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A GIS/Simulation Framework for Assessing Change in Water Yield over Large Spatial Scales 总被引:1,自引:0,他引:1
Recent legislation to initiate vegetation management in the Central Sierra hydrologic region of California includes a focus
on corresponding changes in water yield. This served as the impetus for developing a combined geographic information system
(GIS) and simulation assessment framework. Using the existing vegetation density condition, together with proposed rules for
thinning to reduce fire risk, a set of simulation model inputs were generated for examining the impact of the thinning scenario
on water yield. The approach allows results to be expressed as the mean and standard deviation of change in water yield for
each 1-km2 map cell that is thinned. Values for groups of cells are aggregated for typical watershed units using area-weighted averaging.
Wet, dry, and average precipitation years were simulated over a large region. Where snow plays an important role in hydrologic
processes, the simulated change in water yield was less than 0.5% of expected annual runoff for a typical watershed. Such
small changes would be undetectable in the field using conventional stream flow analysis. These results suggest that use of
water yield increases to help justify forest-thinning activities or offset their cost will be difficult. 相似文献
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The management of endangered species under climate change is a challenging and often controversial task that incorporates input from a variety of different environmental, economic, social, and political interests. Yet many listing and recovery decisions for endangered species unfold on an ad hoc basis without reference to decision‐aiding approaches that can improve the quality of management choices. Unlike many treatments of this issue, which consider endangered species management a science‐based problem, we suggest that a clear decision‐making process is equally necessary. In the face of new threats due to climate change, managers’ choices about endangered species require closely linked analyses and deliberations that identify key objectives and develop measurable attributes, generate and compare management alternatives, estimate expected consequences and key sources of uncertainty, and clarify trade‐offs across different dimensions of value. Several recent cases of endangered species conservation decisions illustrate our proposed decision‐focused approach, including Gulf of Maine Atlantic salmon (Salmo salar) recovery framework development, Cultus Lake sockeye salmon (Oncorhynchus nerka) management, and Upper Columbia River white sturgeon (Acipenser transmontanus) recovery planning. Estructuración de Decisiones para Manejar Especies Amenazadas y en Peligro en un Clima Cambiante 相似文献
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ROBIN L. CHAZDON CARLOS A. PERES DAISY DENT DOUGLAS SHEIL ARIEL E. LUGO DAVID LAMB NIGEL E. STORK SCOTT E. MILLER 《Conservation biology》2009,23(6):1406-1417
Abstract: In the wake of widespread loss of old‐growth forests throughout the tropics, secondary forests will likely play a growing role in the conservation of forest biodiversity. We considered a complex hierarchy of factors that interact in space and time to determine the conservation potential of tropical secondary forests. Beyond the characteristics of local forest patches, spatial and temporal landscape dynamics influence the establishment, species composition, and persistence of secondary forests. Prospects for conservation of old‐growth species in secondary forests are maximized in regions where the ratio of secondary to old‐growth forest area is relatively low, older secondary forests have persisted, anthropogenic disturbance after abandonment is relatively low, seed‐dispersing fauna are present, and old‐growth forests are close to abandoned sites. The conservation value of a secondary forest is expected to increase over time, as species arriving from remaining old‐growth forest patches accumulate. Many studies are poorly replicated, which limits robust assessments of the number and abundance of old‐growth species present in secondary forests. Older secondary forests are not often studied and few long‐term studies are conducted in secondary forests. Available data indicate that both old‐growth and second‐growth forests are important to the persistence of forest species in tropical, human‐modified landscapes. 相似文献
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Abstract: Conservation scientists recognize the urgency of incorporating opportunity costs into conservation planning. Despite this, applications to date have been limited, perhaps partly because of the difficulty in determining costs in regions with limited data on land prices and ownership. We present methods for estimating opportunity costs of land preservation in landscapes or ecoregions that are a changing mix of agriculture and natural habitat. Our approach derives from the literature on estimating land values as opportunity costs of alternate land uses and takes advantage of general availability of necessary data, even in relatively data-poor regions. The methods integrate probabilities of habitat conversion with region-wide estimates of economic benefits from agricultural land uses and estimate land values with a discount rate to convert annual values into net present values. We applied our method in a landscape undergoing agricultural conversion in Paraguay. Our model of opportunity costs predicted an independent data set of land values and was consistent with implicit discount rates of 15–25%. Model-generated land values were strongly correlated with actual land values even after correcting for the effect of property size and proportion of property that was forested. We used the model to produce a map of opportunity costs and to estimate the costs of conserving forest within two proposed corridors in the landscape. This method can be applied to conservation planning in situations where natural habitat is currently being converted to market-oriented land uses. Incorporating not only biological attributes but also socioeconomic data can help in the design of efficient networks of protected areas that represent biodiversity at minimum costs. 相似文献
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Abstract: Marine protected areas (MPAs) are a popular conservation strategy, but their impacts on human welfare are poorly understood. To inform future research and policy decisions, we reviewed the scientific literature to assess MPA impacts on five indicators of human welfare: food security, resource rights, employment, community organization, and income. Following MPA establishment, food security generally remained stable or increased in older and smaller MPAs. The ability of most fishing groups to govern MPA resources changed. Increased resource rights were positively correlated with MPA zoning and compliance with MPA regulations. Small sample sizes precluded statistical tests of the impacts of MPAs on employment, community organization, and income. Our results demonstrate that MPAs shape the social well‐being and political power of fishing communities; impacts (positive and negative) vary within and among social groups; and social impacts are correlated with some—but not all—commonly hypothesized explanatory factors. Accordingly, MPAs may represent a viable strategy for enhancing food security and empowering local communities, but current practices negatively affect at least a minority of fishers. To inform policy making, further research must better document and explain variation in the positive and negative social impacts of MPAs. 相似文献
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MURRAY A. RUDD KAREN F. BEAZLEY STEVEN J. COOKE ERICA FLEISHMAN DANIEL E. LANE MICHAEL B. MASCIA ROBIN ROTH GARY TABOR JISELLE A. BAKKER TERESA BELLEFONTAINE DOMINIQUE BERTEAUX BERNARD CANTIN KEITH G. CHAULK KATHRYN CUNNINGHAM ROD DOBELL ELEANOR FAST NADIA FERRARA C. SCOTT FINDLAY LARS K. HALLSTROM THOMAS HAMMOND LUISE HERMANUTZ JEFFREY A. HUTCHINGS KATHRYN E. LINDSAY TIM J. MARTA VIVIAN M. NGUYEN GREG NORTHEY KENT PRIOR SAUDIEL RAMIREZ‐SANCHEZ JAKE RICE DARREN J. H. SLEEP NORA D. SZABO GENEVIÈVE TROTTIER JEAN‐PATRICK TOUSSAINT JEAN‐PHILIPPE VEILLEUX 《Conservation biology》2011,25(3):476-484
Abstract: Integrating knowledge from across the natural and social sciences is necessary to effectively address societal tradeoffs between human use of biological diversity and its preservation. Collaborative processes can change the ways decision makers think about scientific evidence, enhance levels of mutual trust and credibility, and advance the conservation policy discourse. Canada has responsibility for a large fraction of some major ecosystems, such as boreal forests, Arctic tundra, wetlands, and temperate and Arctic oceans. Stressors to biological diversity within these ecosystems arise from activities of the country's resource‐based economy, as well as external drivers of environmental change. Effective management is complicated by incongruence between ecological and political boundaries and conflicting perspectives on social and economic goals. Many knowledge gaps about stressors and their management might be reduced through targeted, timely research. We identify 40 questions that, if addressed or answered, would advance research that has a high probability of supporting development of effective policies and management strategies for species, ecosystems, and ecological processes in Canada. A total of 396 candidate questions drawn from natural and social science disciplines were contributed by individuals with diverse organizational affiliations. These were collaboratively winnowed to 40 by our team of collaborators. The questions emphasize understanding ecosystems, the effects and mitigation of climate change, coordinating governance and management efforts across multiple jurisdictions, and examining relations between conservation policy and the social and economic well‐being of Aboriginal peoples. The questions we identified provide potential links between evidence from the conservation sciences and formulation of policies for conservation and resource management. Our collaborative process of communication and engagement between scientists and decision makers for generating and prioritizing research questions at a national level could be a model for similar efforts beyond Canada. 相似文献