Gut microbiome composition predicts summer core range size in a generalist and specialist ungulate. Mountain Goat; White-tailed deer

The gut microbiome of animals can vary by age, diet, and habitat, and directly influences individual health. Likewise, variation in an individuals home range can lead to differences in feeding strategies and fitness. Ungulates (hooved mammals) exhibit species-specific microbiomes and habitat use patterns: here, we combined gut microbiome and movement data to assess the relationship between space use and the gut microbiome in a specialist and a generalist ungulate. We captured and GPS radiocollared 24 mountain goats (Oreamnos americanus) and 34 white-tailed deer (Odocoileus virginianus). In mountain goats, we observed a negative relationship between gut diversity and use of both escape terrain and treed habitat. We hypothesize that larger Firmicutes to Bacteroidetes ratios confer body size or fat advantages that allow for larger core ranges, and that relationships between gut diversity and disproportionate habitat use are stronger in mountain goats due to their restricted niche relative to white-tailed deer. This is the first study to relate core range size to the gut microbiome in wild ungulates and is an important proof of concept that advances the information that can be gleaned from non-invasive sampling.