Urbanisation alters habitat structure and acoustic environments, with potential consequences for both occupancy and detectability of nocturnal raptors. We assessed multispecies and seasonal occupancy of owls across Guwahati, a rapidly urbanising subtropical city in northeast India, using a multi-season occupancy framework from November 2023 to July 2025. Surveys were conducted across 33 stratified 1-km² grid cells representing major land-use categories, with owl detections recorded using visual and passive acoustic methods over eight survey occasions per grid. We detected eight species during the surveys; the Barn Owl (Tyto javanica) and the Spotted Owlet (Athene brama) were the most frequently detected. Across species and seasons, naïve occupancy consistently underestimated model-based occupancy estimates, indicating substantial imperfect detection. Ambient noise emerged as the most consistent predictor of reduced detectability in both multispecies and species-specific models. In contrast, site-specific habitat variables showed weaker and more species-specific associations with occupancy. Overall occupancy remained moderate to high across heterogeneous urban habitats, indicating broad tolerance of modified landscapes by urban-adapted owl species. Species-specific analyses revealed that Barn Owl and Spotted Owlet maintained relatively high occupancy across the urban matrix despite low detectability. These patterns suggest a degree of human commensalism, with both species continuing to utilise urban landscapes even when other land use types are spatially nearby. While the Barn Owl and Spotted Owlet were the primary focus of occupancy assessments, incidental detections of other owl species were also recorded to provide a broader ecological context. Our findings demonstrate that while anthropogenic soundscapes strongly influence detectability, common urban owls in tropical cities may persist across diverse land-use contexts. Incorporating detection-corrected approaches into urban biodiversity monitoring will strengthen ecological inference and support evidence-based conservation planning for nocturnal raptors in rapidly expanding cities.
Given the rapid expansion of urbanization, there is an urgent need to understand the drivers of biodiversity decline specially in highly diverse ecosystems such as the Neotropical cities. Specifically, while the influence of ecological factors on biodiversity is well documented, empirical evidence on how specific urban design features such as the spatial arrangement of greenspace patches and sources of anthropogenic disturbance contribute to these patterns remains limited. Here, we assessed how the spatial arrangement of vegetation areas such as lawns, gardens or wooded areas within urban ecosystems (i.e., greenspace patches) relative to their distance to vegetation elements such as trees and shrubs and urban infrastructure and, human disturbances such as pedestrian and pet density associated with avian species richness, abundance, functional diversity and evolutionary distinctiveness by conducting point counts across five cities in the Colombian Andes. Greenspace patches closer to vegetation supported greater bird species richness, abundance and functional diversity. Interestingly, evolutionary distinctiveness was not associated with the ecological variables considered. Overall, our findings highlight the importance of (1) preserving greenspace patches with proximity to surrounding vegetation to maintain biodiversity within urban ecosystems and (2) incorporating taxonomic, phylogenetic and functional dimensions when assessing ecological dynamics as ecological changes may be reflected in certain diversity metrics but not in others. Thus, this study contributes to the understanding of urban biodiversity patterns by identifying key landscape features that support diverse avian communities, offering insights for biodiversity-informed urban planning in rapidly expanding tropical cities.
Urban ecological networks are shaped by habitat distribution, coastal boundary definition, and vertical urban structure. Using Xiamen, China, we compared two-dimensional (2D) and three-dimensional (3D) resistance surfaces and tested corridor-network sensitivity to land-boundary versus nearshore-water inclusion scenarios. Ecological sources were identified using morphological spatial pattern analysis and Conefor connectivity indices, habitat quality was assessed with the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, and potential corridors were extracted using minimum cumulative resistance modeling. Resistance surfaces were evaluated against citizen-science bird-observation intensity from eBird and the China Bird Report Center using Geodetector; observation support was compared among forest-associated birds, waterbirds, and other birds; and network robustness was tested under source-node and corridor-edge loss. Ecological sources were more continuous off-island and more fragmented on Xiamen Island. Nearshore-water inclusion increased corridor number, total length, and connectivity, particularly for secondary and tertiary corridors, by adding cross-bay and waterfront connections. Waterbirds showed medium or high observation support more often than forest-associated birds. The 3D model refined corridor costs in vertically complex settings, especially on Xiamen Island, but did not consistently outperform the 2D model, and explanatory power varied by spatial scale and boundary scenario. Water-connected corridors should therefore be interpreted as boundary-sensitive potential pathways rather than directly constructible ecological corridors. By integrating coastal boundary treatment, vertical urban structure, and bird-observation evidence, this framework supports cautious urban biodiversity conservation and blue-green infrastructure planning in high-density coastal cities.
Urban trees provide critical trophic subsidies for flower visitors, yet the spatiotemporal availability of floral resources in tropical cities remains poorly understood. We evaluated tree composition, floral traits, pollination systems, and spatiotemporal resource distribution along public sidewalks in Campo Grande, Brazil, an internationally recognized “Tree City of the World”. We surveyed 1,934 established trees across 200 stratified urban blocks, classifying species by origin, floral morphology, phenology, and pollination system. Fabaceae dominated in richness (33 species). Non-native species comprised 54
As urbanization intensifies, encounters between people and wildlife are increasing, often generating fear and conflict. A key example is interactions with snakes, which face strong cultural stigmas that hinder their conservation despite their fundamental ecological role in regulating prey populations. The Serpentes do Distrito Federal Project, implemented in Brasília, Brazil, a city where 70
