Biotropica

AimHuman land-use has dramatically altered the amount, quality, and connectivity of habitat for species worldwide. Understanding how these changes affect individual species is essential for predicting the overall consequences of land-use change for biodiversity. LocationThe Caribbean island of Puerto Rico. Forest cover on the island increased from about 18 to 45% from the late 1940s to the early 2000s. MethodsUsing data on geographic distributions and functional traits for 454 tree species, we evaluated how gain of potential habitat was related to species-specific climatic associations and life-history strategies. We estimated species-specific potential habitat (climatically suitable and forested) with species distribution models and data on forest cover. We characterized each species niche breadth (the range of environmental conditions it occupies) and niche position (the environmental conditions it prefers) to compare with the conditions in reforested areas. ResultsSpecies with relatively more potential habitat in 1951 (climatically suitable and forested) also had relatively larger gains in potential habitat from 1951 to 2000. Species that tend to occupy conditions different from those common in reforested areas (i.e., more marginal habitats) gained relatively less potential habitat and species with broad environmental niches gained more potential habitat. Additionally, species with relatively acquisitive functional traits gained more suitable habitat than those with relatively conservative traits. Main conclusionsOur results show that Puerto Ricos reforestation preferentially increased habitat for species that (1) already had suitable habitat in the landscape, (2) tolerate a wide range of climatic conditions, and (3) exhibit fast, acquisitive functional strategies. These findings illustrate how land-use change in heterogeneous tropical landscapes can generate non-uniform habitat gains across species, potentially favoring generalist over specialist species and reshaping community composition.

Stingless bees are key pollinators in tropical ecosystems, yet their ecological dynamics remain poorly understood in highly seasonal environments such as the seasonally dry tropical forests of Ecuador. These ecosystems experience pronounced climatic seasonality, with sharp transitions between dry and wet periods that strongly affect floral resource availability. Understanding interspecific competition and niche partitioning in such systems is critical, particularly given the global decline of pollinators. We investigated resource use and niche dynamics in two native stingless bees, Melipona mimetica and Scaptotrigona sp., by quantifying pollen, nectar, and resin collection across seasons. Log-linear models were used to test the effects of species, season, and their interaction on resource use, while non-metric multidimensional scaling (NMDS) assessed niche overlap. Contrary to the expectation that niche overlap increases under resource scarcity, we found greater overlap during the wet season, when resources are more abundant. This suggests that both species converge on high-quality floral resources during peak availability, reflecting an adaptive response to strong environmental seasonality. Pollen use remained stable across seasons, consistent with generalist foraging behavior. In contrast, nectar collection increased significantly during the wet season, while resin exhibited a shared seasonal peak, likely associated with synchronized nest construction or maintenance. These findings reveal context-dependent competition dynamics and highlight the role of environmental seasonality in shaping pollinator interactions. Our study provides new insights into the ecology of threatened stingless bees and contributes to their conservation in tropical dry forest ecosystems.

Gliding has evolved repeatedly across vertebrates and is often regarded as a classic example of convergent evolution associated with arboreal habitats. However, it remains unclear whether convergent locomotion corresponds to shared ecological responses across taxa. In this study, we investigated the distribution patterns and environmental drivers of gliding vertebrates in Southeast Asia using occurrence records and environmental variables representing climate and forest structure. We analyzed five major groups, including flying lemurs, flying squirrels, gliding lizards, gliding snakes, and gliding frogs, using presence-background logistic regression models. Across taxa, temperature seasonality showed consistently negative effects, while canopy height showed positive effects, indicating a shared association with climatically stable environments and well-developed vertical forest structure. In contrast, other environmental variables exhibited substantial taxon-specific variation. For example, elevation showed a strong negative effect only in gliding snakes, suggesting a tendency toward lowland habitats, whereas precipitation variables had limited explanatory power for gliding frogs. These results demonstrate that, despite the convergent evolution of gliding locomotion, ecological responses to environmental factors are not uniform across vertebrate taxa. Instead, species distributions are shaped by a combination of shared functional constraints and lineage-specific ecological traits. Our findings highlight the importance of vertical forest structure and suggest that habitat alteration affecting canopy structure may disproportionately impact certain taxa.

The small mammals in the tropical savannas of northern Australia, have undergone a degree of change in recent decades, best documented in the Northern Territory. Data is limited from northern Queensland and though the same trends are assumed, the topographic and climatic features differ substantially. In this study we examined data systematically collected from 725 sites between 1998-2012 in three bioregions representing a climatic gradient: from semi-arid to monsoon tropical savannas. We investigated via information-theoretic models and model averaging, the relationship between five mammal groupings and three landscape variables (fractional cover green, elevation and vegetation diversity) to elucidate any consistent or different patterns in the mammal fauna. Key patterns included relationships with increasing elevation (critical weight range species richness positively associated with elevation, rodent species richness negatively associated), increasing rodent and dasyurid species richness with vegetation diversity, and lower macropod and dasyurids abundance with increasing fractional cover green. These relationships underscore a need to consider mammal conservation in Queensland with more nuance than in the more topographically inert Northern Territory. Management strategies need to be more attuned to taxonomic and regional differences, to prevent perverse outcomes.

O_LITropical dry forests are among the most threatened ecosystems globally, yet the consequences of livestock overgrazing for ant communities remain poorly documented, particularly in the Tumbesian biodiversity hotspot of southwestern Ecuador, where uncontrolled goat grazing constitutes the dominant disturbance agent. C_LIO_LIWe sampled ant communities (Formicidae) across a goat-grazing disturbance gradient in Zapotillo (Loja Province, Ecuador), establishing three disturbance levels (Dense, Semi-dense, and Open Forest) with nine 60 x 60 m plots per level (n = 27) and 486 pitfall traps. Community responses were assessed using abundance-based and presence-absence analyses of morphospecies richness, Hill-number diversity, community composition, beta diversity decomposition, and functional guild structure; vegetation structure was characterized using satellite-derived NDVI. C_LIO_LIWe recorded 47,459 individuals belonging to 22 morphospecies in six subfamilies. Morphospecies richness declined with disturbance (Dense: 19, Semi-dense: 15, Open: 12), with four specialist genera exclusive to Dense Forest. Beta diversity decomposition revealed a shift from turnover-dominated dissimilarity at moderate disturbance to nestedness-dominated dissimilarity at high disturbance, indicating progressive habitat filtering as the dominant community-restructuring process. C_LIO_LICommunity composition differed among disturbance levels (PERMANOVA: F = 4.49, R{superscript 2} = 0.272, p = 0.001) and was correlated with NDVI (r{superscript 2} = 0.341, p = 0.013). Cryptic/soil and Leaf-cutter guilds were nearly eliminated from Open forest while the Opportunist guild expanded markedly, indicating that functional homogenization precedes detectable taxonomic impoverishment. C_LIO_LIOvergrazing drives directional ant diversity loss and biotic homogenization at both taxonomic and functional levels in the Tumbesian dry forest, underscoring the conservation value of intact Dense forest. C_LI

Plants, as structural elements of habitats, contribute greatly to the maintenance of local biodiversity through their biological interactions. In this study we explore whether their rarity, according to Rabinowitzs (1981) three criteria, is related to the richness and diversity of arthropods and other plants they are associated to, in a gypsum-rich steppe. We first analysed whether the geographic abundance and ecological specialisation of 32 characteristic and dominant plant species are related to the diversity (richness and phylogenetic diversity (MPD)) and degree of local specialisation of arthropods associated with them (1,694 taxa). Then, we focused on a non endemic and non specialized plant in the study area (Krascheninnikovia ceratoides) to explore the effect of population size on two types of interactions: aerial arthropods and plant facilitation. Results indicate that: 1) plant species abundance (geographical range) is not related to the richness or MPD of communities of associated arthropods, 2) plant species ecological specialization (edaphic endemisms or gypsophiles) do not contribute differentially to the maintenance of singular arthropod communities, and 3) the community of aerial arthropods and plants interacting with K. ceratoides in a small population are not necessarily less diverse than those in patches of similar size in a large population. Results also revealed that the two plant species with fewer interactions (one rare, one widespread) do show the highest singularity in their interactions with arthropods. Our study illustrates the important contribution of rare plants to the conservation of local biodiversity.

Background and aimsThis study combines morphological and environmental data to better understand a Brunfelsia (Solanaceae) species complex, aiming to clarify patterns of variation and identify ecological factors that shape morphotype boundaries. Such an approach provides a broader perspective on how organisms respond to environmental gradients and contributes to a more comprehensive understanding of biodiversity. MethodsWe analyzed 273 herbarium specimens for 13 morphological traits using univariate and ordination analyses, namely PCA and CVA. Climatic and edaphic variables were extracted for 147 specimens with georeferenced records. To assess habitat suitability and the ecological niche of each predefined morphotype, niche models under present conditions and niche overlap tests were conducted. A redundancy analysis (RDA) was applied to evaluate how environmental predictors explain variation in vegetative and floral traits. Finally, DAPC was used to estimate membership probabilities based on morphological and environmental data. Key ResultsTwo well-differentiated groups were recovered: the capitata-hydrangeiformis morphotype, allegedly composing a cline, and the ecologically and morphologically distinct "bahia" morphotype. Variation in floral traits was better explained by environmental predictors than variation in vegetative traits; moreover, floral traits were able to delineate morphotypes more robustly when plotted in isolation. However, when analyzing the results of ecological niche overlap, a significant ecological separation of the "bahia" morphotype from the others was observed. Therefore, key morphological characters for the taxonomy of Brunfelsia covary in part with environmental variables. ConclusionsThese findings support the recognition of "bahia" morphotype as a distinct species to be formally described. This integrative approach contributes to understanding diversification processes in biodiversity hotspots and highlights hidden taxonomic diversity within Brunfelsia, where many rare and narrow-endemic taxa lie.

Large herbivores play a vital role in shaping grassland ecosystems, yet many species face increasing threats from habitat loss, fragmentation, and human disturbance. In northern India, riverine grasslands of the Gangetic floodplains serve as essential habitats for such species, including the swamp deer (Rucervus duvaucelii duvaucelii), a habitat specialist that has experienced severe population declines, especially outside protected areas. We evaluated the structural vegetation composition of grasslands and swamp deer habitat use along the Ganges river, covering both protected regions (Jhilmil Jheel Conservation Reserve and Hastinapur Wildlife Sanctuary) and surrounding non-protected grasslands. Combining field-based vegetation surveys with NDVI-based remote sensing enabled the classification of grasslands into four ecologically significant types structured by Saccharum, Phragmites, and Typha species. Disturbance was prevalent across the landscape, with approximately 77% of grassland plots exhibiting signs of human impact. Pure Saccharum grasslands exhibited the highest disturbance levels, followed by mixed patches, while Phragmites-Typha patches showed the lowest disturbance. Conversely, Phragmites-Typha patches experienced the lowest levels of disturbance. Data from surveys and two radio-collared swamp deer indicated a consistent preference for mixed vegetation types, particularly Saccharum-dominated and Phragmites-Typha mixes, while avoiding heavily disturbed pure Saccharum patches. Seasonal changes in habitat use reflected context-dependent selection influenced by vegetation structure, hydrology, and disturbance regimes. Our results underscore the importance of conserving diverse grassland mosaics and reducing human pressures, especially in unprotected areas to promote the long-term survival of swamp deer and other grassland herbivores within the Gangetic floodplains.

Long-term field observations typically are the "gold-standard" for inferences of phenological sensitivities in montane systems but are spatially limited. Herbarium specimens provide broader spatial coverage, but their utility to accurately capture montane phenology remains poorly known. We compared flowering phenology of 45 species inferred from herbarium specimens with comparable data from nearly 50 years of direct observations at the Rocky Mountain Biological Laboratory. Estimates of flowering time and phenological sensitivity to snow density were consistent between herbarium specimens and observations, but observations revealed secondary flowering peaks. Herbarium specimens additionally yielded shallower estimates of phenological sensitivity to spring temperature than did field observations. Across co-occurring species, "early" flowering individuals inferred from herbarium specimens, rather than the mean response across all individuals, may better approximate community-level phenological responses to temperature changes. We conclude that herbarium specimens are reliable resources for closing gaps in understanding phenological variation along elevational gradients of montane systems.

Lack of sexual reproduction limits the fitness and long-term viability of many plant populations. This may pose a particular problem for populations at the edges of species ranges, which are often small and isolated and therefore may be less likely to attract pollinators. But despite the fact that many range-edge populations are of significant conservation concern and value, there is often little information about which visitors are effective pollinators, and few explicit tests of whether range-edge populations experience reduced pollination. Here, we assess which visitors are effective pollinators of sundial lupine (Lupinus perennis), a legume that is threatened in much of its range, and whether pollination success varies between populations in the range core and those at the species northern range edge. Across six populations in the northern USA and southern Canada (Ontario), sundial lupine was visited almost exclusively by bees, but only large bees (Bombus, Xylocopa) could be confirmed as effective pollinators in single-visit experiments. While seed production varied significantly among populations, visitation rates did not. Neither pollinator visitation, pollen receipt, nor seed production declined at sundial lupines northern range edge. We therefore found no evidence that pollination success constrains either performance of at-risk populations of sundial lupine or the species northern range limit.

O_LIAgricultural intensification can support the expansion of introduced species which are highly adapted to human-modified landscapes, but the mechanisms by which this occurs are often unclear. C_LIO_LIHere we investigate the spatial ecology of a rapidly expanding introduced bumble bee (Bombus impatiens) and a native congener (B. mixtus) in agricultural landscapes of southwestern British Columbia, Canada. We used microsatellite genotyping and spatially explicit capture-recapture models to compare the foraging distance of the two species, and fitted hierarchical models to compare their abundance, behaviour (nest searching vs foraging), and lineage survival as a function of landscape composition and configuration. C_LIO_LIWe found that B. impatiens had a broader foraging range than B. mixtus, and that its colony/worker abundance were positively associated with the surrounding area of residential gardens, but decreased relative to B. mixtus abundance in response to increasing seminatural area. In contrast, B. mixtus colony abundance decreased in landscapes with a greater area of intensively managed berry crops. C_LIO_LIWe observed fewer B. impatiens queens per survey in landscapes with more low-disturbance landcover, and hypothesize space use of this species could be shaped by concentration on potential nesting habitat. Consistent with this observation, nest searching behaviour was more common for B. impatiens queens, while B. mixtus queens were primarily observed foraging, suggesting these two species derive different value from agricultural landscapes during colony establishment. C_LIO_LIFinally, we found that the rate of lineage re-capture between 2022 colonies and 2023 spring queens was nearly 10-fold higher for B. impatiens than for B. mixtus, indicating a greater capacity of the introduced species to complete its life cycle in agro-natural landscape mosaics. C_LIO_LIOur results suggest that differences in spatial ecology may contribute to the differential success of these two species in human-modified landscapes, and provide insight into the mechanisms by which land-use change shapes community composition. C_LI O_FIG O_LINKSMALLFIG WIDTH=184 HEIGHT=200 SRC="FIGDIR/small/723627v1_ufig1.gif" ALT="Figure 1"> View larger version (62K): org.highwire.dtl.DTLVardef@1e72eacorg.highwire.dtl.DTLVardef@a958a0org.highwire.dtl.DTLVardef@1f970b6org.highwire.dtl.DTLVardef@156f522_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical abstract. Coloured diagrams of B. mixtus and B. impatiens are credited to Elaine Evans and the Xerces Society, with permission.

Gene flow shapes the demographic stability and evolutionary potential of tropical forest trees, yet its dynamics may differ depending on the temporal scale at which it is assessed. We combined spatial genetic structure (SGS), parentage analyses, and reproductive success metrics to investigate historical and contemporary gene dispersal in four populations of Dicorynia guianensis across French Guiana, encompassing sites differing in environment and management history. A total of 1,528 individuals were genotyped using 66 nuclear and 23 plastid microsatellite markers, enabling high-resolution inference of biparental and maternal gene dispersal. Historical mating and dispersal parameters inferred from SGS revealed marked contrasts among populations. Some populations exhibited high historical gene dispersal distances and weak spatial genetic structure, whereas others showed stronger SGS and long-term aggregative dispersal patterns. Contemporary parentage analyses further highlighted differences in seed and pollen dispersal distances, parent assignment rates, and reproductive skew. In certain populations, pronounced reproductive inequality and reduced effective connectivity were observed, while others displayed more balanced reproductive contributions. By jointly evaluating long-term dispersal legacies and present-day reproductive patterns, our study demonstrates the value of combining indirect and direct genetic approaches to assess population dynamics and conservation status in tropical forest trees. This multi-temporal perspective provides a comprehensive basis for long-term monitoring and sustainable management in heterogeneous tropical landscapes.

Pollinator populations are facing worldwide declines, underscoring conservation needs. Yet, conservation assessments still mostly rely on occurrence data, often derived from heterogeneous and opportunistic observations. While such data can inform on species presence and distribution, they may overlook important markers of population declines. This is particularly problematic for social species such as bumble bees, which typically exhibit low effective population sizes despite high abundance of workers observed in the field. Despite these putative pitfalls, the relationship between occurrence-based and genetic-based estimates remains largely unexplored in social bees. We here investigated spatio-temporal genetic patterns in five Swiss Bombus species representing contrasting population trajectories over the last century: B. humilis and B. sylvarum (stable), B. ruderatus (increasing), B. pomorum (regionally extinct), and B. veteranus (declining). Museum specimens collected between 1929 and 2023 were genotyped at 11 microsatellite loci to compare spatio-temporal fluctuations in genetic diversity and population structure with occurrence data. Overall, multilocus heterozygosity and allelic richness remained stable in all species during the time period investigated, indicating that the diverging population trends did not result in substantial variation of genetic diversity. In contrast, strong and significant shifts in allelic frequencies between time periods were detected in three species, suggesting recent immigration events. Isolation by distance was detected in the cold-adapted B. veteranus, while the extant warm-adapted species (B. humilis, B. sylvarum, B. ruderatus) showed high levels of gene flow between locations. In B. pomorum, increasing genetic homogenization was observed before extinction. Altogether, these findings show that genetic diversity indexes are not the most adapted tools to monitor conservation status of social bee populations, and that estimates of population structure such as allelic shifts may be more informative. Moreover, these results highlight the importance of monitoring metapopulation dynamics and ensuring connectivity among populations to facilitate gene flow and enable demographic rescue processes.

West African savannahs provide habitats to diverse species assemblages, yet remain understudied compared to their East and Southern African counterparts. The Niokolo-Koba National Park in southeastern Senegal constitutes one of the largest remaining protected areas in West Africa and supports a mosaic of savannah and forest habitats with a diverse assemblage of medium- and large-sized mammals. Here, we analysed camera-trap data originally collected to monitor predator presence in the northwestern sector of the National Park. We deployed 37 cameras across 37 km{superscript 2} from February 2022 to March 2023, resulting in 13,161 camera-trap-days. We assessed alpha diversity indices and spatiotemporal activity patterns of large and medium-sized mammals across habitat types. Evenness values - the degree to which species abundances are distributed uniformly within a community - were higher in the savannah than in forest habitats, although overall species richness was comparable. In contrast, animal sighting rates were higher in forests than in savannahs. Estimated diel activity mostly corresponded with established species-specific behavioural patterns. Our analyses revealed differential use of certain habitat types across the day, likely driven by spatially segregated sleeping sites and foraging locations. Our results provide a reference for future studies and monitoring efforts and highlight the value of the forest-savannah mosaic for the local species assemblage within the larger ecosystem of Niokolo-Koba National Park.

Mangroves play a crucial role in supporting global biodiversity and ecosystem functioning, yet how their multidimensional diversity interact and respond under diverse stress conditions remains underexplored. To address this gap, using species, environmental, functional trait and forest structural data collected from the permanent sample plot (PSP) network (110 PSPs) of the worlds largest mangrove ecosystem, the Sundarbans, we answer three key questions: (Q1) How are structural, functional, taxonomic, and phylogenetic diversities interconnected? We hypothesized that these diversity components are positively correlated (H1). (Q2) What are the key environmental stressors and how the diversity components are influenced by multiple stressors? We hypothesized that these stressors negatively affect all diversity components (H2). (Q3) What spatial patterns emerge in the distributions of these diversity components? Here we hypothesized that these diversity components vary across space under changing environmental conditions (H3). Our results show that taxonomic, functional, structural, and phylogenetic diversity have varying degrees of interconnection. While taxonomic and structural diversity are strongly correlated, functional and phylogenetic diversity exhibit more independent patterns, suggesting distinct ecological processes shape each dimension. Salinity, elevation, silt, community structure and downstream-upstream gradient (i.e., upriver position) have strong influences on all the diversity components although the magnitude of the influence varies. GAM results reveal that salinity and siltation act as the primary negative drivers for most dimensions; however, functional richness and divergence show a unique positive response to salinity. Furthermore, we found that community structure and upriver position significantly influence diversity patterns, often in a non-linear fashion. Though taxonomic, structural, and phylogenetic diversity show higher values mainly in the moderate and low saline areas, functional richness shows higher values in high saline areas. Overall, our results provide strong support for all the hypotheses. Our findings highlight the importance of holistic approach integrating taxonomic, structural, functional, and phylogenetic dimensions for maintaining biodiversity and ecosystem functions in dynamic mangrove ecosystems and emphasize the need for conservation efforts that target moderate-stress zones to preserve both ecological and evolutionary diversity. HighlightsO_LIExplored the interconnection between four dimensions of biodiversity (taxonomic, structural, functional, and phylogenetic) and how they respond to multiple stressors in the worlds largest mangrove forest. C_LIO_LIHigh salinity and siltation act as the primary environmental stressors that negatively affect overall biodiversity. C_LIO_LIStructural diversity is strongly related to species richness, serving as a key indicator of ecosystem health. C_LIO_LIFunctional and phylogenetic diversity follow independent spatial patterns, promoting the need for multi-dimensional monitoring. C_LI

Habitat fragmentation disrupts metapopulation dynamics by altering environmental conditions and constraining demographic processes critical for persistence and recruitment. In the dry Afromontane forests of northern Ethiopia, we investigated how natural and anthropogenic drivers affect seedlings, saplings, and mature tree dynamics of Olea europaea subsp. cuspidata across 34 patches. We used dynamic occurrence models to quantify effects of patch area, altitude, browsing, and disturbance. Our results indicate that high disturbance reduces seedling occurrence probability lower disturbance sites has seedling in 30% of survey plots, high disturbance would bring this down to 10% (median = -1.322, 95% CI: -2.703 to -0.283). Disturbance makes seedling less likely to persist, while large patch size help seedling persists (median = -0.93, 9 5 % CrI -1.87 - -0.02). For mature individuals, disturbance was the only significant predictor of occurrence probability, suggesting greater resistance to environmental and spatial variability compared to earlier life stages. These findings emphasize that while mature trees display resilience, the successful regeneration of Olea europaea is constrained by disturbance, but current level of browsing is not a threat. Management strategies for conservation should prioritise reducing disturbance through community engagement and forest stewardship to enhance regeneration potential and ensure long-term population viability.

O_LIIndigenous peoples play a central role in biodiversity knowledge and conservation, yet their participation in scientific research remains underrepresented. Understanding how Indigenous peoples, traditional knowledge, and Indigenous territories are portrayed in the scientific literature is essential for developing more equitable and culturally grounded conservation strategies. C_LIO_LIWe conducted a bibliometric analysis of 94 articles on biodiversity conservation in the Amazon, published between 1997 and 2025, indexed in Scopus and Web of Science. We examined temporal trends, geographic distribution, institutional leadership, Indigenous co-authorship, focal ecosystems and taxa, and the main contributions attributed to Indigenous peoples. Indigenous perspectives were integrated into this analysis through a participatory approach. C_LIO_LIScientific production increased after 2010. Research leadership remains concentrated in institutions from the Global North, even though Brazil, Ecuador, and Peru were the most frequently studied countries. Indigenous co-authorship was identified in only 6.4 % of the studies. Most studies focused on plants, mammals, and birds, whereas aquatic environments and groups such as insects, amphibians, and reptiles received comparatively less attention. The main contributions attributed to Indigenous peoples were related to community-based monitoring and management (41.48%) and cultural practices and traditional ecological knowledge (38.19%). C_LIO_LIThese findings show that Indigenous peoples are widely recognized as knowledge holders and conservation actors, but are still rarely included as authors or research partners. Our study highlights persistent geographic, epistemic, and collaborative asymmetries in Amazonian biodiversity research. Conservation science and policy will be stronger, fairer, and more effective when they move beyond documenting Indigenous knowledge towards supporting Indigenous leadership, equitable partnerships, and inclusive co-production of knowledge. C_LI

Natural history collections underpin our understanding of species distributions, yet some historical records remain embedded in modern avifaunal checklists despite limited documentation and no independent verification. One such case concerns the Dusky Parrot Pionus fuscus in Colombia: although reported from specimens collected by Melbourne A. Carriker Jr. in 1942 in the Serrania de Perija, the species has not been observed in the country for nearly eight decades yet continues to be included in national checklists and conservation assessments. We reassessed the validity of this record by applying a multi-evidence framework integrating historic archival reconstruction, specimen-based morphological comparisons, climatic niche analyses, biogeographic limit assessment and contemporary survey-effort data. Historical documentation and morphological evidence based on high-resolution specimen images and associated curatorial records demonstrate that the Carriker specimens correspond to Pionus chalcopterus, not P. fuscus. Climatic niche analyses reveal minimal environmental overlap between P. chalcopterus and P. fuscus, and place the Perija locality within the climatic niche of P. chalcopterus, while regional biogeography and extensive modern birdwatching coverage provide no support for the occurrence of P. fuscus in Perija. Together, these concordant lines of evidence demonstrate that P. fuscus does not occur in Colombia. Our findings support its removal from national bird lists and conservation assessments and highlight how integrated, multi-evidence reassessments of historical records strengthen ornithological baselines, improve biogeographic inference and ensure that conservation priorities rest on verifiable evidence.

Peripheral island populations are often especially vulnerable to environmental change, yet they may also represent unique components of biodiversity. We assessed long-term population change in the Egyptian fruit bat (Rousettus aegyptiacus) on Cyprus, the only insular and geographically isolated population of this pteropodid in Europe, and evaluated two non-exclusive explanations for its decline: roost disturbance and reduced food availability. We analysed roost counts from 21 underground sites monitored between 2005 and 2022 and modelled temporal trends in commercially produced fruits used by the species. The monitored population declined from c. 7200 to c. 1050 individuals, corresponding to an estimated decrease of 85.4%. The decline was steepest during 2005-2011, slowed during 2012-2017, and was followed by partial recovery in 2018-2022. Colonies in easily accessible roosts declined significantly faster than those in less accessible roosts, consistent with an important role of human disturbance. Fruit production showed strong long-term declines and multiple structural breaks clustered in the mid-2000s, coinciding with the most severe phase of population decline and a major drought period on Cyprus. The fate of the missing portion of the population remains uncertain. Although large-scale mortality cannot be excluded, there was no clear evidence of widespread starvation-related mortality, and emigration to nearby mainland areas remains a plausible but untested explanation. Overall, our results indicate that the collapse of this peripheral island population was most likely driven by a combination of roost disturbance and reduced food availability associated with climate-related environmental change, highlighting the urgent need for strict roost protection and measures to secure food and water resources.

BackgroundWintering migratory birds must balance energetic requirements, resource availability, and disturbance in increasingly human-modified landscapes. However, individual-level variability in daily movement and winter space use remains poorly understood in South Asian populations of the common crane. We investigated how seasonal dynamics, landscape composition, and individual differences structure winter movement ecology in a semi-arid agro-wetland system in western India. MethodsWe analysed high-resolution GPS telemetry data from multiple tagged cranes tracked across three consecutive winters. Daily movement distances were modelled using mixed-effects approaches to partition variance within and among individuals and among winters. Daily movement trajectories were evaluated using non-linear temporal terms. Landscape predictors, including cropland proportion, built-up area, and habitat heterogeneity, were incorporated to assess environmental drivers. Winter range distributions were estimated using autocorrelation-informed kernel density estimation within a continuous-time movement modelling framework. ResultsMost variation in daily movement occurred within individuals rather than among them, indicating strong behavioural flexibility. Interannual differences explained substantial variance, suggesting sensitivity to changing environmental conditions. Daily movement distance followed a non-linear seasonal pattern consistent with shifts in the profitability of agricultural resources over winter. Cropland proportion and landscape evenness were negatively associated with movement distance, whereas a high proportion of built-up areas increased daily movement distance, reflecting a trade-off between resource concentration and anthropogenic disturbance. Winter range distribution size varied markedly both within individuals across years and among individuals within seasons. ConclusionWinter movement and space use in common cranes are predominantly context-dependent and environmentally driven. Seasonal dynamics, agricultural landscapes, and human disturbance jointly structure movement patterns, with limited but consistent individual differences. Multi-year, individual-based telemetry provides a comprehensive understanding of winter spatial strategies in dynamic semi-arid agro-wetland systems.