Patrick Shaver

RECOMMENDATIONS FOR DEVELOPMENT OF RESILIENCE-BASED STATE-AND-TRANSITION MODELS

Abstract The objective of this paper is to recommend conceptual modifications for incorporation in state-and-transition models (STMs) to link this framework explicitly to the concept of ecological resilience. Ecological resilience describes the amount of change or disruption that is required to transform a system from being maintained by one set of mutually reinforcing processes and structures to a different set of processes and structures (e.g., an alternative stable state). In light of this concept, effective ecosystem management must focus on the adoption of management practices and policies that maintain or enhance ecological resilience to prevent stable states from exceeding thresholds. Resilience management does not exclusively focus on identifying thresholds per se, but rather on within-state dynamics that influence state vulnerability or proximity to thresholds. Resilience-based ecosystem management provides greater opportunities to incorporate adaptive management than does threshold-based management because thresholds emphasize limits of state resilience, rather than conditions that determine the probability that these limits will be surpassed. In an effort to further promote resilience-based management, we recommend that the STM framework explicitly describe triggers, at-risk communities, feedback mechanisms, and restoration pathways and develop process-specific indicators that enable managers to identify at-risk plant communities and potential restoration pathways. Two STMs representing different ecological conditions and geographic locations are presented to illustrate the incorporation and application of these recommendations. We anticipate that these recommendations will enable STMs to capture additional ecological information and contribute to improved ecosystem management by focusing attention on the maintenance of state resilience in addition to the anticipation of thresholds. Adoption of these recommendations may promote valuable dialogue between researchers and ecosystem managers regarding the general nature of ecosystem dynamics.

State-and-Transition Models for Heterogeneous Landscapes: A Strategy for Development and Application

Abstract 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.

National ecosystem assessments supported by scientific and local knowledge

An understanding of the extent of land degradation and recovery is necessary to guide land-use policy and management, yet currently available land-quality assessments are widely known to be inadequate. Here, we present the results of the first statistically based application of a new approach to national assessments that integrates scientific and local knowledge. Qualitative observations completed at over 10 000 plots in the United States showed that while soil degradation remains an issue, loss of biotic integrity is more widespread. Quantitative soil and vegetation data collected at the same locations support the assessments and serve as a baseline for monitoring the effectiveness of policy and management initiatives, including responses to climate change. These results provide the information necessary to support strategic decisions by land managers and policy makers.

Revolutionary land use change in the 21st century: is (Rangeland) science relevant?

Abstract Rapidly increasing demand for food, fiber, and fuel together with new technologies and the mobility of global capital are driving revolutionary changes in land use throughout the world. Efforts to increase land productivity include conversion of millions of hectares of rangelands to crop production, including many marginal lands with low resistance and resilience to degradation. Sustaining the productivity of these lands requires careful land use planning and innovative management systems. Historically, this responsibility has been left to agronomists and others with expertise in crop production. In this article, we argue that the revolutionary land use changes necessary to support national and global food security potentially make rangeland science more relevant now than ever. Maintaining and increasing relevance will require a revolutionary change in range science from a discipline that focuses on a particular land use or land cover to one that addresses the challenge of managing all lands that, at one time, were considered to be marginal for crop production. We propose four strategies to increase the relevance of rangeland science to global land management: 1) expand our awareness and understanding of local to global economic, social, and technological trends in order to anticipate and identify drivers and patterns of conversion; 2) emphasize empirical studies and modeling that anticipate the biophysical (ecosystem services) and societal consequences of large-scale changes in land cover and use; 3) significantly increase communication and collaboration with the disciplines and sectors of society currently responsible for managing the new land uses; and 4) develop and adopt a dynamic and flexible resilience-based land classification system and data-supported conceptual models (e.g., state-and-transition models) that represent all lands, regardless of use and the consequences of land conversion to various uses instead of changes in state or condition that are focused on a single land use. Resumen La creciente demanda de alimentos, fibras y combustibles de manera simultánea con las nuevas tecnologías y la movilidad global del capital están ocasionando cambios revolucionados en el uso de la tierra en todo el mundo. Los esfuerzos para incrementar la productividad de la tierra incluyen la conversión de millones de hectáreas de pastizales a la producción de granos, incluyendo tierras marginales con bajo resistencia y resilencia a la degradación. Sostener la productividad de estas tierras requiere planeación cuidadosa del uso de la tierra y sistemas de manejo innovadores. Históricamente, esta responsabilidad se ha dejado a agrónomos y otros expertos en producción de granos. En este articulo, discutimos que los revolucionados cambios en uso de la tierra necesarios para sostener la seguridad alimentaria nacional y mundial potencialmente hacen a la ciencia del pastizal más relevante ahora que nunca. Mantener e incrementar esa relevancia requerirá de cambios revolucionarios en la ciencia del pastizal de una disciplina que se enfoca en un uso particular de la tierra o cubierta vegetal a una que considere el reto de manejar todas las tierras que en algún tiempo fueron consideradas marginales para la producción de granos. Proponemos cuatro estrategias para aumentar la relevancia de la ciencia del pastizal a un manejo global de la tierra: 1) extender nuestra conocimiento y concientización del ámbito local a tendencias globales económicas, sociales y tecnológicas con el fin de anticipar e identificar conductores y patrones de conversión, 2) enfatizar en estudios empíricos y modelaje que anticipe las consecuencias biofísicas (servicios de los ecosistemas) y sociales de cambios en la cobertura y uso de la tierra en gran escala, 3) aumentar significativamente la comunicación y colaboración con las disciplinas y sectores de la sociedad actualmente responsables en el manejo del nuevo uso de la tierra, y 4) desarrollar y adoptar un sistema de clasificación dinámica y flexible basado en la resilencia de la tierra y modelos conceptuales apoyados en datos (ejm. Modelos de Estado y Transición) que representan todas las tierras, independientemente del uso y las consecuencias en la conversión de tierras para varios usos el lugar de cambios en el estado y condición que se enfocan en un solo uso de la tierra.

State and Transition Models: Theory, Applications, and Challenges

State and transition models (STMs) are used to organize and communicate information regarding ecosystem change, especially the implications for management. The fundamental premise that rangelands can exhibit multiple states is now widely accepted and has deeply pervaded management thinking, even in the absence of formal STM development. The current application of STMs for management, however, has been limited by both the science and the ability of institutions to develop and use STMs. In this chapter, we provide a comprehensive and contemporary overview of STM concepts and applications at a global level. We first review the ecological concepts underlying STMs with the goal of bridging STMs to recent theoretical developments in ecology. We then provide a synthesis of the history of STM development and current applications in rangelands of Australia, Argentina, the United States, and Mongolia, exploring why STMs have been limited in their application for management. Challenges in expanding the use of STMs for management are addressed and recent advances that may improve STMs, including participatory approaches in model development, the use of STMs within a structured decision-making process, and mapping of ecological states, are described. We conclude with a summary of actions that could increase the utility of STMs for collaborative adaptive management in the face of global change.

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

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