Impacts of silvopastoral management intensity and forest age on vegetation and soils of dry tropical forests

Abstract

In recent decades, the loss and degradation of extensive tropical forest areas have accelerated, driven by increased livestock production. Silvopastoral systems (SPS) have been proposed as an alternative for sustainable livestock farming; however, there are controversies regarding the impacts of cattle on forests. This study was carried out in remnants of tropical dry forest with traditional silvopastoral management in western Mexico. The objective was to evaluate the impacts of silvopastoral management intensity (SPMI), which included grazing and selective logging, as well as the age of forest regrowth, on forest vegetation and soils. Data were collected on 21 one-hectare plots, evaluating various aspects of vegetation (established, regenerating, and forage availability) and soil (fertility, structure, water-holding capacity, microbiota, and cover). The results show that SPMI had minimal impacts on forest remnants in terms of the variables measured. The most noticeable ones included decrease of soil aggregate stability with increased grazing and selective logging, as well as a decrease in height of juvenile plants with grazing, and an increase with medium levels of SPMI. However, no impacts were observed on most vegetation and soil components. Forest age had more pronounced effects than SPMI, mainly on the structure and composition of the established vegetation. Furthermore, various interactions between the different components of vegetation and soil were identified. A set of recommendations is offered aiming at compatibility between production and ecological conservation of forest remnants in traditional SPS. It is concluded that moderate forest grazing can reconcile livestock production with the conservation of tropical dry forests, potentially contributing to climate change mitigation and adaptation.