U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2014–3019

March 2014

Future Scenarios of Impacts to Ecosystem Services on 

California Rangelands

The Central Valley of California, the 

surrounding foothills, and the inner Coast 

Ranges include more than 18 million acres 

of rangelands. Much of the Central Valley 

grasslands and foothills are privately owned 

and managed as rangelands for livestock 

production. Many sites on these rangelands 

provide crucial habitat for what were 

previously wider-ranging species, such 

as Swainson’s hawk (Buteo swainsoni), 

California tiger salamander (Ambystoma 

californiense), and San Joaquin kit fox 

(Vulpes macrotis mutica). Ranching is a vital 

part of the State’s economy, providing jobs 

and important food supplies. In addition, 

ranches generate other “ecosystem services,” 

defined as human benefits provided by 

natural ecosystems, which carry considerable 

economic value. Most of the water consumed 

by Californians flows over rangeland, and 

associated grasslands and oak woodlands are 

important for “carbon sequestration.” Carbon 

sequestration is the capture and long-term 

storage of carbon dioxide (CO2

), a greenhouse 

gas associated with climate change. Some 

ranches in California have been in existence 

for more than 100 years and are an important 

part of the State’s historical heritage. 

Much of California’s rangeland 

is being rapidly converted to urban 

T he 18 million acres of rangelands 

in the Central Valley of California 

provide multiple benefits or “ecosystem 

services” to people—including wildlife 

habitat, water supply, open space, 

recreation, and cultural resources. 

Most of this land is privately owned and 

managed for livestock production. These 

rangelands are vulnerable to land-use 

conversion and climate change. To help 

resource managers assess the impacts 

of land-use change and climate change, 

U.S. Geological Survey scientists and 

their cooperators developed scenarios 

to quantify and map changes to three 

main rangeland ecosystem services—

wildlife habitat, water supply, and carbon 

sequestration. Project results will help 

prioritize strategies to conserve these 

rangelands and the ecosystem services 

that they provide. 

development and intensive agriculture. In 

addition, climate change stresses rangelands 

by potentially changing water availability 

and species distributions. The interaction between climate change and land-use 

change can severely affect rangeland 

ecosystem services. Wildlife habitat may 

become fragmented, and rangelands may 

lose the capacity to capture, filter, and 

release water slowly, which could affect 

watershed health. 

It is not known exactly where and how

much change will occur to California rangelands in the future. Given this uncertainty, 

planners use scenarios to consider a variety 

of possible futures to prepare for the potential 

impacts of future climate and land-use change. 

A scenario is a plausible yet simplified description of how the future may develop based on 

a set of assumptions about the main causes of 

change. Scenarios are not predictions but are 

based on a narrative storyline about the future. 

Scenarios for California Rangelands

The U.S. Geological Survey 

(USGS) Western Geographic Science 

Center (WGSC), USGS California Water 

Science Center (CAWSC), and Defenders 

of Wildlife have been working with 

ranchers and several organizations within 

the California Rangeland Conservation 

Coalition (http://www.carangeland.org/) 

to develop six scenarios organized around 

the management question “How can 

we maintain viable ranchland and their 

ecosystem services in light of future 

integrated impacts?” The scenarios represent 

alternative futures of climate, land-use, 

and hydrological change for the California 

Rangeland Conservation Coalition focus 

area, which includes the State’s Central 

Valley, the surrounding foothills of the 

Sierra Nevada to the east, and most of the 

southern inner Coast Ranges to the west. 

These scenarios were used to quantify 

and map three main rangeland ecosystem 

services—wildlife habitat, water supply, 

and carbon sequestration. These results 

were used to conduct an economic analysis 

associated with changes in these services.

The scenarios are based on the 

storylines of the Intergovernmental 

Panel on Climate Change (IPCC) Special 

Report on Emission Scenarios (SRES) 

A2, A1B, and B1 (http://www.ipcc.ch/pdf/

special-reports/spm/sres-en.pdf). Three 

downscaled land-use/land-cover (LULC) 

change scenarios were each paired with two 

downscaled global climate models (a warm 

Cattle on rangeland on Mission Peak, near Fremont, California, in the San Francisco Bay area. This 

image is an example of the expansion of urban areas into former rangeland. (Photograph courtesy 

of David Amme, California Native Grasslands Association.)
wet future and an even warmer dry future). 

Scenarios vary by extent and distribution 

of development, irrigated agriculture, and 

future conservation lands and changes in 

climate and hydrology. A growth model, 

FORE-SCE (FOREcasting SCEnarios of 

future land cover), was used to produce 

maps of LULC change yearly from 2006 to 

2100 at a spatial resolution of 250 meters 

(1 meter = 3.28 feet). 

The USGS Basin Characterization 

Model was used to model change in runoff, 

groundwater recharge, and climatic water 

deficit (a landscape stress indicator) based 

on climate change. For six case-study 

watersheds, it was also used to model 

change in stream discharge based on 

future development and climate change. 

Land-use change was quantified in priority 

conservation areas mapped by The Nature 

Conservancy in 2007. Change in rangeland 

soil carbon stocks was tracked using 

USGS General Ensemble Biogeochemical 

Modeling System output. 

Results 

A Web site, http://climate.calcommons.

org/aux/rangeland/index.html, provides 

a visualization tool to view changes in 

ecosystem services across scenarios and

years. Here results are presented for the

California Rangeland Conservation 

Coalition’s focus area at the scale of 8-digit 

hydrologic unit watershed boundaries. The 

Web site also provides access to download 

underlying raster datasets at 250- to 

270-meter resolution. The visualization 

tool includes maps of (1) change in the 

percentage of watershed area with critical 

habitat relative to 2010; (2) percent change 

in grassland-soil carbon-sequestration 

potential; (3) percent change in climatic 

water deficit relative to the 1981–2010 

climate period; (4) ratio of recharge to 

runoff for three 30-year climate periods; 

(5) water-wildlife hotspots—areas where 

Printed on recycled paper ISSN 2327–6916 (print)

ISSN 2327–6932 (online)

http://dx.doi.org/10.3133/fs20143019

Screenshot of a Web-based visualization tool, developed by U.S. Geological Survey scientists, 

used to view possible future changes in rangeland ecosystem services for the California 

Rangeland Conservation Coalition focus area. Results can be compared across three scenarios 

simultaneously. The tool is available at http://climate.calcommons.org/aux/rangeland/index.html.

Kristin Byrd, Pelayo Alvarez, Lorraine Flint, 

and Alan Flint

Edited by James W. Hendley II

Design by Jeanne S. DiLeo

COOPERATING ORGANIZATIONS

California Rangeland Conservation Coalition

Defenders of Wildlife

For more information contact:

Kristin Byrd

U.S. Geological Survey

345 Middlefield Road, MS 531

Menlo Park, CA 94025

Tel. (650) 329-4279

kbyrd@usgs.gov

http://geography.wr.usgs.gov/

http://climate.calcommons.org/content/integratingscience-decisions/

http://climate.calcommons.org/aux/rangeland/index.html

This Fact Sheet and any updates to it are available online

at http://pubs.usgs.gov/fs/2014/3019/

Ranchers, scientists, 

and other participants of 

the 9th Annual California 

Rangeland Conservation 

Coalition Summit attend a 

field trip to Ichord Ranch 

in Stanislaus County, 

California. (Copyrighted 

photograph courtesy of 

DontFenceMeInPhotos.

com.)

changes in water availability (recharge plus 

runoff) and loss of critical habitat coincide; 

and (6) average percent change in multiple 

ecosystem services from 2010 to 2040.

Raster data available for download 

includes (1) baseline soil organic carbon; (2) 

soil depth; (3) LULC change; (4) conversion 

of critical habitat; (5) climatic water deficit; 

(6) recharge, runoff, and recharge-to-runoff 

ratio; and (7) water availability.

The future scenarios developed by 

WGSC and CAWSC scientists will assist 

ranchers, watershed groups, planners, and 

land managers in ensuring the continuation 

of ecosystem services provided by California 

rangelands. The scenarios will also assist 

government agencies with the design of 

effective conservation plans that consider 

both climate change and land-use change, 

inform water agencies about potential changes 

to water supply, and help conservation 

organizations prioritize their actions. The 

development of the scenarios is only part of 

USGS efforts to better understand the causes 

and consequences of land-use change and 

climate change.