The coexistence of deposit-feeding sea cucumber species with similar ecological and functional roles is common in many coastal ecosystems and may lead to niche overlap. This study investigates the behaviour and feeding ecology of four cohabiting coastal sea cucumbers: Holothuria mammata, H. polii, H. sanctori and H. tubulosa, focusing on the mechanisms that allow their niche segregation in the Mediterranean and Atlantic. Laboratory observations were conducted to examine substrate and microhabitat preferences, circadian activity and sediment intake dynamics. Findings revealed significant interspecific segregation. Holothuria sanctori was associated with hard substrates, while the other species preferred soft substrates, differing further in sediment layer use: H. tubulosa and H. mammata foraged superficially, whereas H. polii also utilised sub-surface layers. Species also differed in their sheltering strategies: H. mammata and H. sanctori sheltered in hard substrate refuges, while H. polii burrowed into soft sediments. Finally, sea cucumbers exhibited distinct feeding strategies, revealing two contrasting patterns: high sediment intake with low organic matter selectivity (H. polii), or high organic matter selectivity with lower sediment ingestion (H. sanctori), with intermediate behaviours (H. tubulosa and H. mammata). This study evidenced that both microhabitat and resource partitioning enable the coexistence of sea cucumber species in coastal ecosystems.

Blue and green: A portrait of two portunoidea crabs from away and their interactive effects on catch.

Trophic niche segregation in small pelagic fishes suggests mesopelagic pearlsides as the main transmission pathway of Anisakis larvae in a Patagonian food web.

Dietary analysis has contributed to our understanding of animal niches, interspecific interactions, community structure and the flow of matter and energy in food webs. We employed three methods of dietary analysis to estimate trophic niche overlap between two peacock bass species, Cichla cataractae and Cichla ocellaris, across sympatric (Essequibo River) and allopatric (Rupununi and Rewa Rivers) populations in Guyana - visual gut contents analysis, gut contents metabarcoding and stable isotope (δ13C, δ15N) analysis. During the dry season, both piscivorous species exhibited generalist feeding strategies and little evidence of trophic niche segregation with respect to prey taxonomic diversity. Metabarcoding identified 92 prey taxa spanning 28 genera, with Characiformes, Siluriformes and Cichliformes dominant in diets of all populations. Visual gut contents analyses corresponded with metabarcoding results but revealed C. cataractae consumed significantly larger prey than C. ocellaris, consistent with the larger mouth gape of C. cataractae. Stable isotope analysis indicated C. cataractae had higher nitrogen ratios than C. ocellaris, and the two species overlapped broadly with respect to carbon ratios. Overall, there was broad isotopic overlap between species and between allopatric and sympatric populations of C. ocellaris (≥ 70%). These findings suggest food resource partitioning with respect to taxonomic diversity is relatively unimportant for coexistence of these cryptic species, and prey size and habitat selection are the principal mechanisms of niche partitioning during the annual low-water season.

Oxygen depletion shifts niche partitioning of AOA and AOB in Bohai Sea sediments.

Agricultural expansion has created mosaic landscapes that are crucial for migratory birds, yet these anthropogenic habitats intensify challenges like interspecific competition. Understanding how sympatric species coexist through nutritional niche adjustments is a critical knowledge gap for conservation. We studied the wintering Black-necked Crane (Grus nigricollis) and Common Crane (G. grus) in an agro-wetland system in southwest China, where seasonal resource decline is expected to drive niche differentiation. Using fecal DNA metabarcoding, we reconstructed and compared their plant-based diets throughout the winter. The two species employed divergent foraging strategies. Black-necked Cranes were conservative generalists, maintaining high dietary richness and consistently relying on a core set of natural food sources (e.g., Poaceae, Solanaceae, and Cyperaceae), using crops only as supplements. Conversely, Common Cranes were dynamic specialists, exhibiting a complete turnover of preferred foods and opportunistically concentrating on the most energy-dense crops available in each period (e.g., Fagopyrum esculentum, Helianthus annuus). This strategic divergence resulted in a continuous decrease in NO, from high initial similarity to complete partitioning by the pre-migration stage, while ND increased correspondingly, reflecting progressive trophic niche separation. We conclude that this dynamic niche partitioning, driven by distinct responses to seasonal resource availability, is the primary mechanism facilitating the coexistence of these two large congeneric species. Our findings reveal profound dietary plasticity and offer a scientific basis for managing anthropogenic landscapes to support multispecies conservation goals.

The study used camera traps (2946 trap days, 60 sites) to investigate the diversity, habitat use, and activity rhythms of six sympatric ungulates in a montane ecosystem of southwestern China: tufted deer (Elaphodus cephalophus), Chinese goral (Naemorhedus caudatus), Chinese serow (Naemorhedus griseus), sambar (Rusa unicolor), wild boar (Sus scrofa), and blue sheep (Pseudois nayaur). Relative abundance indices indicated that sambar were most frequent, while blue sheep and Chinese goral were least common. Species showed distinct elevational, slope, and vegetation preferences, suggesting spatial niche segregation. Kernel density estimates revealed predominantly diurnal activity, with bimodal patterns for tufted deer, sambar, and Chinese goral, and unimodal peaks for blue sheep, wild boar, and Chinese serow. Temporal overlap was highest between sambar and tufted deer, and lowest between tufted deer and blue sheep. These results demonstrate spatial and temporal partitioning as key mechanisms enabling ungulate coexistence and underscore the importance of conserving heterogeneous montane habitats.

Coupling between environmental drivers and microbial networks in shaping marine plankton dynamics.

Understanding how species that share the same habitat coexist can reveal how niche segregation helps reduce competition and structure communities. This study examines foraging niche segregation among six woodpecker species: Brown-fronted Woodpecker Dendrocoptes auriceps, Himalayan Woodpecker Dendrocopos himalayensis, Grey-headed Woodpecker Picus canus, Scaly-bellied Woodpecker Picus squamatus, Greater Yellownape Chrysophlegma flavinucha, and Lesser Yellownape Picus chlorophus in the oak-pine forests of Ranikhet, Kumaon Himalaya, Uttarakhand. Opportunistic observations were conducted to determine key foraging niche dimensions, including foraging tree diameter, foraging height, substrate type, vertical position, and the condition of foraging trees and substrate. The analysis indicates that these woodpecker species exhibit distinct foraging preferences concerning substrate use, foraging height, and vertical stratification, while they did not seem to respond to the presence of dead substrate. Notably, the Grey-headed and Scaly-bellied Woodpeckers, unlike the other species that primarily forage on trees, exhibited a preference for lower foraging heights and were frequently observed foraging on the ground.

Clarifying species boundaries within taxonomically complex groups like Dianthus is paramount for understanding evolutionary processes and biodiversity. This study employed a spatially explicit, integrative ecological approach to assess the niche dynamics of Dianthus pseudocrinitus Behrooz. & Joharchi, a neo-endemic species with debated taxonomic status, alongside Dianthus crinitus subsp. turkomanicus (Schischk.) Rech. f. and Dianthus orientalis subsp. stenocalyx (Boiss.) Rech. f. in northeastern Iran. Utilizing high-resolution environmental variables (bioclimatic, soil, NDVI, topographic) within ecological niche modeling, multivariate analyses (MANOVA, LDA), hypervolume-based quantifications, and density overlap metrics, I demonstrated notable and statistically significant ecological niche differentiation among the three taxa. These findings suggested soil characteristics as the likely primary drivers of niche segregation, with NDVI also playing a potentially important role. Crucially, D. pseudocrinitus exhibited a substantially narrower ecological niche (478.33 units, 18.23–22.66%) and minimal overlap with its congeners (Jaccard indices ≤ 0.162), providing strong ecological indications of its distinct species status despite morphological similarities and geographic proximity, and supporting its previously described functional divergence. The strong ecological segregation and narrow niche of D. pseudocrinitus relative to its geographically adjacent congeners provide compelling evidence for parapatric speciation. This pattern of strong fine-scale ecological divergence, alongside some broader bioclimatic niche conservatism, highlights the dynamic interplay of factors shaping species boundaries. The results underscore the potential importance of microhabitat specialization and local adaptation in driving diversification in complex montane environments and advocate for integrative taxonomic approaches to resolve intricate delimitation challenges.

Managing plant biodiversity in tallgrass prairie ecosystems under changing environmental conditions requires a better understanding of the mechanisms that control and maintain species' distributions. In a landscape with a clear spatial gradient of soil moisture, the concept of “hydrological niche” segregation states that the partitioning of water availability across space significantly explains the pattern of plant community composition and distribution. We evaluated the applicability of this concept to a tallgrass prairie remnant (the Faville Prairie in southern Wisconsin) with a 70-year monitoring history, the Faville Prairie Wisconsin State Natural Area (43.1486N, 88.8779W). We tested the hypothesis that plants occupy distinct hydrological niches by partitioning the soil moisture availability gradient generated by topographic heterogeneity. Using a permanent array of 180 plots across the prairie, we collected plant occurrences in 2022 and topsoil moisture contents monthly from May to August in 2023. We made continuous soil moisture maps with spatial interpolation in ArcGIS Pro. Our results suggest that fine-grained topographic heterogeneity generates significant spatial and temporal variation in soil moisture at Faville. The distribution of plant species differed significantly along the spatial gradient of soil moisture. We describe these species-specific patterns of segregation and posit explanations for each. These results support the conclusion that plants at Faville coexist at a landscape level by segregating based on distinct hydrological niches. This study provides more insight into understanding the mechanisms that govern plant distribution in a tallgrass prairie by taking hydrological affinities of species into account.

The blue shark (Prionace glauca) plays a key ecological role in pelagic ecosystems due to its broad distribution and diverse feeding strategies. To better understand its trophic dynamics in the Northeastern Pacific, we examined the feeding ontogeny of individuals sampled off Baja California Sur (Mexico), a key area within this region, using carbon and nitrogen stable isotope analysis (SIA) from muscle and vertebral tissues. δ¹⁵N values from both tissues indicated broadly overlapping trophic positions across maturity stages, although a slight but significant increase was observed in adults. In contrast, δ¹³C values revealed clear ontogenetic shifts in habitat use: adults occupied more coastal-influenced zones, while juveniles were associated with oceanic waters. Isotopic niche overlap between maturity stages (I-II vs. III) and between sexes was low (<0.25), indicating marked ecological segregation. Significant δ¹⁵N differences linked to maturity stage and sex may reflect female-biased migratory behaviour and broader thermal tolerance. Overall, our results highlight pronounced variation in trophic niches associated with sex and ontogeny, likely driven by sea surface temperature gradients and spatial differences in prey availability. These findings provide new insight into the ecological drivers shaping blue shark feeding strategies in a dynamic subtropical ecosystem.

Availability and quality of food shape the distribution and movements of animal populations. In sympatric species, sharing limited resources, coexistence is typically achieved through niche segregation. However, information on dietary niches is lacking particularly for small and elusive seabirds, which often forage in remote oceanic areas. In this study, we aimed to characterize the trophic ecology of two highly pelagic seabird species, Wilson's storm-petrel Oceanites oceanicus and Black-bellied storm-petrel Fregetta tropica, breeding sympatrically on King George Island, maritime Antarctica, using a combination of methods. Prey species, assayed via metabarcoding of faecal and regurgitate samples, were dominated by teleost fish, primarily lanternfish (Myctophidae), and zooplanktonic crustaceans, mainly krill (Euphausiidae), but also included other prey with lower frequencies of occurrence, such as salps and amphipods. We used carbon and nitrogen bulk stable isotopes and compound-specific isotope analyses of amino acids of blood samples to derive isotopic niches and trophic positions, showing that Black-bellied storm-petrels prey on a slightly higher trophic position than Wilson's storm-petrels (3.7 and 3.5, respectively). Combining results of stable isotope and molecular diet analysis, indicate a diet richer in fish for Black-bellied storm-petrels and thus a potential niche segregation not in regards of general prey spectrum but proportion of specific prey types (prey composition). Additionally, intraspecific segregation in prey spectrum was observed in Wilson's storm-petrels concerning their breeding stage (incubation vs. chick-rearing), suggesting selective chick provisioning. Future studies should investigate a potential interspecific spatial segregation in foraging areas.

Recurrent toxic blooms of Alexandrium minutum, Pseudo-nitzschia spp. and Dinophysis acuminata, impact the European shellfish industry. In temperate latitude embayments with spring-summer upwelling, reset phytoplankton mini-successions develop during short-term (a few days) wind-driven events interspersed by relaxation or downwelling. High resolution observations were made at a reference station during cruise "REMEDIOS-TLP", 2-14 July 2018 to explore assembly dynamics (cluster analysis) and niche structuring (OMI and WitOMI) processes during a relaxation-upwelling event. A well-mixed "Relaxation habitat" (H1) co-occurred with a shallow warmer and fresher "TS stratified surface layer" (H2) (site of Alexandrium cell maximum) from the confined water mass on the shoreward side of the downwelling front. These two habitats preceded a new upwelling pulse of cold nutrient rich waters which raised the Chl-a rich waters and entrained populations of Pseudo-nitzschia through the new "Bottom upwelled water" (H4). Diatoms (central to pennate and back to central) peaked during spin up and spin down phases within the "Upwelling pycnocline" (H3), site of the subsurface chlorophyll maximum (SCML), and a short-lived thin layer (TLP). Leptocylindrus minimus, suspected threat to caged salmon in Canada and Chile, thrived at the "upwelling diatom bloom maximum" phase but spring 2018 anomalies excluded optimal environmental windows for D. acuminata development. Isolated patches of Dinophysis revealed decimetre-scale niche segregation with Alexandrium populations. Detailed biological parameterization presented here will contribute to improve prediction of assemblages and processes which favour harmful algal blooms.

In the wild, individuals consistently differ in movement and space use behaviours, depending on their personality. This variation can lead to personality–habitat associations and spatial structuring, potentially generating individual niche segregation. We explored the link between personality and landscape composition and structure in a population of free‐ranging roe deer Capreolus capreolus , predicting that 1) individuals with similar movement tactics would occupy similar ecological niches, which should result in 2) the spatial clustering of personalities in heterogeneous landscapes with personality‐alike individuals being closer to each other in space than by chance. Using GPS and activity data from 263 roe deer, we calculated five movement‐based personality traits. We evaluated the association between movement phenotypes and habitat by comparing the among‐individual similarity in movement behaviour to their similarity in home range composition and structure. Additionally, we conducted spatially‐explicit analyses to quantify the spatial clustering of these traits. Our results reveal that individuals with similar daytime use of open habitats, an indicator of boldness, occupy the same ecological niche with respect to woodland availability and habitat homogeneity, leading to strong spatial clustering in this trait. In contrast, home range size, average movement speed and road diurnality (i.e. an individual's propensity to get closer to a road during daytime), were spatially structured only at a small‐scale. Additionally, we found no spatial structure in activity level, and neither activity nor road diurnality were associated with landscape composition and structure. Matching movement‐based personality traits with landscape features revealed spatial clustering of personalities. This non‐random distribution could have implications for managing wild ungulate populations, segregating ecosystem services (e.g. nutrient fluxes) and disservices (e.g. road collisions) across the landscape.

ABSTRACT Understanding the trophic ecology of large pelagic fishes is essential to assess their ecological role in marine ecosystems and to develop effective conservation strategies. In the present study, we aimed to provide new information on the trophic ecology of eight large pelagic fish species ( Thunnus atlanticus (blackfin tuna), Thunnus albacares (yellowfin tuna), Katsuwonus pelamis (skipjack tuna), Sarda sarda (Atlantic bonito), Euthynnus alletteratus (little tunny ) , Coryphaena hippurus (dolphinfish), Istiophorus albicans (Atlantic sailfish), and Kajikia albida (white marlin)) using carbon and nitrogen stable isotope analysis. The isotopic data were used to determine the foraging range and trophic position of the species and to assess the isotopic niche widths and resource partitioning between them. Pelagic fish samples ( N = 163) were acquired from the Cabo Frio commercial fleet, Rio de Janeiro, Brazil, between February 2009 and January 2010. We found significant differences in both δ 13 C and δ 15 N values among the species. S. sarda appears to feed at higher trophic levels and shows isotopic niche segregation with the species analyzed. However, there was a high degree of niche overlap between the other species, with the exception of the genus Thunnus . The isotopic niche width varied among species, with C. hippurus and E. alletteratus showing the widest niches, while S. sarda had the narrowest. These results highlight relevant aspects of the trophic dynamics of species of high commercial value in a region that has not been previously studied. The information contained here can serve as a basis for future conservation and management strategies for these species in the southwest Atlantic.

This study investigates the biogeographic barriers and environmental gradients that influence the distribution and niche segregation of seven Hynobius salamander species in South Korea. Using Ecological Niche Models (ENMs) developed with the Maxent software and 48 environmental variables, we conducted four niche overlap tests for each species pair: niche identity tests and background similarity tests to assess niche differentiation, lineage-breaking tests to evaluate species boundaries in relation to environmental shifts, and ribbon tests to determine whether unsuitable habitats serve as distributional barriers. The results indicated that significant biogeographic barriers, including both physical features such as rivers and mountains and environmental gradients, influence the range segregation of these salamanders. The study also identified distinct ecological niches among the species, with environmental gradients and unsuitable habitats acting as key factors shaping their distributions. These findings highlight the crucial role of biogeographic barriers in the distribution and speciation of Hynobius salamanders, emphasizing the need to consider these factors in conservation strategies aimed at preserving their ecological diversity and evolutionary trajectories.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-22226-5.

Isotopic evidence of hydrological niche segregation and species coexisting mechanism of desert shrubs Reaumuria songarica and Nitraria sphaerocarpa

Different migration strategies under warming ocean anomalies in penguins: a study of spatial, oceanographic, and isotopic niche segregation

Trophic ecology analysis of two lanternfish species (Gymnoscopelus bolini and Lepidophanes guentheri) suggests spatial niche segregation in the southwestern Atlantic Ocean