摘要: Grasslands are among the world's most threatened ecosystems, and steppe birds face increasing risks from human activities. This study investigates how human impacts affect the distribution and community structure of breeding steppe birds in Inner Mongolia, a biodiversity hotspot in Asia. We conducted standardized point-count surveys across a gradient from intact grasslands to urbanized areas, integrating species occurrence data, functional traits and the Human Footprint Index(HFI). Using Generalized Linear Models(GLMs) and Conditional Random Fields(CRFs), we assessed trait-environment interactions and shifts in species associations. Our results indicate that the HFI significantly affects bird communities. Habitat specialists, such as Mongolian Lark(Melanocorypha mongolica), showed negative responses, whereas generalists like Eurasian Tree Sparrow(Passer montanus) thrived in disturbed areas. Trait-based analysis showed that species with larger body mass and specialized diets were negatively associated with HFI, whereas those linked to human-modified habitats exhibiting strong positive associations. In areas with high human footprint, co-occurrence networks grew more polarized: specialists faced intensified competition, while species with positive HFI responses formed stronger positive associations. CRF models indicated that human activities restructure species interactions, favoring generalists and simplifying community dynamics. These findings highlight the dual role of human impact in supporting some species while threatening specialists, potentially driving biotic homogenization. Our study emphasizes the need for conservation strategies that protect vulnerable species and manage those that thrive in human-altered environments. By linking traits and interactions to human impacts, this study provides a framework for identifying at-risk species and guiding conservation in the Anthropocene.

摘要: Poyang Lake（PYL） and the Yellow River Delta（YRD） are two critical wintering areas for the Siberian Crane（Leucogeranus leucogeranus） along the East Asian–Australasian Flyway in China. Based on nearly two decades of remote sensing and environmental data, this study used the Max Ent model to assess wintering habitat suitability in Poyang Lake（PYL） and the Yellow River Delta（YRD）. Landscape pattern and ecological network（EN） analyses were integrated to examine habitat changes and their impact on Siberian Crane distribution. In PYL, land use/land cover（LULC） change was driven primarily by water level fluctuations, leading to transitions among natural habitat types. In contrast, LULC change in YRD was dominated by anthropogenic activities, with widespread conversion of natural habitats into artificial habitats. In both regions, Siberian Cranes favored wetlands that are food-rich, flat, and minimally disturbed. In PYL, ecological sources were mainly found in sub-lakes of nature reserves and nearby moist areas, averaging 87.42 km². In the YRD, sources were distributed across tidal flats, paddy land, and grasslands, with a larger mean area of 198.37 km². Mann–Kendall tests showed significant trends in PYL, including increased patch density and decreased EN cumulative resilience. The maximum habitat suitability in the YRD significantly declined. Comparative analysis revealed that PYL had significantly higher habitat suitability and EN cumulative resilience, whereas the YRD had larger but more fragmented habitats. By introducing key stepping-stone nodes to optimize the ENs, the connectivity and resilience of PYL's EN were notably enhanced. Although improvements in the YRD were less marked, the optimization scheme still improved the security of the crane migration network. Based on the findings, it is recommended to implement refined water level management in PYL to maintain the stability of sub-lakes and adjacent wetlands, and to strengthen the protection of natural wetlands in the YRD by limiting the expansion of artificial land use, in order to mitigate habitat fragmentation.

摘要: Understanding the fundamental drivers of large-scale species co-occurrence is a critical issue in ecology and conservation research. Here, we assessed foraging guilds, habitat type and disturbances as drivers of bird species co-occurrence in Ghana's Central Region over six months. Birds were sampled in 120 points across six different habitat types(farmland, forest reserve, urban area, coastal savannah, wetland, and mangrove), using the pointcentred count technique. In total, 4060 individuals belonging to 216 species were recorded across all six habitat types. We found that co-occurring species were more similar in their foraging behaviour and habitat association. About 60% of the birds were found to co-occur randomly, 15% co-occurred negatively, and 25% co-occurred positively. Carnivores like the Black Heron(Egretta ardesiaca) and Spur-winged Lapwing(Vanellus spinosus) randomly co-occurred with other guild groups and were dominant in the mangroves and wetlands. Frugivores from forest reserves had only a 25% chance of randomly co-occurring with other birds and about a 60% chance of positively co-occurring with other birds. Our findings suggest that foraging guilds and habitat type are major factors driving bird co-occurrence and community assemblages in this West African suburban region.

摘要: Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cycle of wintering populations. The ongoing degradation and loss of optimal habitats have forced wintering waterbirds to increasingly rely on alternative foraging sites and modify their behavioral adaptation strategies to cope with food scarcity. The Siberian Crane(Leucogeranus leucogeranus), a large-bodied endangered waterbird species characterized by specialized dietary preferences, demonstrates particular sensitivity to environmental alterations. Faced with diminishing suitable habitats and declining natural food resources, this species has progressively adapted to utilizing artificial habitats, including agricultural landscapes such as paddy fields and lotus ponds, as supplementary wintering foraging grounds to fulfill their energetic requirements. This study examines the hypothesis that Siberian Cranes adapt their foraging behavior through plastic behavioral strategies in artificial habitats under conditions of limited food availability, thereby enhancing population fitness. A comparative analysis of crane foraging behaviors was conducted between mudflats and lotus ponds throughout the 2023–2024 wintering period. This investigation focused on three critical environmental factors: food abundance, food burial depth, and sediment penetrability, examining their influence on foraging patterns across these distinct habitats. The results revealed significant inter-habitat differences: foraging success rates were substantially higher(p < 0.05) and food handling times markedly longer in lotus ponds compared to mudflats, whereas foraging effort and attempt frequency were significantly elevated in mudflat habitats. The superior food availability in lotus ponds facilitated enhanced foraging success rates, enabling cranes to accumulate essential energy reserves for winter survival. However, the deeper burial depth of lotus roots in these habitats required more intensive processing behaviors, including prolonged digging, breaking, and swallowing activities, which consequently increased handling time by approximately 40% and reduced foraging attempts by 25–30% compared to mudflat conditions. These behavioral trade-offs suggest that while lotus ponds provide adequate food resources, their structural characteristics may impose physiological constraints that limit their effectiveness as optimal foraging grounds for Siberian Cranes. These findings offer valuable insights into the behavioral plasticity of wintering Siberian Cranes response to spatial variations in food resource distribution, while contributing to our understanding of the ecological value of lotus roots as alternative winter food sources in artificial wetland ecosystems.

摘要: Bergmann's rule predicts that the larger of two homeotherm species differing only in size would occur at higher latitudes,or in cooler climates than the smaller,because of relative thermoregulatory costs in relation to body mass/surface area ratio.Individual tracking data from two congeneric long-distance migratory northern nesting swan species,Tundra Cygnus columbianus(TS,n=99) and Whooper Swans C.cygnus(WS,61-71% larger mass than TS,n=47) were used to determine their summering and wintering latitudes along similar migration routes and common staging areas along the same flyway.We hypothesised that throughout Arctic and Boreal breeding areas(10℃ in July),summer ambient temperatures mainly exceed the Lower Critical Temperatures(LCT,c.1℃) for both swan species,so the duration of the snow-free summer period will favour smaller body size at highest latitudes,since this constrains the time available to lay,incubate eggs and raise cygnets to fledging.We hypothesised that in contrast,in winter,both species occur in temperatures near to freezing(-3℃ in January),below their respective LCT,so differential thermoregulation demands would constrain TS to winter south of WS.Tracking of individuals showed for the first time that while smaller TS summered significantly north of WS,WS wintered significantly north of TS,with limited overlap in both seasons.We conclude that differences in relative summer distribution of these two closely related migratory herbivores are not to do with latitude per se but are constrained by the time both species require to raise their young to fledging during the short northern summer,when thermoregulation costs are unlikely limiting.In winter,both swan species occur within a climate envelop at or below their respective LCT and smaller TS occurred consistently south of the range of the tracked WS,as predicted by Bergmann's rule.

摘要: Ecological barriers present significant challenges to bird migration by limiting the availability of stopover sites and shelters. The Qinghai-Tibet Plateau, a major migratory barrier located in higher latitude Central Asia, exerts a substantial influence on avian migration patterns. Species traversing such ecological barriers may adopt multiple optimal routes, which can contribute to the formation of migratory divides. From 2018 to 2021, the migration routes of 13 adult Common Cuckoos(Cuculus canorus) breeding in the north of the Qinghai-Tibet Plateau were tracked using satellite transmitters. We found Common Cuckoos have two primary migration routes: western and eastern, respectively following western and eastern edges of the Qinghai-Tibet plateau. The eastern and western routes are likely the optimal routes for the Central Asian Common Cuckoos population to navigate the Qinghai-Tibet Plateau. Furthermore, two individuals exhibited intermediate migration routes, suggesting attempted traverses of the Qinghai-Tibet Plateau, although neither completed the migration. These intermediate routes may indicate migratory behavior influenced by hybridization between eastern and western populations or migratory flexibility. Common Cuckoos exhibit significantly faster migration speed, flight speed, and shorter stopover durations during spring compared to autumn. The observed seasonal differences in migration behavior support birds following time-minimization strategies during spring migration. These results revealed the diverse migration routes of Common Cuckoos shaped by the Qinghai-Tibet Plateau and seasonal variation in migration patterns.

摘要: Understanding migration patterns and spatial connectivity is crucial for conserving long-distance migratory birds. While satellite telemetry has advanced the study of large gulls, Pallas' s Gull(Ichthyaetus ichthyaetus) remains relatively understudied, with limited data on its migration routes and habitat use, particularly in Central Asia. This study integrates 684 ring recoveries(1968–2024) and GPS tracking data to analyze the migration ecology of individuals breeding at Alakol Lake, Kazakhstan. Ring recoveries confirm migratory connectivity across Kazakhstan, Russia, Uzbekistan, Turkmenistan, Iran, and Pakistan, with wintering records as far as India, Kuwait, Bangladesh, and Ethiopia. GPS tracking of a single individual(June 2020–August 2021) revealed a migration route from Alakol Lake to the Arabian Sea, with key stopovers at Zaisan Lake, Balkhash Lake, the Aral Sea, Aydar Lake, and the Amu Darya River. Notably, a post-breeding northward dispersal to Zaisan Lake and southern Russia was identified before the southward migration commenced. These findings highlight the significance of Kazakhstan's lakes as breeding and migratory hubs and the need to protect critical stopover sites in Central Asia. Given increasing anthropogenic pressures on wetland habitats, this research provides essential baseline data for conservation planning and enhances the broader understanding of gull migration ecology.

摘要: Prevailing concerns on mountainous biodiversity are concentrated on the impacts of climate change at higher elevations. However, the lower elevations are facing additional human disturbance and are expected to suffer from higher extinction risk but have attracted less conservation attention. Here, we employed population genomics to compare extinction risk two common songbirds—the Vinous-throated Parrotbill(Sinosuthora webbiana) and the Rufous-capped Babbler(Cyanoderma ruficeps)—at lower and higher elevations on the Taiwan island. As the result, we observed decreased genetic diversity and increased genetic load and thus elevated extinction risk in the low-elevation populations of both birds in the eastern slope of the Central Mountains on the Taiwan island. In contrast, genetic-load patterns of both birds in the western slope might be confused by substantial gene flow across lower and higher elevations. These results, on the one hand, call for conservation efforts to lower elevations in mountains and, on the other hand, highlight the importance of population connection in maintaining population viability under impending global change.

摘要: Elucidating the historical processes that led populations to their current spatial and genetic arrangement is relevant in conserving threatened species. We interpreted the phylogeographic structure of the threatened Yellow-headed Parrot(Amazona oratrix) with mitochondrial markers and analyzed 98 samples from Mexico, Guatemala, and Belize. We performed analyses of genetic structure, genealogical relationships, demographic history, and divergence times and illustrated the phenotypic variation qualitatively of the sampled individuals. The studies revealed that 92% of the genetic variation is explained between the Mexican Tres Marías Islands, the Mexican Pacific Coast, and the Atlantic groups. These three groups were segregated into two main lineages(Pacific and Atlantic), separated by 26 mutations, leaving A. auropalliata within the Atlantic. We found that both lineages diverged 0.55 million years ago, from which the Atlantic lineage experienced population expansion, high levels of genetic diversity, and a low genetic structure with two phenotypes. The Pacific experienced demographic stability, low levels of diversity, and a genetic structure marked with two phenotypes. Our estimates indicate that this separation occurred in the Pleistocene when the Atlantic clade diverged from Panama and dispersed overland to the Gulf of Mexico. Simultaneously, the Pacific clade departed from the same area to Tres Marías Islands and the Mexican Pacific coast. We deduce that this long-distance event was probably produced by assisted dispersal, but other scenarios appear more parsimonious. We conclude that there is no gene flow between both lineages and that the phylogeographic structure resulted significantly from historical events and climatic changes during the Pleistocene. We propose undertaking other analyses in the future to compare our results and the paraphyletic relationships in A. oratrix.

摘要: The Alectoris(Galliformes: Phasianidae) has a wide distribution range in the Palearctic region, with seven species and 27–31 subspecies that were distinguishable by minor morphological differences. The members of the genus exhibit distinct genetic structuring compatible with geography due to their inability to make long flights and ground-dwelling behaviors. In this respect, the evolutionary history of the genus and its populations is a useful tool for identifying potential cryptic refugia, dispersal corridors, and strong barriers for bird species in the Palearctic region. On the other hand, wild populations of the genus are among the bird species most affected by human activities. For this purpose, sequences from the mitochondrial D-loop and Cyt-b regions of individuals from the genus Alectoris were studied to identify the evolutionary history of the genus, determine potential cryptic species, and reveal possible hidden diversification areas in the Palearctic region. The results indicated that: the Mediterranean basin is the ancestral area of the Alectoris, there are two main diversification centers within its distribution range(Mediterranean Basin and China) of the genus, and certain micro-refugia and permanent dispersal corridors have been observed in Eastern Palaearctic region. Additionally, the results showed that the Pleistocene climatic changes acted as a species pump, playing a significant role in the diversification of lineages within the genus. Anatolia served as the ancestral area for the A. chukar and acted as a bridgehead during the species' dispersal in the inner side of the Eastern Palaearctic. High mountain ranges, monsoonal climate types, and deserts in the Eastern Palearctic played a significant role in the dispersal and diversification of the ancestral A. chukar population. Importantly, human activities appear to be the greatest evolutionary force shaping the future evolution of the genus.