Modelling soil carbon content in South Patagonia and evaluating changes according to climate, vegetation, desertification and grazing

PL PERI; YM ROSAS; B LADD; S TOLEDO; RG LASAGNO; G MARTÍNEZ PASTUR

The long-term perspective of human impact on landscape for environmental change and sustainability

MDPI

Lugar: Basel; Año: 2019; p. 165 - 178

In Southern Patagonia, a long-term monitoring network has been established to assessbio-indicators as an early warning of environmental changes due to climate change and humanactivities. Soil organic carbon (SOC) content in rangelands provides a range of important ecosystemservices and supports the capacity of the land to sustain plant and animal productivity. The objectivesin this study were to model SOC (30 cm) stocks at a regional scale using climatic, topographic andvegetation variables, and to establish a baseline that can be used as an indicator of rangeland condition.For modelling, we used a stepwise multiple regression to identify variables that explain SOC variationat the landscape scale. With the SOC model, we obtained a SOC map for the entire Santa Cruzprovince, where the variables derived from the multiple linear regression models were integratedinto a geographic information system (GIS). SOC stock to 30 cm ranged from 1.38 to 32.63 kg C m−2.The fitted model explained 76.4% of SOC variation using as independent variables isothermality,precipitation seasonality and vegetation cover expressed as a normalized difference vegetation index.The SOC map discriminated in three categories (low, medium, high) determined patterns amongenvironmental and land use variables. For example, SOC decreased with desertification due toerosion processes. The understanding and mapping of SOC in Patagonia contributes as a bridgeacross main issues such as climate change, desertification and biodiversity conservation.