Search

The data set covers a 101-yr period (1915-2016) of quadrat-based plant sampling at the Jornada Experimental Range in southern New Mexico. At each sampling event, a pantograph was used to record the location and perimeter of living plants within permanent quadrats. Basal area was recorded for perennial grass species, canopy cover area was recorded for shrub species, and all other perennial species were recorded as point data. The data set includes 122 1 × 1 m permanent quadrats, although not all quadrats were sampled in each year of the study and there is a gap in monitoring from 1980 to 1995. These data provide a unique opportunity to investigate changes in the plant community over 100 yr of variation in precipitation and other environmental conditions. We provide the following data and data formats: (1) the digitized maps in shapefile format; (2) a data table containing coordinates (x, y) of perennial species within quadrats, including cover area for grasses and shrubs; (3) a data table of counts of annual plant individuals per quadrat; (4) a species list indicating growth form and habit of recorded species; (5) a table of dates when each quadrat was sampled; (6) a table of the pasture each quadrat was located within (note that pasture boundaries have changed over time); (7) a table of depth to petrocalcic layer measurements taken at quadrat locations; (8) a table of particle size analysis of soil samples taken at quadrat locations; (9) a table of topographic characteristics of quadrat locations (e.g., concave or convex topography). Pantograph sampling is currently conducted at 5-yr intervals by USDA-ARS staff, and new data will be added periodically to the EDI Data Portal Repository (see section V.E.2). This information is released under the Creative Commons license-Attribution-CC BY and the consumer of these data is required to cite it appropriately in any publication that results from its use.

On the Ground•Ecological sites and their component state-and-transition models are valuable tools for predicting the effects of climatic and management changes on a variety of ecosystem services.•Site-specific information must be able to be both refined to finer scales to account for spatiotemporal variability within a mapped site and expanded to include interactions with other sites in the landscape to identify priorities and account for integrative disturbances and ecosystem services such as wildlife habitat, hydrology, fire, insect outbreak and invasive species.•Ecological site groups, spatially contiguous and behaviorally similar, are an important level in the land hierarchy to organize and interpret information.

The Southwestern US is a five-state region that has supported animal agriculture since the late 16th Century when European settlers crossed the Rio Grande into present day west Texas and southern New Mexico with herds of cattle, sheep, goats and horses. For the past 400 years the rangeland livestock industry, in its many forms and manifestations, has developed management strategies and conservation practices that impart resilience to the climatic extremes, especially prolonged droughts, that are common and extensive across this region. Livestock production from rangelands in the southwest (SW) is adapted to low rainfall and high ambient temperatures, but will have to continue to adapt management strategies, such as reduced stocking rates, proper grazing management practices, employing animal genetics suited to arid environments with less herbaceous production, erosion control conservation practices, and alternative forage supplies, in an increasingly arid and variable climatic environment. Even though the aging demographics of western ranchers could be a deterrent to implementing various adaptations, there are examples of creative management coalitions to cope with climatic change that are emerging in the SW that can serve as instructive examples. More importantly, there are additional opportunities for incorporation of transformative practices and technologies that can sustain animal agriculture in the SW in a warmer environment. Animal agriculture in the SW is inherently resilient, and has the capacity to adapt and transform as needed to the climatic changes that are now occurring and will continue to occur across this region. However, producers and land managers will need to thoroughly understand the vulnerabilities and sensitivities that face them as well as the ecological characteristics of their specific landscapes in order to cope with the emerging climatic changes across the SW region.

The National Wind Erosion Research Network was established in 2014 as a collaborative effort led by the United States Department of Agriculture’s Agricultural Research Service and Natural Resources Conservation Service, and the United States Department of the Interior’s Bureau of Land Management, to address the need for a long-term research program to meet critical challenges in wind erosion research and management in the United States. The Network has three aims: (1) provide data to support understanding of basic aeolian processes across land use types, land cover types, and management practices, (2) support development and application of models to assess wind erosion and dust emission and their impacts on human and environmental systems, and (3) encourage collaboration among the aeolian research community and resource managers for the transfer of wind erosion technologies. The Network currently consists of thirteen intensively instrumented sites providing measurements of aeolian sediment transport rates, meteorological conditions, and soil and vegetation properties that influence wind erosion. Network sites are located across rangelands, croplands, and deserts of the western US. In support of Network activities, http://winderosionnetwork.org was developed as a portal for information about the Network, providing site descriptions, measurement protocols, and data visualization tools to facilitate collaboration with scientists and managers interested in the Network and accessing Network products. The Network provides a mechanism for engaging national and international partners in a wind erosion research program that addresses the need for improved understanding and prediction of aeolian processes across complex and diverse land use types and management practices.

In February 2014 the USDA established regional climate hubs across the United States to assist farmers, ranchers and foresters in adapting to the effects of climate change. The Southwest (SW) region encompasses six states which provide highly diverse agricultural crops including cotton, stone fruit and grapes. Here we report on the hydrologic context within which SW working landowners operate, with focus on regional water resources and likely impacts of climate change. Water is a critical component of agricultural vulnerability in the SW, where high agricultural production can occur with sufficient irrigation. Since 1978, crop yield declines were reported on 11–21% of total irrigated acres, mostly due to surface water shortage. Southwestern agriculture relies on groundwater, using it to supply at least one-third of the agricultural water demand across the region since 1955. Regional groundwater use varies over time, with a decline in the agricultural groundwater fraction in Arizona, but an increase in the fraction in Nevada and Utah. Observed and predicted changes in the southwestern hydrologic cycle can impact regional agriculture. Observed records show an increase in the fraction of precipitation falling as rain, which is expected to continue with future warming, and decrease the natural high-mountain storage reservoir provided by snowpack. Warming causes the snowmelt to peak earlier in the season than observed in historical records, and can reduce water available to crops during the summer months without additional water storage. Observed records indicate streamflow has shifted earlier in the year, most notably in snow dominated watersheds. A continuation of this trend may challenge regional agriculture by further limiting water supplies.

Semi-nomadic pastoralism was replaced by sedentary pastoralism in Inner Mongolia during the 1960's in response to changes in land use policy and increasing human population. Large increases in numbers of livestock and pastoralist households (11- and 9-fold, respectively) during the past 60 yrs have variously degraded the majority of grasslands in Inner Mongolia (78 M ha) and jeopardize the livelihoods of 24 M human inhabitants. A prevailing strategy for alleviating poverty and grassland degradation emphasizes intensification of livestock production systems to maintain both pastoral livelihoods and large livestock numbers. We consider this strategy unsustainable because maximization of livestock revenue incurs high supplemental feed costs, marginalizes net household income, and promotes larger flock sizes to create a positive feedback loop driving grassland degradation. We offer an alternative strategy that increases both livestock production efficiency and net pastoral income by marketing high quality animal products to an increasing affluent Chinese economy while simultaneously reducing livestock impacts on grasslands. We further caution that this strategy be designed and assessed within a social-ecological framework capable of coordinating market expansion for livestock products, sustainable livestock carrying capacities, modified pastoral perceptions of success, and incentives for ecosystem services to interrupt the positive feedback loop that exists between subsistence pastoralism and grassland degradation in Inner Mongolia. © 2015 Published by Elsevier Ltd.

The traditional desertification paradigm focuses on the losses of ecosystem services that typically occur when grasslands transition to systems dominated by bare (unvegetated) ground or by woody plants that are unpalatable to domestic livestock. However, recent studies reveal complex transitions across a range of environmental conditions and socioeconomic contexts. The papers in this Special Issue illustrate how an improved understanding of these dynamics is generating more robust paradigms, where state changes and regime shifts occurring within the context of changes in land use and climate are modified by landform and antecedent conditions. New and emerging technologies are being used to characterize and evaluate processes and outcomes across various scales and levels of organization. At the same time, developments in education are taking advantage of these new perspectives to improve the ecological literacy of future generations, and to better inform land-management decisions. A framework that integrates these perspectives provides a more comprehensive approach for understanding and predicting dryland dynamics.

This report describes the potential vulnerability of specialty crops, field crops, forests, and animal agriculture to climate-driven environmental changes. Here, vulnerability is defined as a function of exposure to climate change effects, sensitivity to these effects, and adaptive capacity. The exposure of specific sectors of the agricultural and forestry industries varies across the region because the Southwest is climatically and topographically diverse. There is also variability in the sensitivity of different systems to the effects of climate change. Most significantly, there is potential within agricultural and forestry systems to adjust to climate-related effects either through inherent resilience or through conservative management practices. The purpose of this analysis is to describe regional vulnerabilities to climate change and adaptive actions that can be employed to maintain productivity of working lands in the coming decades.

On the Ground Loss of grasslands to shrublands continues. Demand for livestock products is expected to continue to grow. Increased demand for red meat may stimulate rangeland livestock production. Methods for increasing shrub use are needed to meet increasing forage demands.

In a previous article, Beschta et al. (Environ Manag 51(2):474-491, 2013) argue that grazing by large ungulates (both native and domestic) should be eliminated or greatly reduced on western public lands to reduce potential climate change impacts. The authors did not present a balanced synthesis of the scientific literature, and their publication is more of an opinion article. Their conclusions do not reflect the complexities associated with herbivore grazing. Because grazing is a complex ecological process, synthesis of the scientific literature can be a challenge. Legacy effects of uncontrolled grazing during the homestead era further complicate analysis of current grazing impacts. Interactions of climate change and grazing will depend on the specific situation. For example, increasing atmospheric CO₂ and temperatures may increase accumulation of fine fuels (primarily grasses) and thus increase wildfire risk. Prescribed grazing by livestock is one of the few management tools available for reducing fine fuel accumulation. While there are certainly points on the landscape where herbivore impacts can be identified, there are also vast grazed areas where impacts are minimal. Broad scale reduction of domestic and wild herbivores to help native plant communities cope with climate change will be unnecessary because over the past 20-50 years land managers have actively sought to bring populations of native and domestic herbivores in balance with the potential of vegetation and soils. To cope with a changing climate, land managers will need access to all available vegetation management tools, including grazing.

Questions What factors explain the variation in plant survival parameters across species and ecosystems? Location Western North America. Methods We compiled six long-term data sets from western North America to test for ecosystem-dependent demographic responses for forbs and grasses. Based on these data, we characterized 123 survivorship curves for 109 species. Three demographic parameters were extracted from these survivorship curves: survival rate at age 1, life expectancy at age 1, and a parameter describing the shape of the survivorship curve. We used a mixed effects model to compare the differences in demographic parameters between life forms (forbs or grasses) and among ecosystems, incorporating ‘ecosystem’ as a random factor, with life form treated as a categorical factor, and mean annual precipitation and mean annual temperature treated as continuous variables. Results Grasses had higher survival and longer life expectancy than forbs at 1 yr of age. Both forbs and grasses followed Type III survivorship curves, although forbs were closer to Type II compared to the grasses. Averaging across species, hazard ratios for whole survivorship curves differed among most ecosystems. While mean annual precipitation had no effect on any demographic parameter, mean annual temperature had a significantly negative effect on both first year survival rates and life expectancy for forbs. Conclusions Our results demonstrate that life form exerts a strong influence on demographic parameters and their response to temperature variation among ecosystems. This unprecedented information on the age-specific demography of herbaceous plants has implications for population modelling and research on life-history evolution and senescence.

Ecosystem services are the benefits that society receives from nature, including the regulation of climate, the pollination of crops, the provisioning of intellectual inspiration and recreational environment, as well as many essential goods such as food, fiber, and wood. Rangeland ecosystem services are often valued differently by different stakeholders interested in livestock production, water quality and quantity, biodiversity conservation, or carbon sequestration. The supply of ecosystem services depends on biophysical conditions and land-use history, and their availability is assessed using surveys of soils, plants, and animals. The demand for ecosystem services depends on educational level, income, and location of residence of social beneficiaries. The demand can be assessed through stakeholder interviews, questionnaires, and surveys. Rangeland management affects the supply of different ecosystem services by producing interactions among them. Trade-offs result when an increase in one service is associated with a decline in another, and win–win situations occur when an increase in one service is associated with an increase in other services. This chapter provides a conceptual framework in which range management decisions are seen as a challenge of reconciling supply and demand of ecosystem services.

Much of the world's rangeland is dominated by woody species. Competing land uses and continued encroachment of woody species into non–woody-dominated rangelands have reduced grasslands in many parts of the world. Land use conversions to fuel and feed global populations, especially the increasing number of middle class people seeking broader, meat-based diets, will certainly continue. Halting and/or reversing further encroachment of woody species into grasslands is slow, expensive, and in some cases not possible. Yet, global livestock numbers continue to increase to meet the growing demand for red meat and other livestock products. How do we reconcile a world with less grass and the concurrent increased demand for forages to feed livestock? Strategies and mechanisms are needed to safely enhance shrub use by ruminants in order to capitalize on a presently underutilized forage resource. A number of approaches are presently available (e.g., choosing appropriate species and breeds, providing dietary supplements and additives, behavior modification, genetic selection) to increase shrub consumption, and new technologies such as biochemical markers of shrub intake need to continue to be identified and developed. Such strategies could provide important means for rural communities to adapt to changing land cover and climate.

A daptive management is widely applied to natural resources management (Holling 1973; Walters and Holling 1990). Adaptive management can be generally defined as an iterative decision-making process that incorporates formulation of management objectives, actions designed to address these objectives, monitoring of results, and repeated adaptation of management until desired results are achieved (Brown and MacLeod 1996; Savory and Butterfield 1999). However, adaptive management is often criticized because very few projects ever complete more than one cycle, resulting in little adaptation and little knowledge gain (Lee 1999; Walters 2007). One significant criticism is that adaptive management is often used as a justification for undertaking actions with uncertain outcomes or as a surrogate for the development of specific, measurable indicators and monitoring programs (Lee 1999; Ruhl 2007). In this paper, we argue for a more holistic and systematic approach to adaptive management. We define holistic adaptive land management (HALM) as a refinement of adaptive management that requires (1) a process-based understanding of ecosystem dynamics and ecological mechanisms, (2) a willingness and ability to identify and consider all possible management alternatives, (3) rigorous monitoring of management effects, and (4) constant adaptation of management based on monitoring data and associated observations. Thus, HALM requires both…

By the early 1900s, concerns were expressed by ranchers, academicians, and federal scientists that widespread overgrazing and invasion of native grassland by woody shrubs were having severe negative impacts upon normal grazing practices in Western America. Ranchers wanted to reverse these trends and continue their way of life and were willing to work with scientists to achieve these goals. One response to this desire was establishment of the USDA Jornada Experimental Range (783 km2) in south central New Mexico by a Presidential Executive Order in 1912 for conducting rangeland investigations. This cooperative effort involved experiments to understand principles of proper management and the processes causing the woody shrub invasion as well as to identify treatments to eradicate shrubs. By the late 1940s, it was apparent that combining the historical ground-based data accumulated at Jornada Experimental Range with rapidly expanding post World War II technologies would yield a better understanding of the driving processes in these arid and semiarid ecosystems which could then lead to improved rangeland management practices. One specific technology was the use of aerial photography to interpret landscape resource conditions. The assembly and utilization of long-term historical aerial photography data sets has occurred over the last half century. More recently, Global Positioning System (GPS) techniques have been used in a myriad of scientific endeavors including efforts to accurately locate historical and contemporary treatment plots and to track research animals including livestock and wildlife. As an incredible amount of both spatial and temporal data became available, Geographic Information Systems have been exploited to display various layers of data over the same locations. Subsequent analyses of these data layers have begun to yield new insights. The most recent technological development has been the deployment of Unmanned Aerial Vehicles (UAVs) that afford the opportunity to obtain high (5 cm) resolution data now required for rangeland monitoring. The Jornada team is now a leader in civil UAV applications in the USA. The scientific advances at the Jornada in fields such as remote sensing can be traced to the original Western America ranching culture that established the Jornada in 1912 and which persists as an important influence in shaping research directions today.

Livestock performance is a critical indicator of grassland production systems and is influenced strongly by precipitation and stocking rates. However, these relationships require further investigation in the arid Desert Steppe region of northeastern China. We employed a randomized complete block design with three replications and four grazing treatments (nongrazed exclosure [Control]), lightly grazed [LG], moderately grazed [MG], and heavily grazed [HG]) by sheep in a continuously grazed system (June to November), to test the effect of stocking rate on sheep performance. The planned stocking rates were 0, 0.15, 0.30, and 0.45 sheep?ha 21 ?mo 21 ,f or the control, LG, MG, and HG treatments, respectively. However, actual stocking rates were calculated for each paddock in each year based on a 50-kg sheep equivalent (SE). Annual net primary production (ANP P) was determined at peak standing crop in August 2004 to 2008. Live weight gain was determined for the summer and fall periods, as well as the total grazing period, in each year. ANPP decreased with increasing stocking rate, and daily live weight gain per head decreased linearly with increasing stocking rates over the total grazing period but in a quadratic manner over the summer period with a plateau at the lower rates. Maximum sheep production per unit area over the total grazing season occurred at about 2 SE ha 21 for about a 5-mo grazing period, but individual gains per sheep were predicted to decline after about 1 SE ha 21 presumably because of forage limitations. However, in order to achieve stable annual production, we recommend that the Desert Steppe be grazed at about 0.77 SE ha 21 for a 5-mo period (0.15 SE ha 21 ?mo 21 ). This estimate is based on published grazing strategies that consider an averag eA NPP with a recommended utilization rate of 30%.

Prescribed burning is a commonly advocated and historical practice for control of woody species encroachment into grasslands on all continents. However, desert grasslands of the southwestern United States often lack needed herbaceous fuel loads for effective prescriptions, dominant perennial graminoids may have poor fire tolerance, and some systems contain fire-tolerant invasive species. We examined long-term vegetation responses of a black grama (Bouteloua eriopoda Torr.) grassland that had been invaded by honey mesquite (Prosopis glandulosa) following a single prescribed burn. Vegetation responses to a 1995 prescribed burn were evaluated in a replicated randomized complete block design with a 2 × 2 factorial treatment structure. Treatments were prescribed burning and livestock exclusion for both a grassland-dominated and a shrub-encroached grassland state within a complex of sandy and shallow sandy ecological sites. Vegetation responses were measured in 2008, 13 years after the burn treatment application. Neither black grama basal cover nor honey mesquite canopy cover were responsive (p < 0.05) to any treatment. A single prescribed burn would be ineffective as a shrub control practice in this environment. Repeated but infrequent prescribed burning within shrub-encroached vegetative states, when used in combination with managed grazing, may be the management required for a transition to desert grassland states within these ecological sites.

Learning Natural Resource Assessment Protocols: Elements for Success and Lessons From an International Workshop in Inner Mongolia, China DOI:10.2458/azu_rangelands_v32i3_Han

season grazing use of individual perennial grasses, such as bluebunch wheatgrass and black grama. We know those identifi ed limits have application to allotment and ranchscale management decisions for maintaining important forage species. Another example would be small-scale work on plant response to fi re. The nature of a fi re may change with scale, but the principles of plant response are consistent across scales. Those small-spatial-scale principles, in a sense, scale up quite effectively. However, there are also cases in which research is diffi cult to scale up. For example, we may know how individual plants respond to grazing, but animal preference and grazing distribution come in to play at larger scales to infl uence plant community response. We may manage to maintain individual species and still shift community structure. We believe this issue of scale deserves much more attention from researchers. There are reasons to be optimistic that we can overcome the obstacles to better integration of management and research. There have been and continue to be plenty of success stories. Some of the newer tools have helped us all gain a better appreciation and description of scale issues (global positioning systems and geographic information systems for example) and our analysis capabilities will only continue to improve. We believe that some of the tools for research on a larger scale will open the door for further collaborations between managers and researchers. We hope that the discussion that follows will 1) point out some of the limitations of traditional fi eld-based research and 2) provide suggestions for some of the approaches that might help us move forward.

Vegetation features radiating from residential areas in response to livestock grazing were quantified for an arid steppe rangeland in the Keshiketeng Banner, Chifeng Prefecture, in northeastern Inner Mongolia in 2004 and 2006. The aim of this study was to estimate grazing impacts on the vegetation dynamics of these historical grazed ecosystems. Grazing intensities were classified as reference area (RA), light (LG), moderate (MG), and heavy (HG) according to the vegetation utilization across the study area. Rangelands were studied along a grazing gradient, where characteristics of plant communities, heights of dominant species, aboveground vertical structures, and belowground biomass were investigated. Along this grazing gradient, vegetation changed from the original dominant plant species Leymus chinensis (Trin.) Tzvel. to a semi-subshrub species Artemisia frigida Willd. when moving from the reference area (RA) to the region around the settlement. Canopy coverage, aboveground productivity, and the number of perennial species declined as one moved toward the residential area. Heights of five dominant species, except for Stipa grandis P. Smirn., declined with increased grazing intensity. Aboveground vertical structure in the RA treatment showed more resilience than the other treatments. There was no difference in root biomass in the top 1 m of soil (P > 0.05) between the RA treatment and the area immediately around settlement (HG treatment). Generally, we found that the intensity of grazing disturbance did not exceed the tolerance of the rangeland ecosystem within LG treatment. However, vegetative conditions in HG treatment became worse with increased grazing pressure. Rangelands in this arid steppe are under tremendous threat due to excessive forage utilization, which cannot be considered a sustainable practice.

Although water-harvesting techniques have been used effectively in irrigated agriculture and domestic water supplies, there seems to have been little continued exploitation of the same techniques in arid and semiarid rangeland water conservation. A review of the history of rangeland water harvesting allows identification of the methods that have been useful in the past and that would likely be effective in the future. It seems that relatively simple water-harvesting approaches work best on rangelands, particularly waterponding dikes to stimulate vegetation growth. Experience from rangeland water harvesting in New Mexico and other locations in the Southwest indicates that the approach is a long-term solution that produces significant vegetation growth, but generally only 10–15 years after installation because of the sporadic and spatially distributed nature of the summer monsoon rainfall. Additionally, the use of water-ponding dikes seems to most reliably produce an “island” of enhanced soil moisture and increased habitat cover and forage. Water-ponding dikes are easy and relatively inexpensive to construct and produce a pattern of vegetation similar to naturally occurring banded vegetation. Even very shallow dikes (7.5 cm) have been shown to produce a significant vegetation response. As climate changes our water supplies, historical techniques of water harvesting used for over 9,000 years are viable rangeland water conservation alternatives now and in the future for adapting to such changes. Environmental Practice 11:84–94 (2009)

It was as if someone else had said the words that had come out of my mouth. There must have been some other idiot, unseen, speaking. I had been only 20 min into an early weekend morning bicycle ride out of town, climbing up away from the river and northeast across the desert piedmont toward the mountains. The driver of an older model sports utility vehicle (SUV) had nearly hit me; he not only failed to change lanes to pass me, a viable option given there was no other traffic on the road, but hadn't even made any effort to at least provide me a little room. These kinds of incidences have become increasingly common as this city has grown tremendously at a steady and incessant rate. Lately, I have taken to racing after the offending driver to try to register objection, only to rapidly lose contact; how ever, that didn't happen on this day. The driver had stopped ahead at a red traffic light, and, winded but determined, I rode up on his right and found the passenger side window slightly and conveniently lowered. Leaning in, I managed to inform him he had nearly hit me and needed to obey the law providing cyclists the right of way. Or, maybe it was a few other words to that effect. Without drawing this out, I will simply recount that the irrational intensity of the dis cussion escalated. Eventually, he resorted to a common hand gesture informing me I was number one, and I abandoned 22 yr of public and private education to employ colloquial isms common from my Irish/Norwegian/Catholic youth, or maybe just the Irish side of that heritage. In the end, I heard myself telling him that he should get out of his car. It was then that I wondered who had actually made this remark, and finally, acknowledging that it was me, thought that was a really idiotic suggestion. Yes, a beautiful fall morning was ei g rapidly spoiled by two idiots at an intersection. My size, at n arly 6 feet 5 inches and 230 pounds (but pretty harmless in truth), the now-green traffic light, or the absur dity of it all caused him to drive on. With a sense of relief, I tur d to the driver of the lone vehicle who had pulled up at the red light behind the SUV during this encounter, smiled, s rugged my shoulders, and said "Sorry." Not sur prisingly, he chose to stay at that green light until I had ridden on. I cycled toward the mountains, again reminded h t the town I first moved to in 1975, and returned to in 1988, had crossed a threshold into being a big city and that I need d to seriously rethink the acceptable limits of my behavio s in this changed environment. Since the 1950s the population of the western United States has grown by more than 46 million people, and is projected to gr w by an additional 20 million or so by 2025. The increased stress on the region's natural resources, especially water (for recent descriptions of this stress see http://www.npr.org/programs/atc/features/2003/aug/ water/ or ht p://www.nytimes.com/2007/10/21/magazine/ 21water-t.html?_r=l&oref=slogin), and the resulting impacts on these l ndscap s and its species are well recognized. H wever, the extent to which this population increase has driven a transition of these regional rangelands from the classic provisioning of food and fiber from livestock grazing to a much more diverse nonagricultural set of goods and services is often not so readily grasped. The extent of this

Interpretation of assessment and monitoring data requires information about how reference conditions and ecological resilience vary in space and time. Reference conditions used as benchmarks are often specified via potential-based land classifications (e.g., ecological sites) that describe the plant communities potentially observed in an area based on soil and climate. State-and-transition models (STMs) coupled to ecological sites specify indicators of ecological resilience and thresholds. Although general concepts surrounding STMs and ecological sites have received increasing attention, strategies to apply and quantify these concepts have not. In this paper, we outline concepts and a practical approach to potential-based land classification and STM development. Quantification emphasizes inventory techniques readily available to natural resource professionals that reveal processes interacting across spatial scales. We recommend a sequence of eight steps for the co-development of ecological sites and STMs, including 1) creation of initial concepts based on literature and workshops; 2) extensive, low-intensity traverses to refine initial concepts and to plan inventory; 3) development of a spatial hierarchy for sampling based on climate, geomorphology, and soils; 4) stratified medium-intensity inventory of plant communities and soils across a broad extent and with large sample sizes; 5) storage of plant and soil data in a single database; 6) model-building and analysis of inventory data to test initial concepts; 7) support and/or refinement of concepts; and 8) high-intensity characterization and monitoring of states. We offer a simple example of how data assembled via our sequence are used to refine ecological site classes and STMs. The linkage of inventory to expert knowledge and site-based mechanistic experiments and monitoring provides a powerful means for specifying management hypotheses and, ultimately, promoting resilience in grassland, shrubland, savanna, and forest ecosystems.

forage production as a primary objective. In this article, we 1) briefl y review the current status of Mongolian rangelands, 2) discuss the relationship between rangeland health and sustainability, and 3) propose a management framework that uses existing rangeland evaluation protocols to identify early-warning signs of degradation. We believe that the issues associated with adapting the rangeland health concept with other rangeland evaluation and assessment tools for Mongolia are common to many parts of the world, including the United States.

Vascular plants have been considered as autonomous organisms especially when their performance has been interpreted at the genome and cellular level. In reality, vascular plants provide a unique ecological niche for diverse communities of cryptic symbi‑ otic microbes which often contribute multiple benefits, such as enhanced photosynthetic efficiency, nutrient and water use and tolerance to abiotic and biotic stress. These benefits are similar to improvements sought by plant scientists working to develop ecologically sustainable crops for food, fiber and biofuels. Native desert plants include a community of indigenous endosymbiotic fungi that are structural components with cells, tissues, cell cultures and regenerated plants. These fungi regulate plant growth and development and contribute genes and natural products that enable plants to adapt to changing environments. A method developed for transferring these endophytes from cell cultures to non‑host plants promises to be a revolutionary approach for the development of novel plant germplasm and has application in the field of plant biotechnology.

The over 300 million ha of public and private rangelands in the United States are characterized by low and variable precipitation, nutrient-poor soils, and high spatial and temporal variability in plant production. This land type has provided a variety of goods and services, with the provisioning of food and fiber dominating through much of the 20th century. More recently, food production from a rangeland-based livestock industry is often pressured for a variety of reasons, including poor economic returns, increased regulations, an aging rural population, and increasingly diverse interests of land owners. A shift to other provisioning, regulating, cultural, and supporting services is occurring with important implications for carbon sequestration, biodiversity, and conservation incentives. There are numerous goods and services possible from rangelands that can supply societal demands such as clean water and a safe food supply. The use of ecologically-based principles of land management remains at the core of the ability of private land owners and public land managers to provide these existing and emerging services. We suggest that expectations need to be based on a thorough understanding of the diverse potentials of these lands and their inherent limits. A critical provisioning service to rangelands will be management practices that either maintain ecological functions or that restore functions to systems that have been substantially degraded over past decades. With proper incentives and economic benefits, rangelands, in the U.S. or globally, can be expected to provide these historical and more unique goods and services in a sustainable fashion, albeit in different proportions than in the past.

This paper addresses the assumed autonomy of vascular plants by revealing the presence of an obligate fungus structurally integrated with leaf anatomy of C4 grasses. We examined leaf surfaces of 26 species representing 14 genera of C4 grasses. In all species, we found similarities between leaf surface microhair-like structures and Uredomycete teliospores. These bicellular structures produced hyphae and spores, confirming they were fungal, rather than plant tissue. The plant-fungus structural morphology was also observed in Bouteloua eriopoda plants regenerated from embryonic meristem cells. The conserved symbiosis between fungi and C4 grasses suggests a lichenous association with evolutionary significance. The structural integration of endosymbiotic fungi with cells and tissues offers novel and unexplored approaches to developing physiological, ecological, and systematic models of C4 grasses.

This report is a joint effort of the Southwest Regional Climate Hub and the California Subsidiary Hub (Sub Hub). The Southwest Regional Climate Hub covers Arizona, California, Hawai‘i and the U.S. affiliated Pacific Islands, Nevada, New Mexico, and Utah and contains vast areas of western rangeland, forests, and high-value specialty crops (Figure 1). The California Sub Hub works with the issues of climate change effects on forests and agriculture in California, including internationally important specialty crops. The southwestern region contains high climatic diversity, with locations that claim the highest and lowest amounts of annual precipitation, and the highest and lowest elevations in the 48 contiguous states. Within the region, producers cope with severe drought effects on crop and animal systems, catastrophic wildfires, insect outbreaks, and sea level rise. The Southwest States grow diverse agricultural crops, including cotton, lettuce, tree fruit, cantaloupes, grapes, onions, macadamia nuts, coffee, and pecans. The region relies on irrigation more heavily than any other region in the United States. Water supplies, primarily from winter snowfall in the Sierra Nevada and Rocky Mountains, are critical to meeting irrigation needs in the Southwest. Total farm income for the region exceeded $56 billion in 2012, $45 billion of which was produced in California. Livestock account for approximately one-third of the agricultural profits in these six States.

Factors with variation at broad (e.g., climate) and fine scales (e.g., soil texture) that influence local processes at the plant scale (e.g., competition) have often been used to infer controls on spatial patterns and temporal trends in vegetation. However, these factors can be insufficient to explain spatial and temporal variation in grass cover for arid and semiarid grasslands during an extreme drought that promotes woody plant encroachment. Transport of materials among patches may also be important to this variation. We used long-term cover data (1915–2001) combined with recently collected field data and spatial databases from a site in the northern Chihuahuan Desert to assess temporal trends in cover and the relative importance of factors at three scales (plant, patch, landscape unit) in explaining spatial variation in grass cover. We examined cover of five important grass species from two topographic positions before, during, and after the extreme drought of the 1950s. Our results show that dynamics before, during, and after the drought varied by species rather than by topographic position. Different factors were related to cover of each species in each time period. Factors at the landscape unit scale (rainfall, stocking rate) were related to grass cover in the pre- and post-drought periods whereas only the plant-scale factor of soil texture was significantly related to cover of two upland species during the drought. Patch-scale factors associated with the redistribution of water (microtopography) were important for different species in the pre- and post-drought period. Another patch-scale factor, distance from historic shrub populations, was important to the persistence of the dominant grass in uplands (Bouteloua eriopoda) through time. Our results suggest the importance of local processes during the drought, and transport processes before and after the drought with different relationships for different species. Disentangling the relative importance of factors at different spatial scales to spatial patterns and long-term trends in grass cover can provide new insights into the key processes driving these historic patterns, and can be used to improve forecasts of vegetation change in arid and semiarid areas.

Selected essays on science, rangelands, and roles of the Society for Range Management, Volume II. DOI:10.2458/azu_rangelands_v28i4_havstad

Around the world rangelands that have been degraded, such as historical desert grasslands now dominated by woody shrubs, are resistant to restoration efforts. The goal of this descriptive research was to examine the potential for black grama (Bouteloua eriopoda [Torr.] Torr.) recovery by remnant plants in a degraded area as a function of plant location across a landscape. Our objectives were 1) to document the historical dominant vegetation as a perennial grassland and determine broad-scale changes in dominance through time and 2) to examine fine-scale patterns of black grama presence and basal area with respect to microenvironmental conditions that indicate the landscape positions favorable for restoration. Historical vegetation maps starting in 1858, a field survey in 2002-2003 of the location of all individual black grama plants in a 29-ha area, and spatial data layers in a geographic information system were used to address these objectives. Upland grasses, including black grama, dominated the study site in 1858, although tarbush (Flourensia cernua DC.) was the dominant species by 1915, and creosotebush (Larrea tridentata [DC.] Cov.) is the current dominant. A total of 3 334 black grama plants were found for an average density of 0.01 plants m-2. High spatial variation was found in the occurrence and basal area of black grama plants that was related to water availability rather than livestock grazing: most plants were found in or adjacent to an arroyo (67%), at a northern aspect (47%), and outside experimental exclosures established in 1930 (43%). Largest average basal areas were found in the livestock exclosure, and in general, average basal area was not related with aspect or canopy microsite. These remnant plants can be used as propagule sources in restoration efforts, and information on microsite conditions for black grama survival can be used to improve restoration potential for similar sites.

We discuss a new conceptual framework for arid and semi-arid systems that accounts for nonlinear dynamics and cross scale interactions in explaining landscape patterns and dynamics. Our framework includes a spatial and temporal hierarchy, and five key interacting components that connect scales of the hierarchy and generate threshold behaviors: (1) historical legacies that include climate, disturbance, and management regimes, (2) dynamic template of patterns in ecological variables and spatial context, (3) vertical and horizontal transport processes (fluvial, aeolian, animal), (4) rate, direction, and amount of resource redistribution between high and low resource areas, and (5) feedbacks among plants, animals, and soils. We illustrate how this framework can be used to understand, forecast, and manage ecological systems that exhibit nonlinear dynamics across a range of spatial and temporal scales. This paper provides the foundation for a series of papers from the Jornada Experimental Range ARS-LTER research site in southern New Mexico, USA that support this new conceptual framework.

Soil properties are well known to affect vegetation, but the role of soil heterogeneity in the patterning of vegetation dynamics is poorly documented. We asked whether the location of an ecotone separating grass-dominated and sparsely vegetated areas reflected only historical variation in degradation or was related to variation in inherent soil properties. We then asked whether changes in the cover and spatial organization of vegetated and bare patches assessed using repeat aerial photography reflected self-organizing dynamics unrelated to soil variation or the stable patterning of soil variation. We found that the present-day ecotone was related to a shift from more weakly to more strongly developed soils. Parts of the ecotone were stable over a 60-year period, but shifts between bare and vegetated states, as well as persistently vegetated and bare states, occurred largely in small (

Measurements of vegetation and soil dynamics used to anticipate (or reverse) catastrophic transitions in arid and semi-arid rangelands are often difficult to interpret. This situation is due, in part, to a lack of empirically based conceptual models that incorporate the effects of multiple processes, scale, spatio-temporal pattern, and soils. Using observations of multi-temporal data from the Chihuahuan Desert, we describe a new approach to classifying vegetation dynamics based on multiple scales of vegetation and soil pattern as well as cross-scale interactions. We propose the existence of six types of mechanisms driving vegetation change including (1) stability, (2) size oscillation of plants, (3) loss and reestablishment of plants within functional groups, (4) loss of one plant functional group and replacement by another, (5) spatial reorganization of vegetation patches, and (6) cascading transitions that spread from small to broad scales. We provide evidence for the existence of these mechanisms, the species involved, and the geomorphic components on which they are observed in the Chihuahuan Desert. These mechanisms highlight the kinds of multi-scale observations that are needed to detect or interpret change and emphasize the importance of soil surface properties for interpreting vegetation change. The classification is potentially general across arid and semi-arid ecosystems and links spatial and temporal patterns in vegetation with ecological and geomorphic processes, monitoring, and restoration strategies.

Selected essays on science, rangelands, and roles of the society for range management. DOI:10.2458/azu_rangelands_v27i6_havstad

Notes made by land surveyors in 1858 were utilized to estimate cover of grasses and shrubs on the Jornada Experimental Range (JER) and the Chihuahuan Desert Range Research Center (CDRRC) in the northern Chihuahuan Desert in southern New Mexico, USA. Portions of these areas have been previously assessed for historical vegetation dynamics but the entire 84,271 ha assessed in the 19th century has not been examined in total. In 1858, fair to very good grass cover occurred on 98% and 67% of the JER and CDRRC, respectively. Shrubs were present throughout both properties but 45% of the JER and 18% of the CDRRC were shrub free. Reconnaissance surveys, made to determine carrying capacity for livestock were made in 1915–1916 and 1928–1929 on the JER and in 1938 on the CDRRC, show that shrubs had made large increases in area occupied at the time of the surveys. Vegetation type maps were made of both properties in 1998. Mesquite ( Prosopis glandulosa ) was the primary dominant on 59% of the JER in 1998 and creosotebush ( Larrea tridentata ) was the primary dominant on 27% of the area. On the CDRRC mesquite and creosotebush were primary dominants on 37% and 46% of the area, respectively. Grass cover has decreased greatly with the increase in shrubs and only shrub control efforts have maintained the once abundant black grama ( Bouteloua eriopoda ) as a primary dominant on 1% or less of the area on both properties.

Lambs were subjected to odors of two monoterpenes (camphor and α-pinene) that decreased intake in a previous study to determine if exposure during feeding modified their effects on subsequent intake. In two experiments, 36 ewe lambs were group-fed alfalfa pellets in enclosed portable buildings each morning for 56 d (phase 1). Camphor (25 g, Experiment 1) or α-pinene (50 ml, Experiment 2) was placed in feeders in a mesh-covered container immediately before feeding. In phase 2, lambs were individually fed alfalfa pellets for 20 min each morning for 10 d (5-d adaptation, 5-d collection). Treatments were sprayed on alfalfa pellets at levels representing the concentration of that chemical in tarbush (Flourensia cernua) or at 10-fold that concentration. No day by treatment interactions were detected for intake during adaptation or collection periods for either chemical (P > 0.05); therefore, data were pooled across day. Exposure to the volatile aroma for 56 d had no effect on intake during the subsequent 10-d interval for either monoterpene (P > 0.05). Moreover, intake during the collection period was not affected by treatment concentration (P > 0.05). Neither concentration of the terpene applied to alfalfa pellets nor previous exposure to the volatile aroma of camphor or α-pinene altered feed intake under the conditions of this study.

We measured CO2 and evapotranspiration (ET) fluxes above a Chihuahuan desert grassland from 1996 through 2001. Averaged across six years, this ecosystem was a source (positive flux) of CO2 in every month. Over that period, sustained periods of carbon uptake (negative flux) were rare. Averaged across all months, we estimated that CO2 was being released into the atmosphere at a rate of +1.5 g CO2 m−2 d−1 (+0.40 g C m−2 d−1) or +533 g CO2 m−2 yr−1 (+145.3 g C m−2 yr−1). Average ET was 299 mm yr−1 with a monthly range of 0.15 mm d−1 in December to 2.15 mm d−1 in August.

The objective of this paper is to provide insights into exotic and native invasive species dynamics using a conceptual model developed from the long history of research on native woody plant invasion into perennial grasslands in the southwestern United States. We first describe our new conceptual model that focuses on landscape characteristics (spatial configuration and connectivity) interacting with environmental drivers and biotic processes across multiple scales. We then provide support for the model using a long-term data set from southern New Mexico. Our results show that both local and spatially contagious processes can be important in generating temporal and spatial variation in native grass cover. Upland grass basal cover was related to both local (soil texture, precipitation, grazing by cattle) and spatial processes (shrub seed dispersal). Lowland grass basal cover was related to local processes associated with plant available water as well as grazing by cattle. We discuss new insights t...

Catastrophic events share characteristic nonlinear behaviors that are often generated by cross-scale interactions and feedbacks among system elements. These events result in surprises that cannot easily be predicted based on information obtained at a single scale. Progress on catastrophic events has focused on one of the following two areas: nonlinear dynamics through time without an explicit consideration of spatial connectivity [Holling, C. S. (1992) Ecol. Monogr. 62, 447–502] or spatial connectivity and the spread of contagious processes without a consideration of cross-scale interactions and feedbacks [Zeng, N., Neeling, J. D., Lau, L. M. & Tucker, C. J. (1999) Science 286, 1537–1540]. These approaches rarely have ventured beyond traditional disciplinary boundaries. We provide an interdisciplinary, conceptual, and general mathematical framework for understanding and forecasting nonlinear dynamics through time and across space. We illustrate the generality and usefulness of our approach by using new data and recasting published data from ecology (wildfires and desertification), epidemiology (infectious diseases), and engineering (structural failures). We show that decisions that minimize the likelihood of catastrophic events must be based on cross-scale interactions, and such decisions will often be counterintuitive. Given the continuing challenges associated with global change, approaches that cross disciplinary boundaries to include interactions and feedbacks at multiple scales are needed to increase our ability to predict catastrophic events and develop strategies for minimizing their occurrence and impacts. Our framework is an important step in developing predictive tools and designing experiments to examine cross-scale interactions.

Agents that can cause important changes in properties of biological communities are referred to as drivers. Drivers may be classed as physical, social and economic/policy, referring to their origin and mode of action. Physical drivers include environmental (weather, climate) and management (livestock grazing, prescribed burning) factors. Social drivers include attitudes and values of land mangers and the public. Economic/policy drivers refer to factors such as tax laws and environmental policies (including penalties and incentives). These drivers seldom operate independently, at similar scales, or in isolation from other drivers, and subtle interactions may confound both interpretation and response. While it is difficult to identify the impact of a specific driver on a specific biological property at a specific time, it is important to monitor changes in drivers to both predict likely impacts on ecological systems and design effective response tactics and strategies. Risk assessments, adaptive management analyses, or management by hypothesis require understanding linkages between environmental drivers and various management options on ecological properties of managed systems. Though our abilities to generate accurate predictions are currently limited, conceptual models of system response to drivers are improving. Continued incorporation and refinement of understanding and monitoring effects and interactions of different drivers will contribute to improvements in these predictive capacities. It is important to remember we are developing monitoring systems for the future, as well as for today. Keywords: adaptive management, environmental, long-term monitoring, risk assessment African Journal of Range & Forage Science 2004, 21(2): 115–121

Shrub encroachment into arid and semi-arid grasslands in the southwestern United States is of concern because increased shrub cover leads to declines in species diversity, water availability, grazing capacity, and soil organic matter. Although it is well known that shrubs have increased over time, we have little quantitative information related to the non-linear nature of this vegetation change over a particular period. On the Jornada Experimental Range (JER; USDA-ARS) and the adjacent Chihuahuan Desert Rangeland Research Center (CDRRC; New Mexico State University) in southern New Mexico, shrub increase has been measured with various ground survey techniques extending back to 1858. For this study, we used 11 aerial photos taken between 1937 and 1996 that covered a 150-ha study area and had sufficient resolution for shrub detection. A QuickBird satellite image provided coverage for 2003. We used image segmentation and object-based classification to monitor vegetation changes over time. Shrub cover increased from 0.9% in 1937 to 13.1% in 2003, while grass cover declined from 18.5% to 1.9%. Vegetation dynamics reflected changes in precipitation patterns, in particular, effects of the 1951–1956 drought. Accuracy assessment showed that shrub and grass cover was underestimated due to the constraint of the pixel size. About 87% of all shrubs N 2m 2 were detected. The use of object-based classification has advantages over pixel based classification for the extraction of shrubs from panchromatic aerial and high-resolution satellite imagery. Incorporating both spectral and spatial image information approximates the way humans interpret information visually from aerial photos, but has the benefit of an automated classification routine. Combining several scales of analysis in a hierarchical segmentation method is appropriate in an ecological sense and allows for determining shrub density in coarser level classes. Despite encountering difficulties in analyzing a greatly varying aerial photo data set, including variability in spectral and spatial resolutions, moisture conditions, time of year of observation, and appearance of grass cover, aerial photos provide an invaluable historic record for monitoring shrub encroachment into a desert grassland.

Encroachment of the shrub Prosopis glandulosa Torr. (honey mesquite) into semi-arid grasslands is a serious concern in the south-western United States, yet little is known about the long-term dynamics of the invasion process. We used ten high-resolution aerial and satellite images taken from 1936 to 1996 to track the population dynamics and spatial pattern of all P. glandulosa greater than 2 m in diameter on a 75 ha area in southern New Mexico. Shrub cover and patch numbers increased from 1936 to the 1970s, then stabilized at 43% cover and 83 patches ha−1. Individual patches were extremely persistent: 95% of the area occupied by shrub patches in 1936 was still occupied in 1996. Recruitment into the 2 m size class was more variable: 0·6–5·2% year−1 (mean 0·8% year−1). Patch-shape complexity increased from 1936 to 1983 as adjacent shrubs merged, and then declined as those clusters filled in and became rounder. Spatial pattern of shrubs showed a distinct trend over time: strongly clustered in 1936 at lag distances up to 250 m, then random arrangement at all scales, and by 1983 pattern was regular at lag distances greater than 100 m. There was no clear relationship with precipitation. The use of remote sensing imagery allowed us to examine one site over time, and revealed patterns in population dynamics and spatial pattern that would not have been visible otherwise. Comparison of field estimates collected in 2001 with 1996 image data suggest that the canopy cover estimates were accurate, but shrub densities were seriously underestimated in the satellite photographs, which do not show shrubs smaller than 2 m diameter. As long as limitations of the imagery are understood, these methods can be applied over a larger and more heterogeneous area to examine environmental correlates of invasion success.

This review addresses the challenges and progress in sensor development and radiometric correction for agricultural applications with particular emphasis on activities within the U.S. Department of Agriculture (USDA) Agricultural Research Service (ARS). Examples of sensor development include on-site development of sensors and platforms, participation in cooperative research and development agreements (CRADA) with commercial companies, and membership on NASA science teams. Examples of progress made in sensor radiometric correction suitable for agriculture are presented for both laboratory and field environments. The direction of future sensor development includes integrated sensors and systems, sensor standardization, and new sensor technologies measuring fluorescence and soil electrical conductivity, and utilizing Light Detection and Ranging (lidar), hyperspectral, and multiband thermal wavelengths. The upcoming challenges include definition of the core spectral regions for agriculture and the sensor specifications for a dedicated, orbiting agricultural sensor, determination of an operational approach for reflectance and temperature retrieval, and enhanced communication between image providers, research scientists, and users. This review concludes with a number of avenues through which USDA could promote sensor development and radiometric correction for agricultural applications. These include developing a network of large permanent calibration targets at USDA ARS locations; investing in new technologies ; pooling resources to support large-scale field experiments: determining ARS-wide standards for sensor development, calibration, and deployment; and funding interagency agreements to achieve common goals.

Aerial photographs are a type of remote sensing data that are especially valuable for rangeland applications. Advantages of these data include relative ease of interpretation and acquisition, affordability, high resolution (1–2 meters), and provision of a common reference for communication among those involved in rangeland management. Additionally, air photos are especially well suited for analysis of historical rangeland remediation treatments because acquisition of widespread aerial photographic coverage began during the 1930s. Several types of treatments can be easily identified and monitored over time, including contour terraces, brush water spreaders, rootplow seeding, water ponding dikes, shrub removal by grubbing, and grazing restrictions. The use of archived aerial photographs allows the opportunity to recreate the management history of rangeland, as well as to serve as a point of departure for involvement in more sophisticated satellite-based remote sensing systems.

The surface bidirectional reflectance distribution function (BRDF) contains valuable information on canopy physiognomy for desert grassland and grass–shrub transition communities. This information may be accessed by inverting a BRDF model against sets of observations, which encompass important variations in viewing and illumination angles. This paper shows that structural canopy attributes can be derived through inversion of the Simple Geometric Model (SGM) of the BRDF developed in this paper. It is difficult to sample BRDF features from the ground because of the discontinuous nature of the canopies and long intrinsic length scales in remotely sensed spectral measures (>10 m). A multispectral digital camera was therefore used to derive spatial multiangular reflectance data sets from the air and the SGM was validated against and inverted with these. It was also validated using 3-D radiosity simulations driven with maps of field-measured plant dimensions. The interpretation of the retrieved parameter maps (shrub density, shrub width and canopy height) reveals variations in canopy structure within desert grassland and grassland–shrubland transition communities, which are clearly related to structural and optical features in high resolution panchromatic and vegetation index images. To our knowledge, this paper reports on the first attempts to acquire structural canopy attributes of desert landscapes using multiple view angle data at scales less than 1 km. The results point to further opportunities to exploit multiangular data from spaceborne sensors such as the Multiangle Imaging SpectroRadiometer (MISR) and the Compact High Resolution Imaging Spectrometer (CHRIS) on the NASA Terra and European Space Agency's PROBA satellites, respectively.