The world's rangelands and drylands are undergoing rapid change, and consequently are becoming more difficult to manage. Big data and digital technologies (digital tools) provide land managers with a ...means to understand and adaptively manage change. An assortment of tools—including standardized field ecosystem monitoring databases; web‐accessible maps of vegetation change, production forecasts, and climate risk; sensor networks and virtual fencing; mobile applications to collect and access a variety of data; and new models, interpretive tools, and tool libraries—together provide unprecedented opportunities to detect and direct rangeland change. Accessibility to and manager trust in and knowledge of these tools, however, have failed to keep pace with technological advances. Collaborative adaptive management that involves multiple stakeholders and scientists who learn from management actions is ideally suited to capitalize on an integrated suite of digital tools. Embedding science professionals and experienced technology users in social networks can enhance peer‐to‐peer learning about digital tools and fulfill their considerable promise.
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 crossscale 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.
Arid and semiarid regions cover more than 40% of Earth's land surface. Desertification, or broadscale land degradation in drylands, is a major environmental hazard facing inhabitants of the world's ...deserts as well as an important component of global change. There is no unifying framework that simply and effectively explains different forms of desertification. In this article, we argue for the unifying concept that diverse forms of desertification, and its remediation, are driven by changes in the length of connected pathways for the movement of fire, water, and soil resources. Biophysical feedbacks increase the length of connected pathways, explaining the persistence of desertified landscapes around the globe. Management of connectivity in the context of environmental and socioeconomic change is essential to understanding, and potentially reversing, the harmful effects of desertification.
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.
Drylands worldwide are experiencing shrub encroachment into grasslands with potential consequences for biodiversity and ecosystem services. Climate change could increase the rate of shrub ...encroachment, amplify precipitation variability, and thus alter bottom‐up processes for animal communities. Desert rodents are important biodiversity elements of arid grasslands and shrublands that exert strong effects on soil, vegetation, and other animal species. We used long‐term data from the Jornada Basin Long Term Ecological Research site in the Chihuahuan Desert of southern New Mexico to ask whether bottom‐up control of desert rodents changes across shrub encroachment gradients. Our design included spatial blocks with replicated ecological states representing transitions from black grama (Bouteloua eriopoda) to honey mesquite (Prosopis glandulosa). Grassland‐to‐shrubland transitions did not produce degraded ecosystems, on average, with reduced net primary production or decreased rodent biomass. However, more rodent biomass was supported on unencroached grasslands following droughts whose frequency and severity may increase in southwestern United States. Hence, the observed evenness in rodent biomass across ecological states should be sensitive to climate change. The best predictors of rodent biomass also differed markedly for two trophic groups. This outcome was explained by considering core‐transient dynamics. Granivores were mostly core species that regularly occurred on sites and responded to lagged net primary production at local scales, whereas folivores included transient species (especially Sigmodon hispidus) that responded to lagged precipitation at broader scales via spillover dynamics. Bottom‐up processes for desert rodents across shrub invasion gradients were understood by integrating lagged responses to productivity pulses with core‐transient structuring of communities.
Abstract
A primary challenge in advancing sustainability in rangelands and drylands is the lack of governance systems that are linked to information about highly variable ecosystem conditions. Here, ...we describe the national‐scale implementation of a resilience‐based management system in the rangelands of Mongolia. The system comprises several interacting elements. Land type‐specific information about rangeland conditions was captured in vegetation state‐and‐transition models (STMs) that allow interpretation of monitoring data and locally tailored restoration recommendations. Rangeland monitoring systems based on standardized protocols were developed and have been adopted by national government agencies, which provide annual, high‐quality data on rangeland conditions on which to base and adjust management decisions. Rangeland use agreements between local governments and herders' collective organizations, called Pasture Users' Groups, define their respective rights and responsibilities and introduce economic and policy incentives for management changes. Pasture Users' Groups also provide a platform for information sharing and collective action. Rangeland condition data and other indicators are linked to the Responsible Nomads product traceability system that provides consumers and industry a means to associate products with sustainable rangeland management practices. The collaboration between national agencies, international donors, scientists, and herders has been essential to initial success, but longer term support and monitoring will be needed to assess whether the adoption of resilience‐based management leads to positive social and ecological outcomes. We draw generalizations and lessons learned from this effort, which can lead to the successful implementation of new management systems across global rangelands.
Quantification of rates and patterns of community dynamics is central for understanding the organization and function of ecosystems. These insights may support a greater empirical understanding of ...ecological resilience, and the application of resilience concepts toward ecosystem management. Distinct types of dynamics in natural communities can be used to interpret and apply resilience concepts, but quantitative methods that can systematically distinguish among them are needed. We develop a quantitative method to analyze long-term records of plant community dynamics using principles of movement ecology. We analyzed dissimilarity of species composition through time with linear and nonlinear statistical models to assign community change to four classes of movement trajectories. Compositional change in each sampled plot through time was classified into four classes, stability, abrupt nonlinear change, transient reversible change, and gradual linear drift, each representing a different aspect of ecological resilience. These competing models were evaluated based on estimated coefficients, goodness of fit, and parsimony. We tested our method's accuracy and robustness through simulations, or the ability to distinguish among trajectories and classify them correctly. We simulated 16,000 trajectories of four types, of which 94–100% were correctly classified. Next, we analyzed 13 long-term vegetation records from North American grasslands (annual grasslands with warm-season and cool-season communities, shortgrass, mixedgrass, and tallgrass prairies, and sagebrush steppe), and a record of primary succession at Mt. St. Helens volcano. Collectively, we analyzed 14,647 observations from 775 plots, between 1915 and 2012. Dynamics could be reliably assigned for 705 plots (91%), and overall statistical fit was high (goodness of fit, 0.77 ± 0.15 SD). Among the perennial grasslands, stability was most common (44% of all plots), followed by gradual linear (22%), abrupt nonlinear (17%), and reversible (6%) change. Among annual grasslands, abrupt nonlinear shifts (33%) were more common in the warm-season community than in the cool-season (20%). As expected, abrupt nonlinear change was common during primary succession (51%) while reversible change was rare (3%). Generally, reversible dynamics often required 2–3 decades. Analysis of long-term community change, or trajectories, with principles of movement ecology provides a quantitative basis to compare and interpret ecological resilience within and among ecosystems.
The rangeland science profession in the United States has its roots in the widespread overgrazing and concurrent severe droughts of the late 19th century. These drivers contributed to rangeland ...resource degradation especially in the American Southwest—what E. O. Wooton (1908) called the “Range Problem.” Although logical for the time, the scientific activities and resulting policies that arose out of this catastrophe were based on reductionist experimentation and productionist emphases on food and fiber. After a century of science and policy, there are two additional perspectives that shape our vision for the emphases of the future. First, rangeland landscapes are extremely heterogeneous; general principles derived from scientific experimentation cannot be easily or generally applied without adjusting to the distinct societal and ecological characteristics of a location. Second, rangeland management occurs at spatial scales considerably larger than those that have typically been addressed in range science. Scaling up science results is not a simple, additive process. The leading features of the emerging science are 1) research at landscape scales and 2) over longer time spans that 3) approaches conservation and management practices as treatments requiring scientific evaluation, 4) incorporates local knowledge, 5) is explicitly applied in nature, and 6) is transparent in its practice. We strongly argue for a science that supports resource management by testing hypotheses relevant to actual conservation practices and iteratively applying its findings in partnership with managers in an ongoing, adaptive fashion.
La profesión de ciencia del pastizal en Estados Unidos tiene sus raíces en el sobrepastoreo y recurrentes y severas sequias a finales del siglo XIX. Estos factores contribuyeron a la degradación de los recursos del pastizal especialmente en el Suroeste de los Estados Unidos—a lo que E. O. Wooton (1908) llamo el “Problema del Pastizal.” Aunque por la lógica del tiempo, las actividades científicas y políticas resultantes que surgen de esta catástrofe fueron basadas en experimentación reduccionista y énfasis en producción de alimentos y fibras. Después de un siglo de ciencia y políticas hay dos perspectivas adicionales que dan forma a nuestra visión para enfatizar en el futuro. Primero, el paisaje del pastizal es extremadamente heterogéneo, principios generales de experimentación científica no pueden ser fácilmente o generalmente aplicados sin ajustes en las marcadas características sociales y ecológicas del lugar. Segundo, el manejo del pastizal ocurre a escalas espaciales considerablemente mayores a aquellas que normalmente se aplican en la ciencia del pastizal. Dimensionar los resultados de la ciencia no es un proceso sencillo y aditivo. Las características importantes de la ciencia emergente son 1) investigación a escala del paisaje y 2) sobre periodos largo de tiempo que 3) abarque practicas de conservación y manejo como tratamientos que requieren evaluación científica, 4) incorporar conocimiento local, 5) ser explicito aplicado a la naturaleza y 6) ser trasparente en su práctica. Argumentamos fuertemente por una ciencia que apoye el manejo de los recursos por medio de evaluar hipótesis relevantes a las prácticas de conservación actuales y que aplique sus resultados en sociedad con manejadores de manera adaptiva.
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