Patterns of dietary niche breadth and overlap are maintained for two closely related carnivores across broad geographic scales

Abstract

Ecological studies investigating niche breadth and overlap often have limited spatial and temporal scale, preventing generalizations across varying environments and communities. For example, it is not clear whether species having restricted diets maintain such patterns relative to closely related species and across their geographic range of co-occurrence. We used stable isotope analysis of hair and fur samples collected from four regions of sympatry for Canada lynx (Lynx canadensis) and bobcat (Lynx rufus) spanning southern Canada and the northern United States, to test the prediction that the more generalist species (bobcat) exhibits a wider dietary niche than the more specialist species (Canada lynx) and that this pattern is consistent across different regions. We further predicted that Canada lynx diet would consistently exhibit greater overlap with that of bobcat compared to overlap of bobcat diet with Canada lynx. We found that Canada lynx had a narrower dietary niche than bobcat, with a high probability of overlap (85–95%) with bobcat, whereas the bobcat dietary niche had up to a 50% probability of overlap with Canada lynx. These patterns of dietary niche breadth and overlap were consistent across geographic regions despite some regional variation in diet breadth and position, for both species. Such consistent patterns could reflect a lack of plasticity in species dietary niches. Given the increasingly recognized importance of understanding dietary niche breadth and overlap across large spatial scales, further research is needed to investigate the mechanisms by which broad-scale patterns are maintained across species and systems.

Niche partitioning of bobcat and Canada lynx near their distribution contact zone

“…Our study examined the ecology of bobcat and lynx at their range contact zone in southeastern Canada. Our data were consistent with previous work indicating that bobcat and lynx exhibit distinct generalist and specialist strategies, respectively (Peers et al 2012;Gobin et al 2022). Lynx throughout our study had a relatively narrow isotopic niche, and we determined there was a strong positive relationship between the stable isotope composition of lynx muscle and liver, indicating individual specialization was prevalent.…”

“…Specialist behaviors may be favored in the environments lynx currently occupy, but reliance on snowshoe hare likely contributes to the severity of lynx population collapse during periods of low hare abundance (Peers et al 2014). Bobcats, on the other hand, have been documented consuming a wide variety of prey--including snowshoe hare when available (Litvaitis and Harrison 1989;Gobin et al 2022). Generalist behaviors in bobcats could potentiate their ongoing range expansions and make them superior competitors in increasingly altered and heterogeneous landscapes (Kassen 2002).…”