Data from: Fecal biomarkers in soils record landscape-scale wild herbivore abundance

In Earth history, our understanding of how large-bodied herbivores shape a
variety of ecosystem processes is limited by the quality of
paleoecological proxies for herbivore composition and abundance. Fecal
stanols are lipids that can be produced by microbes within animal
digestive systems and that could remedy this dearth of proxies. 
We use two multi-decadal herbivore exclosures in Kruger National Park,
South Africa, to constrain whether and how biomarker signatures preserve
signals of herbivore abundance. Soil samples and dung counts were
collected along transects across crest, mid-slope, and sodic sites inside
and outside exclosures. Soils were analyzed for steroid (sterols and
stanols) concentrations and distributions. We found that stanol
concentrations were significantly greater in sodic soils outside
exclosures, where herbivore dung densities were greatest. By contrast,
sterol concentrations did not differ between treatments. Ratios of stanol
isomers to sterols, which account for both compound degradation and
source, increased strongly with herbivore dung counts. Finally, while
herbivore species compositions influenced steroid distributions, total
herbivore abundance was their strongest predictor. Further calibration is
needed, but this work provides strong preliminary evidence that wild
herbivore populations are quantitatively recorded by fecal biomarker
distributions.