Lovelock, C. E. | Search bioRxiv

bioRxiv2025

An integrative review of the impact of ungulates on wetland carbon storage and greenhouse gas emissions

Wetlands, spanning freshwater to saline ecosystems, are seasonally or permanently inundated and store over 30% of the worlds carbon within their soils. Ungulates can remove vegetation, disturb soils, and degrade habitats. Although site-level studies exist, broad evaluations of ungulate impacts on carbon stocks and greenhouse gas emissions remain scarce. We assessed how ungulate presence influences aboveground and soil carbon stocks and greenhouse gas emissions in wetlands. Aboveground carbon stocks declined from 36.9 to 3.70 Mg C per ha in the presence of ungulates. Soil carbon stocks were higher in the absence of ungulates (257 Mg C per ha) than in their presence (112 Mg C per ha). CO2 equivalent emissions were higher in the presence of non-native ungulates (38.4 Mg CO2 eq per ha per yr) than in the presence of native ungulates (27.2 Mg CO2 per ha per yr), and higher in freshwater wetlands of warm temperate dry regions when ungulates were present (27.2 Mg CO2 eq per ha per yr) compared to when ungulates were absent (13.2 Mg CO2 eq per ha per yr). Our findings emphasize the importance of expanding research across different climate regions and soil types to support the development of ungulate management strategies that maintain wetland carbon stocks and reduce greenhouse gas emissions.

ecology↗

bioRxiv2020

Future carbon emissions from global mangrove forest loss

Mangroves have among the highest carbon densities of any tropical forest. These "blue carbon" ecosystems can store large amounts of carbon for long periods, and their protection reduces greenhouse gas emissions and supports climate change mitigation. The incorporation of mangroves into Nationally Determined Contributions to the Paris Agreement and their valuation on carbon markets requires predicting how the management of different land-uses can prevent future greenhouse gas emissions and increase CO2 sequestration. Management actions can reduce CO2 emissions and enhance sequestration, but should be guided by predictions of future emissions, not just carbon storage. We project emissions and forgone soil carbon sequestration potential caused by mangrove loss with comprehensive global datasets for carbon stocks, mangrove distribution, deforestation rates, and drivers of land-use change. Emissions from mangrove loss could reach 2,397 Tg CO2eq by the end of the century, or 3,401 Tg CO2eq when considering forgone carbon sequestration. The highest emissions were predicted in southeast and south Asia (West Coral Triangle, Sunda Shelf, and the Bay of Bengal) due to conversion to aquaculture or agriculture, followed by the Caribbean (Tropical Northwest Atlantic) due to clearing and erosion, and the Andaman coast (West Myanmar) and north Brazil due to erosion. Together, these six regions accounted for 90% of the total potential CO2eq future emissions. We highlight hotspots for future emissions and the land-use specfic management actions that could avoid them with appropriate policies and regulation.

biochemistry↗