SDE Raster Dataset
San Joaquin Valley, environment, California
This analysis of the San Joaquin Valley region was conducted as part of a case study to illustrate one approach for determining and utilizing wildlife movement data for the purposes of regional conservation planning, particularly in agricultural or other mixed use landscapes, where wildlife may move more easily than in urban settings with a core and linkage design for reserve lands.
This data layer represents a gradient of connectivity for the San Joaquin Valley -- connectivity meaning an animal's ability to move across the landscape -- prepared in 2011 by the UC Davis Road Ecology Center and UC Davis Information Center for the Environment. The highest value cells in this raster data set are those most natural and least disturbed, with highest permeability for wildlife. The generation of this data layer comes from five main base layers and a landscape gradient analysis model output. The base layers include 1) a road density layer generated from Caltrans (2007) and TigerLines (2001), 2) the USGS National Landcover Dataset (NLCD), 3) the California Department of Water Resources (DWR) Landcover dataset, 4) the US Forest Service Classification and Assessment with Landsat of Visible Ecological Groupings (CALVEG), and 5) California Parcel Data provided by the state. To create the road density layer, the two input data sources were merged and then built using the ArcGIS function Line Density. The Line Density function was applied with a 100 meter output cell size and 1000 meter search radius. The NLCD and DWR land use data sets provided land use classifications that were reclassified with wildlife movement or naturalness ratings. The CALVEG data provided California Wildlife Habitat Relationships System (WHR) habitat types, used here to reclassify the landscape in terms of wildlife movement. California Parcel Data was used to identify land with various structures and was, again, reclassified for wildlife movement. Details on the transformation and reclassification of attribute data from these input sources and on the landscape gradient analysis performed may be found in Appendices A-D of the technical report from this project: Regional Approach for Connectivity Analysis and Design (Shilling F. and D. Waetjen, 2011) ( http://www.nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=43234) .
Please contact Fraser Shilling at the Road Ecology Center for information on using the connectivity model in your study.