Abstract
There is increasing concern about how human activities could affect the ecosystems of the Galapagos Islands, a globally recognised biodiversity hotspot. Despite the large number of studies related to the ecological relationships between species on these islands, almost no research has been conducted on the description of their soils, a fundamental component of the Galapagos ecosystems. In 1962, Belgian researchers from Ghent University organised a geo-pedological mission to collect detailed information on soil diversity on Santa Cruz Island. Here, we use this legacy data within a Digital Soil Mapping framework to quantify the spatial distribution of Soil Organic Carbon (SOC) stocks in this area. Our results indicate that the soils of Santa Cruz store about 706 Gg of SOC in the upper 10 cm. SOC accumulation is mainly driven by climatic factors, which are strongly influenced by both altitude and the direction of prevailing winds. An increase in rainfall, as predicted by climate change scenarios, will result in an overall increase in SOC stocks and will likely modify the vegetation species composition within the different bioclimatic strata of the islands. An SOC monitoring programme, based on spectroscopic analyses, could be used to determine temporal variations in SOC stocks quickly and cost-effectively while minimising human disturbances in this area.
