Environmental Quality and Aquatic Invertebrate Metrics Relationships at Patagonian Wetlands Subjected to Livestock Grazing Pressures

PLoS One. 2015 Oct 8;10(10):e0137873. doi: 10.1371/journal.pone.0137873. eCollection 2015.

Abstract

Livestock grazing can compromise the biotic integrity and health of wetlands, especially in remotes areas like Patagonia, which provide habitat for several endemic terrestrial and aquatic species. Understanding the effects of these land use practices on invertebrate communities can help prevent the deterioration of wetlands and provide insights for restoration. In this contribution, we assessed the responses of 36 metrics based on the structural and functional attributes of invertebrates (130 taxa) at 30 Patagonian wetlands that were subject to different levels of livestock grazing intensity. These levels were categorized as low, medium and high based on eight features (livestock stock densities plus seven wetland measurements). Significant changes in environmental features were detected across the gradient of wetlands, mainly related to pH, conductivity, and nutrient values. Regardless of rainfall gradient, symptoms of eutrophication were remarkable at some highly disturbed sites. Seven invertebrate metrics consistently and accurately responded to livestock grazing on wetlands. All of them were negatively related to increased levels of grazing disturbance, with the number of insect families appearing as the most robust measure. A multivariate approach (RDA) revealed that invertebrate metrics were significantly affected by environmental variables related to water quality: in particular, pH, conductivity, dissolved oxygen, nutrient concentrations, and the richness and coverage of aquatic plants. Our results suggest that the seven aforementioned metrics could be used to assess ecological quality in the arid and semi-arid wetlands of Patagonia, helping to ensure the creation of protected areas and their associated ecological services.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Argentina
  • Environmental Monitoring*
  • Invertebrates / physiology*
  • Livestock
  • Multivariate Analysis
  • Wetlands*

Grants and funding

This work was supported by Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Secretaría de Ciencia y Técnica and the Universidad Nacional de la Patagonia SJB (SECyT-UNPSJB). Res CS N° 061/07 PI FCN 045/07 LBE MLM. This fund was applicable just for covering fuel cost for survey trips, and for fieldwork equipment; publications cost was not considered in this grant. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.