Estación Biológica de Doñana
  • Sevilla, Sevilla, Spain
Recent publications
Long-term information on species trends is needed to accurately assess the magnitude of biodiversity change. Mining wildlife records from historical documents is a promising option to describe past species distributions and estimate conservation baselines. However, historical species records have multiple biases, and ignoring them can produce distorted views of past species distributions and misinform present-day environmental management. Here, we use recently published analyses of Iberian wolf (Canis lupus signatus) historical ranges in Spain to show how information gaps and biases in historical species accounts may lead to misleading conclusions about range trends and a downgrade of conservation targets. We call for the adoption of predictive models to assess historical species ranges for conservation and propose guidelines for the management and analysis of historical species records.
Coastal urbanization, plastic pollution and climate change are increasingly affecting marine turtles' nesting habitats. In addition to facing risks of mortality due to saltwater inundation or predation, their eggs and hatchlings' might also be affected by plastic debris accumulation on beaches, but no studies to date have analysed such impact. To analyse whether plastic pollution on nests' surfaces affects the embryos' and hatchlings' survival odds, we designed a field experiment in a turtle hatchery on a nesting beach of the loggerhead turtle (Caretta caretta) in Boa Vista Island (Cabo Verde). We applied three treatments with distinct plastic levels (18 nests per treatment): control (no added plastics), low density (64 plastic fragments with 24.5 g of plastic weight per nest) and high density (128 plastic fragments with 49.0 g of plastic weight per nest). Then, we tested 16 variables related to the incubation period, emergence period and hatchlings' fitness. Our results suggest that nests with high plastic density have a significantly lower probability of successful emergence. Moreover, plastics also affected the synchronized emergence of hatch-lings, with more scattered and smaller emergent groups, which might increase the predation risk. Considering that turtle nesting habitats are becoming increasingly threatened, this additional threat might compromise the survival of turtle hatchlings on beaches.
Amphibians have undergone important evolutionary transitions in reproductive modes and life-cycles. We compare large-scale macroevolutionary patterns in these transitions across the three major amphibian clades: frogs, salamanders, and caecilians. We analyse matching reproductive and phylogenetic data for 4025 species. We find that having aquatic larvae is ancestral for all three groups and is retained by many extant species (33–44%). The most frequent transitions in each group are to relatively uncommon states: live-bearing in caecilians, paedomorphosis in salamanders, and semi-terrestriality in frogs. All three groups show transitions to more terrestrial reproductive modes, but only in caecilians have these evolved sequentially from most-to-least aquatic. Diversification rates are largely independent of reproductive modes. However, in salamanders direct development accelerates diversification whereas paedomorphosis decreases it. Overall, we find a widespread retention of ancestral modes, decoupling of trait transition rates from patterns of species richness, and the general independence of reproductive modes and diversification. Here, the authors use reproductive mode data with matching phylogenetic data to explore the evolution of reproductive mode, transitions between reproductive modes, and diversification rates in amphibians.
Energy infrastructure is expanding at a global scale and can represent a major threat to wildlife populations. Power lines are one of the main sources of human-induced avian mortality due to electrocution or collision, but many species use electricity pylons as a structure for nesting. Pylon nesting results in human-wildlife conflict because it can cause power outages and structural damage to power lines. The white stork (Ciconia ciconia) is a large-size semicolonial species that increasingly nests on pylons, causing growing operational and economic issues to power companies and energy consumers. In this study, the likelihood of problematic pylon use by nesting storks was predicted using a suite of explanatory variables related to the availability of foraging habitat and human disturbance. During a five-year period (2015–2019), we assessed the distribution of stork nests removed from the highly-risky top part of transmission pylons (220–400 kV) by power company technicians in South western Spain. A total of 839 nests were removed from 11% of the transmission pylons (n = 1196) during the study period. Pylon use intensified on pylons located near to landfills, surrounded by high proportion of grassland, and when close to freshwater sources (water body or river) and other occupied pylons. Human disturbance was unlikely to deter storks from using pylons and pylon use increased in urban areas. The approach used here to predict pylon use by nesting birds has applications for both human-wildlife conflict mitigation and conservation purposes where endangered species use human infrastructure. Power companies may use this kind of information to install anti-nesting devices (to reduce power outages and avian mortality or nesting platforms on suitable pylons (to promote pylons use by endangered species), and to account for the likelihood of conflict-prone use of pylons when siting future power lines.
Species interactions can propagate disturbances across space via direct and indirect effects, potentially connecting species at a global scale. However, ecological and biogeographic boundaries may mitigate this spread by demarcating the limits of ecological networks. We tested whether large-scale ecological boundaries (ecoregions and biomes) and human disturbance gradients increase dissimilarity among plant-frugivore networks, while accounting for background spatial and elevational gradients and differences in network sampling. We assessed network dissimilarity patterns over a broad spatial scale, using 196 quantitative avian frugivory networks (encompassing 1496 plant and 1004 bird species) distributed across 67 ecoregions, 11 biomes, and 6 continents. We show that dissimilarities in species and interaction composition, but not network structure, are greater across ecoregion and biome boundaries and along different levels of human disturbance. Our findings indicate that biogeographic boundaries delineate the world’s biodiversity of interactions and likely contribute to mitigating the propagation of disturbances at large spatial scales.
Context Soaring birds depend on atmospheric uplifts and are sensitive to wind energy development. Predictive modelling is instrumental to forecast conflicts between human infrastructures and single species of concern. However, as multiple species often coexist in the same area, we need to overcome the limitations of single species approaches. Objectives We investigate whether predictive models of flight behaviour can be transferred across species boundaries. Methods We analysed movement data from 57 white storks, Ciconia ciconia , and 27 griffon vultures, Gyps fulvus . We quantified the accuracy of topographic features, correlates of collision risk in soaring birds, in predicting their soaring behaviour, and tested the transferability of the resulting suitability models across species. Results 59.9% of the total area was predicted to be suitable to vultures only, and 1.2% exclusively to storks. Only 20.5% of the study area was suitable to both species to soar, suggesting the existence of species-specific requirements in the use of the landscape for soaring. Topography alone could accurately predict 75% of the soaring opportunities available to storks across Europe, but was less efficient for vultures (63%). While storks relied on uplift occurrence, vultures relied on uplift quality, needing stronger uplifts to support their higher body mass and wing loading. Conclusions Energy landscapes are species-specific and more knowledge is required to accurately predict the behaviour of highly specialised soaring species, such as vultures. Our models provide a base to explore the effects of landscape changes on the flight behaviour of different soaring species. Our results suggest that there is no reliable and responsible way to shortcut risk assessment in areas where multiple species might be at risk by anthropogenic structures.
Context Mediterranean wetland ecosystems are in continuous decline due to human pressure. Amphibians are key elements of biotic communities of Mediterranean temporary ponds and streams, and their persistence depends on the availability and inter-connectivity of breeding sites. Objectives We investigated the role of different factors potentially driving functional connectivity patterns in two amphibian species at the landscape and local scales. We focused on two Mediterranean endemic pond-breeding amphibians inhabiting semi-arid landscapes of central Spain, the common parsley frog (Pelodytes punctatus) and the common midwife toad (Alytes obstetricans). Methods We genotyped 336 individuals of P. punctatus and 318 of A. obstetricans from 17 and 16 breeding populations at 10 and 17 microsatellite loci, respectively. We used remotely sensed vegetation/moisture indices and land use/cover data to derive optimized resistance surfaces and test their association with estimates of gene flow and migration rates across populations. Results We found evidence for higher population connectivity in common midwife toads than in common parsley frogs, with a strong effect of water availability in patterns of population connectivity of both species. However, the two species differ in the role of landscape features on population connectivity, with the distance and spatial distribution of artificial land-use types positively influencing connectivity in A. obstetricans and meadows/pastureland favouring P. punctatus. This is in line with reported breeding site preferences for the two species, with A. obstetricans successfully breeding in artificial water bodies that P. punctatus generally avoid. Conclusions This study highlights the importance of assessing species–habitat relationships shaping connectivity when developing and implementing conservation and management actions to benefit fragmented amphibian populations in the Mediterranean region. Our results show that amphibian species respond differently, even contrastingly to landscape features and thus require alternative, complementary strategies to improve population connectivity and ensure long-term viability.
Climate change may affect life on Earth in multiple ways. Whereas some populations may encounter detrimental conditions that cause extirpations, those occupying cooler thermal limits of a range may benefit by expanding. For sea turtles, egg maturation in the female oviduct and nest incubation are temperature-dependent and vulnerable to climate change. Mediterranean loggerhead turtles Caretta caretta nest in the eastern basin although sporadic nesting occurs on the western side. To assess the likelihood of a climate-related expansion, we compared historical air and sea surface (SST) temperatures between locations near established eastern nesting areas and western areas where sporadic nesting is increasing (Palinuro, Italy) or just started (Balearic Islands, Spain). Our results suggest that summer air and water temperatures in western sites were suitable for nesting over the last 40-50 yr, at least in July-August, having (1) SSTs above suboptimal threshold temperature (22°C) and (2) similar air temperatures to those of Greece, but among the lowest in the Mediterranean. There was a decreasing east-to-west gradient in SST. However, SSTs were similar around beaches of Zakynthos (Greece), Palinuro and Ibiza (Balearic Islands), where SST was above 22°C for at least 60 d, potentially allowing turtles to lay multiple clutches. A warming trend was detected in air temperature and SST since the 1970s-1980s. Although conditions in the western Mediterranean currently seem suitable for nesting, lower air temperatures in May-June and higher precipitation in September could shrink the nesting window. If warming continues, conditions in the western basin could progressively become more favorable for nesting.
Pollination service is crucial to achieve successful plant sexual reproduction and long-term population persistence. This pollination service can be affected by plant conspecific density and also by intrinsic features of individuals related to their flowering phenology and floral display. However, studies examining intrinsic and extrinsic traits on pollinator visitation and reproductive success of Mediterranean trees with limited reproduction are still scarce. We analyzed the effects of plant isolation, flowering phenology, flower weight and tree size on flower visitation probability, flowering patch visitation probability, fruit set and crop size. To this end, we intensively monitored pollinator visitation and fruit production of 67 (in 2019) and 73 (in 2020) Pyrus bourgaeana Decne trees within a threatened Mediterranean population. Our results revealed that isolated individuals received more pollinators than those on conspecific aggregations, suggesting intraspecific competition for pollinators in dense flowering neighborhoods. However, fruit set was higher in trees close to flowering conspecifics despite having fewer visits from pollinators, suggesting pollen limitation but not pollinator limitation in spatially isolated trees. Interestingly, we found increased crop sizes in spatially isolated trees which could be related to reduced intraspecific competition for resources in low-density neighborhoods (water, nutrients) and/or to higher reproductive investment (i.e. higher flower production). Overall, our results indicated pollen but not pollinator limitation in spatially isolated trees. Under this scenario of sexual reproduction mediated by pollinators, our findings stress the relevance of individuals' spatial distribution for self-incompatible trees exhibiting low individuals’ densities.
A major aim in invasion ecology is to understand the role of exotic species in plant communities. Whereas most studies have explored the traits of exotic species in the context of the introduced community, functional comparisons of entire assemblages of species in their native and introduced communities have rarely been analysed. Taking advantage of the unidirectional invasion of plant species of European origin (i.e. colonizers) into California, this study aims to investigate the relative importance of plant traits, environmental factors, and invasion status in biological invasions. We compared the functional structure (i.e. trait composition and diversity) along resource availability gradients in recipient and native Mediterranean grassland communities in California and Spain, respectively. Traits were related to resource use in above‐ and belowground organs and reproductive strategy. We also investigated how niche differences vary along environmental gradients between coexisting colonizer and native species assemblages within communities. There were clear differences in the functional structure of Mediterranean grassland communities between regions, which were associated with the resource availability gradient. Paradoxically, the most acquisitive communities occurred in resource‐poor sites, highlighting that rapid acquisition and use of resources permit species to cope with environmental stress through stress avoidance. In Spain, colonizer species had greater SLA than non‐colonizers. Yet, differences between colonizer and non‐colonizer species in Spain for other traits were mostly absent and did not change along the gradient. This might be a result of the greater native species richness as a consequence of the agricultural practices that have taken place in Europe for millennia and reflect that the entire species pool of grasslands is adapted to agricultural landscapes. In comparison, in California, colonizer species were more acquisitive in their use of resources than natives under favourable conditions, but functionally converged in resource‐limited sites. Synthesis. These results underscore that the importance of niche differences between native and colonizer species as a community assembly mechanism is strongly subjected to the influence of habitat filtering. Trait comparisons are context dependent, and a correct interpretation of filtering processes in community assembly requires a regional perspective.
Migratory waterfowl are important endozoochory vectors for a range of plants lacking fleshy fruits. Our aim was to study the critical question of how endozoochory rates change throughout the annual cycle, and how this relates to plant life‐form and phenology. Lake Velence, Hungary. 2017–2018. Mallard (Anas platyrhynchos), Angiospermae, Charophyta. We studied waterfowl endozoochory, quantifying seeds and other diaspores dispersed by mallards by collecting faecal samples monthly (ntotal = 670) at a Hungarian lake. We tested the germinability of all seeds recovered from the faecal samples. We extracted 5,760 seeds representing 35 plant taxa from mallard faecal samples, and 40% of these seeds germinated successfully following gut passage. We found major differences between seasons in the species composition of the seeds recovered. The peak in species diversity and in abundance of terrestrial seeds coincided with the spring migration of mallards. Importantly, endozoochory was only strongly synchronized with seed production in submerged, but not in emergent or terrestrial plants, illustrating the potential for endozoochory of seeds ingested from the soil seed bank. Overall, our results suggest that endozoochory by migratory waterfowl is a strong and underestimated driver of plant distributions, and is likely to facilitate plant range shifts under climate change, and after introduction of alien species.
Living organisms are exposed to a wide range of substances - internal and external - which act like reactive oxygen species (ROS). Oxidative damage accurs when the balance between ROS and antioxidant defenses is altered. Urbanization and parasite infection are both important sources of ROS with different harmful effects on wildlife health, but the potential synergies between both factors are poorly known. Here, we analyse the oxidative stress of wild juvenile male house sparrows (Passer domesticus) along an urbanization gradient in relation to the infection status by three common blood parasites (Plasmodium, Haemoproteus and Leucocytozoon) and bird body condition. We analysed samples from 688 birds captured at 45 localities from southern Spain grouped into triplets including an urban, a rural and a natural habitat, with 15 localities per habitat type. We measured i) thiobarbituric acid reactive substances (TBARS) levels as indicator of the oxidative damage to lipids, and the activity of three antioxidant enzymes ii) glutathione peroxidase (GPx), iii) superoxide dismutase (SOD) and iv) glutathione reductase (GR) as indicators of bird's antioxidant capacity. Birds infected with Haemoproteus and urban birds showed significantly and marginally higher levels of TBARS than uninfected and rural birds, respectively. The relationship between TBARS and body condition is different regarding the infection status (significative) and habitat (marginally significant) being negative for Haemoproteus infected and urban birds but positive for uninfected and non-urban birds. The antioxidant activity was significantly lower in Plasmodium infected birds but marginally higher in Leucocytozoon infected birds than in uninfected ones. Individuals with higher body condition had higher GPx and SOD activity in relation to a lower GR activity. Overall, these results suggest that blood parasites infections and urbanization affect the oxidative status of wild birds and highlight the role of bird's body condition on the regulation of the oxidative stress status.
Aim Over the last decades, the study of movement through tracking data has grown exceeding the expectations of movement ecologists. This has posed new challenges, specifically when using individual tracking data to infer higher‐level distributions (e.g. population and species). Sources of variability such as individual site fidelity (ISF), environmental stochasticity over time, and space‐use variability across species ranges must be considered, and their effects identified and corrected, to produce accurate estimates of spatial distribution using tracking data. Innovation We developed R functions to detect the effect of these sources of variability in the distribution of animal groups when inferred from individual tracking data. These procedures can be adapted for their use in most tracking datasets and tracking techniques. We demonstrated our procedures with simulated datasets and showed their applicability on a real‐world dataset containing 1346 year‐round migratory trips from 805 individuals of three closely related seabird species breeding in 34 colonies in the Mediterranean Sea and the Atlantic Ocean, spanning 10 years. We detected an effect of ISF in one of the colonies, but no effect of the environmental stochasticity on the distribution of birds for any of the species. We also identified among‐colony variability in nonbreeding space use for one species, with significant effects of population size and longitude. Main conclusions This work provides a useful, much‐needed tool for researchers using animal tracking data to model species distributions or establish conservation measures. This methodology may be applied in studies using individual tracking data to accurately infer the distribution of a population or species and support the delineation of important areas for conservation based on tracking data. This step, designed to precede any analysis, has become increasingly relevant with the proliferation of studies using large tracking datasets that has accompanied the globalization process in science driving collaborations and tracking data sharing initiatives.
A collective understanding of economic impacts and in particular of monetary costs of biological invasions is lacking for the Nordic region. This paper synthesizes findings from the literature on costs of invasions in the Nordic countries together with expert elicitation. The analysis of cost data has been made possible through the InvaCost database, a globally open repository of monetary costs that allows for the use of temporal, spatial, and taxonomic descriptors facilitating a better understanding of how costs are distributed. The total reported costs of invasive species across the Nordic countries were estimated at $8.35 billion (in 2017 US$ values) with damage costs significantly outweighing management costs. Norway incurred the highest costs ($3.23 billion), followed by Denmark ($2.20 billion), Sweden ($1.45 billion), Finland ($1.11 billion) and Iceland ($25.45 million). Costs from invasions in the Nordics appear to be largely underestimated. We conclude by highlighting such knowledge gaps, including gaps in policies and regulation stemming from expert judgment as well as avenues for an improved understanding of invasion costs and needs for future research.
Quantifying space use and segregation, as well as the extrinsic and intrinsic factors affecting them, is crucial to increase our knowledge of species-specific movement ecology and to design effective management and conservation measures. This is particularly relevant in the case of species that are highly mobile and dependent on sparse and unpredictable trophic resources, such as vultures. Here, we used the GPS-tagged data of 127 adult Griffon Vultures Gyps fulvus captured at five different breeding regions in Spain to describe the movement patterns (home-range size and fidelity, and monthly cumulative distance). We also examined how individual sex, season and breeding region determined the cumulative distance travelled and the size and overlap between consecutive monthly home-ranges. Overall, Griffon Vultures exhibited very large annual home-range sizes of 5,027 ± 2,123 km2, mean monthly cumulative distances of 1,776 ± 1,497 km, and showed a monthly home-range fidelity of 67.8 ± 25.5 %. However, individuals from northern breeding regions showed smaller home-ranges and travelled shorter monthly distances than those from southern ones. In all cases, home-ranges were larger in spring and summer than in winter and autumn. Moreover, females showed larger home-ranges and less monthly fidelity than males, indicating that the latter tended to use the similar areas throughout the year. Overall, our results indicate that both extrinsic and intrinsic factors modulate the home-range the social Griffon Vulture and that spatial segregation depend on sex and season at the individual level, without relevant differences between breeding regions in individual site fidelity.
Oceanic islands are usually difficult for mammals to colonize; consequently, the native mammal fauna is typically species-poor, often consisting of just a few species of bats. The oceanic islands of the Gulf of Guinea are no exception to this pattern. Still, the known mammal richness is relatively high for the small size of the islands. Out of a total of 13 native species, including 11 bats and 2 shrews, at least 7 species and 3 subspecies are single-island endemics. In addition to native species, at least 6 other wild mammals have been introduced to the islands purposely or accidentally by humans. Some of these are among the world’s most notorious invasive species and cause damage to native species, ecosystems, and humans. Predation by exotic species can threaten native island mammals, which are especially sensitive due to their small populations and limited ranges. These impacts are likely worsened by other threats, such as forest degradation and climate change, and a general lack of knowledge about the natural history of most species also hampers the implementation of conservation measures. Therefore, fostering further research on the endemic-rich mammal fauna of these islands is vital to ensure their persistence
Hominin footprints were recently discovered at Matalascañas (Huelva; South of Iberian Peninsula). They were dated thanks to a previous study in deposits of the Asperillo cliff to 106 ± 19 ka, Upper Pleistocene, making Neandertals the most likely track-makers. In this paper, we report new Optically Stimulated Luminescence dating that places the hominin footprints surface in the range of 295.8 ± 17 ka (MIS 9-MIS 8 transition, Middle Pleistocene). This new age implies that the possible track-makers are individuals more likely from the Neandertal evolutionary lineage. Regardless of the taxon attributed to the Matalascañas footprints, they supplement the existing partial fossil record for the European Middle Pleistocene Hominins being notably the first palaeoanthropological evidence (hominin skeleton or footprints) from the MIS 9 and MIS 8 transition discovered in the Iberian Peninsula, a moment of climatic evolution from warm to cool. Thus, the Matalascañas footprints represent a crucial record for understanding human occupations in Europe in the Pleistocene.
Studies on brood desertion in birds have been mainly conducted on species with biparental care, and less often on uniparental species. Females of many duck species remain with their ducklings, unassisted by males, during variable periods of time before the chicks can fledge. In this paper, we examined factors that influence brood desertion by female red-crested pochards ( Netta rufina), common pochards ( Aythya ferina) and white-headed ducks ( Oxyura leucocephala) during a 10-year period in lakes in southern Spain that experienced interannual variations in water levels. At an interspecific level, we found that brood desertion was less frequent in the species that nested earlier (red-crested pochard), while it was more frequent in the species that nested later (white-headed duck). Larger (older) ducklings were deserted more frequently than smaller ones in the three species. However, an interaction between flooding conditions in wetlands and species identity on brood desertion, after accounting for chick age, suggests that there were variations between the ducklings of the three species in their requirements for maternal care, conditioned by environmental conditions. Therefore, our study indicates that environmental conditions may affect parental care. A longer duration of brood attendance by female ducks may buffer against adverse effects of environmental conditions.
Traditional agro-pastoral practices are more beneficial for biodiversity than intensified agricultural systems. Promotion of growth of natural herbaceous vegetation in pastoral fields can enhance rodent populations and consequently influence ecological aspects of carnivores with rodent-based diets, like prey consumption in the European wildcat (Felis silvestris). In this article, we investigated the effects of pastoral field extent, season and prey abundance on wildcat consumption of several prey species in the Cantabrian Mountains (NW Spain). Prey consumption in areas with presence of pastoral fields (even in low proportions) was dominated by profitable field-dwelling rodent species such as Arvicola monticola. Consumption of Arvicola was not correlated with its abundance and was higher during summer and autumn. Apodemus dominated wildcat diet in areas with higher forest proportion and far from pastoral fields particularly during spring. Our results suggest that varying habitat use and seasonal changes in prey accessibility may determine wildcat prey consumption in pastoral landscapes. Our results can contribute to highlight the potential benefits of traditional and sustainable pastoral activities for the conservation of the European wildcat across its distribution range.
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137 members
Irene Mendoza
  • Integrative Ecology
José L Tella
  • Conservation Biology
Andy J Green
  • Wetland Ecology
Joaquín Ortego
  • Integrative Ecology
Jordi Figuerola
  • Department of Wetland Ecology
Avenida Américo Vespucio, 26, 41092, Sevilla, Sevilla, Spain
Head of institution
Eloy Revilla
0034 954 46 67 00