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1.
A common goal in conservation planning is to acquire areas that are critical to realizing biodiversity goals in the most cost‐effective manner. The way monetary acquisition costs are represented in such planning is an understudied but vital component to realizing cost efficiencies. We sought to design a protected‐area network within a forested urban region that would protect 17 birds of conservation concern. We compared the total costs and spatial structure of the optimal protected‐area networks produced using three acquisition‐cost surrogates (area, agricultural land value, and tax‐assessed land value). Using the tax‐assessed land values there was a 73% and 78% cost savings relative to networks derived using area or agricultural land value, respectively. This cost reduction was due to the considerable heterogeneity in acquisition costs revealed in tax‐assessed land values, especially for small land parcels, and the corresponding ability of the optimization algorithm to identify lower‐cost parcels for inclusion that had equal value to our target species. Tax‐assessed land values also reflected the strong spatial differences in acquisition costs (US$0.33/m2–$55/m2) and thus allowed the algorithm to avoid inclusion of high‐cost parcels when possible. Our results add to a nascent but growing literature that suggests conservation planners must consider the cost surrogate they use when designing protected‐area networks. We suggest that choosing cost surrogates that capture spatial‐ and size‐dependent heterogeneity in acquisition costs may be relevant to establishing protected areas in urbanizing ecosystems.  相似文献   

2.
Modeling Opportunity Costs of Conservation in Transitional Landscapes   总被引:4,自引:0,他引:4  
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   

3.
Understanding the social dimensions of conservation opportunity is crucial for conservation planning in multiple‐use landscapes. However, factors that influence the feasibility of implementing conservation actions, such as the history of landscape management, and landholders’ willingness to engage are often difficult or time consuming to quantify and rarely incorporated into planning. We examined how conservation agencies could reduce costs of acquiring such data by developing predictive models of management feasibility parameterized with social and biophysical factors likely to influence landholders’ decisions to engage in management. To test the utility of our best‐supported model, we developed 4 alternative investment scenarios based on different input data for conservation planning: social data only; biological data only; potential conservation opportunity derived from modeled feasibility that incurs no social data collection costs; and existing conservation opportunity derived from feasibility data that incurred collection costs. Using spatially explicit information on biodiversity values, feasibility, and management costs, we prioritized locations in southwest Australia to control an invasive predator that is detrimental to both agriculture and natural ecosystems: the red fox (Vulpes vulpes). When social data collection costs were moderate to high, the most cost‐effective investment scenario resulted from a predictive model of feasibility. Combining empirical feasibility data with biological data was more cost‐effective for prioritizing management when social data collection costs were low (<4% of the total budget). Calls for more data to inform conservation planning should take into account the costs and benefits of collecting and using social data to ensure that limited funding for conservation is spent in the most cost‐efficient and effective manner.  相似文献   

4.
In addition to the usual fixed costs, we introduce variable costs in a community's effort to cooperate in extracting from a common pool resource. Using a standard supervision mechanism, these variable costs are shown to be an increasing function of individual members' incentives to default. The model explains why we frequently observe communities that all cooperate and have relatively similar resource endowments, and yet achieve very different levels of extraction.  相似文献   

5.
In this paper, the European Union's Water Framework Directive 2000/60/EC (WFD) that is intended to foster protection of water resources is examined, focusing on the improvement of ecological and chemical quality of surface and groundwater. The WFD includes the concept of full cost recovery (FCR) in accordance with the Polluter-Pays Principle, as one of the tools of an adequate and sustainable water resource management system. The WFD defines three different costs associated with water: resource costs (RC), financial costs (FC), and environmental costs (ECs).The FCR of water is examined from a biophysical perspective using emergy evaluation to: (1) establish resource values of water from different sources, (2) establish the full economic costs associated with supplying water, and (3) the societal costs of water that is used incorrectly; from which the resource costs, financial costs, and environmental costs, respectively, can be computed. Financial costs are the costs associated with providing water including energy, materials, labor and infrastructure. The emergy based monetary values vary between 0.15 and 1.73 €/m3 depending on technology. The emergy based, global average resource value (from which resource costs can be computed) is derived from two aspects of water: its chemical potential and its geopotential. The chemical potential monetary value of different sources such as rain, groundwater, and surface water derived from global averages of emergy inputs varies from 0.03 to 0.18 €/m3, depending on source, and the geopotential values vary from 0.03 to 2.40 €/m3, depending on location in the watershed. The environmental costs of water were averaged for the county of Spain and were 1.42 €/m3.Time of year and spatial location within the watershed ultimately influence the resource costs (computed from emergy value of chemical potential and geopotential energy) of water. To demonstrate this spatial and temporal variability, a case study is presented using the Foix watershed in northeastern Spain. Throughout the year, the resource value of water varies from 0.21 to 3.17 €/m3, depending on location within the watershed. It is concluded that FCR would benefit from the evaluation of resource costs using spatially and temporally explicit emergy accounting.  相似文献   

6.
It is often necessary to estimate the weight that an individual may be capable of gaining depending on its degree of activity. A simple individual-based model was developed for studying the dynamics of weight in terms of daily behavior and ingestion rate. It was based on the balance between the individual's energy intake and the cost of its daily activities. Costs depend on the weight of the individual and the photoperiod, as well as on the time spent on each activity. Different combinations of ingestion rate, individual's weight, photoperiod length, and time assigned to different activities were used for simulating the weight dynamics, taking the species Rhea americana as a study case. Estimations of energetic costs of the activities were obtained from specialized literature. Using different photoperiods and individual behaviors, the model yields field metabolic rate (FMR) values in agreement with those obtained from direct measurements for other omnivorous bird species.  相似文献   

7.
The purpose of this paper is to consider the implicatons of model complexity for the quality of the information provided by models of production activities that account for the processes involved in residuals generation and treatment. Using each of the three primary technologies for iron and steel-making industry and models of varying detail for each, the paper compares the estimated levels of residuals generated and treatment costs for both atmospheric and waterborne effluents. The findings suggest that there are strategic details in model construction which have fundamental implications for the design of environmental policies. Moreover, preliminary estimates of the costs of model construction and operation suggest that policymakers may not be able to afford complexity for its own sake. Rather these costs will require the development of methods to isolate the strategic details in each technology that are potentially important to environmental policies.  相似文献   

8.
Selection imposed by male competition (intrasexual selection) and female choice (intersexual selection) can be con- or discordant. Specifically, females may or may not prefer mating with dominant males, and direct costs of interacting with dominant (and possibly more harassing) males have been suggested to explain avoidance of dominant males. Here, we exemplify that inter- and intrasexual selection may normally act in the same direction, but can be temporarily conflicting when social information becomes available. Using video playback techniques, we presented females of the Mexican livebearing fish Poecilia mexicana with two size-matched males and established association preferences. Half of the females could then observe the same two males fight and establish dominance, while control females saw both males side by side, but physically separated, and female preferences were subsequently re-evaluated. Females in the control group showed a significant preference for future winners in the subsequent testing, confirming an innate or acquired preference for male traits that are indicative of physical superiority, even when body size as a choice criterion is excluded. When allowed to eavesdrop on male fights, however, females did not show a preference for observed winners and even decreased time spent with them relative to the control treatment in which no fight was shown. A subsequent experiment found contest winners to show elevated levels of sexual behavior, so we argue that the temporary offset of the intrinsic female preference for dominant males after having observed a fight is indeed driven by direct costs females expect from more harassing contest winners.  相似文献   

9.
Effective conservation management interventions must combat threats and deliver benefits at costs that can be achieved within limited budgets. Considerable effort has focused on measuring the potential benefits of conservation interventions, but explicit quantification of the financial costs of implementation is rare. Even when costs have been quantified, haphazard and inconsistent reporting means published values are difficult to interpret. This reporting deficiency hinders progress toward a collective understanding of the financial costs of management interventions across projects and thus limits the ability to identify efficient solutions to conservation problems or attract adequate funding. We devised a standardized approach to describing financial costs reported for conservation interventions. The standards call for researchers and practitioners to describe the objective and outcome, context and methods, and scale of costed interventions, and to state which categories of costs are included and the currency and date for reported costs. These standards aim to provide enough contextual information that readers and future users can interpret the cost data appropriately. We suggest these standards be adopted by major conservation organizations, conservation science institutions, and journals so that cost reporting is comparable among studies. This would support shared learning and enhance the ability to identify and perform cost‐effective conservation.  相似文献   

10.
The evolution of life history characters, including parental care behaviors, depends on costs and benefits. When offspring can influence parental behaviors, parent-offspring conflict over parental care can occur, but only if these parental behaviors are costly. Mother burrower bugs (Sehirus cinctus) exhibit extended and complex care of offspring. Mothers guard eggs until hatching and then attend and provision offspring for approximately 2 weeks after hatching. Using four experimental treatments, we attempted to identify the costs associated with specific components of these behaviors. Under laboratory conditions, egg guarding increases inter-clutch interval, but provisioning does not appear to be very costly. We discuss additional ecological factors that may be important in mediating provisioning costs under natural conditions. Through analysis of individual maternal performance, we find no evidence for trade-offs between successive clutches. These data suggest that variation in overall condition may obscure variation in allocation strategies.Communicated by F. Trillmich  相似文献   

11.
Ecological Costs of Livestock Grazing in Western North America   总被引:24,自引:0,他引:24  
Livestock grazing is the most widespread land management practice in western North America. Seventy percent of the western United States is grazed, including wilderness areas, wildlife refuges, national forests, and even some national parks. The ecological costs of this nearly ubiquitous form of land use can be dramatic. Examples of such costs include loss of biodiversity; lowering of population densities for a wide variety of taxa; disruption of ecosystem functions, including nutrient cycling and succession; change in community organization; and change in the physical characteristics of both terrestrial and aquatic habitats. Because livestock congregate in riparian ecosystems, which are among the biologically richest habitats in arid and semiarid regions, the ecological costs of grazing are magnified in these sites. Range science has traditionally been laden with economic assumptions favoring resource use. Conservation biologists are encouraged to contribute to the ongoing social and scientific dialogue on grazing issues.  相似文献   

12.
亚热带常绿阔叶林下分布着可塑性强的耐荫植物,其叶片应对外界干扰的防御对策至少有物理性防御和化学性防御两种,这两种防御代价在一定的昆虫取食压力下在理论上应该存在权衡.为检验这种权衡是否普遍存在,分别测定了重庆缙云山4个常绿物种——光叶山矾(Symplocos lancifolia)、四川山矾(S.setchuensis)、四川毛蕊茶(Camellialawii)和细枝柃(Eurya loquaiana)在林窗和林下两种对照光环境下个体叶片的光饱和下的净光合速率、叶面积干重和部分化学防御物质含量.结果表明,4个物种生活在林窗的个体单位叶面积干重、叶片氮含量和单位面积净光合速率通常高于林下的个体,但是单位质量和单位面积的总酚含量和C/N值却低于林下的个体.蛋白质和非结构性碳水化合物含量在不同生境中没有显著差异.因为不同物种叶片对光照条件的响应不同,不同参数的变化在两种生境间的差异并不完全一致.本研究结果在一定程度上暗示了物种在林窗和林下分别倾向于采取物理和化学性防御对策,并初步证实了两种防御强度之间存在权衡关系.图4参40  相似文献   

13.
Using an input-output framework, this paper investigates the magnitude of the impact that environmental protection costs had on prices in the United States in 1977. With the imposition of environmental protection costs, the projected total price increases for individual industries range from 0.12% to 6.58%. Due to data limitations, the constraints of input-output analysis, and the structural changes that occurred in the economy from 1972 to 1977, the results should not be taken as definitive. However, the results do indicate the typical sort of variation in impact likely to occur across industries and that the average impact on prices was modest.  相似文献   

14.
A simultaneous equation model of the behavior of a mosquito abatement district based on biological and economic data is presented. Results indicate high long term costs if heavy reliance on chemical pesticide control methods continue, due to a pesticide resistance buildup in the mosquito populations. Physical source reduction methods were shown to be more efficient both in the short and long run. A linear programming model is presented which optimizes the inix of chemical and physical control methods. Results indicate increasing costs of mosquito abatement as pesticide effectiveness declines.  相似文献   

15.
This paper examines how enforcement affects the structure and performance of emissions trading programs with price controls under uncertainty about firms' abatement costs. The analysis highlights how an enforcement strategy can cause abatement-cost risk to be transmitted to enforcement costs via the price of permits. When this occurs, accommodating the effect of abatement-cost risk with an optimal policy results in higher expected emissions and lower expected permit price than their second-best optimal values. However, it is possible to design an enforcement strategy that shields enforcement costs from abatement-cost risk by tying sanctions directly to permit prices. This enforcement strategy stabilizes enforcement effort, the optimal permit supply and price controls are independent of enforcement costs, and the policy produces the second-best optimal outcome.  相似文献   

16.
Hermit crabs are unique among crustaceans in that they choose their shell and can, therefore, be used to investigate apparent preferences for the presence of epizoic fauna. These may be beneficial due to increased protection from predators via enhanced crypsis but may also make the shell more difficult to carry. The effects of encrusting fauna on the physical properties of empty gastropod shells, the shell preferences of hermit crabs and the physiological costs of shell carrying were examined in the present laboratory study. Heavily encrusted shells weighed more than shells of the same internal volume that were free of epizoic fauna, hermit crabs showed a clear preference for un-encrusted shells and those that occupied encrusted shells had elevated haemolymph lactate in comparison to those supplied with un-encrusted shells. Under laboratory conditions, any benefit from increased crypsis is, therefore, outbalanced by the increased costs of carrying encrusted shells.  相似文献   

17.
Activities of the primary enzyme responsible for monovalent ion regulation, Na+-K+-adenosine triphosphatase (Na+-K+-ATPase), were measured in gills of marine teleost fishes with different depths of occurrence (0 to 4800 m), body weights (a range of five orders of magnitude), and locomotory capacities. Specimens were collected off the coasts of California and Oregon in 1983–1989, and at the Galápagos Spreading Center and 13°N East Pacific Rise hydrothermal vent sites in 1987 and 1988, respectively. Except for two hydrothermal vent fishes, deep-sea species had much lower Na+-K+-ATPase activities g–1 gill filament than shallow-living species, indicating that osmoregulatory costs, like total metabolic rate, are greatly reduced in most deep-living fishes. Within a species, the total branchial Na+-K+-ATPase activity per individual was dependent on size; the average allometric scaling exponent was 0.83. Using published values for oxygen consumption rates, and the total branchial Na+-K+-ATPase activities as an index of osmoregulatory costs, we estimated the maximal cost (as percent of ATP turnover) for osmoregulation in ten teleosts. Osmoregulatory costs averaged about 10% of total ATP turnover among these species, and maximal costs were no greater than about 20%. The percent costs of osmoregulation did not differ between shallow- and deep-living fishes. The reduced total ATP expenditure for osmoregulation in deep-living fishes is proposed to result from the sluggish locomotory habits of these fishes, not from selection for reduced osmotic coastper se. Thus, the reduced swimming abilities of these fishes lead to lower rates of water flow over the gills and less blood flow through the gills due to reduced demands for oxygen. Consequently, passive flux of water and ions through the gills is much lower than in more active fishes, and osmotic costs are thereby minimized. The relatively high activities of Na+-K+-ATPase in gills of the two hydrothermal vent fishes suggest that these fishes may be more active and have higher metabolic rates than other deep-sea fishes.  相似文献   

18.
Restoration scientists and practitioners have recently begun to include economic and social aspects in the design and investment decisions for restoration projects. With few exceptions, ecological restoration studies that include economics focus solely on evaluating costs of restoration projects. However, economic principles, tools, and instruments can be applied to a range of other factors that affect project success. We considered the relevance of applying economics to address 4 key challenges of ecological restoration: assessing social and economic benefits, estimating overall costs, project prioritization and selection, and long‐term financing of restoration programs. We found it is uncommon to consider all types of benefits (such as nonmarket values) and costs (such as transaction costs) in restoration programs. Total benefit of a restoration project can be estimated using market prices and various nonmarket valuation techniques. Total cost of a project can be estimated using methods based on property or land‐sale prices, such as hedonic pricing method and organizational surveys. Securing continuous (or long‐term) funding is also vital to accomplishing restoration goals and can be achieved by establishing synergy with existing programs, public–private partnerships, and financing through taxation.  相似文献   

19.
In the regulation of pollutant emissions, a regulator may treat different sources (with different costs and environmental damage) as though they were the same—for institutional, informational, or transaction cost reasons. This may occur despite the efficiency gains from regulatory differentiation of sources. This issue has been a source of much controversy in the environmental economics literature and is examined here from a theoretical perspective. Using a two pollutant economy, emissions and net social benefits are compared for the case of efficient, differentiated regulation and the case of uniform, undifferentiated regulation of the aggregate of the two pollutants. We show when aggregate emissions will be greater than, equal to, or less than efficient emissions and we derive conditions for each of these three possibilities. Further, we show that when marginal costs and benefits become more steeply sloped, the inefficiency associated with undifferentiated regulation increases.  相似文献   

20.
Using the contamination episode at Price Landfill, New Jersey, as a case study, major analytical and informational issues characterizing groundwater pollution, with special emphasis on uncertainty associated with the environmental medium, especially solute-transport processes, and the valuation of health risks, principally dose-response relationships, are addressed. Alternative approaches to modeling the physical-chemical processes are described and subsequently coupled with mortality risk predictions to derive estimates of expected pollution costs: reduced longevity (pollution damage costs) and cost of control and remedial measures (damage reduction costs).  相似文献   

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