Human activities in a tropical Mexican desert: Impact of rainfed agriculture and firewood extraction on vegetation and soil

Abstract

AbstractThe impacts of human activities on temperate and subtropical deserts have been evaluated worldwide. However, data about tropical deserts are scarce. In this study, we evaluated the impacts of rainfed agriculture and firewood extraction on vegetation and soil of abandoned croplands (mesquite cropland and goldeneye cropland) and mesquite shrublands (open‐canopy mesquite and closed‐canopy mesquite) in a tropical Mexican desert. We interviewed peasants to understand their management practices and evaluated vegetation traits and soil properties of sites. We also examined the impacts of land management on vegetation and soil with structural equation modeling. Rainfed agriculture consisted of cultivating crops, fertilizing with manure, and introducing goats to croplands after harvest. Goldeneye cropland had higher canopy cover, vegetation structure, and litter cover than mesquite cropland. However, soil in both croplands was highly compacted with low infiltration rate, organic matter, and nutrient content. Firewood extraction only consisted of removing mesquite branches. Open‐canopy mesquite had lower canopy and litter cover and higher biological soil crust cover than closed‐canopy mesquite. The soil in both shrublands was less compacted with relatively high infiltration rate, organic matter, and nutrient content. Rainfed agriculture decreased soil nutrient content due to removal of native vegetation, plowing, and goat introduction to croplands. In contrast, firewood extraction maintained a relatively high soil nutrient content because branch removal enables the establishment of biological soil crusts, which increased the infiltration rate and nutrient availability. Thus, firewood extraction has a lower impact on the structure and function of fluvial terraces than rainfed agriculture in this tropical desert.