Niche Overlap Between Two Sympatric Steppe Birds in Inner Mongolia: Habitat Selection and Insights for Conservation

The destruction and degradation of natural ecosystems is a major driver of biodiversity loss. The steppe ecosystem is under threat from human activities and habitat degradation. Fine-scale breeding habitat selection is critical for the survival of steppe birds, but understanding the factors that drive this selection remains challenging. This study uses field point-count surveys to examine factors influencing habitat selection and quantify niche overlap between two closely related steppe bird species: Jankowski's Bunting (Emberiza jankowskii) and Meadow Bunting (E. cioides) in Inner Mongolia, China. These species share similar ecological traits and overlapping habitats, making them ideal for exploring how fine-scale habitat selection and resource differentiation enable coexistence despite ecological similarity. We use generalized linear models (GLMs) and niche modeling algorithms to analyze the data. The results reveal distinct habitat preferences at both local and landscape scales. Jankowski's Bunting favors areas with higher vegetation cover and height, while Meadow Bunting prefers sites with greater edge density. GLM results show non-linear responses of both species to habitat variables, with distinct thresholds for optimal occurrence. Niche overlap analysis indicates considerable overlap (Schoener's D = 0.57), but significant differences in niche centroids suggest niche differentiation between the two species. Our findings emphasize the importance of considering fine-scale habitat characteristics and non-linear species –habitat relationships in conservation planning for steppe birds. Understanding how these species respond to habitat changes resulting from anthropogenic activities—such as land-use conversion and agricultural intensification—can help tailor conservation efforts to mitigate negative impacts and promote species coexistence in sensitive habitats.