Grazing for biodiversity: Assessing the effects of cattle management practices on wetlands and amphibian communities in central Argentina

Abstract

Argentina is widely recognized as a key player in the production and consumption of beef, occupying a prominent position in the global context. However, there is a lack of comprehensive research on the environmental consequences of beef production, particularly concerning wetlands and aquatic biodiversity. We aim to assess the effects of cattle management practices (grazing types and stocking density) on wetland attributes and associated amphibian diversity in central Argentina. During two amphibian breeding seasons, we surveyed 117 wetland sites in paddocks with different cattle grazing types (continuous grazing, glyphosate-promoted pastures and rotational grazing) and stocking densities (low and high). We analyzed the effects of cattle management practices on wetland attributes, including water quality parameters, nutrient concentrations, wetland morphometry, and vegetation cover. Effects on amphibian communities were explored using richness, abundance, and species occurrence. General Mixed-effects Models revealed significant increases in nutrients (total solid dissolved, total nitrogen and soluble reactive phosphorous) and a significant decrease in vegetation cover in sites with high cattle stocking density. Likewise, we observed increased soluble reactive solids in wetlands associated with rotational grazing and decreased vegetation cover in those wetlands related to glyphosate-promoted pastures. Generalized Mixed-effects Models revealed that amphibian communities were negatively affected mainly by high stocking density, while abundance and species occurrence of hylids (Boana pulchella and Scinax squalirostris) were also affected by glyphosate-promoted pastures and rotational grazing treatments. Our results indicate that different types of grazing at low stocking density favor amphibian diversity and improve wetland water quality, therefore, reduced stocking density may result in improved wetland conditions and more diverse amphibian communities. Our results also suggest that glyphosate-promoted pastures and rotational grazing, although beneficial in terms of pasture management, may have unintended consequences on water quality in wetlands and amphibian communities. This study will contribute to our understanding of how cattle management practices influence wetland ecosystems and aquatic biodiversity in the most important cattle breeding area of South America, providing valuable insights for conservation efforts in cattle ranching landscapes.