MAPPING SOIL MOISTURE AND CARBON HOTSPOTS IN A MONTADO ECOSYSTEM: A CASE STUDY IN COMPANHIA DAS LEZÍRIAS, PORTUGAL

Abstract

Montado landscapes in Portugal are high-nature-value agro-silvo-pastoral systems that provide multiple ecosystem services. These systems face increasing pressures from climate change, land-use transformations, and declining tree regeneration. Soil health plays a central role in ecosystem resilience and carbon storage. This study investigates the spatial and temporal relationships between soil moisture and carbon stocks in the Companhia das Lezírias eLTER site using Landsat-8-derived Soil Moisture Index (SMI) for the period 2017–2024 and field soil sampling across three depths (0–10, 10–20, 20–30 cm) in 13 plots. The objective of the study is to quantify drought-related changes in the soil system, focusing on carbon stocks, and associate them with information derived from remote sensing data by mapping moisture regimes and detecting soil hotspots. Results reveal persistent soil moisture patterns, with distinct carbon-rich and carbon-poor zones. Pearson correlation connecting carbon stocks to summer soil moisture suggests that wetter areas in the montado system accumulate more carbon. Spatial patterns of soil carbon, mapped using kriging interpolation, align with persistent moisture regimes, identifying drought-prone hotspots. The findings underscore the importance of hydrological drivers for carbon dynamics in montado ecosystems and suggest that integrated monitoring using remote sensing and field data can inform targeted management strategies to enhance soil health, maintain productivity, and improve resilience under increasing drought pressures.