Interest in conserving and rehabilitating ecosystems that reduce atmospheric greenhouse gas concentrations is increasing with the need for actions that mitigate global warming. Freshwater wetlands have the capacity to act as both substantial carbon sinks and potential carbon sources, highlighting the importance of research that helps better understand this balance shift in the context of the global carbon budget.
Although freshwater wetlands store carbon and provide other important ecosystem services (i.e. flood mitigation, improved water quality, supply of water resources), their value has been underappreciated, resulting in considerable loss of wetland area. Globally, freshwater wetlands have decreased by up to two-thirds of their original expanse. Currently, there is limited knowledge regarding best management practices for freshwater wetland carbon dynamics, in part due to the countless number of variables acting on these systems.
Using a multi-pronged approach of analysing wetland soil carbon, greenhouse gas, and microbial communities, our research highlights the importance of freshwater wetland rehabilitation practices for carbon emission reduction and storage potential. Rehabilitating wetlands through environmental watering practices reduced carbon emissions by 84% from a degraded wetland ecosystem. Excluding grazing from wetlands within the Wimmera region would increase above-ground biomass and soil carbon storage by 7,700 tons of C while reducing CO2 emissions by 770,700 tons of CO2 yr-1.
This research identifies key drivers of carbon retention and release from wetlands under different management regimes. Results from these studies provide guidance about how and where freshwater wetland conservation and rehabilitation should occur to maximise carbon offset opportunities.