Drylands Home | Human Health | Native Lands | Public Lands

Project Overview

Statement of Problem

Objectives

Strategy

Project Tasks and Activities

• Task 1: Interactions among geology, biogeochemistry, and ecological biology - past, current, and future
• Task 2: Dust - climatic, geomorphic, and hydrologic factors and societal effects
• Task 3: Sand-dune dynamics - history and processes of eolian sand movement in American drylands
• Task 4: Valley Fever - determination of geological/ecological occurrence models for Coccidioides Immitis
• Task 5: Land-use change and water quality in the Tsezhin Bii' region, Navajo Nation
• Task 6: Sediment dynamics in dryland rivers - relations to climate, groundwater, and land use
• Monitoring and forecasting

Statement of Problem

Arid and semi-arid lands compose about one half of the U.S. and are among the Nation's most sensitive regions to climatic variability and land-use practices (ref 1). Combinations of natural factors (such as short-term climatic variability) and vastly expanding population, especially in the Southwest, are placing unprecedented pressures on our dry landscapes and their ecologic resources. The existing and potential impacts make American drylands a national priority for understanding environmental change and its effects on both human dominated and natural systems. In particular, interactions among land management, societal adjustment, and local to regional planning require contributions and collaborations across many arenas of natural and social sciences (refs 2, 3, 4). Examples of key problems include physical impacts of drought and wet periods, ecosystem health (e.g., invasive plant species), human health, water quality and quantity, carbon cycling, as well as fire frequency and impacts (refs 1, 5). This project addresses the urgent need to understand and monitor physical landscape change and its influence on ecosystems and the human communities that depend on ecological services such as water, productivity, and landscape stability. On the scale of ecosystems to physiographic regions of American drylands, we will develop new understanding of interactions among physical, biogeochemical, and human systems, and responses of these systems to forcing from climate and demographic change. With this understanding, we will forecast expectable, near-term changes in physical and ecologic landscapes. We will provide information, forecasts, and educational materials to federal, state, local, and Native American agencies and communities, for their land-use planning, management of resources, and protection of human health

Objectives

1. Examine interactions among geologic, hydrologic, biologic, and atmospheric processes in drylands to (i) understand contemporary physical and ecologic landscapes; (ii) determine how physical and ecologic processes interact to influence ecosystem dynamics, including plant invasions; and (iii) document how sediment (soil) erosion and deposition by wind and water over time is affected by climatic variability and by geologic, physiographic, and land-use setting.
1. Understand landscape responses to changes in climate over different time scales (past seasons, decades, centuries, millennia) in terms of dust emission and deposition, sand-dune activity, and fluvial erosion & deposition.
2. Understand landscape responses to land uses over time scales of past seasons and decades in terms of dust emission and deposition, sand-dune activity, and fluvial erosion and deposition and evaluate these responses in a framework of climatic variability.
3. Understand how geologic substrates and processes control vegetation distributions, plant invasions, soil moisture, water infiltration rates, plant-nutrient status.
4. Understand interactions among eolian, fluvial, lacustrine, surface-water, and groundwater processes that have produced or eroded surficial deposits; determine ages of these deposits, the environmental/climatic conditions under which they formed, and respective vulnerabilities of these deposits to future erosion.
2. Monitor land surface and ecologic changes in response to climate and human activity in several ecologically sensitive dryland areas, as a basis for:
1. understanding surficial processes
2. developing geologic and ecologic response models.
3. Forecast the responses of dry landscapes to climatic variability using newly developed and established geologic, hydrologic, and biogeochemical models of landscape processes.
1. Forecast geo-ecologic responses to environmental change from interactions among geologic substrates, hydrology, climate, land use, and biogeochemical cycling of carbon, nitrogen, phosphorus, and other nutrients (e.g., pathways of cheatgrass invasion).
2. Forecast future dust emissions and reactivated sand dunes by linking process-response models to empirical models and regional climate models.
4. Elucidate the effects of environmental change (natural and human-related) on human health, with focus on emissions of dust containing toxic metals and on the soil occurrence and airborne transmission of the infectious agent for Valley Fever.
5. Provide information and educational materials to agencies and communities, for their land-use planning, management of resources, and protection of human health:
1. Federal land-management agencies (National Park Service, BLM, BoR, USDA)
2. Dept. of Defense
3. Health and environment agencies (e.g., EPA, CDC)
4. States and communities
5. Native American nations

Strategy and Approach

The approach involves: (1) examining past records of physical, biological, and landscape changes in response to climatic and human-mediated forces; (2) monitoring these changes today, including emerging human health risks; (3) comparing observations of modern processes with the records of past changes; and (4) integrating the knowledge gained from (1), (2), and (3) to provide forecasts of future land-surface and ecologic change under likely climatic and demographic conditions for time scales relevant for land-use decisions.

Relevance and Impact

We address problems in: (1) conditions of dry landscapes, their vulnerability to degradation (e.g., cheatgrass invasion, soil loss), and their potential for recovery to sustain desirable functions; (2) sources, amounts, and composition of wind-eroded dust, including dust containing toxic metals or fungal spores, that cause disease in humans; (3) impacts of sand-dune activation on society; (4) effects of climatic variability (e.g., drought, flooding events) and land-use practices on arid landscapes, ecology, and communities. We aim to anticipate societally important changes and effects that are likely to occur over the next few seasons, years, and decades.

Our research on how geologic and ecologic processes are linked to ecosystem dynamics is at the heart of our capability to interact with land managers. We provide information about key national issues, such as plant invasion; carbon-storage; expected ecologic change; sand-dune reactivation; dust emission; effects of drought and flood damage related to erosion and alluviation in urban, grazed, and protected settings. We are producing definitive results on urban flooding and erosion in Las Vegas Valley that carry lessons for land-use planning there and in other growing desert communities.

The work on soil habitats for the pathogen causing Valley Fever, combined with new methods in mapping vulnerability to wind erosion, is designed to lead to forecasts of disease outbreaks via atmospheric transport of biologic contaminants.

New methods developed by the project and adopted by other researchers include imaging and monitoring dryland surfaces and wind erosion, detection of eolian dust in soil, development of new physical process models, as well as modeling of soil habitat for a pathogen. Some of our new imaging techniques have been adopted by other USGS projects (San Francisco Bay; Hawaiian coral reefs; Colorado River). Our studies also bear on interpreting results from the USGS North American Landscape Geochemistry project.

We maintain strong associations with other drylands researchers and a variety of the earth-science research communities to advance understanding of issues facing the Nation's drylands and related problems of desertification. Nearly 90% of North America's drylands are moderately to severely desertified (degraded) and do not provide beneficial services to a desirable capacity (ref 8).

The project adheres to goals of GD Science, USGCRP (ref 2), and the 2002 Climate Change Research Science Program (CCSP) and Initiative (CCRI; ref 3): (1) "Anticipate the environmental effects of climate change -monitoring, modeling, and forecasting"; (2)"Understand interactions among physical, biogeochemical, and human systems-regions and ecosystems"; (3) "Interpret the links between human health and geologic processes". Our advances in understanding impacts of climatic variability are directly in line with one of most pressing national environmental research needs identified in CCRI.

References Cited

1. Meredith, R., Liverman, D., Bales, R., and Patterson, M., 1998, Climate Variability and Change in the Southwest: Impacts, Information Needs, and Issues for Policymaking: Udall Center for Studies in Public Policy, Univ. of Arizona, 81 p.

2. U.S. Global Change Research Program, 2002, Our Changing Planet: The FY2002 U.S. Global Change Research Program: National Science and Technology Council, 100 p.

3. U.S. Federal Administration, 2002, The U.S. Climate Change Research Initiative (CCRI): Survey of Research Strategies to Reduce Scientific Uncertainties: Dept of Commerce (Draft)

4. Intergovernmental Panel on Climate Change, 2001, Climate Change 2001: Impacts, Adaptation, and Vulnerability: Cambridge, Cambridge Univ. Press, 98 p.

5. National Assessment Synthesis Team, 2000, Climate Change Impacts on the United States: The Potential Consequences of Climate Variability and Change: Cambridge, Cambridge Univ. Press

6. Intergovernmental Panel on Climate Change, 2001, Climate Change 2001: The Scientific Basis: Cambridge, Cambridge Univ. Press, 98 p.

7. Woodward, F.I., 1992, Global Climate Change: The Ecological Consequences: London, Academic Press, 337 p.

8. Dregne, H. E. 1986. Desertification of arid lands. In Physics of desertification, ed. F. El-Baz and M. H. A. Hassan. Dordrecht, The Netherlands: Martinus, Nijhoff.