Stabilising effects of karstic groundwater on stream fish communities

Ecology of Freshwater Fish
By: , and 

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Abstract

Although groundwater exchange processes are known to modulate atmospheric influences on stream temperature and flow, the implications for ecological stability are poorly understood. Here, we evaluated temporal change in stream fish communities across a gradient of groundwater influence defined by karst terrain (carbonate parent materials) within the Potomac River basin of eastern North America. We surveyed 12 sites in 2022 that had been sampled 29–30 years previously with similar methods. We also collected stream temperature data from each site and used the regression slope of the air-water temperature relationship to index stream thermal sensitivity and groundwater exchange processes. Sites in karst terrain exhibited strong groundwater controls on stream temperature, and fish communities were more stable over time in these locations than elsewhere. However, stream thermal sensitivity was a stronger predictor of species persistence than the spatial distribution of karst terrain in contributing areas, highlighting the ecological importance of local variation in groundwater discharge processes. The presence of calcium precipitates (marl) in stream substrates was associated with low thermal sensitivity and ecological stability over time, and we suggest such visible features may be a useful indicator of climate change refugia in stream ecosystems.

Publication type Article
Publication Subtype Journal Article
Title Stabilising effects of karstic groundwater on stream fish communities
Series title Ecology of Freshwater Fish
DOI 10.1111/eff.12705
Volume 32
Issue 3
Publication Date February 07, 2023
Year Published 2023
Language English
Publisher Wiley
Contributing office(s) Leetown Science Center, New England Water Science Center, Eastern Ecological Science Center
Description 14 p.
First page 538
Last page 551
Additional publication details