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 human – 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 produce 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, while dominant species are much more resistant.
Only two instances were identified in these records that are 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 in climate that 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 involves large geographic variability in response to unique ambient climatic conditions and the disproportionate regional impacts of climate drivers. Sensitivity represents the impacts of the projected exposures on ecological and social systems, especially those components and interactions affecting human livelihoods. Adaptive capacity describes the successes and failures of previous and current adaptions to climatic variability, as well as, barriers and incentives for future adaption. Vulnerability assessment is 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 these 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 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 to promote effective climate-change adaptation.
Co-Produced Knowledge to Guide Management and Policy
Applied ecological disciplines are attempting to reconcile discrepancies between management (local) and scientific knowledge regarding natural resource management. 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 creation that is more inclusive of diverse stakeholder participation. A limited understanding of the contribution of adaptive management with varying management intensities represents a major omission and source of confusion. An adaptive management framework that explicitly supports development of co-produced knowledge among managers, researchers, and policy makers is required to develop effective site-specific management and policy recommendations. A vision of collective ownership for natural resource challenges among academic, land management, and policy making institutions is necessary to promote greater development of management and policy–relevant science.
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. This indicates that major barriers currently separate these two knowledge sources.
An additional knowledge source termed 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. are symptomatic of a narrow management framework that does not possess the capacity to effectively address varied knowledge sources and values in human dominated systems.
A procedure has not yet been developed to effectively blend management and scientific knowledge sources to synergistically enhance their value without compromising the integrity of either source. Knowledge co-production within manager – agency personnel – scientist partnerships is currently viewed as the most effective means to produce greater management and policy relevant science.