@article {JRN55378, title = {Adaptive monitoring for multiscale land management: Lessons learned from the Assessment, Inventory, and Monitoring (AIM) principles}, journal = {Rangelands}, volume = {44}, year = {2022}, month = {03/1/2022}, pages = {50-63}, abstract = {On the Ground {\textbullet} The BLM Assessment, Inventory, and Monitoring (AIM) strategy recommends five principles for building multiscale monitoring programs: standardized methods and indicators; data management and stewardship; appropriate sample designs; remote sensing integration; and structured implementation. These principles guide monitoring across public lands. {\textbullet} We find the AIM principles are sound and worthy of consideration for design and adaptation of rangeland monitoring programs worldwide. {\textbullet} An emergent principle, standard workflows and analysis frameworks for using data, connects data to land management decision-making and empowers land managers. {\textbullet} The AIM principles inspire and provide opportunities for the rangeland management community to implement adaptive management.}, keywords = {data management, decision-making, design, indicators, public lands, rangeland monitoring}, doi = {10.1016/j.rala.2021.08.006}, url = {files/bibliography/22-008.pdf}, author = {Emily Kachergis and Scott W. Miller and Melissa Dickard and Shannon Savage and Lindsay V. Reynolds and Nika Lepak and Chris Dietrich and Adam Green and Aleta Nafus and Karen Prentice and Zoe Davidson} } @article {JRN55316, title = {Monitoring agroecosystem productivity and phenology at a national scale: A metric assessment framework}, journal = { Ecological Indicators}, volume = {131}, year = {2021}, month = {8/27/2021}, chapter = {108147}, abstract = {Effective measurement of seasonal variations in the timing and amount of production is critical to managing spatially heterogeneous agroecosystems in a changing climate. Although numerous technologies for such measurements are available, their relationships to one another at a continental extent are unknown. Using data collected from across the Long-Term Agroecosystem Research (LTAR) network and other networks, we investigated correlations among key metrics representing primary production, phenology, and carbon fluxes in croplands, grazing lands, and crop-grazing integrated systems across the continental U.S. Metrics we examined included gross primary productivity (GPP) estimated from eddy covariance (EC) towers and modelled from the Landsat satellite, Landsat NDVI, and vegetation greenness (Green Chromatic Coordinate, GCC) from tower-mounted PhenoCams for 2017 and 2018. Overall, our analysis compared production dynamics estimated from three independent ground and remote platforms using data for 34 agricultural sites constituting 51 site-years of co-located time series. Pairwise sensor comparisons across all four metrics revealed stronger correlation and lower root mean square error (RMSE) between end of season (EOS) dates (Pearson R ranged from 0.6 to 0.7 and RMSE from 32.5 to 67.8) than start of season (SOS) dates (0.46 to 0.69 and 40.4 to 66.2). Overall, moderate to high correlations between SOS and EOS metrics complemented one another except at some lower productivity grazing land sites where estimating SOS can be challenging. Growing season length estimates derived from 16-day satellite GPP (179.1 days) were significantly longer than those from PhenoCam GCC (70.4 days, padj < 0.0001) and EC GPP (79.6 days, padj < 0.0001). Landscape heterogeneity did not explain differences in SOS and EOS estimates. Annual integrated estimates of productivity from EC GPP and PhenoCam GCC diverged from those estimated by Landsat GPP and NDVI at sites where annual production exceeds 1000 gC/m-2 yr-1. Based on our results, we developed a {\textquotedblleft}metric assessment framework{\textquotedblright} that articulates where and how metrics from satellite, eddy covariance and PhenoCams complement, diverge from, or are redundant with one another. The framework was designed to optimize instrumentation selection for monitoring, modeling, and forecasting ecosystem functioning with the ultimate goal of informing decision-making by land managers, policy-makers, and industry leaders working at multiple scales.}, keywords = {Agricultural management, eddy covariance, GPP, Growing season length, indicators, LandsatPhenoCam, Long-Term Agroecosystem Research (LTAR) network, Sustainable agriculture}, doi = {10.1016/j.ecolind.2021.108147}, url = {files/bibliography/21-031.pdf}, author = {Dawn M. Browning and Eric S. Russell and Guillermo E. Ponce-Campos and N. E. Kaplan and Andrew D. Richardson and Bijan Seyednasrollah and S. Spiegal and Nicanor Z. Saliendra and Joseph G. Alfieri and J. M. Baker and Carl Bernacchi and Brandon T Bestelmeyer and David D. Bosch and Elizabeth H. Boughton and Raoul K. Boughton and Patrick E. Clark and Gerald N. Flerchinger and Nuria Gomez-Casanovas and Sarah Goslee and Nick Haddad and David L. Hoover and Abdullah Jaradat and Marguerite Mauritz and Gregory McCarty and Gretchen R. Miller and John Sadler and Amartya Saha and R.L. Scott and Andrew Suyker and Craig Tweedie and Jeffrey D. Wood and Xukai Zhang and Shawn D. Taylor} } @article {JRN55341, title = {Parameterizing an aeolian erosion (AERO) model for rangelands}, journal = {Aeolian Research}, volume = {54}, year = {2021}, month = {12/13/2021}, chapter = {100769}, abstract = {Aeolian processes are fundamental to arid and semi-arid ecosystems, but modeling approaches are poorly developed for assessing impacts of management and environmental change on sediment transport rates over meaningful spatial and temporal scales. For model estimates to provide value, estimates of sediment flux that encapsulate intra- and inter-annual and spatial variability are needed. Further, it is important to quantify and communicate transparent estimates of model uncertainty to users. Here, we present a wind erosion and dust emission model parameterized for rangelands using a Generalized Likelihood Uncertainty Estimation framework. Modeled horizontal sediment flux was calibrated using data from five diverse grassland and shrubland sites from the USDA National Wind Erosion Research Network. Observations of wind speed, vegetation height, length of gaps between vegetation, and percent bare ground were used as model inputs. Horizontal sediment flux estimates from 10,000 independently selected parameter sets were compared to flux observations from 44 \~{} month-long collection periods to calculate a likelihood measure for each model. Results show good agreement for individual sampling periods across sites with few observations falling outside prediction bounds and a one-to-one relationship between median predictions and observations. Additionally, combined distributions of sediment flux estimates from all sample periods for a given site closely approximated the probability of observing a given flux at that site. These results suggest AERO effectively represents temporal variability in aeolian transport rates at rangeland sites and provides robust assessments suitable for assessing land health and better predicting changes in air quality and the impacts of land management activities.}, keywords = {aeolian, assessment, dust emission, indicators, land management, monitoring, wind erosion}, doi = {10.1016/j.aeolia.2021.100769}, url = {files/bibliography/21-052.pdf}, author = {Brandon Edwards and Nicholas Webb and Magda Galloza and Justin Van Zee and Ericha Courtright and Brad Cooper and Loretta Metz and Jeffrey E. Herrick and Gregory S. Okin and Danielle Duni and John Tatarko and Negussie Tedela and Daniel N. Moriasi and Beth Newingham and Frederick B. Pierson and David P. Toledo and Scott Van Pelt} } @article {50024, title = {Assessing transportation infrastructure impacts on rangelands: Test of a standard rangeland assessment protocol}, journal = {Rangeland Ecology and Management}, volume = {63}, year = {2010}, month = {07/2010}, pages = {524-536}, chapter = {524}, abstract = {

Linear disturbances associated with on and off-road vehicle use on rangelands has increased dramatically throughout the world in recent decades. This increase is due to a variety of factors including increased availability of all-terrain vehicles, infrastructure development (oil, gas, renewable energy, and ex-urban) and recreational activities. In addition to the direct impacts of road development, the presence and use of roads may alter resilience of adjoining areas through indirect effects such as altered site hydrologic and eolian processes, invasive seed dispersal, and sediment transport. There are few standardized methods for assessing impacts of transportation-related land-use activities on soils and vegetation on arid and semi-arid rangelands. Interpreting Indicators of Rangeland Health (IIRH) is an internationally accepted qualitative assessment that is applied widely to rangelands. We tested the sensitivity of IIRH to impacts of roads, trails, and pipelines on adjacent lands by surveying plots at three distances from these linear disturbances. We performed tests at 16 randomly selected sites in each of 3 ecosystems (Northern High Plains, Colorado Plateau, and Chihuahuan Desert) for a total of 208 evaluation plots. We also evaluated the repeatability of IIRH when applied to road-related disturbance gradients. Finally, we tested the extent to which IIRH plot attribute departure classes are correlated with trends in a suite of quantitative indicators. Results indicated that the IIRH technique is sensitive to direct and indirect impacts of transportation activities. Trends in degradation detected with qualitative assessments were highly correlated with quantitative data. Qualitative and quantitative assessments employed in this study can be used to assess impacts of transportation features at the plot scale. Through integration with remote sensing technologies, these methods could also potentially be used to assess cumulative impacts of transportation networks at the landscape scale.

}, keywords = {disturbance, IIRH, indicators, off-highway vehicles, oil and gas, rangeland health, roads}, doi = {10.2111/REM-D-09-00176.1}, url = {/files/bibliography/10-024.pdf}, author = {Danielle Duni and Jeffrey E. Herrick and D.A. Pyke and David P. Toledo} } @article {50137, title = {Unmanned aerial vehicle-based remote sensing for rangeland assessment, monitoring, and management}, journal = {Journal of Applied Remote Sensing}, volume = {3}, year = {2009}, month = {08/2009}, pages = {033542}, abstract = {

Rangeland comprises as much as 70\% of the Earth\’s land surface area. Much of this vast space is in very remote areas that are expensive and often impossible to access on the ground. Unmanned Aerial Vehicles (UAVs) have great potential for rangeland management. UAVs have several advantages over satellites and piloted aircraft: they can be deployed quickly and repeatedly; they are less costly and safer than piloted aircraft; they are flexible in terms of flying height and timing of missions; and they can obtain imagery at sub-decimeter resolution. This hyperspatial imagery allows for quantification of plant cover, composition, and structure at multiple spatial scales. Our experiments have shown that this capability, from an off-the-shelf mini-UAV, is directly applicable to operational agency needs for measuring and monitoring. For use by operational agencies to carry out their mandated responsibilities, various requirements must be met: an affordable and reliable platform; a capability for autonomous, low altitude flights; takeoff and landing in small areas surrounded by rugged terrain; and an easily applied data analysis methodology. A number of image processing and orthorectification challenges have been or are currently being addressed, but the potential to depict the land surface commensurate with field data perspectives across broader spatial extents is unrivaled.

}, keywords = {aerial photography, autonomous flight, indicators, rangeland applications, Small unmanned aerial vehicles}, doi = {10.1117/1.3216822}, url = {/files/bibliography/09-025.pdf}, author = {A. Rango and Andrea S. Laliberte and Jeffrey E. Herrick and Craig Winters and Kris Havstad and Caitriana Steele and Dawn M. Browning} } @article {50456, title = {Monitoring ecological processes for restoration projects}, journal = {Journal of Nature Conservation}, volume = {14}, number = {3-4}, year = {2006}, month = {September 2006}, pages = {161-171}, abstract = {Restoration of ecological processes is key to restoring the capacity of ecosystems to support social, economic, cultural and aesthetic values. The sustainability of the restored system also depends on processes associated with carbon, nutrient and hydrologic cycles, yet most restoration monitoring is limited to plant community composition. Our research has shown that short-term plant composition monitoring is a necessary but insufficient predictor of long-term restoration success. Long-term (up to 75 years) studies in the western United States show that short-term monitoring of plant community composition alone incorrectly predicted the failure of treatments that were ultimately successful, and the success of treatments that ultimately failed. We propose that vegetation composition monitoring be combined with one or more ecological process indicators reflecting changes in three fundamental ecosystem attributes on which restoration success depends: soil and site stability, hydrologic function and biotic integrity. These simple, rapid, plot-level indicators reflect changes in resource redistribution and vegetation structure. We include a case study involving restoration of mixed grass prairie on mineland in the west-central United States.}, keywords = {ecosystem services, erosion, indicators, landscape, monitoring, restoration, runoff, spatial pattern, spatial variability}, url = {/files/bibliography/06-032.pdf}, author = {Jeffrey E. Herrick and G.E. Schuman and A. Rango} } @book {50587, title = {Interpreting Indicators of Rangeland Health, Version 4.0}, volume = {1734-6}, year = {2005}, month = {September 2005}, publisher = {USDI, BLM, NSTC, Division of Science Integration, Branch of Publishing Services}, organization = {USDI, BLM, NSTC, Division of Science Integration, Branch of Publishing Services}, address = {Denver, CO}, abstract = {This book describes a protocol for using 17 qualitative soil and vegetation indicators to evaluate the status of three ecosystem attributes: soil and site stability, hydrologic function, and biotic integrity. Qualitative assessments of rangeland health provide land managers and technical assistance specialists with a good communication tool for use with the public. Many of these tools have been used successfully for this purpose over the past 100 years. The technique described in this book can be used to provide early warnings of resource problems on upland rangelands. It can also be used to help identify specific resource issues (e.g., erosion or invasive species) that must be addressed and to prioritize land for management resources. Version 4 is the second published edition of this technique. The changes in Version 4 are designed to improve the consistency in the application of the process. The most significant modification was the replacement of the Ecological Reference Area Worksheet with the Reference Sheet. The Reference Sheet facilitates consistent application of the process throughout an ecological site by integrating all available sources of data and knowledge to generate a single range of reference conditions for each indicator. }, keywords = {ecosystem attributes, evaluate, indicators, interpreting, rangeland health, soil, technical reference, vegetation}, url = {/files/bibliography/05-010.pdf}, author = {M. Pellant and P. L. Shaver and D.A. Pyke and Jeffrey E. Herrick} } @article {51015, title = {Detecting fragmentation of cover in desert grasslands using line intercept}, journal = {Journal of Range Management}, volume = {54}, number = {1}, year = {2001}, month = {January 1, 2001}, pages = {61-66}, abstract = {We examined the relationship between a Chihuahuan Desert grassland keystone species (banner-tailed kangaroo rat, Dipodomys spectabilis) and several vegetation and soil indicators of rangeland health in order to define a threshold indicator value for irreversible change in ecosystem structure and function. The abundance of occupied and/or abandoned D. spectabilis burrow-mounds was assessed at 117 sites in south central New Mexico where previous studies had reported vegetation cover and composition. The most robust indicator for presence/absence of D. spectabilis was shrub cover. D. spectabilis did not occur at sites with shrub cover greater than 20\%. It was concluded that a threshold value of 20\% shrub cover could be applied to assessment and monitoring of Chihuahuan Desert rangelands because higher shrub cover results in the local extinction of this keystone species. The combination of data on the presence/absence of a keystone species with vegetation and soil indicators provides a method for identifying thresholds of degradation that may be irreversible.}, keywords = {Chihuahuan Desert, grassland, indicators, keystone species, rangeland health, shrub cover}, url = {http://jrm.library.arizona.edu/jrm/GetFileServlet?file=file:///data1/pdf/TheJournalOfRangeManagement/Volume54/Number1/azu_jrm_v54_n1_61_66_m.pdf\&type=application/pdf}, author = {Kuehl, R.O. and M.P. McClaran and Justin Van Zee} } @proceedings {51053, title = {Locally led conservation activities: Developing a soil quality assessment tool}, year = {2001}, month = {May 24-29, 1999}, pages = {529-534}, address = {Purdue University and the USDA-ARS National Soil Erosion Research Laboratory}, abstract = {Farmers base many management decisions on a variety of personal observations of their crops and soils. However, there was no soil assessment procedure applicable to farms across the country to help farmers record these observations and to use them to guide their future management decisions. To address this need, the Soil Quality Institute of the USDA-NRCS, university research and USDA-CES partners in Oregon and Maryland developed the Soil Quality Card Design Guide. Using the guide, facilitators followed a nine-step meeting procedure to help farmers identify locally important soil quality indicators, develop descriptive terms for soil quality assessments, and design the format of their soil quality card. Seven cards were developed by local groups of farmers during the period 1997 to early 1999. The farmer meeting provides an opportunity for USDA-NRCS, USDA-CES, conservation districts, producers and others to jointly create soil quality cards for farmers in each unique cropping region of the country. The collaborative process used to create the cards offers locally led conservation opportunities for dialogue and idea sharing, thus blending the scientific knowledge of conservationists and soil scientists with the common-sense experience of producers. Farmers can use soil quality cards to assess changes in soil quality resulting from different management systems and to track changes from year to year. Agricultural professionals, educators, students and others with an interest in soil quality and the impact of management practices on soil can use the cards to enhance communication and learning.}, keywords = {indicators, management systems, soil assessment procedure, Soil Quality Card Design Guide}, url = {/files/bibliography/01-050.pdf}, author = {A.J. Tugel and Seiter, S. and Friedman, D. and J. Davis and Dick, R.P. and McGrath, D. and Weil, R.R.}, editor = {E.E. Stott and R.H. Mohtar and G.C. Steinhardt} } @article {51121, title = {Indicators of Great Basin rangeland health}, journal = {Journal of Arid Environments}, volume = {45}, number = {4}, year = {2000}, month = {August 1, 2000}, pages = {289-304}, abstract = {

Early-warning indicators of rangeland health can be used to estimate the functional integrity of a site and may allow sustainable management of desert rangelands. The utility of several vegetation canopy-based indicators of rangeland health at 32 Great Basin rangeland locations was investigated. The indicators were originally developed in rangelands of the Chihuahuan Desert. Soil resources are lost through wind and water-driven erosion mainly from areas unprotected by plant canopies (i.e. bare soil). Study sites in Idaho had the smallest bare patches, followed by sites in Oregon. The more arid Great Basin Sagebrush Zone sites in Utah had the largest bare patches. Several vegetational indicators including percent cover by vegetation, percent cover by life-form, percent cover by sagebrush, and percent cover by resilient species were negatively related to mean bare patch size and are potential indicators of Great Basin rangeland condition. Plant community composition and the range of bare patch sizes were different at sites in the three locations in Idaho, Oregon and Utah. Therefore, expected indicator values are location specific and should not be extrapolated to other locations. The condition of study sites were often ranked differently by different indicators. Therefore, the condition of rangeland sites should be evaluated using several indicators.

}, keywords = {Great Basin, indicators, management, rangeland health}, doi = {10.1006/jare.2000.0645}, url = {/files/bibliography/00-014.pdf}, author = {A.G. de Soyza and Justin Van Zee and Walter G. Whitford and A.C. Neale and Tallent-Hallsel, N. and Jeffrey E. Herrick and Kris Havstad} } @proceedings {51122, title = {Soil surface indicators of desertification from the northern Chihuahuan Desert and the Great Basin}, volume = {1}, year = {2000}, month = {July 19-23, 1999}, pages = {137}, address = {Townsville, Australia}, abstract = {We measured vegetation canopy and litter cover in ungrazed exclosures and adjacent pastures at three locations in the Chihuahuan Desert, five locations near Burns, Oregon, seven locations near Milford, Utah, and six near Idaho Falls, Idaho, all of which are in the Great Basin. We found that vegetation cover is not a good surrogate for estimating litter cover. Refinements that take into account vegetation species composition may improve the ability to predict litter cover from vegetation data.}, keywords = {Chihuahuan Desert, desertification, Great Basin, indicators, soil surface}, url = {/files/bibliography/00-002.pdf}, author = {A.G. de Soyza and Walter G. Whitford and Justin Van Zee and Jeffrey E. Herrick and Kris Havstad} } @proceedings {51083, title = {Integrating soil processes into management: From microaggregates to macrocatchments}, volume = {1}, year = {2000}, month = {July 17-23, 1999}, pages = {91-95}, address = {Townsville, Australia}, abstract = {

Soil properties and processes are rarely considered in range management, or in monitoring or assessment of range condition. An implicit assumption of most management programs is that soil properties are correlated with vegetation, so it is only necessary to manage and monitor the plant community. However, most range managers recognize that the plant communities which could exist at a particular site fundamentally depend on soil properties, and that many of these properties are dynamic and respond to management. A reduction in soil organic matter content, or a change in its distribution (dynamic properties), are frequently cited as indicators of land degradation (Northup \& Brown 1999a,b). There are numerous reports demonstrating relationships between soil properties and processes and the capacity of rangelands to support diverse plant and animal communities (National Research Council 1994) and plant and animal production (Elkins et al. 1986; Whitford et al. 1987; Whitford \& Parker 1989; Whitford \& Herrick 1995), and maintain air quality (Belnap \& Gillette 1998) and water quality (National Research Councill993).

}, keywords = {ecosystem health, indicators, management, monitoring, soil processes}, url = {/files/bibliography/00-001.pdf}, author = {Jeffrey E. Herrick and Walter G. Whitford} } @book {51100, title = {Interpreting Indicators of Rangeland Health, Version 3}, year = {2000}, note = {Interagency Technical Reference 1734-6}, month = {December 1, 2000}, pages = {115}, publisher = {USDI, Bureau of Land Management}, organization = {USDI, Bureau of Land Management}, address = {Denver, CO}, abstract = {

This technical reference describes a new qualitative assessment protocol to be used for interpreting indicators of rangeland health. Use of the reference will allow for more consistent interpretations of rangeland health indicators, thus making assessment results more comparable. The procedure has been developed for use by experienced, knowledgeable land managers as it requires a good understanding of ecological processes, vegetation, and soils for each of the sites to which it is applied. If used by knowledgeable and experienced people, they will be able to make rapid and preliminary evaluations of soil and site stability, hydrologic function, and biotic integrity on rangelands. It is not to be used for monitoring. The procedure requires that evaluators rate 17 indicators to assess 3 attributes (soil/site stability, hydrologic function, and biotic integrity) for a given location.

}, keywords = {biotic integrity, hydrologic function, indicators, rangeland health, soil and site stability}, url = {files/bibliography/00-021.pdf}, author = {M. Pellant and P. L. Shaver and D.A. Pyke and Jeffrey E. Herrick} } @proceedings {51189, title = {Methods for assessing the health of America{\textquoteright}s rangelands}, volume = {Report QNRM02143}, year = {1999}, note = {August 1-6, 1999Conference was held in 1999 but proceedings weren{\textquoteright}t published until 2002 and reprint not received until December 2003.}, month = {2002}, pages = {1-17}, publisher = {Queensland Department of Natural Resources and Mines}, address = {Brisbane, Australia}, abstract = {Since the publication of the National Research Council{\textquoteright}s {\textquoteright}RANGELAND HEALTH {\textquoteright} New Methods to Classify, Inventory, and Monitor Rangelands,{\textquoteright} and the Society for Range Management report by the Unity in Concepts and Terminology Committee, there has been much activity toward developing a common method to assess rangelands in the United States. Many individuals from several different federal and state agencies have worked together to develop a multi-indicator matrix to determine the {\textquoteright}health{\textquoteright} status of rangelands. Healthy rangelands have been defined as: The degree to which the integrity of the soil, the vegetation, the water, and the air, as well as the ecological processes of the rangeland ecosystem, are balanced and sustained. The site potential is the standard by which {\textquoteright}health{\textquoteright} is judged. A rangeland ecological site must be judged against itself and not against an arbitrary standard or that of a different ecological site. It is apparent that a multi-indicator method of evaluation is necessary. Currently, the evaluation consists of a series of observational questions, some of which can be answered by observation or measurement. Characteristics such as canopy and ground cover, dominant plant species, invasive and noxious plants, and composition of functional/structural plant groups can be measured or observed. The observable data are arranged in a matrix with 17 indicators. Each indicator is compared against the rangeland ecological site description and reference areas that represent the natural range of variability in the ecological site. Each indicator is rated on a sliding scale of five choices from most similar to most dissimilar to the ecological site. Similarity is referenced to the ecological site description and the reference areas. Interagency personnel, universities, scientists, and landowners have tested this methodology in the field in several locations. The indicators have been grouped into three attributes of rangeland health. The three attributes give an indication of the soil or site stability, hydrologic function and biotic integrity of the site. The indicators currently include: rills, water flow patterns, pedestals or terracettes, bare ground, gullies, wind-scoured areas, litter movement, soil surface resistance to erosion, soil surface loss, plant community composition and distribution relative to infiltration and runoff, compaction layer, plant functional/structural groups, plant mortality, litter amount, annual production, invasive plants, and perennial plant reproductive capability. The ratings for each indicator are recorded in a manner that allows for a visual interpretation based on the preponderance of evidence.}, keywords = {assessment, common method, health, indicators, rangelands}, isbn = {0 7345 2668 7}, url = {/files/bibliography/02-106.pdf}, author = {P. L. Shaver and M. Pellant and D.A. Pyke and Jeffrey E. Herrick}, editor = {Lawrence, P.A. and Robinson, J.} } @article {51249, title = {Early warning indicators of desertification: Examples of tests in the Chihuahuan Desert}, journal = {Journal of Arid Environments}, volume = {39}, number = {2}, year = {1998}, month = {June 1, 1998}, pages = {101-112}, abstract = {

Perennial grasslands that dominated the south-west United States during the past 10,000 years have been desertified to varying extents. Desertification is a temporal phenomenon, defined in this paper as a change in the scale of the spatial distribution of resources. We report here on several indicators of desertification, using bare patch indices as surrogates for direct measures. A bare patch index based on canopy cover, which is relevant for precipitation and wind-driven erosion, is not equivalent to another bare patch index based on soil surface measurements, which is relevant for overland water flow-driven erosion. Per cent grass cover, per cent long-lived grass cover, per cent cover of vegetative reproducers, and a relative preference index all yielded sensitive indicators of desertification. The usefulness of some indicators, such as organic litter, depends upon recent environmental history. Other indicators, such as per cent cover due to grazing-resistant species, appear not to be sensitive to desertification and need further development. Range site type may also be important in determining indicator responses, where some indicators were sensitive to a range site while others were not. Overall, we have identified several sensitive indicators of desertification based on vegetational characteristics in varied range sites in the northern Chihuahuan Desert.

}, keywords = {bare patch index, Chihuahuan Desert, ecosystem health, indicators, litter}, doi = {10.1006/jare.1998.0391}, url = {/files/bibliography/607.pdf}, author = {A.G. de Soyza and Walter G. Whitford and Jeffrey E. Herrick and Justin Van Zee and Kris Havstad} } @conference {51345, title = {Indicators of Soil Quality for Southwestern Rangelands}, booktitle = {Soil Qualilty: A Guide to Conservation Workshop}, year = {1996}, month = {July 17-18, 1996}, address = {Ames, IA}, keywords = {indicators, rangelands, soil quality, southwestern}, author = {Jeffrey E. Herrick} }