Seasonal variations in niche partitioning between two sympatric sandgrouse

Abstract Background Understanding how species with similar ecological niches coexist in sympatric environments, where interspecific competition often drives niche partitioning, remains challenging, as traditional niche modelling approaches often lack resolution to capture complex behaviours and fine-scale niche dynamics. However, advances in high-resolution GPS tracking and remote sensing now offer finer insights into habitat preferences and niche overlap across dynamic ecosystems. Here, we combined GPS and remote sensing data to investigate habitat suitability and niche overlap between pin-tailed ( Pterocles alchata ) and black-bellied sandgrouse ( P. orientalis ), two steppe birds with narrow environmental requirements, in an Iberian biodiversity hotspot where both coexist year-round. Results We integrated high-resolution GPS data from 33 P. alchata and 22 P. orientalis (2021–2023) with 10-m-resolution environmental data from Sentinel-1 and Sentinel-2 imagery and used Random Forests models to assess habitat suitability for each species across breeding and non-breeding seasons, hence to compare key environmental drivers. We then compared two complementary representations of niche dynamics, namely realised niche overlap in geographic space ( G-space ), estimated using kernel density estimates, and potential niche overlap in environmental space ( E-space ), estimated from habitat suitability projections onto G-space . Overlap was compared across seasons within species (intraspecific) and between species (interspecific). For both species, habitat suitability was primarily influenced by topographic (e.g. elevation) and vegetation-related variables (e.g. cover, productivity). At intraspecific level, P. alchata showed greater seasonal potential niche segregation than P. orientalis . Interspecific potential niche overlap was high, especially during breeding. Despite high potential niche overlap, strong realised spatial segregation was detected across seasons at both intra- and interspecific levels, suggesting that sandgrouse species coexistence and temporal niche dynamics are mediated not only by seasonal variations in suitability but also by additional biotic or ecological processes (e.g. habitat specialisation, trophic divergence, anti-predator strategies) that promote greater niche partitioning. Conclusions These findings enhance our understanding of niche dynamics and coexistence at an unprecedented scale and underscore the conservation value of heterogeneous agricultural mosaics for sandgrouse, where natural and semi-natural habitats persist alongside low-intensity traditional farming.