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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.
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Aridity Drives Streamflow, Network Connectivity and Climate Change Impacts in Non‐Perennial Stream Networks
ABSTRACT Non‐perennial streams are globally prevalent. These streams are vital components of ecosystems, yet their drying patterns and resulting impacts on hydrologic connectivity remain poorly understood at the watershed scale. Aridity is a dominant driver of stream drying, but its influences on hydrologic connectivity have not been fully explored. In this study, we investigated the role of aridity in shaping streamflow and connectivity patterns in non‐perennial stream networks that span the continental United States aridity gradient. Using hydrologic models, we simulated daily streamflow and stream network connectivity under current and future climate scenarios. Our findings support previous research showing that aridity and streamflow are strongly linked. We also found that connectivity was related to aridity, although this relationship was weaker. Under the future climate scenario, mean runoff increased in most watersheds in the future, while mean connectivity decreased in the majority of watersheds. This difference is an indicator of the complex relationship between streamflow and connectivity. Aridity was a strong predictor of changes in very high and very low connectivity periods that resulted from climate change, but aridity did not predict changes in mean connectivity. Arid watersheds tended to experience more high connectivity days due to climate change while humid networks tended to have more low connectivity days. By modelling climate impacts at the network scale and across a broad hydroclimatic gradient, we highlight the importance of considering context‐dependent changes in network connectivity in river flow management and watershed conservation plans.
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- Award ID(s):
- 1802811
- PAR ID:
- 10656616
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Ecohydrology
- Volume:
- 18
- Issue:
- 8
- ISSN:
- 1936-0584
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/eco.70155
