Sierra Nevada:

Population Growth and Environmental Impacts

Interactive GIS Map Server

Evan Girvetz

Fraser Shilling

Robert Johnston

Department of Environmental Science and Policy

University of California, Davis

May 15, 2002

This is a preliminary set of maps we have put on the web to demonstrate the types of data that citizens groups can use to look at population trends and their impact on the surrounding ecosystems.

Ecological Value Map

Human Population Map

Data Sets Used:

Lakes: from National Hydrologic Dataset (NHD)

Major Rivers: from NHD

Highways Average Annual Daily Travel (AADT): from Caltrans

Jepson Bioregions: from California GAP analysis

Ownership Threats: from California GAP analysis

Census data: U.S. Census Bureau

Ecological Value: Ecological value was calculated based on aquatic integrity (aquatic fauna, road proximity to stream, etc.), forest integrity (old-growth, roadless patch characteristics, etc.) and terrestrial vertebrate habitat (e.g. species distributions, WHR vertebrate richness, etc).  We used the GIS extension program “Ecosystem Management Decision-Support” (EMDS, Reynolds el al. 1996, Reynolds, 1999) to combine these data sets. Each 500x500m grid cell of the landscape was scored for its ecological value.

Vertebrate Richness: Bird, mammal, reptile, and amphibian species potential richness values were found using the California wildlife habitat relations (WHR) based on vegetation data from the California GAP analysis.