Accounting for groundwater in stream fish thermal habitat responses to climate change

Ecological Applications
By: , and 

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Abstract

Forecasting climate change effects on aquatic fauna and their habitat requires an understanding of how water temperature responds to changing air temperature (i.e., thermal sensitivity). Previous efforts to forecast climate effects on brook trout habitat have generally assumed uniform air-water temperature relationships over large areas that cannot account for groundwater inputs and other processes that operate at finer spatial scales. We developed regression models that accounted for groundwater influences on thermal sensitivity from measured air-water temperature relationships within forested watersheds in eastern North America (Shenandoah National Park, USA, 78 sites in 9 watersheds). We used these reach-scale models to forecast climate change effects on stream temperature and brook trout thermal habitat, and compared our results to previous forecasts based upon large-scale models. Observed stream temperatures were generally less sensitive to air temperature than previously assumed, and we attribute this to the moderating effect of shallow groundwater inputs. Predicted groundwater temperatures from air-water regression models corresponded well to observed groundwater temperatures elsewhere in the study area. Predictions of brook trout future habitat loss derived from our fine-grained models were far less pessimistic than those from prior models developed at coarser spatial resolutions. However, our models also revealed spatial variation in thermal sensitivity within and among catchments resulting in a patchy distribution of thermally suitable habitat. Habitat fragmentation due to thermal barriers therefore may have an increasingly important role for trout population viability in headwater streams. Our results demonstrate that simple adjustments to air-water temperature regression models can provide a powerful and cost-effective approach for predicting future stream temperatures while accounting for effects of groundwater.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Accounting for groundwater in stream fish thermal habitat responses to climate change
Series title Ecological Applications
DOI 10.1890/14-1354.1
Volume 25
Issue 5
Year Published 2015
Language English
Publisher Ecological Society of America
Contributing office(s) Leetown Science Center
Description 23 p.
First page 1397
Last page 1419
Country United States
State Virginia
Other Geospatial Shenandoah National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N