Centro de Investigación Esquel de Montaña y Estepa Patagónica (CONICET-UNPSJB), Roca 780, Esquel, Chubut, Argentina; Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia San Juan Bosco, Esquel, Chubut, Argentina.
Centro de Investigación Esquel de Montaña y Estepa Patagónica (CONICET-UNPSJB), Roca 780, Esquel, Chubut, Argentina; Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia San Juan Bosco, Esquel, Chubut, Argentina.
Sci Total Environ. 2019 Aug 15;678:62-73. doi: 10.1016/j.scitotenv.2019.04.392. Epub 2019 Apr 27.
Freshwater biodiversity is showing a global decline in relation to environmental change and there is an urgent need to quantify different facets of biodiversity to assess the conservation value of freshwater ecosystems. Identifying the ecological drivers of arid and semiarid Patagonian waterbodies is a critical requirement for planning action to conserve these still poorly understood habitats. We tested the responses of alpha and beta diversity of invertebrates (presence-absence, abundance, and biomass) to local, landscape, and climatic features, in 45 Patagonian freshwater bodies classified in three groups: isolated ponds, connected ponds, and lotic systems. We first compared the invertebrate community compositions of the different waterbodies. Secondly, using a co-inertia analysis we assessed the relative roles of local, landscape and climatic factors in driving variation in assemblage composition. Finally, we compared different facets of beta diversity and modelled their responses to environmental variables (predictors), by generalized dissimilarity modelling (GDM). Unexpectedly, lotic systems with a total of 109 taxa, were richer than lentic ones, but isolated ponds contributed most to beta diversity and supported more unique and proportionally more endemic species. Alpha and beta diversity were mainly driven by local features and secondly by climatic descriptors. However, these patterns shifted according to different community composition measures. Collectively, our results suggest that isolated ponds have a higher biodiversity value and would be more vulnerable than connected ponds and lotic systems to environmental changes. However, all waterbody types contributed to gamma biodiversity, reinforcing the importance of conserving a diversity of freshwater ecosystems in any landscape and particularly in arid and semiarid Patagonia. Our findings are a first step to resolving and quantifying the amount of changes occurring in Patagonian waterbodies, and are a prerequisite for predicting changes in species distributions in the face of global change.
淡水生物多样性与环境变化相关呈全球性下降趋势，因此迫切需要量化生物多样性的不同方面，以评估淡水生态系统的保护价值。确定干旱和半干旱巴塔哥尼亚水域的生态驱动因素，是规划行动以保护这些仍未被充分了解的栖息地的关键要求。我们检验了节肢动物（存在-缺失、丰度和生物量）的α多样性和β多样性对局部、景观和气候特征的响应，在 45 个巴塔哥尼亚淡水体中进行了测试，这些水体分为三组：孤立池塘、连通池塘和流水系统。我们首先比较了不同水体的无脊椎动物群落组成。其次，使用共协方差分析评估了局部、景观和气候因素在驱动群落组成变化方面的相对作用。最后，我们比较了不同方面的β多样性，并通过广义差异模型（GDM）对其对环境变量（预测因子）的响应进行建模。出乎意料的是，尽管总共有 109 个分类单元的流水系统比静水系统更丰富，但孤立池塘对β多样性的贡献最大，并支持更多独特和比例更高的特有物种。α多样性和β多样性主要受局部特征驱动，其次受气候描述符驱动。然而，这些模式根据不同的群落组成措施而变化。总的来说，我们的研究结果表明，孤立池塘具有更高的生物多样性价值，与连通池塘和流水系统相比，它们更容易受到环境变化的影响。然而，所有水体类型都有助于γ多样性，这强化了在任何景观中保护多种淡水生态系统的重要性，特别是在干旱和半干旱的巴塔哥尼亚地区。我们的研究结果是解决和量化巴塔哥尼亚水体中发生的变化数量的第一步，也是预测全球变化下物种分布变化的前提。
