Study reveals importance of groundwater for stability of freshwater fish populations and resilience to climate change Completed
Issue: Climate change is warming streams and rivers of the Chesapeake Bay watershed, and this is a critical concern for fisheries management and conservation. To address this issue, the Chesapeake Bay Program (CBP) recently identified four actions:
• address the threats of climate change in all aspects of the partnership’s work;
• prioritize communities, working lands, and most vulnerable habitats;
• apply the best scientific, modeling, monitoring, and planning capabilities; and
• connect restoration outcomes with emerging opportunities.
The USGS Chesapeake Science Strategy supports CBP through research to improve understanding of climate change across the watershed, including the resiliency of headwater streams and the fisheries they support.
USGS Study
A new USGS study investigated how groundwater affects fish population stability and resiliency to climate change. Researchers surveyed stream fish communities where they were sampled 29-30 years previously (see map) and evaluated biological changes based on groundwater processes that promote stable environmental conditions. This study is unique because researchers evaluated how fish populations have changed over multiple decades and how these changes are linked to climate resiliency.
Major Findings
Groundwater in karst terrain promotes resiliency to climate change in streams.
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Extensive aquifers associated with karst terrain (e.g., limestone) were less sensitive to air temperature fluctuations than streams elsewhere, indicating the importance of karstic groundwater inputs for climate change refugia in streams.
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The presence of calcium precipitates (marl) in stream substrates was associated with thermal resiliency and ecological stability over time, indicating that such features may be a useful indicator of climate change refugia in stream ecosystems.
Fish populations were most stable over time in streams underlain by karst.
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Sites in karst terrain were characterized by species persistence whereas streams elsewhere were characterized by species colonization and extirpation.
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Species such as checkered sculpin were only observed in karst terrain and were stable over time, consistent with prior research demonstrating their reliance on stable environmental conditions (Hitt et al. 2022).
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Some species colonized several sites (e.g., green sunfish) indicating their broad tolerance to environmental conditions across the watershed.
-
Smallmouth bass, an important species for fisheries management, were absent in several sites where they had been observed previously. Prior research showed declining populations of smallmouth bass in the Potomac River (Hitt and others 2020), and the new study suggests smallmouth bass may be declining in headwater streams as well.
Management Applications
This study helps identify refugia from climate change and can assist the CBP’s Climate Resiliency and Fish Habitat workgroups. This research also underscores the importance of long-term fish community data.
For More Information
This study is titled “Stabilising effects of karstic groundwater on stream fish communities” and was published in the journal Ecology of Freshwater Fish. https://onlinelibrary.wiley.com/doi/10.1111/eff.12705
More information about USGS Chesapeake studies can be found here.
More information about the USGS Eastern Ecological Science Center can be found here.
Issue: Climate change is warming streams and rivers of the Chesapeake Bay watershed, and this is a critical concern for fisheries management and conservation. To address this issue, the Chesapeake Bay Program (CBP) recently identified four actions:
• address the threats of climate change in all aspects of the partnership’s work;
• prioritize communities, working lands, and most vulnerable habitats;
• apply the best scientific, modeling, monitoring, and planning capabilities; and
• connect restoration outcomes with emerging opportunities.
The USGS Chesapeake Science Strategy supports CBP through research to improve understanding of climate change across the watershed, including the resiliency of headwater streams and the fisheries they support.
USGS Study
A new USGS study investigated how groundwater affects fish population stability and resiliency to climate change. Researchers surveyed stream fish communities where they were sampled 29-30 years previously (see map) and evaluated biological changes based on groundwater processes that promote stable environmental conditions. This study is unique because researchers evaluated how fish populations have changed over multiple decades and how these changes are linked to climate resiliency.
Major Findings
Groundwater in karst terrain promotes resiliency to climate change in streams.
-
Extensive aquifers associated with karst terrain (e.g., limestone) were less sensitive to air temperature fluctuations than streams elsewhere, indicating the importance of karstic groundwater inputs for climate change refugia in streams.
-
The presence of calcium precipitates (marl) in stream substrates was associated with thermal resiliency and ecological stability over time, indicating that such features may be a useful indicator of climate change refugia in stream ecosystems.
Fish populations were most stable over time in streams underlain by karst.
-
Sites in karst terrain were characterized by species persistence whereas streams elsewhere were characterized by species colonization and extirpation.
-
Species such as checkered sculpin were only observed in karst terrain and were stable over time, consistent with prior research demonstrating their reliance on stable environmental conditions (Hitt et al. 2022).
-
Some species colonized several sites (e.g., green sunfish) indicating their broad tolerance to environmental conditions across the watershed.
-
Smallmouth bass, an important species for fisheries management, were absent in several sites where they had been observed previously. Prior research showed declining populations of smallmouth bass in the Potomac River (Hitt and others 2020), and the new study suggests smallmouth bass may be declining in headwater streams as well.
Management Applications
This study helps identify refugia from climate change and can assist the CBP’s Climate Resiliency and Fish Habitat workgroups. This research also underscores the importance of long-term fish community data.
For More Information
This study is titled “Stabilising effects of karstic groundwater on stream fish communities” and was published in the journal Ecology of Freshwater Fish. https://onlinelibrary.wiley.com/doi/10.1111/eff.12705
More information about USGS Chesapeake studies can be found here.
More information about the USGS Eastern Ecological Science Center can be found here.