Small increases in stream drying can dramatically reduce ecosystem connectivity
Small increases in stream drying can dramatically reduce ecosystem connectivity
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DOI：
10.1002/ecs2.4450
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发表时间：
2023-03
期刊：
影响因子：
2.7
通讯作者：
Megan C. Malish;Shang Gao;D. Kopp;Yang Hong;Daniel C. Allen;T. Neeson
中科院分区：
文献类型：
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作者：
Megan C. Malish;Shang Gao;D. Kopp;Yang Hong;Daniel C. Allen;T. Neeson
栖息地破碎化导致世界各地河流生物多样性丧失。尽管人为障碍对河流连通性的影响众所周知，但对于河流干涸可能如何改变栖息地和资源之间的联系的研究却很少。鉴于许多地区溪流干涸现象日益严重，迫切需要了解干涸对栖息地破碎化的影响。在这里，我们量化了俄克拉荷马州蓝河流域上游当前和未来气候情景下的时空干燥模式。我们使用水文模型来模拟九种气候情景的每日水流。对于每种情景，我们从模拟的每日水流中计算了水流时间连续性（干旱天数、干旱期和干旱期持续时间）和空间连通性（湿润长度、干流片段数量、干流片段长度和树突连通指数）的指标。我们发现，在未来的所有气候情景中，溪流干涸都可能会加剧，而溪流干涸的加剧会降低连通性。然而，水流干燥对连通性的影响是高度非线性的。具体来说，我们观察到一个阈值，在该阈值附近，河流干燥的小幅增加会导致连通性迅速下降。我们还发现，溪流干涸的最大增加与最高排放情景无关，这突显了气候、水资源可用性和连通性之间的复杂联系。鉴于连通性对于生态系统的结构和功能至关重要，我们讨论了根据溪流干涸的影响制定的水管理策略。
Habitat fragmentation drives biodiversity loss in rivers around the world. Although the effects of anthropogenic barriers on river connectivity are well known, there has been little research on the ways in which stream drying may alter connections among habitats and resources. Given that stream drying is increasing in many regions, there is a pressing need to understand the effects of drying on habitat fragmentation. Here, we quantify spatiotemporal drying patterns under current and future climate scenarios in the Upper Blue River Basin, Oklahoma. We used a hydrologic model to simulate daily streamflow for nine climate scenarios. For each scenario, we calculated metrics of streamflow temporal continuity (dry days, dry periods, and dry period duration) and spatial connectivity (wetted length, number of dry stream fragments, length of dry stream fragments, and dendritic connectivity index) from simulated daily streamflow. We found that stream drying is likely to increase in all future climate scenarios and that increases in stream drying reduce connectivity. However, the effects of stream drying on connectivity were highly nonlinear. Specifically, we observed a threshold around which a small increase in stream drying led to a rapid drop in connectivity. We also found that the greatest increases in stream drying were not associated with the highest emission scenarios, underscoring the complex linkages among climate, water availability, and connectivity. Given that connectivity is essential to ecosystem structure and function, we discuss water management strategies informed by impacts of stream drying.