U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2011–3059

June 2011

RESEARCH AT THE USGS WESTERN GEOGRAPHIC SCIENCE CENTER

Geographic Science for Public and Tribal Lands Management

here are more than 650 million 

acres of U.S. public and Tribal 

lands, most found west of the 

Mississippi River. Scientists with 

the U.S. Geological Survey’s Western 

Geographic Science Center are 

working to increase the scientific 

information available for natural 

resource decision making, while 

continuing productive collaborations 

with Federal land managers, Tribal 

leaders, and local communities.

Healthy, functioning landscapes provide 

us with food, water, clean air, and many other 

natural resources and uses. There are more 

than 650 million acres of U.S. public and Tribal lands, most west of the Mississippi River. 

More than 94% of these lands are administered by five Federal agencies—Bureau of 

Land Management (BLM), Bureau of Indian 

Affairs (BIA), U.S. Fish and Wildlife Service, 

U.S. National Park Service (NPS), and USDA 

Forest Service (USFS). With the exception of 

USFS, these agencies are part of the Department of Interior (DOI). 

The U.S. Geological Survey (USGS) 

is DOI’s primary science organization. 

Scientists with its Western Geographic Science Center (WGSC) work to increase the 

scientific information available for natural 

resource decision making, while continuing productive collaborations with DOI 

bureaus, Federal land managers, Tribal 

leaders, and local communities. Maintaining healthy landscapes is a major challenge 

for public and Tribal land managers. They 

must cope with invasive species, pest and 

disease outbreaks, increased needs for 

urban and agricultural water resources, 

catastrophic fires, and other issues. Remotely sensed data from ground- and satellite-based platforms and data from other 

geographic tools are used to monitor and 

understand changing landscape conditions. 

Tools to Assess Landscape Change

The response of ecosystems to natural 

variations in weather from year to year often 

masks longer-term trends that signal change 

in landscape condition and degradation that 

can affect biological productivity. These 

responses can be better understood by measuring and analyzing the timing and vigor 

of seasonal biological events and growth, 

a major focus of the science of phenology. 

WGSC scientists are working on BLM lands 

to track phenological changes in vegetation 

using ground-based cameras (phenocams) 

and data from earth observing satellites. 

Phenocams provide daily snapshots of vegetation productivity on the Owhyee Plateau, 

where Idaho, Oregon, and Nevada converge, 

the largest contiguous expanse of sagebrush 

in the Western United States. Productivity 

measures are critically important in the effective management of various land uses or 

“co-occurring benefits,” such as livestock 

ranching and habitat for greater sage-grouse 

(Centrocercus urophasianus). Daily phenocam 

data are combined with meteorological data 

and soil-moisture data to explore the relations 

between the timing of water availability from 

snow melt, springtime signals (such as longer 

and warmer daylight periods), and the arrival 

and abundance of migrant songbird species.

In Arizona, WGSC scientists are working 

closely with the San Carlos Apache Tribe 

to use satellite imagery to map and monitor the condition of grasslands in the desert 

Southwest. It is important to pay close attention to the conditions of rangelands, because 

desertification processes can be rapidly accelerated during times of drought, and the 

region is currently experiencing a drought of 

significant duration and magnitude. WGSC 

research provides San Carlos land managers 

with easily interpretable image products that 

are increasing the effectiveness of Tribal 

T

Denali National Park, Alaska, is part of our Nation’s 650 million acres of public lands. Together with lands of Tribal nations, they provide crucial benefits and uses and must be carefully managed. The USGS Western Geographic Science 

Center is providing scientific data and understanding to address the challenges of managing these lands. The scientist shown in this photograph is studying potential linkages between landscape condition and the health of Dall sheep 

(Ovis dalli) (see inset), a species of concern in the park. (USGS photos by Dennis G. Dye/Ed Pfeifer.)
rangeland management practices over vast 

areas. Satellite-based rangeland-condition 

and seasonal-productivity maps at varying 

spatial resolutions and across several decades have been collaboratively developed, 

with very promising results. Close WGSC 

cooperation with the San Carlos Apache 

Tribe, along with a program of training in 

the use and processing of remotely sensed 

data, is creating custom computer-based 

tools tailored to Tribal land-management 

needs. A similar program is underway with 

the Navajo Nation to analyze desertification processes, sand dune morphology, and 

changes in vegetation phenology.

Geographic Science for Land 

Managers

The NPS Vital Signs Program monitors 

indictors of natural resource health to help 

land managers take the pulse of their ecosystems. These vital signs—population statistics 

of species of concern, water quality and flow 

parameters, air quality and visibility, and other 

factors—can be analyzed to identify where 

to concentrate management activities, such as 

restoring watersheds with endangered Coho 

salmon (Oncorhynchus kisutch). WGSC 

research focuses on synthesizing these indicators to better understand the feedbacks among 

system elements to discover how parks as a 

whole respond to cumulative impacts, such 

as increased visitation, recovery from prior 

resource extraction, and other factors such as 

climate change.

In Denali National Park, Alaska, a species 

of concern is Dall sheep (Ovis dalli), which 

may provide an early warning of the cascading effects of changing climate. A 30-year 

analysis of Landsat data for the park shows 

a 47% decrease in glacial extent, as well as 

upslope expansion of woody plants in the 

park. These observations appear to correspond 

to decreases in the natural forage plants that 

the sheep eat and increases in tall plant cover 

that can both create barriers to sheep movement and provide cover for large predators, 

such as wolves. Ongoing studies are analyzing sheep fecal pellets to see if changes in 

the availability of forage plants are affecting 

the diet quality of the animals. Complex 

landscape factors that could be affecting lamb 

survival and Dall sheep population dynamics 

are also being explored. 

The work of Western Geographic Science 

Center (WGSC) scientists to increase the 

scientific information available for natural 

resource decision making is only part of WGSC’s efforts to better understand the causes 

and consequences of land-cover change. 

WGSC works closely with public land managers, Tribal leaders, and local communities 

to help ensure that they have the crucial information they need to make informed decisions 

about ongoing and future land-use choices.

Alicia Torregrosa

Edited by James W. Hendley II

Graphics and layout by Judy Weathers

For more information, contact:

Alicia Torregrosa

U.S. Geological Survey 

345 Middlefield Road, MS 531

Menlo Park, CA 94025

Tel. (650) 329-4091

atorregrosa@usgs.gov

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

This Fact Sheet and any updates to it are 

available online at

http://pubs.usgs.gov/fs/2011/3059/

In Arizona, WGSC scientists have been working closely 

with the San Carlos Apache Tribe to develop technology 

to use satellite imagery to map and monitor the condition 

of rangelands. This computer generated map shows 

changing rangeland conditions over a 15-year period. 

The photographs are from site visits showing rangeland 

in very good (top), slightly degraded (middle), and very 

degraded condition. (USGS photos by Barry Middleton.) 

WGSC is working to provide Federal land managers with 

crucial landscape change information. For example, 

WGSC scientists are tracking phenological changes 

(the timing and vigor of seasonal biological events) 

in vegetation on lands on 

the Owhyee Plateau (Idaho, 

Oregon, and Nevada) administered by the Bureau of Land 

Management. This photo 

shows a scientist installing 

a ground-based camera or 

“phenocam” (inset photo). 

The data from the phenocam 

is compared to those from 

satellite-based sensors to 

gain a better understanding 

of vegetation changes over 

the entire ecosystem. (USGS 

photos by Mara Tongue/

Alicia Torregrosa.)

AR I Z O N A Study

region

ARIZONA

N

3 MILES

5 KILOMETERS

0

0

Mapping and Monitoring Rangelands

Very good

Slightly degraded

Very degraded