Conservation and environmental management are principal countermeasures to the degradation of marine ecosystems and their services. However, in many cases, current practices are insufficient to reverse ecosystem declines. We suggest that restoration ecology, the science underlying the concepts and tools needed to restore ecosystems, must be recognized as an integral element for marine conservation and environmental management. Marine restoration ecology is a young scientific discipline, often with gaps between its application and the supporting science. Bridging these gaps is essential to using restoration as an effective management tool and reversing the decline of marine ecosystems and their services. Ecological restoration should address objectives that include improved ecosystem services, and it therefore should encompass social–ecological elements rather than focusing solely on ecological parameters. We recommend using existing management frameworks to identify clear restoration targets, to apply quantitative tools for assessment, and to make the re-establishment of ecosystem services a criterion for success.
Climate changes, associated with accumulation of greenhouse gases, are expected to have a profound influence on agricultural sustainability in Israel, a semi-arid area characterized by a cold wet winter and a dry warm summer. Accordingly this study explored economic aspects of agricultural production under projected climate-change scenarios by the "production function" approach, as applied to two representative crops: wheat, as the major crop grown in Israel's dry southern region, and cotton, representing the more humid climate in the north. Adjusting outputs of the global climate model HadCM3 to the specific research locations, we generated projections for 2070-2100 temperatures and precipitations for two climate change scenarios. Results for wheat vary among climate scenarios; net revenues become negative under the severe scenario (change from −145 to −273%), but may increase under the moderate one (−43 to +35%), depending on nitrogen applied to the crop. Distribution of rain events was found to play a major role in determining yields. By contrast, under both scenarios cotton experiences a considerable decrease in yield with significant economic losses (−240 and −173% in A2 and B2 scenarios, respectively). Additional irrigation and nitrogen may reduce farming losses, unlike changes in seeding dates.
The contingent valuation method estimates individuals' willingness to pay (WTP) for non-market environmental assets via preferences elicited by either open-ended or dichotomous choice questions. Traditional analysis of such data has tended to ignore zero WTP values, or treat them in an unsatisfactory manner. Recently, spike models, which explicitly allow for and incorporate zero responses, have been suggested. The paper extends the spike model approach to allow for explanatory covariates, and shows how standard computer software can be used to carry out the computations. In addition, the paper develops estimates of mean or median willingness to pay as a function of these covariates.2 McFadden (1994) suggests use of the highest likelihood or the Akaike information criteria in order to choose the`best' parametric model. Whether these criteria can eectively distinguish between various skewed models without exceedingly large amount of data is questionable and needs to be further studied.
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