Cold-Water Climate Shield

The Climate Shield habitat occupancy models provide stream-specific probabilistic predictions about the occurrence of juvenile Bull Trout and Cutthroat Trout throughout the northwestern U.S. Those predictions can be used as prior probabilities to design efficient population monitoring programs and distributional assessments. For example, the electrofishing site detection efficiency estimates derived in Appendix 2 of the Climate Shield manuscript can be used with the spatial information at this website to plan where and how much sampling is necessary to detect either native trout species within a cold-water habitat as described in Peterson and Dunham (2003) and Isaak et al. (2009). The prior probabilities and spatial information can also be used with other sampling techniques like environmental DNA that is being rapidly adopted because of its low cost and high sensitivity for detecting species (Wilcox et al. 2013, 2014; National Genomics Center for Wildlife and Fish Conservation). As more samples are collected in future years, the precision of the Climate Shield models may be increased or new models developed for other aquatic species of concern.

The original Climate Shield Cutthroat Trout and Bull Trout models published by Isaak et al. (2015) were developed from electrofishing fish surveys conducted at >4,500 locations in >500 natal streams patches across Montana, Idaho, and Oregon as described in the peer-reviewed studies and agency reports listed below.

A revised Climate Shield bull trout model was published by Isaak et al. (2022) based on an expanded data set of 9,857 surveys in 991 stream patches that included eDNA surveys from the Rangewide Bull Trout eDNA Project (Young et al. 2017). This data set with the covariate values used in model fitting and selection is available here in Excel and ArcGIS file formats. Please refer to this ReadMe document for descriptions of the covariates and the Isaak et al. (2022) publication for additional details.

Special thanks to the many biologists with the National Forest system for providing data from their fish monitoring programs and Leslie Nyce with Montana Fish, Wildlife and Parks for assistance with accessing information through the MFISH database. 

Climate Shield Download Unit

The Climate Shield models developed by Isaak et al. (2015) provide stream-specific rangewide probabilistic predictions about the occurrence of juvenile Bull Trout and Cutthroat Trout under different scenarios of climate change and Brook Trout invasions. That information is available here as easy-to-use digital maps (.pdf files) and ArcGIS shapefiles for all streams within the historical ranges of these two native trout species across the western U.S. The geographic areas match the NorWeST production units because those stream temperature scenarios are integral to Climate Shield. 

The climate scenarios used in this project represent baseline (1980s), moderate (2040s), and extreme (2080s) climate change conditions and were chosen because they bracket what might be considered a “pristine” historical condition and “worst-case” end-of-century conditions. 

The full dataset is available for download from the FSGeodata Clearinghouse. 

Data are added as basins are completed and are subject to periodic revision -  General Metadata for shapefiles | Climate Shield Download Units Polygon Shapefile 

Note: Reaches coded as “intermittent” in the NHD streams used to develop these maps were not deleted to provide users with maximum flexibility in applying this information. But those reaches can be highlighted or deleted from shapefiles below simply by linking then to the NHD stream dataset. 

Citation

Isaak, D., M. Young, D. Nagel, D. Horan, M. Groce, and S. Parkes. 2017. Climate Shield bull trout and cutthroat trout population occurrence scenarios for the western U.S. Rocky Mountain Research Station, U.S. Forest Service Data Archive, Fort Collins, CO. DOI: pending.

Posters of Rangewide Distribution

Revised Bull Trout Climate Shield Model

Isaak et al. (2022) published a revised Climate Shield model for juvenile bull trout that provides stream-specific probabilistic predictions about occurrence within 991 natal habitat patches across Montana, Idaho, and eastern Oregon. The model is more accurate than the original Climate Shield model and was used in 16 scenarios to assess the effects of habitat restoration and brook trout removals on improving population resilience under three climatic conditions (baseline, moderate change, and extreme change). That information is available from the table below as digital maps (.pdf files) and ArcGIS shapefiles. Please refer to this ReadMe document for descriptions of the scenarios and the Isaak et al. (2022) publication for additional details.

Dynamic Online Map Viewers and GIS Data

Stream Temperature and Native Trout

USFS Office of Sustainability and Climate Story Map on Stream Temperature and Native Trout, including Stream Temperature, Bull Trout Habitat, and Cutthroat Trout Habitat. 

Climate Shield Cold-Water Refuge Streams For Native Trout

 ArcGIS Online map 

Boise Spatial Streams Group

These datasets can be viewed in ArcGIS Online or in the interactive Climate Shield viewer; they are also available from the FSGeodata Clearinghouse, or for individual processing units see the table below.

Note that because the distribution of Brook Trout is poorly known in many areas, making precise predictions about their effects within each stream is impossible so only two scenarios are provided in the digital map .pdf files (0% and 50%). However, the Climate Shield predictive models can be used to assess a broad range of Brook Trout invasions so ‘look-up’ tables that provide stream-specific native trout occurrence probabilities for Brook Trout invasions of: 0%, 25%, 50%, 75%, and 100% are also provided. Those tables are linked to the ArcGIS shapefiles to enable dynamic spatial queries where local information is available about Brook Trout densities. More details are included in the Climate Shield manuscript published in Global Change Biology.