Ocean acidification modifies site fidelity and patterns of seagrass habitat use by a herbivorous fish.

Exposure to environmental contaminants, such as halogenated flame retardants (HFRs) and trace elements, has been associated with a several health effects, including neurotoxicity. However, information on contaminant concentrations in brain tissue and factors influencing their accumulation and exposure-related effects are limited in wild birds. We quantified 45 HFRs and 16 trace elements in brain of ring-billed gulls (Larus delawarensis) breeding in a highly urbanized environment and related their concentrations to foraging habitat use and a range of coarse and fine-scale neuroanatomical measures. Ten polybrominated diphenyl ethers (PBDEs), hexabromobenzene (HBB), pentabromoethylbenzene (PBEB), and anti-dechlorane plus (anti-DP) were detected in over 80% of brain samples, as well as cobalt, nickel, copper, selenium, silver, cadmium, lead, and mercury. For certain compounds or elements, brain concentrations correlated with foraging habitat use, for example, PBDEs and lead increased with the proportion of time gulls spent foraging in waste management facilities. Additionally, we found correlations between brain contaminant concentrations and certain brain measures. For example, the number of immature neurons in the nucleus pretectalis principalis (Pt), a region in the visual system in birds, correlated negatively with brain concentrations of PBDEs and lead. Our results showed that urban-adapted ring-billed gulls accumulate a wide range of HFRs and trace elements in brain tissue, and that some of these contaminants might be associated with variations in selected neural measures. Although the present correlative study cannot establish causality, these findings highlight potential toxicity pathways in the avian brain that warrant mechanistic investigation under controlled conditions.

Habitat-driven distribution patterns of sparid species: Insights from a north Atlantic artisanal fishery.

ABSTRACT Three‐spined sticklebacks ( Gasterosteus aculeatus ) have become dominant in many Baltic Sea coastal fish assemblages, yet life‐stage‐specific habitat use remains poorly understood. We surveyed shallow water habitats along the coast of Gotland, Sweden, to examine how juvenile and adult stickleback abundances relate to variables such as submersed aquatic vegetation (SAV) biomass and vertical structure, macrophyte species richness, biomass of drift filamentous algae and potential invertebrate prey abundance. Juvenile stickleback abundance increased with SAV variables, macrophyte species richness, and drift filamentous algae, whereas, in contrast, adult abundance was only significantly associated with potential prey (invertebrate abundance). Our findings reveal life‐stage‐specific habitat associations of three‐spined sticklebacks and highlights the importance of both long‐living vegetation and ephemeral drift algae in supporting juvenile sticklebacks. This study contributes to a better understanding of sticklebacks’ coastal ecology in the central Baltic Sea.

Shoreline alteration from human development and armouring is a major driver of biodiversity loss in freshwater ecosystems. While biologically inspired shoreline armouring has been explored in marine systems, its application in freshwater remains limited. This study advances freshwater research by moving from lab-based choice experiments to field trials, allowing fish to interact freely with textured panels under natural conditions. We compared fish community assemblages across four shoreline treatments: natural, textured panel, flat panel, and altered shorelines. Fish abundance, species richness, and diversity indices were assessed using snorkelling surveys over a single summer season. Species-specific patterns emerged. Bluegill and pumpkinseed were most abundant across all treatments, whereas textured panels supported higher abundances of largemouth and smallmouth bass, particularly young-of-the-year individuals. Age-class composition and proximity distributions differed significantly among treatments for several species, indicating treatment-specific habitat use rather than changes in overall diversity. These findings suggest shoreline modification influences fish community composition and spatial use more strongly than overall abundance or richness, especially within largely natural landscapes. Despite their limited size and short deployment, textured panels may provide functional habitat for select species, highlighting the importance of species-specific responses in evaluating eco-engineered shoreline designs.

Climate change is increasingly recognized as one of the most important drivers of biodiversity change worldwide. Birds are particularly sensitive to environmental variations because their life cycles, including breeding and feeding behaviour, are closely associated with climatic conditions. The Indian peafowl (Pavo cristatus), the national bird of India, is widely distributed across forests, agricultural landscapes, and rural ecosystems throughout the country. Although the species is currently categorized as “Least Concern,” recent studies indicate that environmental changes may influence its behaviour, habitat use, and reproductive ecology. Reproductive activities in birds are strongly governed by climatic factors such as rainfall patterns, temperature fluctuations, vegetation growth, and food availability. In India, the breeding season of the Indian peafowl generally coincides with the monsoon period when ecological conditions are favourable for reproduction and chick survival (Yogeshwari & Varunprasath, 2020). However, increasing climatic variability, irregular rainfall patterns, and habitat modification may disrupt these ecological relationships. This review synthesizes recent research (2020–2026) focusing on the reproductive ecology of Pavo cristatus in India and discusses how climate change may influence breeding behaviour, nesting success, and population dynamics. The review also highlights important research gaps and emphasizes the need for long-term ecological monitoring and conservation strategies to ensure the sustainability of peafowl populations in changing environmental conditions.

Edge formation through moderate retention forestry creates transitional zones that shape environmental gradients and influence arthropod behavior. We examined fine-scale movement dynamics of ground-dwelling arthropods, quantified as orientation-specific activity along and across hard forest edges, in temperate lowland forests of Central Europe. The study focused on buffer-zone stands transitioning toward oak dominance. Drift-fence pitfall traps were placed across retention clearcuts, ecotones, and forest interiors, between April and October 2023. In total, 8643 individuals from 188 species were recorded and classified into five functional groups: predators, herbivores, omnivores, saproxylics, and detritivores. Arthropod activity varied among habitats, with along-edge orientation consistently exceeding across-edge orientation. This pattern is consistent with microclimatic gradients and behavioral orientation cues. Seasonal trends included elevated detritivore activity in the "along" orientation within ecotones during spring, suggesting corridor-like use of transitional habitats, and reduced across-orientation activity of omnivores in forest interiors during summer, consistent with seasonal changes in habitat use. Saproxylics were most active in the "along" orientation within forest interiors during autumn, reflecting their specialization for canopy-closed forests. Ordination analysis and species-level response models identified distinct movement dynamics among functional groups. Detritivores oriented along edges, whereas omnivores were associated with across-oriented activity, particularly outside ecotones. These findings highlight forest edge structure as a key ecological boundary shaping orientation-specific arthropod activity and provide a functional context for interpreting behavioral responses to edge environments. Incorporating functional group responses into retention forestry can support the development of more connected and resilient forest landscapes.

Abstract The Tibetan antelope chiru ( Pantholops hodgsonii ), a highly specialized ungulate endemic to the Tibetan Plateau, exhibits a unique seasonal migration of a male-dominated population to the cold, arid Changchenmo Valley in eastern Ladakh, India, raising important ecological and conservation concerns. Over three years, we examined the population structure, spatial distribution, and habitat use of chiru in relation to four sympatric ungulates: argali ( Ovis ammon ), wild yak ( Bos mutus ), Tibetan wild ass kiang, ( Equus kiang ), and bharal ( Pseudois nayaur ). Across 162 surveys covering 918.6 km, we recorded 1,670 individuals, including 710 male chiru. Chiru had a mean encounter rate of 1.19 ± 1.17 individuals/km and a typical group size of 13.69. Our results indicate that sympatric ungulates partition resources through habitat selection, facilitating summer co-occurrence, while competition intensifies in winter and spring. Chiru and kiang exhibited facilitative interactions, whereas chiru showed strong segregation from other species. Notably, we observed previously unrecorded overwintering by chiru. Despite a seemingly stable population, habitat overlap, climate change, infrastructure development, and livestock competition pose significant threats. Urgent conservation measures focusing on habitat protection, reducing human disturbance, and engaging local stakeholders are critical to ensure the long-term survival of chiru and other ungulates in this fragile Trans-Himalayan ecosystem.

Local ecological knowledge is acknowledged to be a valuable source of information about wildlife; however, it is not clear whether it can be mobilized appropriately for wildlife conservation. Using pangolins as a case study in Assam state, north-eastern India, we explored whether local ecological knowledge (LEK) and environmental values can inform the distribution and conservation of cryptic and threatened species. We employed semi-structured interviews to document forest-dwelling communities' knowledge regarding species occurrence, habitat use, and population status and their beliefs and values in relation to pangolins. Findings from our study show that LEK is a reliable tool for detecting cryptic species, with older respondents exhibiting higher likelihood of pangolin recognition. Value analysis revealed a strong inclination towards illegal hunting and trade, highlighting the conservation challenges involved in protecting a cryptic wildlife species. We advocate the need to integrate LEK and environmental values for holistic conservation strategies of cryptic species.

Effectiveness of forest restoration efforts depends on the methods employed. Here, we compared tree species composition, niche characteristics, and mammal habitat use in primary, secondary, and artificial forests in Wanglang Nature Reserve. Results showed that primary forests were mainly indicated by Abies fargesii var. faxoniana (Af), Picea purpurea (Pp), and Juniperus saltuaria (Js); secondary forests were mainly indicated by Af and Betula albosinensis (Ba); and artificial forests were mainly indicated by Picea asperata (Pa) and Acer caesium (Ac). Af had the broadest niche breadth in natural forests, and Pa had the broadest niche breadth in artificial forests. Low niche overlap among common species was observed in natural forests, whereas high niche overlap between Pa and Ba occurred in artificial forests. Interspecific correlations showed that Af was negatively correlated with Pp in primary forests and Populus szechuanica (Ps) in secondary forests. In artificial forests, Af and Ac were positively correlated. Furthermore, no traces of the three National Class I protected species were found in artificial forests, while traces of two representative mammals were associated with Af. These findings highlight the differences among the three types of forests.

Analysis on the wintering habitat use of waterbird Pied Avocet based on geo-tracking and remote sensing technology

Context The white shark (Carcharodon carcharias) is a large, highly migratory, apex predator typically found in coastal, continental shelf and pelagic environments of temperate and subtropical waters worldwide. In the western North Atlantic (WNA), white sharks have been studied for decades through catch data and other observations along the US Atlantic coast. Aims Beginning in 2012, OCEARCH has coordinated a comprehensive, long-term study of this population that includes tagging sharks with satellite-linked and acoustic tags to track their movements, understand their life history, and map their critical habitats. Methods Tagging occurred between Nova Scotia, Canada, and Jacksonville, Florida, USA, on the Atlantic coast. Four life stages (young-of-the-year, juvenile, subadult, adult) were tagged, showing the migratory cycles of this WNA population from age zero through maturity. Key results A combination of satellite-linked and acoustic tags showed all four life stages enter the Gulf of Mexico (GoM) through the Straits of Florida and use this habitat primarily during the overwintering period. Of 92 white sharks tagged, 57 (62.0%) showed activity in the GoM or the Straits of Florida, spending most of their time (91.2%) in epipelagic waters and moving mainly from the Florida Keys north along the outer West Florida Shelf. Specific areas of extensive habitat use and evidence of philopatry were identified, particularly in the Pulley Ridge area off south-western Florida. Some animals crossed into the western GoM and into Mexican coastal waters; movements along the northern coast of Cuba were also noted. Conclusions These tagging results clearly demonstrated the importance of this region as an overwintering habitat for white sharks, particularly in shelf edge waters of the eastern GoM, and indicated a more widespread and persistent use of the GoM by this recovering species than previously known. Implications Our results demonstrated the wide-ranging nature of the WNA white shark population and the faunal connectivity between Atlantic Canada and the GoM, including territorial waters of other nations. Continued monitoring of this population, fine-scale analysis of movements in critical habitats, and further research on the drivers of migration are needed for science-based policy to conserve this vulnerable species.

Birds of prey and photovoltaic installations in an intensively managed agricultural landscape: year-round habitat use across different habitats.

A variety of human activities, especially urbanization, are not only homogenizing species composition but also eroding behavioral diversity. This Essay introduces the concept of behavioral homogenization: the human-driven convergence of behavioral traits across individuals, populations, and species across space and time. Global examples of fear responses, foraging, communication, activity patterns, social behavior, cognition and exploration, habitat use, breeding-site choice, migration, and heterospecific interaction networks are used to argue that spatial and temporal beta-diversity in behavior is shrinking in human-dominated landscapes. Ecological and evolutionary consequences, including for animal cultures and human-wildlife conflict, are outlined and opportunities to quantify and integrate behavioral homogenization into biodiversity conservation and management are highlighted.

Muskrat (Ondatra zibethicus) populations have been declining in North America for decades. The precise cause of these widespread declines has not yet been identified. Over a similar timeframe, wetlands across large regions of North America have been experiencing an invasion of hybrid cattail Typha x glauca. This invasion is associated with many negative consequences for wetlands, including a reduction in biodiversity, open water habitat, and interspersion of water and vegetation. Muskrats are strongly tied to wetlands, especially where there is a high degree of interspersion of water and emergent vegetation. Therefore, a widespread reduction in interspersion caused by T. x glauca invasions may be contributing to widespread muskrat population declines. We sought to better understand the impact of marsh interspersion on fine-scale muskrat habitat use in light of widespread invasions of T. x glauca. We measured intensity of habitat use by muskrats in a large, Typha-dominated marsh in south-central Ontario using camera traps, stratifying camera placement along a gradient of interspersion. We found no correlation between interspersion and intensity of use. The ubiquity of T. x glauca and low overall interspersion at our study site may have prevented a robust test of our hypothesis. Further research is needed to determine precisely how interspersion affects muskrat habitat use at a fine scale, and how potential changes in habitat quality and use may be contributing to widespread muskrat population declines.

Changes in land use and climate can have important consequences for natural environments, operating as multilevel processes affecting population dynamics, demography and spatial activity of small mammals, potentially leading to cascading ecosystems effects. In a large-scale replicated field study, the response of small mammals to two climate conditions (ambient versus temperature and precipitation expected for the end of the century) and five land use types (conventional farming, organic farming, intensive meadow, extensive meadow and extensive pasture) was studied. For two years, small mammals were live-trapped monthly throughout the breeding season in open plots, individually marked and species, body measures, sex and reproductive status recorded. Common voles (Microtus arvalis; 74%) and wood mice (Apodemus sylvaticus; 22%) dominated. The effects of climate manipulation were sparse, restricted to 14% higher residency in common voles in autumn and more than doubling abundance of wood mice in spring and summer. Common voles seasonally preferred (extensive) land use with little disturbance (at least doubling abundance and increasing residency 39-128%). Seasonally, reproductive activity in common voles was twice as high in grassland than in croplands but in wood mice 5.2-9.5-fold higher in conventional farming than in extensive meadow and organic farming. Common voles were clearly affected by land use while in wood mice climate seemed to matter more. Habitat effects seemed to override climate effects in common voles indicating only marginal changes in habitat use at future climate conditions. However, seasonally there could be larger resident populations of common voles and higher wood mouse abundance that may cause damage in agriculture and/or forestry, affect food webs and pathogen transmission patterns.

Identification of differences in habitat use patterns by individuals from separate animal populations through machine learning techniques

Glacier-fed streams (GFSs) make ideal systems for studying climate-related changes. Some of the best-studied GFSs are found in the McMurdo Dry Valleys (MDVs) of Antarctica, one of the Earth's coldest and driest deserts. Despite their harsh and isolated nature, MDV GFSs represent an oasis of life in a landscape visually devoid of it, with biomass dominated by photosynthetic microorganisms (including chlorophytes, cyanobacteria, and diatoms) and manifesting as benthic "mats." Mats form the basis of MDV GFS ecosystems, drive biogeochemical cycles, and harbor high proportions of the regional biodiversity. Furthermore, the biomass and composition of these mats respond to environmental fluctuations, making them ideal bioindicators for ecological monitoring. In this review, we have (1) distinguished the three major photosynthetic mat types by their taxonomic structure, habitat use, and elemental composition; (2) demonstrated how mat type distribution, coverage, and biomass are dictated by a combination of geomorphology, suspended sediment loads, and hydrology, among other factors; (3) introduced MDV diatoms as model organisms for investigating mat community assembly; and (4) speculated on how the biomass, community structure, and functional process rates of different mat types will change in a warmer and more connected world. Synthesizing this information, we suggest future opportunities for research, with the most promising avenues centering upon questions, methodologies, and scales that would have been inconceivable for the Heroic Age explorers that discovered them, ranging from studies of gene expression to cataloging changes in mat abundance by satellite.

Bird habitat use can be influenced by the structural complexity of exotic plantations. Management practices such as pruning and thinning can promote understory development, increasing structural complexity and enhancing ecosystem integrity. Given the rapid expansion of fast-growing tree species, understanding bird responses to different forestry practices is crucial for sustainable management. In northeastern Argentina, we assessed bird habitat use, including trophic guild composition, behavioral patterns, and strata use across native forests and exotic Pinus and Eucalyptus plantations managed to promote or limit understory development. Using non-metric multidimensional scaling (NMDS), hierarchical cluster analysis, and PERMANOVA, we evaluated differences in bird assemblages among these forest types. Our results indicate that plantations with developed understory exhibit habitat use patterns more similar to native forests; however, certain ecologically important species, such as large fruit dispersers, were absent. Among plantation types, Pinus plantations with understory development were the most comparable to native forests in strata use and behavior categories. Birds in both native forests and plantations with developed understory used all available strata and were abundant in the shrub layer, including insectivorous and insectivorous-frugivorous species, whereas plantations lacking understory were functionally similar, exhibiting reduced diversity in trophic guilds. Although Eucalyptus plantations showed greater functional differences from native forests than Pinus plantations, the variation within Eucalyptus plantations based on management practices was particularly striking. We found that although plantations with developed understory cannot fully replicate the ecological functions of native forests, they can mitigate habitat simplification impacts by supporting similar but less abundant trophic guilds with comparable strata use and behaviors. As the demand for exotic plantations increases, effective management practices will become essential for maintaining biodiversity and promoting sustainable land use. Practices such as regular thinning and the establishment of mixed-species plantations can help better replicate the functional roles of native forests, thereby maintaining biodiversity and promoting sustainable land use.

Abstract Vision plays a central role in the ecological success of birds, and morphological specialisations of the eye often reflect habitat use and behavioural strategies. As the principal refractive surface of the eye, the cornea is a key structure for visual performance, and its architecture may reflect ecological specialisation. In this study, we describe ocular morphology and corneal histology in four bird species with contrasting ecological profiles: the Eurasian sparrowhawk ( Accipiter nisus ), the booted eagle ( Hieraaetus pennatus ), the little bittern ( Ixobrychus minutus ), and the stone-curlew ( Burhinus oedicnemus ). Using light and transmission electron microscopy, we analysed morphometric parameters, tissue thickness, and cellular densities in both central and peripheral corneal regions. Interspecific differences were recorded in total corneal thickness, in the thickness of individual layers (epithelium, stroma, Bowman’s and Descemet’s membranes, and endothelium), and in keratocyte, epithelial, and endothelial cell densities. Accipiter nisus and Hieraaetus pennatus , two diurnal predators from open habitats, exhibited thicker corneas with greater stromal compactness and higher endothelial cell density. Ixobrychus minutus , a crepuscular species from dense wetlands, had a proportionally large cornea relative to eye size but reduced thickness, characterised by high epithelial cell density and frequent intracellular vacuolisation, possibly related to osmotic stress. Burhinus oedicnemus , adapted to arid and exposed habitats, presented a thickened Descemet’s membrane and more complex endothelial interdigitations. These descriptive findings document interspecific variation in ocular and corneal organisation among species occupying different ecological niches and establish a morphological reference for future comparative and functional studies.