Used to create the core area network

Aquatic index of ecological integrity

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The index of ecological integrity (IEI) is a measure of relative intactness and resiliency of environmental change. By intactness, we mean freedom from human modifications and human-induced disturbance. By resiliency, we mean ability to remain intact and high quality despite disturbances and climate change. It is a composite index based on 19 different measures of landscape intactness and resiliency. This version of IEI (compare to “weighted index of ecological integrity”) displays values only for aquatic systems as a convenience for users.

For this project, IEI was rescaled to each ecological system, and by HUC6 watershed. In contrast to the terrestrial IEI, the aquatic IEI was not modified by weighting any aquatic systems.

View this product as a web map on Data Basin.

Access this data as a GIS download from the North Atlantic LCC website.

Read the Technical Abstract for this data layer (ieiAquatic.tif).

USGS stream temperature tolerance

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The USGS stream temperature tolerance layer measures the relative sensitivity of stream temperatures to rising air temperatures. It predicts how quickly a stream’s temperature will rise as air temperatures rise. Lower values, which indicate that a stream’s temperature is not heavily influenced by air temperature, are interpreted as indicative of greater resilience to the warming of air temperatures projected under climate change. For example, groundwater fed and high gradient streams often show greater resilience to warming air temperatures.

View this product as a web map on Data Basin.

Access this data as a GIS download from the North Atlantic LCC website.

Read the Technical Abstract for this data layer (streamTolerance.tif).

Brook trout current probability of occurrence

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Brook trout current probability of occurrence is based on a model developed by Ben Letcher and associates at the USGS Conte Anadromous Fish Lab. It is an index applied to headwater creeks within the watershed, and is analogous to the landscape capability index used for the terrestrial wildlife species in that it represents current habitat suitability. It is applied at the scale of small catchments associated with a given stream segment, rather than 30m cells as used for terrestrial wildlife. This index is used to generate the aquatic core area selection index.

View this product as a web map on Data Basin.

Access this data as a GIS download from the North Atlantic LCC website.

Read the Technical Abstract for this data layer (brookTroutLc.shp).

Anadromous fish index

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The anadromous fish index identifies large and medium rivers that provide habitat for five anadromous fish species: American shad, blueback herring, shortnose sturgeon, alewife, and sea lamprey. The layer is based on The Nature Conservancy’s Connecticut River Basin Program spatial data product of diadromous fish habitat. That layer was created in 2010 and updated by Renee Farnsworth of the North Atlantic LCC. River segments accessible by more species received a higher score. All river segments accessed by at least one species are included in the lotic cores. Also, all segments were labeled “free-flowing,” “impounded,” or “unknown.”

Habitat includes the mainstem and major tributaries of the Connecticut River from the mouth of the river upstream to the limit of passability for these species. This product should not be used to assess habitat suitability for aquatic species since it does not account for habitat characteristics such as flow, water temperature, gradient or substrate.

View this product as a web map on Data Basin.

Access this data as a GIS download from the North Atlantic LCC website.

Read the Technical Abstract for this data layer (anadromous.shp).

Photo Credit: Alewives in Connecticut, by NOAA