Abstract
Biogeographical regions provide a framework for understanding species’ ecological patterns, yet their application to herbivore dietary studies remains limited. The European roe deer ( Capreolus capreolus ) presents an ideal candidate for biogeographical dietary analysis due to its widespread distribution and well-documented feeding patterns across Europe. Here, we analysed microhistological diet data using linear mixed-effects models to investigate regional and seasonal variations in roe deer feeding ecology across European Biogeographical Regions (EBRs), moving beyond traditional geographical classifications to understand dietary adaptations. The review encompassed 55 studies (54 included in statistical analyses) conducted over 52 years across 69 sites. While initially covering six EBRs, statistical analyses were constrained to three regions—Atlantic, Continental, and Mediterranean—due to insufficient data from the Boreal, Pannonian, and Alpine regions. We found complex dietary patterns, with intra-regional seasonal shifts in key food categories including coniferous trees, deciduous trees, shrubs, and half-woody plants. The Atlantic region showed significantly higher consumption of grasses, sedges, and rushes compared to Continental regions, while Mediterranean populations exhibited distinct autumn feeding patterns. Despite regional variations, consistent seasonal patterns in forb consumption were observed across all regions, peaking during spring and summer. Our findings suggest that roe deer modulate their feeding strategies according to regional conditions while maintaining some fundamental nutritional patterns. The biogeographical framework provides new understandings of herbivore dietary ecology not evident in previous studies using broader geographical classifications. These findings have important implications for understanding roe deer adaptation and informing regional management strategies.