Carbon stocks in a highly fragmented landscape with seasonally dry tropical forest in the Neotropics

Abstract

Global modeling of carbon storage and sequestration often mischaracterizes unique ecosystems such as the seasonally dry tropical forest of the central region of the Gulf of Mexico, because species diversity is usually underestimated, as is their carbon content. In this study, aboveground and soil carbon stocks were estimated to determine the climate mitigation potential of this highly degraded landscape (<25% of forest cover). Tree species in the study area had carbon content values that were 30%–40% higher than the standard value proposed by the IPCC (i.e., 50%). Tropical oak forest in the region, despite its restricted distribution and low species richness, accounted for the highest mean carbon stocks per unit area. The main factors driving spatial variability in carbon stocks were: maximum precipitation, soil organic matter, clay and silt content. No strong relationship was found between aboveground carbon stocks and soil organic carbon in the study area. Quantification of carbon stocks is an important consideration in the assessment of the conservation value of remnants of native vegetation in human-modified landscapes. This study demonstrates the importance of the highly fragmented tropical dry regions of the Neotropics in maintaining landscape functionality and providing key ecosystem services such as carbon sequestration. Our results also highlight how crucial field-based studies are for strengthening the accuracy of global models. Furthermore, this approach reveals the real contribution of ecosystems that are not commonly taken into account in the mitigation of climate change effects.