of land use is mainly obtained by establishing mathematical models [22,23]. ...
The matching degree between agricultural water and land resources directly determines the sustainable development of regional agriculture. Based on climate data corrected by delta statistical downscaling from five global climate models (GCMs) in the Coupled Model Intercomparison Project Phase 6 (CMIP6) and a multi-model ensemble, this study simulated the runoff used by the Variable Infiltration Capacity (VIC-3L) model under four emission scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) and analyzed the land use changing trend to obtain the matching degree between agricultural water and land resources. The results demonstrate that annual climate factors exhibit an increasing trend, and the average annual runoff was 2128.08–2247.73 × 108 m3, during 2015–2100 under the four scenarios. The area of farmland changed with an increased area of 4201 km2 from 1980 to 2020. The agricultural water and land resources would be well matched under the SSP1-2.6 and SSP2-4.5 scenarios in 2021–2100. However, the risks of mismatch would occur in the 2030–2040 and 2050–2060 periods under the SSP3-7.0 scenario, and the 2030–2040 and 2080–2090 periods under the SSP5-8.5 scenario. This study can provide insight into the scientific decision support for government departments to address the challenges of mismatching risks of agricultural water and land resources.
... This is the natural protected area that hosts the largest number of Lauraceae species in Mexico (Lorea-Hernández, 2002). Unfortunately, more than 80% of the original rainforest cover has been removed by deforestation in this region, causing a dramatic landscape fragmentation (Dirzo et al., 2007), and this trend is expected to persist in the next years (Von Thaden et al., 2018). The situation is particularly worrying because most of the Mexican Lauraceae species are likely to be under some degree of extinction threat due to habitat loss, and the difficulty of most of them to establish under disturbance conditions or secondary vegetation (Lorea-Hernández, 2002). ...
Besides recruitment and dispersal, fruits are key resources for the maintenance of insect communities. This study is focused on the insects inhabiting the fruits of 4 wild Lauraceae species. Although the trees of this family are important elements of tropical forests, their interaction with insects, especially in association with fruits, remains poorly studied in wild tree species. Our study aims to characterize the diversity of insects associated with fruits of Damburneya ambigens, Damburneya gentlei, Damburneya salicifolia, and Nectandra turbacensis, in the rainforest of Los Tuxtlas, Veracruz. We present an illustrated taxonomic list of species, annotated with a comprehensive review of the insects’ natural history and their interactions with Lauraceae species. We reared 54 insect species from approximately 6,500 fruits, some of which represent potential new species and records for Mexico. Insect species diversity was high and differed between Lauraceae species. The reared insects comprise a wide variety of distributional ranges, feeding types, and habitats. This research provides novel information about the interactions among insects and fruits of Lauraceae and the complexity of their trophic networks in tropical rainforests. Furthermore, it evidences the importance of wild fruits as resources for insect communities.
... When the area was declared a biosphere reserve by the Mexican government in November of 1998, prospects of a better future for biodiversity, including nonhuman primates, grew. In the following years, numerous conservation initiatives were boosted by federal and international funding, further suggesting that this natural preserve could become a model for socioecological sustainability (Von Thaden et al., 2018). Twenty-four years after the 1998 milestone, it is with dismay that we see mantled howler monkey habitat within the biosphere reserve being disturbed by mining operations endorsed by the Mexican government. ...
Most primate taxa are threatened by extinction and their populations are decreasing. The persistence of primates is thus conditional on conservation actions aimed at protecting them and their habitat. Here, we focus on the conservation of mantled howler monkeys (Alouatta palliata) in the Los Tuxtlas Biosphere Reserve, Mexico. Following the creation of the reserve in 1998, habitat availability and howler monkey abundance increased, suggesting that progress was being made in terms of the conservation of this species. Recent events, however, suggest otherwise, as mantled howler monkey habitat within the biosphere reserve is being disturbed by mining operations endorsed by the Mexican government. We report this case to raise awareness about the challenges for primate and habitat conservation in protected areas.
... The region's climate is humid and warm throughout the year with annual means of temperature and rainfall of approximately 26 • C and 4000 mm, respectively. The original vegetation is tropical rainforest (Villaseñor et al., 2018), but due to the expansion of agriculture and livestock in the last 50 years, the forest has been converted to other land cover types, thus creating isolated primary forest patches immersed within a highly heterogenous anthropogenic matrix (Von Thaden et al., 2018). ...
In the last decade, the number of studies dealing with how species interaction networks are structured by landscape has increased in the literature. However, many studies quantify landscape metrics at one single spatial extent, without considering the effect at multiple spatial extents. To the best of our knowledge, no study has explicitly addressed and discussed the spatial extent at which landscape structure best predicts the organization of ecological networks, which is key to understanding how ecological interactions are affected by landscape modifications. Therefore, two important research questions arise: can the spatial scale at which landscape structure best predicts an ecological response (i.e., scale of effect) magnify our ability to understand ecological networks or can the suboptimal scale just blind our view about what really happens? Motivated by these concerns, we used ant-plant relationships obtained from 16 landscapes in a human-dominated tropical rainforest of Mexico to assess and discuss the spatial extent at which forest cover (%) that best predicts ant-plant interaction network patterns (i.e., network size, interaction diversity, network specialization, and nestedness). In general, we observed that smaller scales best predicted the interaction diversity (50 m) and specialization (250 m) of ecological networks involving ants and plants, which are descriptors associated to abundance and the distribution of interactions between plant and ant species. This is possibly because ant-plant relationships are being modulated by processes that act at the microclimatic level due to the biotic and abiotic conditions that forest provides. However, we found that network size and nestedness (i.e., descriptors associated to species detectability and emergent properties) were not associated with forest cover at any analyzed spatial extent. These findings indicate that the ant-plant ecological network structure can be influenced by processes that occur at different spatial extents. Moreover, the results presented here have a direct impact on our theoretical and empirical understanding of how the landscape structure shapes biotic interactions at different spatial extents in highly diverse tropical rainforests.
... (Soares-Filho et al., 2010), Costa Rica(Min-Venditti et al., 2017) and Mexico(Figueroa and Sánchez-Cordero, 2008;Figueroa et al., 2011;Von Thaden et al., 2018), which show examples where PA have been partially successful at maintaining natural covers. ...
Coastal areas host nearly 30 % of the world population and are among the most diverse and disturbed environments on Earth. In consequence, spatial policies have been implemented to manage this socio-ecological complexity from different perspectives. Protected Areas (PA) and Land Planning (LP) have been co-implemented worldwide, but they have divergent objectives: the former seeks ecosystem preservation, while the latter seeks land use development. Despite the importance PA and LP have in coastal management worldwide, we found little information on how they interact and what effects does this policyscape have on the coastal landscape. To bridge this information gap, this paper proposes a novel method to assess the interaction of overlapping PA and LP, by employing land cover and population density proxy indicators in order to determine if they are complementary or inhibitory. Using the terrestrial coast of Mexico as a case study, we found that all coastal regions exhibited overlaps between PA and LP: from the 101 instruments analyzed, 60.4 % showed overlap but they only corresponded to 5.9 % of the total Mexican terrestrial coast. The similarities between the natural cover type in PA and its overlap with LP (both ≈89 %) suggest that a complementary interaction between both instruments exists in the terrestrial coast of Mexico. Nevertheless, our results found that overlapped PA had 11 % of anthropic cover and a slightlu y higher population density (62 people/km²) than PA alone (11.5 people/km²), which suggests that LP can have deleterious effects through spillover effects due to poorly integrated buffer zones and LPs’ planning hierarchy. Therefore, evidence from our results and international research suggests that a lack of integration between both spatial policies should be further addressed, especially at local case studies within regional scopes. We discuss on how the fragmentation between these spatial policies can be further assessed using allocation and attribution frameworks, concluding on integrated recommendations to Mexican coastal authorities. Our results and conclusions can be useful to other countries with similar coastal characteristics.
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... Among the natural protected areas in Mexico, the Los Tuxtlas Biosphere Reserve harbors the greatest number of Lauraceae species (Lorea-Hernández, 2002). During the last decades, yhis reserve has suffered deforestation and fragmentation (Dirzo et al., 2007;von Thaden et al., 2018), causing soil deterioration and nutrient loss (Tobón et al., 2011;Roa-Fuentes et al., 2015b) that could be especially harmful to Damburneya species with small population sizes. ...
Premise:
Although ecological differentiation driven by altitude and soil is hypothesized to promote coexistence of sympatric tree species of Damburneya (Lauraceae), the mechanistic role of leaf functional variation on ecological differentiation among co-occurring species remains unexplored. We aimed to determine whether the patterns of leaf trait variation reflect ecological differences among sympatric Damburneya species. We tested whether trait correlations underlying functional strategies and average species traits vary in response to local soil heterogeneity along an altitudinal gradient, potentially affecting species distributions.
Methods:
At two contrasting altitudes (100, 1100 m a.s.l.) in a Mexican tropical rainforest, we characterized soil chemical and physical properties and sampled four Damburneya species to quantify five leaf functional traits. We used linear models to analyze paired and multivariate trait correlations, spatial and interspecific effects on trait variation, and trait response to local soil heterogeneity. Relative contributions of intra- and interspecific variation to local trait variability were quantified with an ANOVA.
Results:
Soil nutrient availability was higher at low altitude, but all species had a high leaf N:P ratio across altitudes suggesting a limited P supply for plants. Species distribution differed altitudinally, with some species constrained to low or high altitude, potentially reflecting soil nutrient availability. Leaf traits responded to altitude and local soil properties, suggesting interspecific differences in functional strategies according to the leaf economics spectrum (conservative vs. acquisitive).
Conclusions:
The interspecific divergence in functional strategies in response to local environmental conditions suggests that trait variation could underlie ecological differentiation among Damburneya sympatric species.
... For over 50 yr, the region of Los Tuxtlas has experienced high rates of deforestation and fragmentation (von Thaden et al. 2018). Despite the Los Tuxtlas Biosphere Reserve protecting the last large remnants of tropical forest in the Gulf of Mexico (Guevara et al. 2004), > 80% of the region's forest cover has been lost as a result of land-use change (Vega-Vela et al. 2018). ...
Translocation is increasingly being used as a conservation tool in wildlife management, but long-term assessments of the animals’ establishment in the new habitat are rarely done. In addition, finding protected areas for translocations can often be a limitation, but habitat patches managed for productive purposes could potentially be used for translocations. Here, we present a translocation case study of the Endangered Mexican howler monkey Alouatta palliata Mexicana into a forest fragment managed as an agroforest in the Los Tuxtlas Biosphere Reserve (Mexico). We compared the behavior of the translocated focal group 6 yr after translocation with that observed 1 yr after translocation (Year 1 vs. Year 6), and with reference parameters for conserved forest. We also examined the 14 yr trajectory of the translocated population through published data. We found that in Year 6, monkeys spent less time on locomotion and more time consuming fruit than in Year 1. The focal group in Year 6 had doubled its activity area compared to Year 1. All behavioral parameters during Year 6 were similar to those reported for the species in conserved forest. During the first 14 yr, the translocated population increased at a rate of 1.29 find. yr−1. We conclude that this translocation succeeded in establishing a thriving population and that certain agroforestry systems may be adequate habitat for primate translocations. We also discuss how the translocation of howler monkeys into defaunated habitats might help restore ecological functions associated with these primates, such as the dispersal of large-seeded plants. Long-term information on successful primate translocations has high practical value for designing adequate conservation strategies in anthropogenic landscapes.
... Similar criteria should be used to select or favor tree species for widening riparian corridors, however in this case the goal can be achieved by simply protecting the area adjacent to the current corridor from domestic livestock and stopping weeding practices to take advantage of natural tree regeneration (i.e. passive restoration) alongside the arboreal elements already present (see Guevara et al., 2005;Von Thaden et al., 2018), which are also important sources of native species' seeds and attract vertebrate seed dispersers (Lindenmayer et al., 2000;Arroyo-Rodríguez et al., 2020). Implemented together, these two restoration strategies (i.e., planting tree islets and widening riparian corridors) would also promote much faster forest regeneration through nucleation (in planted tree islets) and expansion (along the corridors) of secondary succession. ...
Agriculture is one of the main drivers of deforestation worldwide, generating highly fragmented landscapes that severely limit the mobility of forest species. Knowledge of the state of previously forested landscapes, taking into account all of its arboreal elements (including isolated trees, living fences, riparian corridors, and others) is a necessary first step to gaining a better understanding of the ecological dynamics of anthropic landscapes, and for designing conservation and management plans that enhance functional connectivity within these landscapes. We used high-resolution images (2.5 m/pixel) to identify all of the arboreal elements—from single tree crowns up to large forest fragments—for 40,000 ha of the Los Tuxtlas Biosphere Reserve. We included isolated trees, usually ignored in most inventories of fragmented landscapes, but which together with the other arboreal elements play an important role as landscape connectors and extra habitat for many species. Using a graph theory approach, we assessed landscape connectivity at six inter-patch distances across open areas (from 50 to 500 m), and propose two strategies for improving landscape connectivity: the creation of woodland islets and the widening of forested riparian corridors in the agricultural matrix. The main arboreal elements that influenced connectivity were old-growth forest fragments and widespread treed living fences, each increasing connectivity by up to 57% (depending on the threshold distance), while riparian corridors and isolated trees contributed 38% and 6%, respectively. Isolated trees in pastures substantially increased the number of effective connections at all distances (>85%). The GIS-simulated restoration proposals to establish circular woodland islets (10 m radius) in the middle of open agricultural areas increased connectivity by 26%, while widening riparian corridors by up to 10 m per riverside increased it by 11%. Increasing the number of arboreal elements within the agricultural matrix at key sites would enhance landscape connectivity considerably, benefiting the organisms that live in forest remnants in the study area without the need to stop agricultural activities.
... Alterations of tropical rainforests are mainly determined by land use change such as deforestation, agricultural and urban expansion (Gatti et al. 2015, Parrotta et al. 2002, Urquiza-Haas et al. 2007, Sales et al. 2020. In southeast Mexico, the region of Los Tuxtlas represents the northernmost limit of tropical rainforests in the Americas which has suffered extensive habitat loss over the last decades (Dirzo & Garcia 1992, Von Thaden et al. 2018. Most remaining old-growth forests of Los Tuxtlas are isolated fragments lying within a pasture matrix (Dirzo & Garcia 1992, Guevara et al. 2004. ...
The magnitude of facilitation by shelter-building engineers on community structure is expected to be greater when they increase limited resources in the environment. We evaluated the influence of local environmental context on the colonisation of leaf shelters by arthropods in a Mexican evergreen tropical rainforest. We compared the species richness and abundance of arthropods (total and for different guilds) colonising artificially rolled leaves in habitats differing in understory heterogeneity (forest edge > old-growth forests > living fences). Arthropod abundance of the most representative arthropod taxa (i.e., Araneae, Blattodea, Collembola and Psocoptera) colonising the rolled leaves was greater at forest edge, a trend also observed for average arthropod abundance, and for detritivore and predator guilds. In addition, fewer arthropod species and individuals colonised the rolled leaves in the living fence habitat, a trend also observed for most arthropod guilds. As forest edge is expected to have a greater arthropod diversity and stronger density-dependent interactions, a greater limitation of refuges from competitors or predators may have determined the higher colonisation of the rolled leaves in this habitat. Our results demonstrate that local environment context is an important factor that affects the colonisation of arthropods in leaf shelters.
... No se pudieron obtener datos que demostraran claramente cuáles tipos de vegetación han sido los más afectados por la deforestación en términos relativos. Van Thaden et al. (2018), estimaron que, si la tendencia de los últimos años previo al 2011 persistía, desde este año hasta el 2025 se iba a perder el 14 % de la cobertura forestal. Los estudios citados carecen de un análisis exhaustivo de las causas del cambio del uso del suelo. ...
Una de las principales estrategias para conservar las selvas tropicales del planeta es la declaración de áreas naturales protegidas. No obstante, se ha cuestionado si esta protección es efectiva para mitigar uno de los mayores riesgos para las selvas: los incendios forestales. El presente estudio analizó esta situación en un área natural protegida específica, la Reserva de la Biosfera Los Tuxtlas (México). La investigación se inició con una revisión del marco normativo y de los instrumentos de gestión relevantes, así como de su implementación por parte de los actores locales, con base en entrevistas semi-estructuradas. A continuación, se evaluó la efectividad de esta gestión, basada tanto en datos estadísticos oficiales como en el análisis de imágenes satelitales. Si bien los datos disponibles carecen de continuidad y precisión, se puede reconocer que las actividades de gestión empleadas han logrado evitar los impactos a gran escala que ocurrieron previos a la creación del área protegida en 1998 y que se ha observado una tendencia a la baja entre 2005 y 2020. Aun así, sigue siendo preocupante el número de hectáreas afectadas anualmente. Se indica que esto se debe principalmente al presupuesto limitado de las dependencias involucradas, restringiendo su alcance temporal y espacial. Una de las principales estrategias para conservar las selvas tropicales del planeta es la declaración de áreas naturales protegidas. No obstante, se ha cuestionado si esta protección es efectiva para mitigar uno de los mayores riesgos para las selvas: los incendios forestales. El presente estudio analizó esta situación en un área natural protegida específica, la Reserva de la Biosfera Los Tuxtlas (México). La investigación se inició con una revisión del marco normativo y de los instrumentos de gestión relevantes, así como de su implementación por parte de los actores locales, con base en entrevistas semi-estructuradas. A continuación, se evaluó la efectividad de esta gestión, basada tanto en datos estadísticos oficiales como en el análisis de imágenes satelitales. Si bien los datos disponibles carecen de continuidad y precisión, se puede reconocer que las actividades de gestión empleadas han logrado evitar los impactos a gran escala que ocurrieron previos a la creación del área protegida en 1998 y que se ha observado una tendencia a la baja entre 2005 y 2020. Aun así, sigue siendo preocupante el número de hectáreas afectadas anualmente. Se indica que esto se debe principalmente al presupuesto limitado de las dependencias involucradas, restringiendo su alcance temporal y espacial.
... This is explained by two main processes: the minimum land-use conversion of older forest classes and the succession of abandoned milpas into younger forest covers and from younger forests into medium secondary forest. These results support previous studies in Mexico (e.g., [43,44]) and worldwide (e.g., [42,45,46]) that suggest that even when factors such as management capacity, funding, level of protection, size, and location are important drivers of PAs effectiveness, in general, they reduce deforestation and promote vegetation regrowth, benefiting local biodiversity. As an example, the overall relative abundance of the two monkey species inhabiting OMYK (Ateles geoffroyi and Alouatta pigra) was stable from before the PA establishment to 2015 and increased in old-growth forest, indicating that the PA has been effective in maintaining primate populations [47]. ...
Protected areas (PA) are effective means for protecting biodiversity, but less is known about their effect on the social-ecological system (SES). Using a semi-experimental approach and a descriptive case study based evaluation, we analyzed the effect of a PA in the Yucatan Peninsula on land-cover and household resource management strategies in time and space (before and after the PA establishment; inside and outside its limits). To assess the changes of land-use practices in the areas surrounding the communities inside and outside the PA, and their change over time (from 2003 to 2015), we used remote sensing analysis and semi-structured interviews. Our results show that after the PA was established, the forest increased and agricultural plots decreased inside and to a lesser extent outside the PA. However, fires reduced the area of old-growth forest and increased young secondary forest, highlighting the system’s vulnerability to uncommon events. Resource management strategies were also affected: while inside the PA households tended toward specializing on tourism, outside the PA household strategies implied a diversification of productive activities. Overall, the establishment of the PA proved to be an effective tool to promote forest recovery and prevent deforestation in the regions surrounding the communities both inside and outside the PA.
... Para el mantenimiento de la biodiversidad nativa de Los Tuxtlas es indispensable la conservación de los fragmentos de selva más extensos que aún quedan en la región y para ello detener la tala es crucial (Von Thaden, et al., 2018). En este sentido, el decreto de la Reserva de la Biosfera de Los Tuxtlas (Guevara et al., 2004) es alentador. ...
El incremento de las actividades productivas prósperas y sustentables y el mantenimiento de la diversidad biológica de las selvas húmedas y secas del estado de
Veracruz, requiere del conocimiento y manejo del paisaje actual. La estructura y el funcionamiento del paisaje están vinculados a los eventos recurrentes de carácter natural y a la presencia de actividades humanas ocurridas a lo largo del tiempo; esos cambios provocados en el paisaje son una especie de memoria de su historia ambiental.
El paisaje de la selva seca y húmeda de la planicie costera del Golfo de México ha sido modificado por la frecuente incidencia de intensos vientos, fuertes precipitaciones y por el movimiento sísmico y actividad volcánica que ocasionaron inundaciones y deslizamientos de tierra. Por otro lado, está la larga historia de colonización humana de esta región, con culturas como la olmeca, totonaca y huasteca, que por sus altas densidades de población y por el amplio desarrollo agrícola alteraron grandes extensiones (Stark y Arnold, 1997).
En este ensayo nos ocupamos de la costa veracruzana, un territorio muy vasto enclavado en Mesoamérica, región que abarca la mitad meridional de México, Guatemala, El Salvador y Belice, así como el occidente de Honduras, Nicaragua
y Costa Rica.
... The transition rules for the CA model are built based on the driving forces of LUCC. Factor selection in building the model is vital as the inclusion of too many factors in the model leads to multi-collinearity effect thus degrading the efficiency of the model (Feng and Tong 2017;Thaden et al. 2018;Feng et al. 2019). To overcome this issue, appropriate selection of the dominant driver of the LUCC is essential. ...
Accurate identification of the dominant driving factors in the expansion of a city is essential for cellular automata (CA)-based urban expansion modelling. The current study aimed at analyzing the drivers of change for Vijayawada city, a tier-II developing city in south-east Asia, India and then applies them to model the future scenario of the city in a CA-based environment. Furthermore, the study also aims at comparing the efficiency of the renowned CA-based urban growth model, SLEUTH (Slope, Land use, Exclusion, Urban extent, Transportation, Hill shade), and a self-designed CA-based hybrid model developed in combination with genetic algorithm (GA) for developing future scenario of the city. The models were built, calibrated, and validated for the city using land use maps derived from temporal Landsat satellite images. Analysis of the statistical significance of the driving factors shows that the terrain and population density are the two dominant factors influencing expansion of the city. Both the models output on predicting the urban growth indicate that the available open spaces within the existing city extent gets further converted to built-up indicating infill development, and more growth occurs along the fringes of the existing city. Also, emergence of new urban centers merged with the existing city areas for predictions till 2050 and extended into the dense vegetation on the north resulting in further reduction of green cover around the city. Validation of both the models showed overall accuracy higher than 85%. The inclusion of the demographic variable and utilization of the GA ensured that the hybrid model performs better than the SLEUTH model. Analysis on the built-up densification of the cityscape showed a shift in the pattern of built-up dynamics over time. The built urban expansion scenario for Vijayawada informs urban modelers and policymakers the possible evolution of the city.
... Approximately 80 years ago in southern Veracruz, Mexico, the lowlands of the Los Tuxtlas volcanic mountain range were almost completely covered by a tropical rainforest (<750 m a.s.l.), and a cloud forest covered the higher elevations, but that rainforest currently occupies only 15% of its original area (Von Thaden et al. 2018). The remaining rainforest in Los Tuxtlas is highly fragmented, with forest fragments of varying sizes now surrounded by manmade pastures and other types of agricultural lands. ...
In the fragmented landscape of Los Tuxtlas, adult fig trees are found in both rainforest remnants and in pastures. Syconium (fig) development is known to vary between and within Ficus species, but it is not known whether it differs between rainforest and pasture trees. Here, we describe syconium development for two Ficus species with different life forms (free-standing and hemi-epiphytic) in two contrasting, adjacent habitats: an undisturbed rainforest and active pastures. Over three months, we monitored 15 reproductive events in Ficus (subg. Pharmacosycea) yoponensis Desv. and Ficus (subg. Spherosuke) colubrinae Standl., collecting and dissecting syconia every 3–4 days (1291 and 815 syconia per species, respectively). External and internal structural changes in the syconia are described, including foundress occurrence and the maximum duration of the receptive phase while waiting for pollinators. The duration of both the reproductive events (<8 weeks) and the developmental phases in the two species did not differ between rainforest and pasture trees and are within the lower range of time reported for other Ficus species. After pollinator exclusion, the receptive phase lasted up to four times its normal duration. Syconia were slightly larger in rainforest trees than in pasture trees, and the infestation of F. yoponensis syconia by non-pollinating insects was higher in rainforest trees.
... This is a function of both where conservation programs are targeted and who signs up for programs such as PES. Previous Table 6 Ecosystem service benefits from avoided loss of primary forest and total forest cover due to PHS policy reported as the average per grid square (1 ha Von Thaden et al., 2018), locating protected areas and PES policies in the same place has been shown to significantly reduce the additional impact of PES programs on forest cover (Robalino et al., 2015). We find a similar effect in this study in that we find a smaller treatment effect for the PHS policy on total forest cover in the two regions where PES policy overlaps with protected areas. ...
... This resulted in the transformation of more than 50% of the original forest cover in Los Tuxtlas, which was replaced mainly by cattle pastures (Dirzo & Gacia, 1992;Guevara et al. 2000;Vega-Vela et al. 2018). To reverse biodiversity loss and disruption of ecological processes in the region, the Los Tuxtlas Biosphere Reserve (LTBR) was created in 1998, leading to a drastic arrest of deforestation practices (Guevara et al. 2000;Vega-Vela et al. 2018;von Thaden et al. 2018). ...
Studies addressing the temporal changes of ecological communities within fragmented forests transformed into natural protected areas are urgently needed. The creation of the Los Tuxtlas Biosphere Reserve (LTBR) in 1998 stopped the deforestation process of the northernmost tropical rainforest of the Neotropical region, allowing the analysis of the long-term effects on native communities after the halting of habitat fragmentation. We compared the diversity of dung beetles in 11 forest fragments and eight pastures in the LTBR between two periods: 1999–2000, the early years after the creation of the LTBR; and 2016–2017, i.e., 17 years later. Species richness and abundance of dung beetles were similar in both periods, being higher in forest fragments than in pastures; however, the dominant species were different in each period in both forest fragments and pastures. The number of habitat indicator species increased in 2016–2017 compared to 1999–2000, with a high species diversity of forest indicators relative to pasture indicators at both periods. Alpha and gamma diversities were lower in 1999–2000 than in 2016–2017. Beta-diversity at the spatial level was strongly driven by species turnover, which was higher in pastures than in forest fragments. All functional groups (dwellers, rollers, and tunnellers) showed higher abundances in forest fragments than in pastures in both 1999–2000 and 2016–2017 periods. Our results suggest that stopping the fragmentation process in the LTBR has allowed the survival of native dung beetle assemblages, which are undergoing a recovery process of their populations and ecological functions over the years.
... Human occupancy in the area dates to 6,000 years ago with the establishment of the Olmec culture (Gonzalez-Soriano et al. 1997). More recent changes by humans in land use policy have reduced its surface to 5 % distributed in approximately 60 fragments (Guevara et al. 2004;Von Thaden et al. 2018). ...
Spider community inventories have relatively well-established standardized collecting protocols. Such protocols set rules for the orderly acquisition of samples to estimate community parameters and to establish comparisons between areas. These methods have been tested worldwide, providing useful data for inventory planning and optimal sampling allocation efforts. The taxonomic counterpart of biodiversity inventories has received considerably less attention. Species lists and their relative abundances are the only link between the community parameters resulting from a biotic inventory and the biology of the species that live there. However, this connection is lost or speculative at best for species only partially identified (e. g., to genus but not to species). This link is particularly important for diverse tropical regions were many taxa are undescribed or little known such as spiders. One approach to this problem has been the development of biodiversity inventory websites that document the morphology of the species with digital images organized as standard views. Their main contributions are the dissemination of phenotypic data for species difficult to identify or new with the assignment of species codes, allowing species comparisons between areas regardless of their taxonomic status. The present paper describes a protocol to produce these websites almost automatically. This protocol was successfully applied to 237 species from a tropical primary forest in Mexico. The time and infrastructure required for the documentation of these species are discussed. Taxonomic information in terms of identification challenges, possible new species, and potential nomenclatural issues is described. In addition, the conventional community parameters (e. g., inventory completeness, species richness estimations, sampling intensity) are also calculated and compared through time and between methods. An optimized version for sampling allocation effort per season is presented and compared with protocols optimized for other tropical forests.
... Moreover, these areas are mountainous regions surrounded by plains where human activities occur that facilitate land-cover loss inside the PAs. Los Tuxtlas, a mountain system surrounded by a leeward marine plain, is mainly affected by livestock production (Figueroa & Sánchez-Cordero, 2008;Halffter, 2011;Urquiza-Haas, 2009;Von Thaden et al., 2018). In our study, distinctive areas of strict, subaquatic and tolerant aquatic species show a similar pattern, where higher richness occurred outside of PTRs and PAs with flat lands, and medium richness was frequent at medium elevations and lower richness at higher elevations. ...
Protected areas (PAs), priority terrestrial regions (PTRs) and priority terrestrial sites (PTSs) are strategies for conserving natural resources. However, loss of coverage on the peripheries can lead to isolation between these conservation areas. The present study analyzed the association of the change of coverage inside and outside 2 PAs, 5 PTRs and 128 PTSs in Tamaulipas with the richness and geographic distribution of 5 species groups (strict, semiaquatic and tolerant hydrophiles, as well as gastropods and pteridophytes in 3 periods (1986, 2002 and 2011). In addition, we identified areas with similar species composition and socioeconomic-environmental factors related to the change in coverage. The highest richness and geographic distribution of aquatic plants occurred outside the conservation areas, while the greatest richness of ferns and gastropods was present inside them. The greatest loss of coverage occurred outside the El Cielo Biosphere Reserve and the Sierra de Tamaulipas PA. The loss of native cover increased in the last 30 years and is greater outside the conservation areas, therefore is necessary to propose and implement strategies to reduce the isolation of these areas.
Biosphere Reserves (BR) manage large territories with diverse natural covers and land uses to preserve biodiversity,
promote local development and preserve ecosystems. This study evaluated how their zoning (buffer and
core) and policy timeframes (decree period, management plan period, and land planning period) influence four
landscape management outcomes: deforestation, natural cover recovery, and anthropic and natural permanence.
For three Mexican BR case studies, land use and cover transitions were calculated and compared to contrafactual
sites. Observed rates of land cover change were marginal within all three BR zoning and across their policy
timeframe (<0.02 % change rate), suggesting that BR effectively promote the permanence of both natural and
anthropic covers. Nevertheless, the predicted probability of uncommon deforestation and recovery outcomes at
local levels showed that the effect of a BR over its regulated landscape is not spatiotemporally static, contrasting
the effect of individual allocation vs a group or network. Poverty, land tenure, agriculture aptitude and distance
to markets adds to this dynamic and is modelled and discussed. This study shows that BR zoning schemes and its
regulatory sequence influence the rates of land cover change and the predicted probability of landscape management
outcomes across space and time.
The Neotropics is a biodiversity rich area yet one of the most heavily threatened by several ongoing stressors that include fragmentation, deterioration and loss of natural and semi-natural habitats, agro-economic pressure, urbanization, pollution, and climate change. Insect biodiversity and its conservation are among the main global topics in conservation science and one of the major challenges for the present and coming generations in the Neotropics. The fact that these animals have been poorly studied or undescribed renders them less tractable than other groups to see how much under risk they are. This chapter sets the scene of what this book is about and briefly describes the contents, main achievements, and further directions of each contribution. The book provides the first assessment of actual stressors, patterns, processes, and/or consequences of insect decline and conservation in the Neotropics. We also outline some key topics for insect conservation on a regional and local scales: a country-based insect regulation agenda, standardized monitoring schemes to assess insect conservation status, citizen science approaches for gathering robust data on insect identity and abundance, and climate change effects.
Agro-landscapes are the workspace of agriculture and the living space of the rural population: they can support a rich insect diversity. Yet, some practices, such as intensification, technification, and/or abandonment of fields, along with landscape changes arising from habitat fragmentation and native vegetation deforestation, pose a major threat to many insect species. In this chapter, we discuss study cases from southern and western Mexico as examples of change in insect assemblages and single species in agro-landscapes under different regimes, particularly involving (semi) intense land management and habitat succession after abandonment. Case studies showed that non-crop habitats act as important reservoirs for insect diversity in agro-landscapes and that some landscape elements within this template could favor the persistence of insect populations. To halt further losses of insect diversity in agro-landscapes, agri-environmental schemes and conservation measures could be integrated by applying an array of different approaches, particularly stimulating landowners to implement practices for insect conservation, designing restoration efforts, and monitoring programs and a significant reduction in pesticide application.
Habitat loss and land-use change in tropical forests have modified the composition and configuration of natural landscapes, driving biodiversity loss. Through studies covering different approaches to diversity and functional traits, a more holistic comprehension may be drawn regarding the effects of habitat transformation. In this study, we evaluated how the forest cover and landscape heterogeneity shape the taxonomic and functional diversity and biomass of dung beetles. Dung beetles were sampled in 16 landscape units of the “Los Tuxtlas” Biosphere Reserve (Mexico). We collected a total of 2396 individuals of 25 species in 14 genera. Taxonomic and functional diversity and biomass of dung beetles were positively related to the amount of primary forest and negatively related to increased landscape heterogeneity. These results indicate that tropical rainforests are highly sensitive to landscape transformation, which jeopardizes the different aspects of biodiversity. By showing the importance of evaluating different facets of biodiversity we conclude that implementing different landscape descriptors and different diversity components is a complementary and efficient approach to assessing the effects of landscape composition on dung beetles’ assemblages in tropical rainforests.
Implications for insect conservation
Landscape composition plays a pivotal role in elucidating the various components that define the dung beetle community in tropical forests. Furthermore, it is of utmost significance to encompass a diverse array of biodiversity components, alongside species biomass, in order to comprehensively evaluate the impact of human-induced landscape transformation.
Metro stations are considered high-quality resources for promoting urban development, which have great influences on the surrounding land use changes. The simulation and prediction of land use change can provide a scientific basis for urban land planning. In this work, the cellular automata (CA)-Markov model was adopted by taking into account point of interest (POI) kernel density and station accessibility as driving factors to predict the land use change of station surrounding areas. Then, the land type compositions of different years, temporal and spatial evolution of landscape patterns, and strategies of different metro stations were explored. The results show that the Kappa coefficients of the Zoo Station and the Lu Xiao Station are 87% and 79%, respectively, indicating that the improved CA-Markov model can predict land use changes more accurately by considering POI kernel density and station accessibility. Finally, different optimized strategies based on systematic predictions of land use landscape patterns according to the spatial and temporal distribution of metro stations were proposed. The work provides important references for predicting the impact of new metro stations on land use in the future and guides the adjustment and optimization of land use policy planning.
Neotropical forested landscapes have become agricultural areas and human settlements, causing forest fragmentation, land degradation, and habitat loss. Nonetheless, complex tree cover loss and recovery processes may occur even while urban areas expand. Biophysical, social, political, and economic drivers influence forest loss or recovery over time. This study analyzes land-use change dynamics in urban and peri-urban landscapes in the western sector of Xalapa City between 1966–2018 and identifies the primary drivers that have played a significant role in deforestation and forest recovery processes. The main finding denotes the city’s expansion between 1966 and 2018, initially covering 8% of the study area and increasing to 27%. However, between 1966 and 2018, 15% of forest cover was lost in net terms, a finding ascribed to forest recovery in some abandoned areas. Social and biophysical variables significantly influenced deforestation and forest recovery trends, and few variables were singular to one process. The deceleration of forest loss and accomplishing tree cover recovery are possible in some urban settings. In this context, green urban and peri-urban landscapes become strategic to achieve more sustainable cities. Among other benefits, green areas provide landscape connectivity, temperature regulation, air quality improvement, noise dampening, and recreational areas.
En los últimos años, han cobrado importancia los estudios que resaltan el papel de los diferentes actores sociales que participan en la gestión del fuego. Recientemente, algunos trabajos también han incorporado una visión geográfica, indagando en los aspectos territoriales de la gestión. No obstante, hasta la fecha, existe una carencia de investigaciones de esta índole en las zonas tropicales del mundo. El presente trabajo pretende contribuir a subsanar parcialmente esta laguna de conocimiento, analizando la situación en los últimos años (2016 a 2020) en la sierra de Los Tuxtlas, México, un área con una notable incidencia de incendios forestales. Para ello, se han revisado datos oficiales y se han efectuado entrevistas con representantes de los actores involucrados. El procesamiento de los datos ha incluido el análisis de textos que revela las diversas actividades realizadas por los actores. Para profundizar en la comprensión de la configuración territorial de los actores, se presenta una cartografía de la geografía organizativa y de las redes de cooperación. Se demuestran áreas con una presencia destacada de diferentes actores y una densa red social pero también otras zonas con poca o nula actividad y se discuten las razones de esta configuración.
Ecosystem services (ES) are the benefits that people derive from ecosystem processes that contribute to their well-being. To safeguard the ecosystems providing these services, a wide range of economic and policy tools have been developed, including payments for ES programs (PES). However, the scientific understanding of relationships between pairwise ES and the multifunctionality of the landscape is scarce. These programs also suffer from a lack of information on how changing land-use/cover (LULC) and climate (CC) can affect current and future levels of ES supply. This research integrates in-depth information about the factors affecting the spatial distribution of key ES and thus strengthen the effectiveness of programs making payments for hydrological services (PHS) in Veracruz. The objectives were to: (i) quantify the spatial relationships among target and non-target ES; (ii) link ES mapping tools and spatial analysis to identify priority areas and assess the targeting performance of PHS; and (iii), modelling future changes in ES provisioning caused by separate and joint effects of CC and LULC changes in the near future (2039). Two water-related ES targeted by PHS (soil retention and water yield) were evaluated along with carbon storage. By testing for spatial overlaps between prioritizing areas for ES and those targeted by PHS, we found considerable spatial mismatches indicating low program effectiveness. Significant pairwise correlations among ES suggested synergistic relationships and the possibility for designing PHS to conserve multiple ES simultaneously. Potential changes in HS provisioning versus baseline conditions (2014) were compared using eight alternative scenarios of changing LULC and climate, based on two contrasting scenarios from the IPCC-Emission Narratives (RCPs 4.5 & 8.5), and consistent with the B2 and A2 IPCC-SRES storylines. Overall, CC appears to have more pronounced effects than LULC-induced changes. Combined scenarios showed significant negative impacts by decreasing surface water yield and increasing soil erosion, due to strong increases in precipitation and evapotranspiration. These findings highlight the importance of scenario building, analysis of ES interactions, and spatial characterization of SH for improving the effectiveness of PHS programs. Overall, this approach may has broad applicability in other regions and facilitates the analysis of potential contributions of PES to ES provisioning, for guaranteeing the well-being of society.
The increase in tobacco production while ameliorating the condition of the participant households has caused challenges to stakeholders particularly those in the governance of forest resources upon which the sector is hinged. Massive deforestation has proceeded at an alarmingly high level, in a way that threatens the long term viability of the tobacco sector and sustainability of natural forest resources. The entrance of previously disadvantaged majority into the once minority-dominated tobacco sector (and economy) in a quest to improving their livelihoods, is driving forest landscape changes that pose inherent environmental challenges including climate change. This article adopts institutional and landscape approaches to explore and explain the drivers, nexus and implications of smallholder tobacco as a livelihood strategy to the forest landscape changes and the subsequent imperative for governance of the sustainable utilization of forest resources in Zimbabwe. Drawing on documentary evidence the paper concludes that this situation poses a dilemma to forest and livelihood policies, hence the need to examine new institutional and livelihood initiatives.
Land change models are amongst the most widely developed tools for spatial decision support. Despite this progress, only a few models have been created thus far that simulate urban growth that incorporate two important aspects of uncertainty inherent to land use dynamics: fuzziness and roughness. Combining fuzziness and roughness into models will enhance the use of these tools for decision support. This study applied and evaluated a fuzzy-based approach to the feature selection effects on the accuracy of a land change model. Fuzzy rough set theory (FRST) was employed here as feature selection method and was integrated with a support vector regression (SVR) algorithm to simulate urban growth of Tabriz mega city in northwest Iran. In order to apply feature selection to a FRST algorithm, incoming data has been first fuzzified by an adaptive neural fuzzy inference system (ANFIS). To evaluate the application of FRST, SVR was used with and without FRST (SVR and SVR-FRST), while for performance evaluation logistic regression (LR) and kernelled LR (KLR) models were integrated with and without FRST (LR, LR-FRST, KLR, and KLR-FRST). The accuracy of the simulated maps of all models were evaluated by calculating the overall accuracy (OA), true positive rate (TPR), true negative rate (TNR), total operating characteristic (TOC) and their area under curve (AUC). The results showed that integrating FRST with the above-mentioned models enhanced the overall performances based on the above criteria. Among the above mentioned models, SVM-FRST and KLR-FRST yielded the best goodness of fit measures. Moreover, SVM-FRST with 83.6% OA, 41.6% TPR, and 90.4% TNR performs better than KLR-FRST with 82.4% OA, 37.4% TPR, and 89.8% TNR. However, KLR-FRST has more AUC, less green area destruction, more barren to urban areas conversion, and fast tuning process related to SVR-FRST. Finally, we suggest that KLR-FRST and SVR-FRST are, among those evaluated, the most appropriate models for urban growth modelling of the Tabriz mega city of Iran when considering uncertainty.
Tuberculosis is the main cause of death from a single infectious agent. Globally, according to the World Health Organization, in 2018, there were an estimated 1.2 million tuberculosis deaths. Moreover, there is a continuous appearance of drug-resistant strains. Thus, development of new antituberculosis medicines should receive high priority. Plant-derived natural products are promising candidates for this purpose. We therefore screened alkaloid extracts obtained from the root and stem barks of the Mexican Apocynaceae species Tabernaemontana alba and Tabernaemontana arborea, as well as the pure alkaloids ibogaine, voacangine, and voacamine, tested for activity against Mycobacterium tuberculosis H37Rv and cytotoxicity to mammalian Vero cells using the resazurin microtiter and the MTT assays, respectively. The extracts were analyzed by GC-MS and HPLC-UV. T. arborea root bark alkaloid extract showed the highest activity against M. tuberculosis (MIC100 = 7.8 µg/mL) of the four extracts tested. HPLC suggested that voacangine and voacamine were the major components. The latter was isolated by column chromatography, and its chemical structure was elucidated by 1H and 13C NMR, and MS. Unambiguous assignation was performed by HSQC, HMBC, and NOESY experiments. Voacamine is a dimeric bis-indole-type alkaloid and is 15 times more potent than the monomeric ibogan-type alkaloids ibogaine and voacangine (MIC100 = 15.6, 250.0, and 250.0 µg/mL, respectively). However, all of these compounds showed cytotoxicity to Vero cells, with a poor selectivity index of 1.00, 0.16, and 1.42, respectively. This is the first report of voacamine activity against M. tuberculosis.
Under suitable conditions, deforested land used for agricultural crops or pastures can revert to forest through the assisted or unassisted process of natural regeneration. These naturally regenerating forests conserve biodiversity, provide a wide array of ecosystem goods and services, and support rural economies and livelihoods. Based on studies in tropical and temperate forest ecosystems, we summarize cases where natural regeneration is occurring in agricultural landscapes around the world and identify the socio-ecological factors that favor its development and affect its qualities, outcomes and persistence. We describe how the economic and policy context creates barriers for the development, persistence, and management of naturally regenerating forests, including perverse outcomes of policies intended to enhance protection of native forests. We conclude with recommendations for specific economic and policy interventions at local, national, and global scales to enhance forest natural regeneration and to promote the sustainable management of regrowth forests on former agricultural land while strengthening rural communities and economies.
This paper presents an evidence gap map of forest conservation interventions in low- and middle-income countries based on evidence published over the period 2016 to mid-2018. It serves as an update to a similar effort by 3ie, with refinements to the framework that distributes studies across three tiers based on quality and considers environmental and socioeconomic outcomes. Compared to the previous evidence gap map, the evaluation of forest conservation outcomes has clearly accelerated in recent years, but from a modest base: the body of evidence still remains insufficient across most intervention types. Community-based management (especially in South Asia) and protected areas are well represented, though the latter distinguishes few subcategories. In turn, both PES and REDD+ evaluations are less available, and the latter surprisingly features more welfare than forest conservation or carbon impacts. Capacity-building interventions are almost absent in the matrix. It is also notable that policy mixes, often dominant in real-world implementation, have so far received little scrutiny. Among forest types, conservation interventions in mangroves lag behind, despite their environmental importance. Geographically, Asia and Latin America generally publish much more evaluated evidence than Africa. In conclusion, despite the incipient progress we have undoubtedly seen, many important knowledge gaps still remain.
Conservation and restoration interventions can be mutually reinforcing and are converging through an increased focus on social dimensions. This paper examines how to more effectively integrate the complementary goals of conservation and restoration of tropical forests. Forest conservation and restoration interventions are integral components of a broad approach to forest ecosystem and landscape management that aims to maintain and restore key ecological processes and enhance human well‐being, while minimizing biodiversity loss. The forest transition model provides a useful framework for understanding the relative importance of forest conservation and restoration interventions in different regions. Harmonizing conservation and restoration presents serious challenges for forest policy in tropical countries, particularly regarding the use and management of secondary forests, fallow vegetation, and forests degraded by logging and fire. Research to implement restoration more effectively in tropical regions can be stimulated by transforming questions that initially focused on conservation issues. Examination of papers published in Biotropica from 2000–2018 shows that most studies relevant to tropical forest conservation do not address forest restoration issues. Forest restoration studies, on the other hand, show a consistent association with conservation issues. There is much scope for further integration of conservation and restoration in research, practice, and policy. Securing a sustainable future for tropical forests requires developing and applying integrated approaches to landscape management that effectively combine knowledge and tools from multiple disciplines with practical experience and engagement of local stakeholders.
Abstract in Portuguese is available with online material.
http://polired.upm.es/index.php/pastos/article/view/2250.
The current landscape of the Mesoamerican rain forest has been shaped by the migration of plant and animal species, natural events, and human intervention. This current reflection on the effects of livestock ranching in this region focuses on the impact to both the structure and the functioning of the landscape. Los Tuxtlas, Veracruz, Mexico, is both a case study and a reflection of the larger Mesoamerican landscape, where cattle livestock were first introduced in the 16 th century and subsequently replaced with a new variety of cattle in the 19 th century. Thus, Los Tuxtlas is an enclave of tropical rain forest in southeastern Mexico and illustrative of the environmental history of Mesoamerica as a whole, representing a landscape of flora and fauna that have resisted climatic changes, intense volcanic activity, and frequent hurricanes and tropical storms that have continuously occurred across time. More recently, human activities, such as hunting, gathering, and agriculture, have also formed the landscape beginning with the Olmecs, considered to be the mother culture of Mesoamerica. In the 16 th century the European colonizers introduced on the northern tip of the volcanic range of San Martin in Los Tuxtlas several cattle varieties of Bos taurus, imported from the region of Guadalquivir, Spain. These cattle rapidly adapted to free-range grazing, probably due to the absence of large native herbivores that had disappeared in Mesoamerica by the end of the Holocene, as well as due to the considerable extensions of secondary vegetation of abandoned agricultural fields, resulting from the disappearance of the indigenous farmers after the arrival of the Spanish. The cattle grazed on " grama " grasses, which proliferated during this time and emerged as part of the process of secondary succession, in addition to other plants and
In Amazonia, millions of hectares of forest have been converted to cattle pasture then abandoned. On sites with histories of heavy use, forest recovery is slow. We compared the process of tree establishment in an abandoned pasture with a history of heavy use and in a mature forest through a series of field studies in northeastern Amazonia. Tree seedling and sprout emergence was greater than or equal to 20 times lower in the abandoned pasture than in forest understory and forest gaps. Tree emergence was restricted in the abandoned pasture by a lad: of tree seeds in the soil (3 tree genera vs 15 in the forest), and a low rate of tree and liana seed deposition by birds and bats in the open vegetation of the abandoned pasture (2 m(-2) yr(-1)). Tree and liana seed deposition in the abandoned pasture was higher beneath treelets (990 m(-2) yr(-1)). Rates of seed removal and consumption by ants and rodents were also higher in the abandoned pasture (>80% removal within 20 d for 6 tree species) than in forest understorey and forest gaps. Cutter ants (Atta sexdens) hindered tree seedling survivorship and growth in the abandoned pasture by clipping leaves and stems, and preferred tree seedlings to grass and shrub seedlings. In the absence of herbivores, survivorship and height growth of seedling transplants in the abandoned pasture were generally lower than in experimental treefali gaps, and were correlated with harsh environmental conditions in the former. Air temperature, air vapor pressure deficit and soil moisture stress in the abandoned pasture exceeded conditions measured in both treefall gaps and intact forest during the 5-month dry season. Seedling growth in the abandoned pasture was also restricted during the wet season. These barriers to tree establishment help explain the low density and emergence rates of tree seedlings in this abandoned pasture relative to the adjacent mature forest.
Reducing atmospheric carbon emissions from tropical deforestation is at present considered a cost-effective option for mitigating climate change. However, the forces associated with tropical forest loss are uncertain. Here we use satellite-based estimates of forest loss for 2000 to 2005 (ref. 2) to assess economic, agricultural and demographic correlates across 41 countries in the humid tropics. Two methods of analysis-linear regression and regression tree-show that forest loss is positively correlated with urban population growth and exports of agricultural products for this time period. Rural population growth is not associated with forest loss, indicating the importance of urban-based and international demands for agricultural products as drivers of deforestation. The strong trend in movement of people to cities in the tropics is, counter-intuitively, likely to be associated with greater pressures for clearing tropical forests. We therefore suggest that policies to reduce deforestation among local, rural populations will not address the main cause of deforestation in the future. Rather, efforts need to focus on reducing deforestation for industrial-scale, export-oriented agricultural production, concomitant with efforts to increase yields in non-forested lands to satisfy demands for agricultural products. Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Abstract Text Return: Query Results Return items starting with number Query Form Database: Astronomy Physics arXiv e-prints
Habitat loss is a critical threat to tropical biodiversity and its quantification constitutes a central conservation issue. Typically, assessments have been based on deforestation rates statistics. However, this overlooks the effects brought about by the spatial reconfiguration of the remaining habitat: fragmentation. We present an analysis of fragmentation in a Neotropical site aimed at: (a) devising a protocol for its quantification, (b) using such protocol to provide insights on the ecological consequences of fragmentation, (c) exploring its applicability to address the hypothesis that forest size-inequality decreases with elevation, an indicator of habitat accessibility. We applied the Gini coefficient (G) and the Lorenz curve to analyze fragment-size variation using a satellite-generated map. We also estimated edge effect, fragment shape and isolation. Remaining forest includes 1,005 fragments, ranging from 0.5 to 9.356 ha (median = 0.89). Size inequality was very high (G = 0.928), producing a flattened Lorenz curve. Forty percent of the fragments did not maintain an area free of a 30-m edge effect, and larger fragments showed a marked deviation from ideal circular forms. Eighty-four percent of the fragments lay further than 500 m from the largest forest tract and their size decreased with distance. Fragment size distribution changed with altitude: the Gini coefficient was lowest and forest coverage was greatest at the highest altitude, but inequality peaked at an intermediate elevation. Given the current pace of habitat deterioration, application of similar analyses may improve global assessments of tropical ecosystems and their perspectives for biodiversity conservation.
This study evaluated the extent to which natural protected areas (NPAs) in Mexico have been effective for preventing land
use/land cover change, considered as a major cause of other degradation processes. We developed an effectiveness index including
NPA percentage of transformed areas (agriculture, induced vegetation, forestry plantations, and human settlements) in 2002,
the rate and absolute extent of change in these areas (1993–2002), the comparison between rates of change observed inside
the NPA and in an equivalent surrounding area, and between the NPA and the state(s) in which it is located. We chose 69 terrestrial
federal NPAs, decreed before 1997, that were larger than 1,000 ha, not urban/reforested with non-native vegetation, not islands
and not coastal strips, and estimated the extent of transformed areas using 1993 and 2002 land use/land cover maps. Over 54%
of NPAs were effective, and were heterogeneously distributed by management categories: 65% of Biosphere Reserves, 53% of Flora
and Fauna Protection Areas, and 45% of National Parks. 23% of NPAs were regarded as weakly effective, and the remaining 23%
as non-effective. We recognize the importance of NPAs as a relevant conservation instrument, as half of NPAs analyzed (particularly
biosphere reserves) prevented natural vegetation loss compared with their geographic context. Our results suggest that conservation
based on NPAs in Mexico still faces significant challenges. Our approach can be expanded for evaluating the effectiveness
of NPA in other regions, as land use/land cover maps are now available almost worldwide.
A nationwide multidate GIS database was generated in order to carry out the quantification and spatial characterization of land use/cover changes (LUCC) in Mexico. Existing cartography on land use/cover at a 1:250,000 scale was revised to select compatible inputs regarding the scale, the classification scheme and the mapping method. Digital maps from three different dates (the late 1970s, 1993 and 2000) were revised, evaluated, corrected and integrated into a GIS database. In order to improve the reliability of the database, an attempt was made to assess the accuracy of the digitalisation procedure and to detect and correct unlikely changes due to thematic errors in the maps. Digital maps were overlaid in order to generate LUCC maps, transition matrices and to calculate rates of conversion. Based upon this database, rates of deforestation between 1976 and 2000 were evaluated as 0.25 and 0.76% per year for temperate and tropical forests, respectively.
An empirical modeling of road related and non-road related landslide hazard for a large geographical area using logistic regression in tandem with signal detection theory is presented. This modeling was developed using geographic information system (GIS) and remote sensing data, and was implemented on the Clearwater National Forest in central Idaho. The approach is based on explicit and quantitative environmental correlations between observed landslide occurrences, climate, parent material, and environmental attributes while the receiver operating characteristic (ROC) curves are used as a measure of performance of a predictive rule. The modeling results suggest that development of two independent models for road related and non-road related landslide hazard was necessary because spatial prediction and predictor variables were different for these models. The probabilistic models of landslide potential may be used as a decision support tool in forest planning involving the maintenance, obliteration or development of new forest roads in steep mountainous terrain.
The expansion of cities entails the abandonment of forest and agricultural lands, and these lands’ conversion into urban areas, which results in substantial impacts on ecosystems. Monitoring these changes and planning urban development can be successfully achieved using multitemporal remotely sensed data, spatial metrics, and modeling. In this paper, urban land use change analysis and modeling was carried out for the Concelhos of Setúbal and Sesimbra in Portugal. An existing land cover map for the year 1990, together with two derived land cover maps from multispectral satellite images for the years 2000 and 2006, were utilized using an object-oriented classification approach. Classification accuracy assessment revealed satisfactory results that fulfilled minimum standard accuracy levels. Urban land use dynamics, in terms of both patterns and quantities, were studied using selected landscape metrics and the Shannon Entropy index. Results show that urban areas increased by 91.11% between 1990 and 2006. In contrast, the change was only 6.34% between 2000 and 2006. The entropy value was 0.73 for both municipalities in 1990, indicating a high rate of urban sprawl in the area. In 2006, this value, for both Sesimbra and Setúbal, reached almost 0.90. This is demonstrative of a tendency toward intensive urban sprawl. Urban land use change for the year 2020 was modeled using a Cellular Automata based approach. The predictive power of the model was successfully validated using Kappa variations. Projected land cover changes show a growing tendency in urban land use, which might threaten areas that are currently reserved for natural parks and agricultural lands.
Cellular automata can be significantly applied in image processing tasks. In this paper, a novel method to train two dimensional cellular automata for detection of edges in digital images has been proposed and experiments have been carried out for the same. Training of two dimensional cellular automata means selecting the optimum rule set from the given set of rules to perform a particular task. In order to train the cellular automata first, the size of rule set is reduced on the basis of symmetry. Then the sequential floating forward search method for rule selection is used to select the best rule set for edge detection. The misclassification error has been used as an objective function to train the cellular automata for edge detection. The whole experiment has been divided in two parts. First the training was performed for binary images then it is performed for gray scale images. A novel method of thresholding the image by Otsu's algorithm and then applying the cellular automata rules for the training purpose has been proposed. It has been observed that the proposed method significantly decreases the training time without affecting the results. Results are validated and compared with some standard edge detection methods both qualitatively and quantitatively and it is found better in terms of detecting the edges in digital images. Also the proposed method performs much better in corner detection as compared to the standard edge detection methods.
Management effectiveness assessment of protected area has become a major environmental concern, being an effective way to guarantee the management quality and to achieve the management targets of protected areas. Rapid assessment and prioritization of protected area management ( RAPPAM) methodology is one of the most popular methodologies. Based on the researches on the assessment indices and assessment characteristics of RAPPAM, and on the results of 8 executions of national level, this paper analyzed the evaluation scope, targets, results, and related suggestions. The RAPPAM methodology could rapidly confirm the threats and functions of protected area system, make next steps and recommendations, and provide foundations for policy makers. To understand and apply this methodology would be very necessary for realizing and improving the management status of nature reserves in China.
The necessity for the development of repeatable, efficient, and accurate monitoring of land cover change is paramount to successful management of our planet’s natural resources. This study evaluated a number of remote sensing methods for classifying land cover and land cover change
throughout a two-county area in northeastern Oregon (1986 to 2011). In the past three decades, this region has seen significant changes in forest management that have affected land use and land cover. This study employed an accuracy assessment-based empirical approach to test the optimality
of a number of advanced digital image processing techniques that have recently emerged in the field of remote sensing. The accuracies are assessed using traditional error matrices, calculated using reference data obtained in the field. We found that, for single-time land cover classification,
Bayes pixel-based classification using samples created with scale and shape segmentation parameters of 8 and 0.3, respectively, resulted in the highest overall accuracy. For land cover change detection, using Landsat-5 TM band 7 with a change threshold of 1.75 standard deviations resulted
in the highest accuracy for forest harvesting and regeneration mapping.
T HE Sierra de Tuxtla is a small mountain range which forms an isolated topographic uplift from the nearly level Gulf coastal plain of southern Veracruz about 90 km southeast of Veracruz city (Fig. 1). Within the Sierra is one of the most extensive humid tropical forest areas in Mexico. The region' s varied habitats not only provide suitable ecological conditions for many bird migrants (Andrle, 1966) but support an abundance of re-sident species. This paper deals with the Sierra' s nontransient bird species and attempts to analyze briefly their composition and affinities, distribution and abundance, and some aspects of their ecology. Since Sclater' s (1857 a,b) reports appeared on birds collected near San AndrCs Tuxtla and Sontecomapan, and Nelson and Goldman secured specimens in the region in 1894, apparently the only published ornithological studies have been those by Wetmore (1943) on part of the western section, by Davis (1952) on a small area south of Lake Catemaco, and by Edwards and Tashian (1959) on the section about Coyame. My investigations were carried out in short periods in 1951, 1952, and 1960, and during about eleven months residence in 1962. The Sierra is a volcanic range about 4,200 square km in area whose four largest volcanoes culminate an uplift that in most directions slopes gradu-ally to the coastal plain. Exceptions to this are where long ridges form headlands at the Gulf and where Cerros Tuxtla and Blanco, two outlying volcanoes, interrupt the descent to the lowlands (Fig. 2). The northwestern massif, centered on Volcin San Martin Tuxtla, has a surface characterized by medium to small-sized, cratered cones and rounded hills interspersed among ridges, valleys, and undulating terrain. The line of cones extending from Volcan San Martin southeast across the north side of the Lake Catemaco basin merges into the southeastern massif dominated by Volcin Santa Marta. There deep gorges and dissected lava ridges radiate toward the coast, while broad ridges and narrow valleys lead southward from the peaks. The Sierra is a well-watered region with Lake Catemaco lying in a large basin partially bordered by volcanic cones and hills, Bahia Sontecomapan on the Gulf, about ten scattered crater lakes, and many permanent streams. For study purposes I set the inland border of the Sierra at about the 100 m contour. The more abrupt descent to the Gulf and the general proximity of the range to the coastline make sea level there a practical delimitation for avifaunal analysis.
Effectiveness of 44 federal protected areas (PA) for preventing land use and land cover changes (LULC) in Mexico is examined, comparing results and methodological approaches used in previous studies. We quantified the percentage of transformed area (TS) in 2002 and its rate of change between 1993 and 2002. We compared observed TS rate of change in PA, adjacent areas, and their ecoregions of location. An effectiveness index was build to produce a characterization of LULC processes developed for each PA. In 2002, 77% PA showed less than 20% covered by TS; nearly 30% of PA showed a reduction of TS. Additionally, in 30% of PA, TS increase exceeded the mean rate for all PA. More than 70% of PA showed lower LULC rates than their surrounding areas, and in 80% of PA, these rates were lower than those observed in their corresponding ecoregions. Overall, PA were effective to prevent LULC processes as previously suggested. However, trends derived from this type of analyses depend on methodological specifications. Effectiveness indexes should be complemented with a detailed characterization of LULC processes and their interpretation should correspond to the specific methodological approach used.
Improper practices of land use and land cover (LULC) including deforestation, expansion of agriculture and infrastructure development are deteriorating watershed conditions. Here, we have utilized remote sensing and GIS tools to study LULC dynamics using Cellular Automata
(CA)–Markov model and predicted the future LULC scenario, in terms of magnitude and direction, based on past trend in a hydrological unit, Choudwar watershed, India. By analyzing the LULC pattern during 1972, 1990, 1999 and 2005 using satellite-derived maps, we observed that the biophysical and socio-economic drivers including residential/industrial development, road–rail and settlement proximity have influenced the spatial pattern of the watershed LULC, leading to an accretive linear growth of agricultural and settlement areas. The annual rate of increase from 1972 to 2004 in agriculture land, settlement was observed to be 181.96, 9.89 ha/year, respectively, while decrease in forest, wetland and marshy land were 91.22, 27.56 and 39.52 ha/year, respectively. Transition probability and transition area matrix derived using inputs of (i) residential/industrial development and (ii) proximity to transportation network as the major causes. The predicted LULC scenario for the year 2014, with reasonably good accuracy would provide useful inputs to the LULC planners for effective management of the watershed. The study is a maiden attempt that revealed agricultural expansion is the main driving force for loss of forest, wetland and marshy land in the Choudwar watershed and has the potential to continue in future. The forest in lower slopes has been converted to agricultural land and may soon take a call on forests occurring on higher slopes. Our study utilizes three time period changes to better account for the trend and the modelling exercise; thereby advocates for better agricultural practices with additional energy subsidy to arrest further forest loss and LULC alternations.
Spatially land use models are indispensable for sustainable land use planning. This study demonstrates a combined Markov–Cellular Automata model to analyze temporal change and spatial distribution of land use stressed by natural and socioeconomic factors in Saga, Japan. Firstly, area change and spatial distribution of land use are calculated using GIS technology, and then the transition among different land use types is analyzed to obtain the transformation matrices during a period of 1976–2006. Meanwhile, an integration evaluation procedure with natural and socioeconomic data is used to generate the transition potential maps. Secondly, using the transition potential maps and transition matrices, a Markov–Cellular Automata model is established to simulate spatial distribution of land use in 2006. Finally, we use this Markov–Cellular Automata model to forecast the future land use changes during the period of 2015–2042. As a consequence, area change simulation predicts a continuing downward trend in agriculture land and forestland areas, as well as an upward trend in built-up areas; spatial distribution simulation indicates that built-up land will expand toward suburban regions, and land use of urban center is at the decline stage. Hence, if the current trends keep constant without holistic sustainable development measures, severe land use decline will ensue. The study is anticipated to help local authorities better understand and address a complex land use system, and develop the improved land use management strategies that can better balance urban expansion and ecological conservation.
The growing prevalence of fragmentation and fire in tropical forests makes it imperative to quant fy changes in these disturbances and to understand the ways in which they interact across the landscape. I used a multitemporal series of Landsat images to study the incidence and coincidence of fire and fragmentation in two areas of Para state in the eastern Brazilian Amazon,, Tailandia and Paragominase. In both areas, deforestation and forest fires were quantified for time series of 6-10years. The Tailandia study area typifies a landscape with The herringbone pattern of government-settled colonists, and the Paragominas area is dominated by large cattle ranches. In both areas, over 90% of the forests affected by fire were associated with form est edges. Although most burned forest occurred within 500 m of forest edges, some fires occurred in deep forest, several kilometers from any edge. The obvious synergism between forest fragmentation and fire poses serious risks to tropical ecosystems and has important implications for land management.
On the basis of ground surveys, aerial photographs (for 1967 and 1976), and satellite imagery (for 1986), maps of rain forest distribution were developed for the northern part of the Sierra de Los Tuxtlas (Veracruz, southeast Mexico).
Forest coverage maps for 1967, 1976, and 1986 show dramatic deforestation proceeding up from the lowlands, with the remaining natural vegetation now increasingly restricted to the high, steep, and less accessible parts of the Sierra. From the digitizing of the maps it was estimated that (1) during the nearly 20 years of this analysis the vegetation was reduced by 56%, and (2) by early 1986, approximately 84% of the original forest area had been lost.
The derived annual deforestation rates (expressed as the percentage of remaining forest that is cleared per year) were 4.2% for the interval 1967–1976 and 4.3% for 1976–1986. Were these trends and rates to continue, only 8.7% of the original vegetation would persist by the year 2000, and then only in the form of an archipelago of very small forest fragments of which the largest would be the now‐protected areas (e.g, the Los Tuxtlas Biological Station with only 640 ha), and the most inaccessible tracts.
Immediate action is urgently needed to protect these small but rich remnants and preserve them as foci of potential biological inocula for future ecorestoration of these, the northernmost tropical forests on the continent.
This paper presents an image noise filter based on cellular automata (CA), which can remove impulse noise from a noise corrupted image. Uniform cellular automata rules are constructed to filter impulse noise from both binary and gray scale images. Several modifications to the standard CA formulation are then applied to improve the filtering performance. For example, a random CA rule solves the noise propagation present in deterministic CA filters. A mirrored CA is used to solve the fixed boundary problem. The performance of this CA approach is compared with the classical median filter and different switching filters in terms of peak signal to noise ratio. This comparison shows that a filter based on cellular automata provides significant improvements over the standard filtering methods.
Spatially explicit land use/cover models are indispensable for sustainable rural land use planning, particularly in southern African countries that are experiencing rapid land use/cover changes. Using Zimbabwe as an example, we simulated future land use/cover changes up to 2030 based on a Markov-cellular automata model that integrates Markovian transition probabilities computed from satellite-derived land use/cover maps and a cellular automata spatial filter. A multicriteria evaluation (MCE) procedure was used to generate transition potential maps from biophysical and socioeconomic data. Dynamic adjustments of transition probabilities and transition potential map thresholds were implemented in the Markov-cellular automata model through a multi-objective land allocation (MOLA) procedure. Using the normalised transition probabilities, the Markov-cellular automata model simulated future land use/cover changes (up to 2030) under the 2000 calibration scenario, predicting a continuing downward trend in woodland areas and an upward trend in bareland areas. Future land use/cover simulations indicated that if the current land use/cover trends continue in the study area without holistic sustainable development measures, severe land degradation will ensue.
Forest fragmentation threatens biodiversity in one of the last remaining temperate rainforests that occur in South America. We study the current and future impacts of fragmentation on spatial configuration of forest habitats at the landscape level time in southern Chile. For this purpose, we identify the geophysical variables (“pattern drivers”) that explain the spatial patterns of forest loss and fragmentation between 1976 and 1999 using both a GIS-based land-use change model (GEOMOD) and spatially explicit logistic regression. Then, we project where and how much forest fragmentation will occur in the future by extrapolation of the current rate of deforestation to 2010 and 2020. Both modeling approaches showed consistent and complementary results in terms of the pattern drivers that were most related to deforestation. Between 1976 and 1999, forest fragmentation has occurred mainly from the edges of small fragments situated on gentle slopes (less than 10°) and far away from rivers. We predict that patch density will decline from 2010 to 2020, and that total forest interior area and patch proximity will further decline as a result of forest fragmentation. Drivers identified by these approaches suggest that deforestation is associated with observed local socio-economic activities such as clearance of forest for pasture and crops and forest logging for fuelwood.
Questions of land use/land cover change have attracted interest among a wide variety of researchers concerned with modeling the spatial and temporal patterns of land conversion and understanding the causes and consequences of these changes. Among these, geographers and natural scientists have taken the lead in developing spatially explicit models of land use change at highly disaggregate scales (i.e. individual land parcels or cells of the landscape). However, less attention has been given in the development of these models to understanding the economic process — namely, the human behavioral component — that underlies land use change. To the extent that researchers are interested in explaining the causal relationships between individual choices and land use change outcomes, more fully articulated economic models of land use change are necessary.
Object based image analysis (OBIA) is an approach increasingly used in classifying high spatial resolution remote sensing images. Object based image classifiers first segment an image into objects (or image segments), and then classify these objects based on their attributes and spatial relations. Numerous algorithms exist for the first step of the OBIA process, i.e. image segmentation. However, less research has been conducted on the object classification part of OBIA, in particular the spatial relations between objects that are commonly used to construct rules for classifying image objects and refining classification results. In this paper, we establish a context where objects are areal (not points or lines) and non-overlapping (we call this “single-valued” space), and propose a framework of binary spatial relations between segmented objects to aid in object classification. In this framework, scale-dependent “line-like objects” and “point-like objects” are identified from areal objects based on their shapes. Generally, disjoint and meet are the only two possible topological relations between two non-overlapping areal objects. However, a number of quasi- topological relations can be defined when the shapes of the objects involved are considered. Some of these relations are fuzzy and thus quantitatively defined. In addition, we define the concepts of line-like objects (e.g. roads) and point-like objects (e.g. wells), and develop the relations between two line-like objects or two point-like objects. For completeness, cardinal direction relations and distance relations are also introduced in the proposed context. Finally, we implement the framework to extract roads and moving vehicles from an aerial photo. The promising results suggest that our methods can be a valuable tool in defining rules for object based image analysis.
The anthropogenic deforestation occurring throughout the tropical world is one of the great crises of our time. To better understand the dimensions of this problem, a number of studies have sought to quantify the extent and rate of tropical forest loss. However, environmental planners and managers need to know more than the extent and rate of tropical deforestation. There is a need for predictability, i.e. which areas are most susceptible to deforestation. This study demonstrates a methodology for predicting those areas with the greatest propensity for deforestation based on natural and cultural landscape variables. Logistic regression analysis was used to determine variables most closely associated with deforestation. The independent variables most strongly associated with the forested/deforested dependent variable were location of forested areas in relation to the forested/deforested edge in an earlier time period, to the location of access in an earlier time period, and to the location of habitation in an earlier time period. GIS analysis was then used to verify spatially the close statistical relationship between the dependent variable and each of the independent variables selected by the logistic regression modeling.
Land-cover and land-use (LCLU) change was quantified for the last 35 years within and in the vicinity of a fast growing city in Mexico, using rectified aerial photographs and geographic information systems (GIS). LCLU change was projected for the next 20 years using Markov chains and regression analyses. The study explored the relationships between urban growth and landscape change, and between urban growth and population growth. The analysis of Markov matrices suggests that the highest LCLU attractor is the city of Morelia, followed by plantations and croplands. Grasslands and shrublands are the least stable categories. The most powerful use of the Markov transition matrices seems to be at the descriptive rather than the predictive level. Linear regression between urban and population growth offered a more robust prediction of urban growth in Morelia. Hence, we suggest that linear regression should be used when projecting growth tendencies of cities in regions with similar characteristics.
Firstly, this paper analyzes the basic principles and processes of the spatial pattern changes of land use in towns and villages, and the result shows that the land resource demands of urban development and population growth lead to the spatial pattern changes. Secondly, in order to grip land use changes better, the paper proposes a method for the simulation of spatial patterns. The simulating method can be divided into two parts: one is a quantitative forecast by using the Markov model, and the other is simulating the spatial pattern changes by using the CA model. The above two models construct the simulative model of the spatial pattern of land use in towns and villages. Finally, selecting Fangshan which is a district of Beijing as the experimental area, both the quantity and spatial pattern changing characteristics are investigated through building a changing dataset of land use by using spatial analysis methods based on the land use data in 2001, 2006 and 2008; CA–Markov is used to simulate the spatial pattern of land use in Fangshan for 2015.
Incluye bibliografía e índice
Human population and development activities affect the rate of deforestation in biodiversity hotspots. We quantified the effect of human population growth and development on rates of deforestation and analyzed the relationship between these causal factors in the 1980s and 1990s. We compared the averages of population growth, human development index (HDI, which measures income, health, and education), and deforestation rate and computed correlations among these variables for countries that contain biodiversity hotspots. When population growth was high and HDI was low there was a high rate of deforestation, but when HDI was high, rate of deforestation was low, despite high population growth. The correlation among variables was significant for the 1990s but not for the 1980s. The relationship between population growth and HDI had a regional pattern that reflected the historical process of development. Based on the changes in HDI and deforestation rate over time, we identified two drivers of deforestation: policy choice and human-development constraints. Policy choices that disregard conservation may cause the loss of forests even in countries that are relatively developed. Lack of development in other countries, on the other hand, may increase the pressure on forests to meet the basic needs of the human population. Deforestation resulting from policy choices may be easier to fix than deforestation arising from human development constraints. To prevent deforestation in the countries that have such constraints, transfer of material and intellectual resources from developed countries may be needed. Popular interest in sustainable development in developed countries can facilitate the transfer of these resources.
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