IDENTIFYING INFORMATION

Project title: Mojave Desert Ecosystem Science Program

Geographic area: Mojave Desert of California, Nevada, Utah, and Arizona

Project start date: October 1, 1997

Project end date: September 30, 2003

Project chief: Leonard Gaydos

Region/DivigiontTeam/Section: National Mapping Division

Email: lgaydos@usgs.gov

Phone: 650-329-4330

Fax: 650-329-4710

Mail address: USGS, Ames Research Center 242-4, Moffett Field, CA 94035

Program: INATURES

Program Elements: not applicable

BACKGROUND NARRATIVES

Project summary: The Mojave Desert Ecosystem Science Program is a six-year interdisciplinary study of vulnerability of the ecosystem to natural and human-induced disturbances and recoverability of land and biota from these disturbances. It is conducted in partnership with several land-management groups in the region, particularly the California Desert Managers Group. The ultimate goal is to help land managers devise policies that allow human use of the desert while also protecting its vulnerable resources. The program operates by integrating activities within an interdisciplinary science project with land management clients. In this project, we will develop an improved understanding of basic physical and biological processes necessary for assessing the vulnerability and recoverability of desert ecosystems.

Project objectives and strategy:

GENERAL - Field and integrative studies are being conducted to examine and measure vulnerability and recoverability rates in the Mojave Desert. On-going, intensive site-specific studies started during FY98 will be extended to several additional sites. Work will vary among sites depending on local characteristics and data availability; all will address improved understanding of the vulnerability of each site (and similar sites) to various natural and human-induced disturbances. Evidence of disturbance is measured by soil compaction, wind erosion, water erosion, disruption of overland water flow, and plant and animal species composition, density, and richness. Vulnerability to disturbances will be estimated for specific sites and extended to environmentally similar locations using a geographic information system containing mapped data describing soil particle size, vegetation and cover types, vertebrate species distribution, age of geomorphic surface, soil moisture, soil chemistry, ground cover, rainfall frequency and intensity, frequency of freeze-thaw cycles, topographic roughness, and similar variables. An important part of the study is scale-appropriate compilation and integration of these data, which together characterizes the landscape.

Remote sensing will be investigated for its potential to extend local landscape characterization to larger areas -- eventually at reduced reliability to the entire ecosystem -- or to obtain specific variables (such as soil particle size). Sensors to be investigated may include AVIRIS, Radarsat, TM, ERS, AVHRR, MODIS, ASTER, and new commercial sources, together with digital orthophotographs and historic data.

The field and process studies and insights gained from these background studies will form the scientific framework necessary to conceptualize and parameterize vulnerability and recoverability models for desert ecosystems.These models will use the detailed data and measurements available from the field sites to estimate vulnerability and recoverability rates for regions surrounding the sites and then to larger regions and the entire ecosystem at decreasing levels of reliability. A soil moisture model will be developed and linked with climate to enable vulnerability and recoverability risk to vary seasonally Research on multiscale integration of data and model development and methods for displaying vulnerability and recoverability indices and estimating error ranges is critical. The objective is to provide information to a decision support system that uses scientific findings from the program to help land managers. Recovery models require a knowledge of natural variability of the ecosystem on time scales of years, decades, and centuries. These temporal variability studies form a vital component of the project.

Subsequent to the initiation of site studies and model development will be development of a comprehensive regional monitoring strategy for land managers to assess, on a continuing basis, the vital signs of the ecosystem. This strategy will make use of remote sensing to supplement field observation to improve efficiency and improve spatial attributes of desert health estimates. Incorporation of these assessment measures (particularly over time) with vulnerability and recoverability models in a decision support system will give land managers a multiscale look at ecosystem health yesterday, today, and tomorrow.

Though conducted as an integrated project, work is organized around evidence of ecosystem stress seen in soil compaction and surface erosion, urban encroachment as an indicator or predictor of ecosystem stress, and the response of vegetation and vertebrates to those stresses. Information integration provides a means of synthesizing all findings into a decision support system and conveying all results to land managers, other scientists, and the public. Addressing a complete list of stress factors is beyond the scope of this project; those we will undertake are chosen for their wide-ranging impact and which we feel can be completed in the next five years.

SOIL COMPACTION -- Soil compaction has a major influence on erosion rates, plant re-establishment and growth, and wildlife populations. The vulnerability of Mojave Desert soils to compaction can be determined using modifications of engineering geology techniques and theory. The major factors associated with this vulnerability are the amount of normal stress applied to the soil surface, the particle-size distribution of the soil, and the soil-moisture content; other lesser factors include amount of organic material and structure of near-surface roots. Recoverability of compacted soils is dependent upon the climatic processes of freeze-thaw loosening and wetting-and-drying cycles, as well as the biological processes of bioturbation and soil displacement by root elongation. Soil compaction study requires (1) development of a desert-wide GIS layer, using a combination of remote sensing and ground-truthing techniques, that describes particle-size distributions of surficial deposits described in terms of Quaternary surfaces; (2) a wide-ranging sampling of surficial particle-size distribution and mapping of Quaternary surfaces as the major element in the ground truthing; (3) development of a regional model of climate, particularly daily precipitation and temperature; (4) development of a regional model of soil moisture, described in a variety of time domains (daily, weekly, seasonally); (4) experimental work on the compactibility of desert soils; (5) analyses of the recovery from compaction of historically disturbed sites, such as ghost towns; (6) experimental work on the physical processes of compaction recovery, and (7) development of transfer functions between the climatic, geologic, and particle-size GIS layers to produce maps depicting the spatial variability in vulnerability to compaction and recoverability from compaction in the entire Mojave Desert.

SURFACE EROSION -- Desert surfaces are inherently fragile, and many land uses disrupt the thin crusts that typically protect the landscape from wind and water erosion. Depiction of the vulnerability of soils to wind erosion requires development of a wind-erosion GIS model, measurement of wind speed, direction, and duration at specific sites, experimentation using portable wind tunnels on disturbed and undisturbed geomorphic surfaces, and the development of GIS data layers depicting wind potential and other factors related to wind erosion. Increased water-erosion potential following disturbances is an important part of landscape vulnerability, and quantification of sediment yields allows an assessment of the natural variability in water-transported sediment and organic material, including seeds of native and non-native plants. One of the key landscape elements that minimizes both wind and water erosion is the presence and types of cryptobiotic crusts mantling soil surfaces. Soil crusts are an important process control on surficial erosion and also influence wind dispersal of vascular plants. A regional assessment will be conducted of the distribution and species composition of crusts, as well as their fragility to disturbance.

URBAN ENCROACHMENT -- The rapid expansion of urban areas in the Mojave Desert poses a number of threats to natural ecosystems. Recreation associated with local residents causes dispersed soil compaction, removal of vegetation, and disruption of wildlife populations. Exotics associated with urban landscaping, or encouraged in their establishment by soil disruption in and adjacent to urban areas, are spread to adjacent and otherwise undisturbed ecosystems. Garbage dispersal, noise, and light pollution, among other factors, also serve to disrupt wildlife, creating zones of disturbance radiating out from the urban edge into the desert ecosystem.

VEGETATION RESPONSE -- The goal of studying vegetation response is to develop the necessary information to develop maps of vegetation vulnerability and recoverability, monitoring protocols, and decision making indices to be included in the decision support system. The overall scientific objectives are to describe vegetation of disturbed and undisturbed sites and to develop models (quantitative where possible) that describe the physiological mechanisms for the vegetation distribution. The general approaches are to: 1) ensure that an adequate baseline map of vegetation alliances is developed and applied to this project (in conjunction with the USGS Mojave Mapping Project component of the DoD Mojave Desert Ecosystem Program), 2) make field measurements in intensive study plots that provide additional insight into the response of vegetation to the suite of disturbance factors of concern, 3) make measurements that quantify the natural variability of vegetation spatially and temporarily and intensively and extensively, 4) synthesize existing data and literature, the results of field measurements in intensive study plots, and the results of natural variability studies to develop transfer functions that relate vegetation response to the disturbance factors, 5) make field measurements extensively across the Mojave ecosystem for the purpose of testing the predictions of the transfer functions hypothesis, 6) design and test methods for intensive and extensive monitoring of vegetation response, and 7) integrate the vegetation base data and transfer functions to developed vulnerability and recoverability maps and indices appropriate for the MDESP decision support system. The vegetation response studies will be done in conjunction with the other four elements of the project. Measurements of select physical parameters will be required at the intensive sites. Development of large area baseline spatial databases will be necessary to develop extensive sampling designs and make coarse level correlations of vegetation with environmental factors. GIS techniques will be needed at critical points to manage, analyze and integrate the spatial data and products.

VERTEBRATE RESPONSE -- The goal of studying vertebrate response is to develop the necessary information to develop maps of vertebrate vulnerability and recoverability, monitoring protocols, and decision making indices to be included in the decision support system. Our strategy is to integrate and remeasure past studies, take advantage of significant work by affiliated projects and study vertebtrate response to encroaching human impacts. Roads and off road vehicles negatively affect Mojave Desert animal populations by fragmenting habitat, forming corridors that enhance invasion of alien plants, and acting as a potential death zone or sink for animals that are collected from the road or are killed by vehicles. Three questions are frequently asked: (1) how much effect do roads have on adjacent animal populations, (2) what are the effects of traffic volume and road history, (3) how far do the effects extend from the road edge, and (4) what is an "appropriate" or "safe" density of roads, given the potential impacts. The desert tortoise and other vertebrates will be used to evaluate these impacts in the Mojave. We will also conduct a study supported by an affiliated project, Geology and Geochemistry of Desert Tortoise Habitat in the Southwestern U. S, to determine if heavy metals associated with vehicle traffic along roads is detectable in of shell-skeletal remains of desert tortoise and if these materials have any discernible effect on tortoises.

INFORMATION INTEGRATION -- The Mojave Desert Ecosystem Science program is a unique opportunity for multidisciplinary USGS scientists located in several science centers to collaborate on understanding basic ecosystem processes important for land management decisions. Information integration is critical to this effort and is required to (1) extrapolate site specific findings to larger regions; (2) make accessible and maintain all data developed for the program; (3) maintain a program web site for internal use of program scientists and for client use including the public; (4) integrate discipline-specific models; (5) hold workshops and publish integrative scientific findings; and (6) develop a decision support system to help land managers apply scientific findings.

Potential impacts and major products: Throughout the life of the program, data, interpretations, and models will be made available to desert land managers and other clients in an expeditious fashion. Evolving Internet technologies allow land managers and interested parties easy access to all the products of this program. Important program findings will be interpreted and made available to the general public through print and web publications to enhance popular understanding and appreciation of desert ecosystems and USGS science. Scientists will also publish their results in the peer reviewed scientific literature and present their findings at appropriate conferences. Maps, digital/geospatial data, and models will be produced within a geographic information system and made available to citizens, local and state governments, tribes, DOI bureaus, and other Federal agencies who need to make informed decisions concerning land management.

Collaborators, clients: The primary client of the products of the Mojave Ecosystem Project will be the Desert Land Managers Group, which comprise most of the major land-management entities concerned with the Mojave Desert. In addition, the program will be conducted in parallel with several other USGS activities including Climate Change in the Southwest, Effects of Ground-Water Development and Climatic Variability in the Southwest, the National Cooperative Geologic Mapping Program, the Mineral Resources Program, and the DOI High Priority Mapping Program. Strong ties will be maintained with the DOD Mojave Desert Ecosystem and Strategic Environmental Research and Development Programs, National Park Service, and the Bureau of Land Management.

WORK PLAN

Time line (FY 1999 to project end):

Major Task	Scientist	98	99	00	01	02	03
Soil Compaction Studies	Webb	X	X	X	X	X
Surface Erosion Studies	Belnap	X	X	X	X	X
Urban Encroachment Studies	Berry/Benjamin		X	X	X	X	X
Vegetation Response Studies	Thomas		X	X	X	X	X
Vertebrate Response Studies	Lovich		X	X	X	X	X
Information Integration/DSS	Gaydos/Benjamin		X	X	X	X	X

FY 1999 activities:

SOIL COMPACTION -- (1) Continue mapping geomorphic surfaces in selected intensive study sites in the Mojave desert. Bulk compactibility samples will be collected and stratified by the type of geomorphic surface; this type of sample will also be collected from other areas of the Mojave Desert. These study sites will also be used to calibrate remote sensing data. (2) Continue to develop and refine a GIS layer depicting daily temperature and precipitation, both in terms of historical variation and prediction of spatial distribution. (3) Determine ways to refine and extend an existing regional model of soil moisture. (4) Continue measurement of compaction recovery in historically disturbed sites, particularly ghost towns in the Death Valley region and the Nevada Test site; make plans to measure additional sites disturbed during World War II (Patton tank tracks) and the 1964 Desert Strike training. (5) Use existing Landsat TM data to create a vegetation density map of the ecosystem. (6) Continue the development of transfer functions between surficial particle size, compactibility of desert soils, and recoverability of desert soils.

SURFACE EROSION -- (1) Continue field experimental work using a portable wind tunnel in intensive study areas on mappable geomorphic surfaces. (2) Establish additional GEOMET micrometeorological stations in the Mojave Desert for quantifying characteristics of winds as input to a regional wind-erosion model. (3) Continue sediment yield studies related to linear features and their disruption of drainage systems. (4) Begin a regional assessment of cryptobiotic crusts, particularly with respect to their effects on ecosystem function and soil stability to wind erosion. (5) Begin to assess wind-transport potential of the seeds of dominant perennial species as well as exotic annuals. (6) Begin the assembly of a GIS layer that provides the physical data of wind speed and direction for the eventual map of vulnerability to wind erosion.

URBAN-DESERT INTERFACE -- (1) Begin planning for a desert-wide remote sensing/GIS project to assess projected long-term expansion of disturbed areas in the Mojave Desert. (2) Begin to develop GIS databases related to the distribution of roads and vehicular recreation areas, stratified by several categories including freeways, paved, graded dirt roads, and single-track dirt roads.

VEGETATION RESPONSE -- (1) ensure that an adequate baseline map of vegetation alliances is developed and applied to this project (in conjunction with the USGS Mojave Mapping Project component of the DoD Mojave Desert Ecosystem Program). (2) Document characteristics of overland flow disruption: 1999 activities will be at Valjean, an abandoned railroad line. Additional sites will be evaluated for next year activities. Two interrelated studies are planned. (3) Cross correlate Valjean data with analysis of rainfall variability derived from existing weather stations. (4) Experiment with determining plant physiological response in one site. Stable isotopes will be used to analyze effects on nutrient and water uptake when overland flow is disrupted. (5) Vegetation species composition and cover will be measured at a few dated ghost town sites. These studies are a repeat of vegetation measurements made in the 1980s and will use similar measurement and repeat photography methods. (6) Structure and composition of vegetation will be measured along a gradient at right angles to several paved roads. These measurements will be in conjunction with measurement of vertebrate populations, desert tortoise populations, and heavy metals uptake studies (see Vertebrate Response). (7) Synthesize vegetation data at Nevada Test Site. A report will be prepared by an independent contractor compiling data previously collected on the Test Site by previous projects. (8) A group will convene to assess data sources (datasets, oblique photography and aerial photography) and techniques for future year work. (9) A group will convene to assess existing data on plant dynamics.

VERTEBRATE RESPONSE -- (1) Conduct sampling of vertebrates abundance and distribution in conjunction with the Analysis and Assessment of Impacts on Biodiversity project being conducted by EPA. (2) Synthesize existing data collected for the Nevada Test Site.

INFORMATION INTEGRATION -- (1) Build and maintain a program web site for utilization internally by program scientists and externally by clients and the public. The web site will be integrated with the DOD Ft. Irwin server and contain data, photos, papers, and interpretations. (2) Make digital orthophotos available in a compressed and mosaicked form for ease of use. (3) Review with desert managers the simulated Decision Support System completed in FY98. (4) Develop a plan for a Decision Support System in concert with a scoping effort being funded by DOD through the Science Data Management team. (5) Help to organize scientific workshops and publish proceedings and other papers.

FY 1999 deliverables/products:

SOIL COMPACTION -- (1) Geomorphic surface maps for selected intensive study sites in the Mojave desert. (2) Daily temperature and precipitation digital maps descriptive of historical variation and prediction of spatial distribution. (3) Regional-scale interpolations of daily precipitation and temperature indicative of soil moisture. (4) A vegetation density map of the ecosystem using existing Landsat TM data. (5) Transfer functions between surficial particle size, compactibility of desert soils, and recoverability of desert soils.

SURFACE EROSION -- (1) Establishment of several GEOMET micrometeorological stations in the Mojave Desert.

VEGETATION RESPONSE -- (1) Documentation of the characteristics of overland flow disruption and sediment deposition at Valjean. (2) Additional measurements of vegetation species composition and cover at several dated ghost town sites. (3) A report will be prepared by an independent contractor compiling data previously collected on the Nevada Test by previous projects.

VERTEBRATE RESPONSE -- (1) Synthesis of existing data collected for the Nevada Test Site. (2) A manuscript on vertebrate abundance and distribution in conjunction with the Analysis and Assessment of Impacts on Biodiversity project being conducted by EPA.

INFORMATION INTEGRATION -- (1) Maintenance of program web site and integration DOD Ft. Irwin server. (2) Release of digital orthophotos in a compressed and mosaicked form for ease of use. (3) Development of a plan for a Decision Support System.

FY 1999 outreach:

The program will be conducted closely with desert managers through the Desert Managers Group, the Science Data Management Team, the Restoration Team, and other coordinating groups. Coordination will be maintained through active participation at meetings of these groups and with other scientists conducting related research. The program web site will be a major method of outreach. Several briefings will be conducted for clients. Several presentations by program scientists will be given at the Mojave Desert Science Symposium in Las Vegas February 25-27, 1999. Papers will be published on the web site and as part of the conference proceedings.

ACCOMPLISHMENTS, OUTCOMES, PRODUCTS, OUTREACH

FY 1998 accomplishments and outcomes, including outreach:

In FY98, the Mojave Ecosystem Project devoted its efforts to intensive field studies at three sites in the Mojave Desert. In addition, the GIS team devoted significant time to integrating the DOD/Legacy database into the GIS system to be used for the Mojave Ecosystem project. At the Greenwater Valley sites, recovery of soils and vegetation was measured in six sites in three ghost towns, providing data on recoverability 90 years after disturbance. Comparison with 1981 data suggests that recovery is continuing, and we determined a basis for developing conceptual and quantitative models of soil and vegetation recovery. In addition, geomorphic surfaces were mapped in the vicinity of the ghost towns, and wind erosion studies were conducted to determine if areas abandoned 90 years ago continued to have elevated wind-erosion rates. We began an assessment of the recovery of cryptobiotic soils in ghost towns, and we began the regional assessment of the distribution and species composition of cryptobiotic soils in the Mojave Desert. In one ghost town, abandoned 72 years, crust cover had recovered but species richness was much lower in the townsite compared to a control area. At the Valjean site, stratigraphic studies indicate that as many as 18 overland flow events occurred in the last 92 years. Capture of the sediment transported by these flows behind an abandoned railroad grade provides the basis for a model of sediment yield as a function of drainage area and geomorphic surface, which will be on-going research. Geomorphic surfaces in the vicinity of the Valjean site were mapped, and wind erosion studies were conducted on a subset of the mapped surfaces. The wind-tunnel studies showed that disturbance increased sediment production by up to 35 times, whereas surfaces mantled by cryptobiotic soils showed no measurable wind erosion. The mapping indicated a wide-range of geomorphic surfaces separated spatially, instead of vertically, across the broad alluvial fans issuing from the Kingston and Shadow Mountains. We began a systematic study of the effect of surface disruption on wind erodibility over a variety of substrates and geomorphic surfaces. At the Ivanpah Valley site, studies continued on the effects of livestock grazing on desert soils and vegetation. In addition, preliminary mapping of geomorphic surfaces yielded information on the nature of playa-fan systems in the Mojave Desert. This work, combined with the mapping at Valjean, will be important calibration data for development of a facies model that will be incorporated into the GIS layer on surficial particle size. Soil samples required for calibration of GIS layers depicting surficial particle size distribution were collected from a variety of surfaces in the Greenwater Valley and at Valjean. We began a systematic sampling of desert surfaces to assess compaction potential using modified laboratory techniques. GIS data layers related to human disturbance were integrated and modeled to produce a map of potential human influence on the ecosystem. A simulated decision-support system was developed in anticipation of products to be completed in the latter years of the project.

FY 1998 deliverables, products completed:

(1) A web site that provides client accessibility to products produced by the Mojave Ecosystem project, including GIS data layers, descriptions of the project objectives and accomplishments, and photography of study areas: (2) A simulated decision-support system for demonstration purposes to the Desert Land Managers Group; (3) Repeat photography of ghost towns, made available on web site; (4) Preliminary digital map of surficial geology for Valjean, Ivanpah Valley, and Greenwater Valley. (5) Manuscripts for the program workshop by key scientists.

PROJECT SUPPORT REQUIREMENTS

Names and expertise (e.g. carbonate petrology) of key project staff (list by fiscal year for duration of project):

Other required expertise for which no individual has been identified (list by fiscal year for duration of project):

Major equipment/facility needs (list by fiscal year for duration of project):

FY 1999 FUNDING

FY 1999 project budget request: Attach Project Personnel and Operating Expenses Worksheets or BMS staffing sheets.

Approval: ________________________________________ Date: _______________

Approval: ________________________________________ Date: _______________

Approval: _________________________________________Date: _______________

Management for all key named project personnel must approve all work plans. Copies of faxed or emailed approvals are acceptable.

(Approval officials: GD - Chief Scientist; WRD - local Administrative Officer; NMD - Associate Chief for Science; BRD - local administrative officer).