Remote sensing and bioacoustics reveal avian niche partitioning and habitat filtering

Abstract A species’ ecological niche impacts it vulnerability to threats like climate change and habitat loss. Despite its importance, the ecological niche remains notoriously difficult to quantify. However, advancements in remote sensing and geospatial datasets now offer unprecedented opportunities to describe niches across scales. In this study, we quantify avian species' preferred habitats to identify patterns of niche partitioning and competitive exclusion. We utilized automated detections of 90 bird species collected from 577 autonomous recording units deployed throughout the Sierra Nevada, USA. These data were combined with remotely sensed habitat variables to measure habitat specificity and niche area overlap. Known species breeding ranges and breeding range overlap were also analyzed. We observed a negative relationship between range overlap and preferred habitat overlap among congeneric species pairs, indicating that closely related species have more distinct ranges when their preferred habitats are similar, consistent with niche partitioning and competitive exclusion principles. Sister species pairs exhibited low range overlap and similar preferred habitats, suggesting recent allopatric speciation events. In contrast, more distantly related species demonstrated a positive correlation between range overlap and preferred habitat, aligning with the concept of habitat filtering. Our results highlight how different ecological drivers shift in prominence as species diverge.