Epele Luis Beltrán, Miserendino María Laura
Centro de Investigaciones Esquel de Montaña y Estepa Patagónica (CONICET-UNPSJB), Roca 780 (9200), Esquel, Chubut, Argentina.
PLoS One. 2015 Oct 8;10(10):e0137873. doi: 10.1371/journal.pone.0137873. eCollection 2015.
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.
牲畜放牧会损害湿地的生物完整性和健康，尤其是在像巴塔哥尼亚这样的偏远地区，这些地区为多种地方性陆生和水生物种提供了栖息地。了解这些土地利用方式对无脊椎动物群落的影响有助于防止湿地退化，并为湿地恢复提供见解。在本论文中，我们评估了巴塔哥尼亚30个湿地中基于无脊椎动物（130个分类单元）的结构和功能属性的36个指标的响应情况，这些湿地受到不同程度的牲畜放牧强度影响。根据八个特征（牲畜存栏密度加上七个湿地测量指标），这些强度水平被分为低、中、高三个等级。在整个湿地梯度中检测到环境特征的显著变化，主要与pH值、电导率和养分值有关。无论降雨梯度如何，在一些受到高度干扰的地点，富营养化症状都很明显。七个无脊椎动物指标对湿地的牲畜放牧做出了一致且准确的响应。所有这些指标都与放牧干扰水平的增加呈负相关，其中昆虫科的数量是最可靠的衡量指标。多元分析方法（RDA）表明，无脊椎动物指标受到与水质相关的环境变量的显著影响：特别是pH值、电导率、溶解氧、养分浓度以及水生植物的丰富度和覆盖度。我们的结果表明，上述七个指标可用于评估巴塔哥尼亚干旱和半干旱湿地的生态质量，有助于确保保护区及其相关生态服务的建立。
