Responses of Tibetan antelope population to environment changes during the Holocene

Tibetan antelope is the only genus of large mammal endemic to the Tibetan Plateau. In the past decades, the antelope population has been significantly affected by human activities, including massive illegal hunting, followed by strict protection policies and establishments of natural reserves. Various techniques and many efforts have been devoted to monitoring changes in antelope population as well as migration recently. However, it remains unclear how the antelope population changed in the past, and how it varied with climate and environment. Here, we present sedimentary records at Lake Zonag, one of the major calving grounds for the Tibetan antelope, to study past changes in antelope population and response to environment changes. The sedimentary fecal sterols, produced by antelopes, captured the sudden decrease in antelope due to illegal hunting in past decades, as well as the recent recovery. The antelope population varied significantly during the past 9000 years, generally following environment changes revealed by geochemical elements in the same sediment core. Large antelope population likely lived in environment with relatively warm, humid and dense vegetation cover, while small antelope population occurred in adverse environment with relatively cold, dry and sparge vegetation cover. Two periods with notably low antelope population were observed at 5100-4500 and 4100-3700 cal yr before present. The increase in antelope population in the past 400 years likely result from protection from early Tibetans. This study provides a perspective method to reconstruct past changes in antelope population, to study its response to environment changes, and to provide historical comparison for wildlife protection.