Resilience-based Ecosystem Management
Previous natural resource management strategies have attempted to sustainably maximize yield of one or a few ecosystems services by controlling system variability. These approaches are now recognized to have contributed to management failures by minimizing system resilience.
Resilience-based management provides alternative strategies to guide system change in a dynamic and uncertain future to provide ecosystem services and support human well-being. It focuses on drivers external to, and controlling variables within, rangeland systems – both ecological and social – to evaluate system proximity to thresholds of concern. This approach provides greater opportunities for adaptive management and learning by monitoring ecological indicators describing the direction and rate of change in system resilience. Recent work has focused on analysis of long-term (> 25 yrs) vegetation records throughout western North America. These analyses have producee metrics of frequency, magnitude of compositional change, and reversibility of community transitions to provide greater insight into both resilience theory and its application to ecosystem management. These results provide an empirical foundation to support the design and application of state-and-transition models.
What Has Been Learned?
The ability to distinguish among transient and permanent vegetation dynamics represents a major challenge to resilience application. Grassland records indicate the frequent occurrence, of often large, changes in species composition that are readily reversible. This suggests that rangeland systems may be more resilient that previously assumed.
Only two instances were identified in multiple records that were suggestive of thresholds conditions. Both occurred in response to external drivers that reduced the abundance of dominant species. In one case, the driver was a severe multi-year drought in a desert grassland and the other was the invasion of cheatgrass in sagebrush steppe.
Data indicate that dynamics of herbaceous species are characterized by large fluctuations of numerous subordinate species that are anchored by a small number of dominant species within few basins of attraction. Dominant species may represent an important controlling variable of rangeland systems and the proportion of dominant:subordinate species may provide an important ecological indicator of resilience.
Vulnerability and Adaptation to Climate Change
Recent climatic trends and projections indicate continued directional change and increasing variability will influence the delivery of ecosystem services on which humans depend. This unprecedented challenge requires a comprehensive assessment of the vulnerability of social-ecological systems, including exposure, sensitivity and adaptive capacity, to climate change. Exposure describes the combination of regionally specific climate change drivers that are anticipated to affect systems beyond those of ambient conditions. Sensitivity represents the impacts of the projected exposures on ecological and social systems, especially those components and interactions affecting human livelihoods. Adaptive capacity involves the ability of human actors to mobilize resources to anticipate and respond to perceived or current climate stressors. Although exposure and sensitivity to climate change drivers often receive greatest attention, adaptive capacity establishes the foundation upon which adaption strategies are conceptualized, implemented and evaluated. Vulnerability assessments are intended to enhance recognition and prioritize actions to contend with the emerging consequences of climate change by informing research agendas, promoting social learning networks, and alerting policy makers to viable adaptation strategies. Current work focuses on climate change adaption planning in the Great Plains of the U.S. and it is being conducted in collaboration with the U.S.D.A. Climate Hubs program.
What Has Been Learned?
Human livelihoods derived from rangelands are highly vulnerable to climate change because limited financial, natural resource, and social capital provide few options to diversity incomes beyond livestock grazing – resource dependency is very high in arid and semi-arid regions.
Climate change will produce both positive and negative consequences depending on geographic location. Adaptation will be required to capitalize on opportunities as well as to minimize adverse impacts.
The ability of managers to assess risk and prepare for climate change varies greatly and reflects a broad array of adaptive capacities. Adaptation planning must recognize and accommodate both the geographic specificity and varied adaptive capacity of managers and social organizations to promote effective climate-change adaptation.
Translation science originated within the medical profession as a systematic means to convert scientific knowledge into practical applications that enhance human health and well-being. It’s a means of producing ‘actionable science’ by demonstrating the utility, value, and means by which scientific knowledge can help to alleviate contemporary human concerns. When applied to natural resource management, translational science encounters a major step that does not occur in medicine – the conversion of an ecological perspective to a human perspective. This difference in perspective has produced discrepancies between management (local) and scientific knowledge in applied ecological disciplines. The intensive rotational grazing debate represents one such discrepancy in the rangeland profession. Research is being conducted to examine the limits of scientific knowledge; knowledge flows between science, management and policy; and a method for knowledge production that is more inclusive of diverse stakeholder participation. Translational science partnerships among managers, researchers, and policy makers may represent the most effective approach to develop effective, site-specific management and policy recommendations.
What Has Been Learned?
Management and scientific knowledge are both of vital importance to natural resource management, but they frequently operate in parallel, rather than in combination. The major barriers currently separating these two knowledge sources need to be identified and minimized to increase the efficacy of natural resource management.
Professional ecological knowledge (PEK) is founded upon codification of broad ecological principles, but not necessarily scientific evidence, to legitimize agency programs and support operational efficiency. Natural resource management agencies may use PEK, rather than local or scientific knowledge, to make management decisions.
The inability of the rangeland profession to resolve the intensive rotational grazing debate, shrub removal – water yield controversy, and the wild horse and burro dilemma on public lands in the western U.S. is symptomatic of a limited capacity to recognize, evaluate, and share knowledge among diverse stakeholder groups.