Impact of reintroduced elaphure on soil carbon storage in eastern Jiangsu Province, China

Introduction The reintroduction in the wild of elaphure or Père David's deer ( Elaphurus davidianus ) in a coastal wetland in Dafeng, Jiangsu Province, in the absence of an apex predator has been shown to negatively impact the ecosystem through overgrazing, which, over time, can also degrade the soil's ability to sequester atmospheric carbon. Objectives The study's objective was to determine the impact of reintroducing Père David's deer on soil carbon content, an indicator of ecosystem productivity. To assess the potential impact of reintroduction, we conducted a field study at a controlled site to quantify the reduction in vegetation cover and determine whether grazing by Père David's deer significantly altered the soil carbon content and, subsequently, soil productivity. Methods Data were collected within exclosures and outside them at three different areas of the reserve. We measured soil carbon content, soil moisture content, soil carbon dioxide flux, plant canopy cover, and average plant height. Statistical tests and logistic regression models were employed to assess the impact of deer grazing on soil quality. Results A reduction in leafing volume (plant cover area × plant height) was associated with a decline in soil carbon content. Within the reintroduction site, soil carbon content decreased by 8.9% annually from 2017 to 2019. Conclusions Evidence suggests that if the current trend of reintroduction persists, this section of the wetland will continue to decline in its capacity to sequester and store carbon, with similar declines likely across the larger reintroduction area.