Large herbivore effects on terrestrial nitrogen availability in Late Pleistocene Britain
At the end of the Late Pleistocene period there were marked changes in nitrogen availability within ecosystems globally. Given the association in time of changing nitrogen availability with the loss of the largest mega-herbivores (e.g. woolly mammoth and the giant deer from Eurasia), an important research question to be addressed is to what extent did the extinction of these species drive the observed changes in nitrogen availability within ecosystems. To address this question, palaeoecological records of change in mega-herbivore density (Sporormiella accumulation rates) and nitrogen availability (sedimentary δ15N) were analysed from three sites across Britain during this period of faunal community change. Statistical modelling of these data was used to infer the relationships between mega-herbivore density and nitrogen availability through time.
Results show that the impacts of mega-herbivores on nitrogen availability are context-dependent, which is in keeping with findings from modern studies of large herbivores. The fossil bone record at each of the sites shows clear differences in the faunal assemblages and suggests that the differential impacts of the mega-herbivores on nitrogen availability may be attributable to the unique digestive strategies of each faunal community.