Does a forested Caatinga hold more water?

Abstract:

The Caatinga is a tropical dry forest unique to northeastern Brazil. It is a strongly seasonal biome and has a relatively high degree of endism. Despite sporadic rainfall and a dry season extending 4 to 8 months, the Caatinga supports a population of about 20 million subsistence farmers. Yet, it is threatened by accelerated deforestation and fragmentation, land use change, and reduced periods of forest regrowth and recovery. How these perturbations affect hydrology is unclear, but may have implications for biodiversity and ecosystem services such as forage and wood production. Therefore, understanding key hydrological processes is critical. In this study, a detailed soil water budget from September 2013 to April 2014 was calculated. The main objective is to understand seasonal soil water dynamics (wet / dry), and differences between a pasture and forest cover. Specific questions are 1) under what conditions does a forest hold more soil water than a pasture? 2) What is the amount of water lost from each system and what are the likely pathways of loss (i.e. evaporation, transpiration, and drainage)? Compared to the pasture, it is expected that the forested Caatinga will store more soil water during the wet season, and less during the dry season. Elucidating these dynamics could guide land use and management strategies related to land cover and soil water storage.