Metabarcoding Reveals Fine Scale Patterns of Trophic Resource Use and Partitioning Along Gradients of Land Use and Deer Density in a Multi-Species Ungulate Community.

Across the northern hemisphere, ungulates are expanding in range and abundance, forming novel communities in increasingly human-modified landscapes. These shifts drive new interactions over available food resources, but patterns of resource use and partitioning in Europe's multi-species systems remain poorly understood. This study examined seasonal diets and resource partitioning in diverse cervid communities (moose, roe deer, red deer, and fallow deer) across two Swedish landscapes (coastal-boreal and boreo-nemoral) differing in deer density and land use. Based on their foraging strategies, we expected (Hypothesis 1) diet richness and dietary niche width to be greater in intermediate feeders (red and fallow deer) than in browsers (moose and roe deer), (Hypothesis 2) trophic partitioning between browsers and intermediate feeders to be driven mainly by graminoid use, and (Hypothesis 3) intra- and interspecific overlap to vary with season, deer density, habitat diversity, and proportion of arable land. DNA metabarcoding of 2568 fecal samples showed that deer consumed plants from over 70 families, though diets were typically dominated by fewer than 10.