Managing fish habitat for flow and temperature extremes
Citation:
Detenbeck, N., R. Abele, AND A. Morrison. Managing fish habitat for flow and temperature extremes. Northeast Association of Environmental Biologists (NEAEB) 41st Annual Conference, Hartford, CT, March 14 - 16, 2017.
Impact/Purpose:
This presentation will provide information to state and tribal agencies and NGOs in New England on drivers of fish habitat suitability and the role of natural and constructed green infrastructure in protecting fish communities.
Description:
Summer low flows and stream temperature maxima are key drivers affecting the sustainability of fish populations. Thus, it is critical to understand both the natural templates of spatiotemporal variability, how these are shifting due to anthropogenic influences of development and climate change, and how these impacts can be moderated by natural and constructed green infrastructure. Low flow statistics of New England streams have been characterized using a combination of regression equations to describe long-term averages as a function of indicators of hydrologic regime (rain- versus snow-dominated), precipitation, evapotranspiration or temperature, surface water storage, baseflow recession rates, and impervious cover. Difference equations have been constructed to describe interannual variation in low flow as a function of changing air temperature, precipitation, and ocean-atmospheric teleconnection indices. Spatial statistical network models have been applied to explore fine-scale variability of thermal regimes along stream networks in New England as a function of variables describing natural and altered energy inputs, groundwater contributions, and retention time. Low flows exacerbate temperature impacts by reducing thermal inertia of streams to energy inputs. Based on these models, we can construct scenarios of fish habitat suitability using current and projected future climate and the potential for preservation and restoration of historic habitat regimes through use of natural and constructed green infrastructure. For example, restoration of forested riparian zones across New England has the potential to increase stream miles of coldwater fish habitat by 44 percent, while loss of existing forested buffers would reduce existing coldwater habitat by 60 percent.