A study revealing differences in the gut microbiomes of wild American martens living in areas either impacted by human activity or largely undisturbed appears in PLOS One this week, highlighting a new tool for tracking the ecological status of wild carnivore populations. Human-mediated environmental changes can influence the evolution and ecology of diverse wildlife, with terrestrial carnivores some of the most threatened on Earth. Hypothesizing that trophic level and gut bacterial composition could help track human impacts on carnivore ecological status, researchers from Northern Michigan University and elsewhere used fecal samples to analyze the gut microbiomes of 21 martens: 16 from regions affected by human activity and five from the Huron Mountain Club, a preserved area of primeval forest in Michigan's Upper Peninsula. They find clear differences in the gut microbiomes between the two groups, reflecting the more carnivorous diet of the Huron Mountain Club martens. "Our data underscore the utility of the gut microbiome as a tool for wildlife management — both for monitoring the health of populations and for appreciating the importance and ramifications of gut microbial diversity and community composition across species with diverse ecological roles and requirements," the study's authors write.