Climate change modifies carbon sequestration in copper-polluted forest soils

Abstract

Soil carbon (C) storage is a key ecosystem function which can provide globally important services such as climate regulation. The effect of climate change on the restoration of soil C storage potential on post-mining land, where the development of both soil and vegetation starts de novo, is still insufficiently understood. In this work we discuss how the recent changes of climate, effectuating temperature increase and overall habitat xerophytization have, during about 40 years, markedy modified the course of spontaneous succession and concomitantly the soil C sequestration potental in a model floodplain severely altered by long-term deposition of sulphidic waste from a copper (Cu) mine. Excessive Cu strongly reduces turnover of soil organic matter and adversely affects the revegetation process. Natural floods in this complex geomorphic setup on the other hand bring both pollutants and deficient nutrients to the affected floodplain. As the recent climate changes reduce the intensity of natural floods, two very different but highly specialized forest types are developing along the microelevation gradient (transects perpendicular to water channel) with up to 3-fold different topsoil C sequestration. This work shows how climate change can increase the vunerability of spontaneous restoration process primarily by reducing nutrient fluxes.