Large herbivore functional guilds and soil carbon storage in a semi-arid southern African landscape

Soils store approximately 75% of the global terrestrial carbon pool and can sequester varying levels of organic carbon depending on wildlife, livestock, and human activity on the landscape. Large-bodied herbivores (LH) are hypothesized to influence soil carbon dynamics through a variety of biogeochemical processes that vary in the direction and magnitude of their effects on terrestrial carbon storage. Because these effects across ecosystems remain unacknowledged, estimates of ecosystem carbon budgets may be inaccurate. Here, we explored how functional traits across multi-species domesticated and wild LH assemblages influence soil carbon storage, in a semi-arid landscape of north-central Botswana. We examined LH spatial occurrence patterns with soil carbon across an existing livestock-wildlife gradient that ranges from a national park to adjacent community rangelands. Weselected dominant ecological, behavioral, morphological, and physiological traits to characterize LH functional diversity. Our results identify key functional groups influencing soil carbon measures in the landscape, in different contexts of soil biophysical conditions. Livestock and wildlife generally have positive effects on soil carbon, but the magnitude of effect varies with soil biophysical context and the exact species occupying a landscape location.