Drought-Induced, Punctuated Loss of Freshwater Mussels Alters Ecosystem Function Across Temporal Scales
Drought-Induced, Punctuated Loss of Freshwater Mussels Alters Ecosystem Function Across Temporal Scales
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DOI：
10.3389/fevo.2019.00274
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发表时间：
2019-07-18
影响因子：
3
通讯作者：
Golladay, Stephen W.
中科院分区：
文献类型：
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作者：
DuBose, Traci P.;Atkinson, Carla L.;Golladay, Stephen W.
对于许多动物分类群来说，间断性的大规模死亡事件正在增加，通常与干旱等极端气候有关。淡水贻贝正在经历与水文干旱相关的大规模死亡事件增加。由于贻贝在河流中发挥着重要的功能作用，因此了解这些死亡对生态系统的影响非常重要。在这里，我们解决了大规模死亡事件的贻贝干旱可能会影响流生态系统功能。我们首先提出了一个概念模型，根据文献，贻贝的质量死亡率应如何影响不同的生态系统功能，在不同的生态时间尺度，从几个小时到几十年。接下来，我们强调两个案例研究干旱相关的，贻贝大规模死亡事件从美国南部的河流，然后我们提出的实验结果，我们进行量化的生态系统影响的间歇贻贝死亡。最后，我们将联合收割机的实验结果与最近贻贝死亡的现场数据相结合，预测贻贝损失将如何影响生态系统功能。基于所提出的案例研究，我们的围隔实验，和我们的外推营养脉冲由于贻贝死亡，我们得出结论，河流生态系统被广泛改变贻贝大规模死亡事件。贻贝损失受干旱严重程度、在河流网络中的位置以及物种特异性干旱耐受性的影响。在短期内，贻贝死亡后腐烂的腐肉会向水中释放大量的营养物质，从而刺激食物网的生产力。从长远来看，贻贝生物量的总体损失以及随着更敏感物种的减少而丧失的功能特征，导致生态系统功能下降，这可能需要数十年的时间才能恢复。干旱和人类对水的需求将使贻贝在未来更有可能死亡，如果不改变水管理和通过贻贝繁殖恢复种群，对干旱敏感的物种就不太可能恢复。我们的研究提供了一个例子，说明一个丰富的、长寿的生物体的损失如何对生态系统产生级联和长期影响。
Punctuated, mass mortality events are increasing for many animal taxa and are often related to climatic extremes such as drought. Freshwater mussels are experiencing increased mass mortality events linked to hydrologic drought. Because mussels play important functional roles in rivers it is important to understand the ecosystem effects of these die-offs. Here, we address how mass mortality events of mussels caused by drought may impact stream ecosystem function. We first present a conceptual model, based on the literature, of how mussel mass mortality should affect different ecosystem functions across various ecological time scales, from hours to decades. Next, we highlight two case studies of drought-linked, mussel-mass mortality events from rivers in the southern U.S. We then present the results of an experiment we performed quantifying the ecosystem effects of a punctuated mussel die-off. Finally, we combine our experimental results with field data from a recent mussel die-off to predict how mussel losses will in fluence ecosystem function. Based on the presented case studies, our mesocosm experiment, and our extrapolated nutrient pulse due to a mussel die-off, we conclude that streamecosystems are extensively altered following mussel mass mortality events. Mussel loss is governed by drought severity, location within the river network, and species-specific drought tolerances. In the short term, decomposing carrion from mussel die-offs releases a large pulse of nutrients into the water which stimulates food web productivity. In the long term, the overall loss of mussel biomass, and the loss of functional traits as more sensitive species decline, leads to decreases in ecosystem function which may take decades to recover. Drought and human demand for water will make mussel die-offs more likely in the future and it is unlikely that drought sensitive species will recover without changes in water management and restoration of populations through mussel propagation. Our research provides an example of how the loss of an abundant, long-lived organism has cascading, and long-term impacts on ecosystems.