Equip de Biologia de la Conservació (EBC-UB), Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals & Institut de la Recerca de la Biodiversitat (IRBIO), Universitat de Barcelona (UB), Diagonal 643, 08028 Barcelona, Spain; Departament de Ciències Ambientals, Universitat of Girona, C/Maria Aurèlia Capmany 69, 17003 Girona, Catalonia, Spain.
Equip de Biologia de la Conservació (EBC-UB), Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals & Institut de la Recerca de la Biodiversitat (IRBIO), Universitat de Barcelona (UB), Diagonal 643, 08028 Barcelona, Spain.
Sci Total Environ. 2024 Nov 25;953:175917. doi: 10.1016/j.scitotenv.2024.175917. Epub 2024 Aug 30.
Amphibians, the most threatened vertebrates globally, face risks due to climate change, habitat loss, and fragmentation. Their sensitivity to environmental changes highlights their importance as ecological indicators. Temporary rivers, influenced by geological, climatic, and anthropogenic factors, play a critical role in shaping biodiversity and community structure. Some species of amphibians may be adapted to these temporary waters, a fact reflected in their life cycles and various biological traits. However, to develop effective conservation strategies for amphibians, it is essential to address the knowledge gaps surrounding the complex interactions between biological dynamics and fluvial habitat conditions. In this study, we investigated how trophic interactions between amphibians and other aquatic organisms (diatoms, macroinvertebrates, and fish), coupled with environmental factors (water availability and riparian structure), can affect amphibian abundance and diversity in temporary rivers. The study was conducted in a Mediterranean river network located in Sant Llorenç del Munt i l'Obac Natural Park (Catalonia, Spain). Our expectations were that habitats suitable for egg deposition, lacking predators (e.g. tadpole-predators and fish), and abundant in food sources would likely support higher amphibian abundance and diversity. However, water availability was identified as a crucial factor shaping abundance and diversity in the studied amphibian communities, even if it correlated with fish presence, and especially impacting amphibian species usually linked to permanent water bodies. Concerning biotic interactions, while our results suggested that amphibian populations in temporary rivers are more dependent on top-down than bottom-up interactions, the presence of aquatic predators was not as conclusive as expected, suggesting that in temporary rivers the fish-avoiding amphibian species can survive using microhabitats or breeding opportunities linked to natural river dynamics. Overall, our findings highlight the importance of considering multi-trophic interactions, hydroperiod and habitat heterogeneity in temporary river ecosystems for effective amphibian conservation.
两栖动物是全球受威胁最严重的脊椎动物之一，它们面临着气候变化、生境丧失和破碎化等多种威胁。它们对环境变化的敏感性凸显了它们作为生态指标的重要性。受地质、气候和人为因素影响的暂时性河流对生物多样性和群落结构的形成起着至关重要的作用。一些两栖动物物种可能适应这些暂时性水域，这反映在它们的生命周期和各种生物学特征上。然而，为了制定有效的两栖动物保护策略，必须解决生物动态与河流栖息地条件之间复杂相互作用的知识空白。在这项研究中，我们调查了两栖动物与其他水生生物（硅藻、大型无脊椎动物和鱼类）之间的营养相互作用，以及环境因素（水的可用性和河岸结构）如何影响暂时性河流中两栖动物的丰富度和多样性。该研究在西班牙加泰罗尼亚Sant Llorenç del Munt i l'Obac 自然公园的一个地中海河流网络中进行。我们的预期是，适合产卵、缺乏捕食者（如蝌蚪捕食者和鱼类）且食物资源丰富的栖息地可能会支持更高的两栖动物丰富度和多样性。然而，水的可用性被确定为影响研究中两栖动物群落丰富度和多样性的关键因素，即使它与鱼类的存在相关，并且尤其影响通常与永久性水体相关的两栖动物物种。关于生物相互作用，虽然我们的结果表明，暂时性河流中的两栖动物种群更依赖于自上而下的相互作用，而不是自下而上的相互作用，但水生捕食者的存在并不像预期的那样确定，这表明在暂时性河流中，鱼类回避的两栖动物物种可以通过利用微生境或与自然河流动态相关的繁殖机会来生存。总的来说，我们的研究结果强调了在临时性河流生态系统中考虑多营养相互作用、水期和栖息地异质性对于有效保护两栖动物的重要性。
