Measuring Protected‐Area Isolation and Correlations of Isolation with Land‐Use Intensity and Protection Status

Abstract: Protected areas cover over 12% of the terrestrial surface of Earth, and yet many fail to protect species and ecological processes as originally envisioned. Results of recent studies suggest that a critical reason for this failure is an increasing contrast between the protected lands and the surrounding matrix of often highly altered land cover. We measured the isolation of 114 protected areas distributed worldwide by comparing vegetation‐cover heterogeneity inside protected areas with heterogeneity outside the protected areas. We quantified heterogeneity as the contagion of greenness on the basis of NDVI (normalized difference vegetation index) values, for which a higher value of contagion indicates less heterogeneous land cover. We then measured isolation as the difference between mean contagion inside the protected area and mean contagion in 3 buffer areas of increasing distance from the protected‐area border. The isolation of protected areas was significantly positive in 110 of the 114 areas, indicating that vegetation cover was consistently more heterogeneous 10–20 km outside protected areas than inside their borders. Unlike previous researchers, we found that protected areas in which low levels of human activity are allowed were more isolated than areas in which high levels are allowed. Our method is a novel way to assess the isolation of protected areas in different environmental contexts and regions.     

Preserving Population Allele Frequencies in Ex Situ Conservation Programs

Abstract: Optimization of contributions of parents to progeny by minimizing the average coancestry of the progeny is an effective strategy for maintaining genetic diversity in ex situ conservation programs, but its application on the basis of molecular markers has the negative collateral effect of homogenizing the allelic frequencies at each locus. Because one of the objectives of a conservation program is to preserve the genetic composition of the original endangered population, we devised a method in which markers are used to maintain the allele frequency distribution at each locus as closely as possible to that of the native population. Contributions of parents were obtained so as to minimize changes in allele frequency for a set of molecular markers in a population of reduced size. We used computer simulations, under a range of scenarios, to assess the effectiveness of the method in comparison with methods in which contributions of minimum coancestry are sought, either making use of molecular markers or genealogical information. Our simulations indicated that the proposed method effectively maintained the original distribution of allele frequencies, particularly under strong linkage, and maintained acceptable levels of genetic diversity in the population. Nevertheless, contributions of minimum coancestry determined from pedigree information but ignoring the genealogy previous to the conservation program, was the most effective method for maintaining allelic frequencies in realistic situations.     

Building a Regionally Connected Reserve Network in a Changing and Uncertain World

Abstract: Habitat connectivity is required at large spatial scales to facilitate movement of biota in response to climatic changes and to maintain viable populations of wide‐ranging species. Nevertheless, it may require decades to acquire habitat linkages at such scales, and areas that could provide linkages are often developed before they can be reserved. Reserve scheduling methods usually consider only current threats, but threats change over time as development spreads and reaches presently secure areas. We investigated the importance of considering future threats when implementing projects to maintain habitat connectivity at a regional scale. To do so, we compared forward‐looking scheduling strategies with strategies that consider only current threats. The strategies were applied to a Costa Rican case study, where many reserves face imminent isolation and other reserves will probably become isolated in the more distant future. We evaluated strategies in terms of two landscape‐scale connectivity metrics, a pure connectivity metric and a metric of connected habitat diversity. Those strategies that considered only current threats were unreliable because they often failed to complete planned habitat linkage projects. The most reliable and effective strategies considered the future spread of development and its impact on the likelihood of completing planned habitat linkage projects. Our analyses highlight the critical need to consider future threats when building connected reserve networks over time.     

Traditional Ecological Knowledge Trends in the Transition to a Market Economy: Empirical Study in the Doñana Natural Areas

Abstract: Researchers and conservation managers largely agree on the relevance of traditional ecological knowledge for natural resource management in indigenous communities, but its prevalence and role as societies modernize are contested. We analyzed the transmission of traditional knowledge among rural local people in communities linked to protected areas in Doñana, southwestern Spain. We studied changes in knowledge related to local practices in agriculture and livestock farming among 198 informants from three generations that cover the period in which the area transited from an economy strongly dependent on local ecosystem services to a market economy with intensified production systems. Our results suggest an abrupt loss of traditional agricultural knowledge related to rapid transformations and intensification of agricultural systems, but maintenance of knowledge of traditional livestock farming, an activity allowed in the protected areas that maintains strong links with local cultural identity. Our results demonstrate the potential of protected areas in protecting remaining bodies of traditional ecological knowledge in developed country settings. Nevertheless, we note that strict protection in cultural‐landscape‐dominated areas can disrupt transmission of traditional knowledge if local resource users and related practices are excluded from ecosystem management.     

Estimating the Value of Non‐Use Benefits from Small Changes in the Provision of Ecosystem Services

Abstract: The unit of trade in ecosystem services is usually the use of a proportion of the parcels of land associated with a given service. Valuing small changes in the provision of an ecosystem service presents obstacles, particularly when the service provides non‐use benefits, as is the case with conservation of most plants and animals. Quantifying non‐use values requires stated‐preference valuations. Stated‐preference valuations can provide estimates of the public's willingness to pay for a broad conservation goal. Nevertheless, stated‐preference valuations can be expensive and do not produce consistent measures for varying levels of provision of a service. Additionally, the unit of trade, land use, is not always linearly related to the level of ecosystem services the land might provide. To overcome these obstacles, we developed a method to estimate the value of a marginal change in the provision of a non‐use ecosystem service—in this case conservation of plants or animals associated with a given land‐cover type. Our method serves as a tool for calculating transferable valuations of small changes in the provision of ecosystem services relative to the existing provision. Valuation is achieved through stated‐preference investigations, calculation of a unit value for a parcel of land, and the weighting of this parcel by its ability to provide the desired ecosystem service and its effect on the ability of the surrounding land parcels to provide the desired service. We used the water vole (Arvicola terrestris) as a case study to illustrate the method. The average present value of a meter of water vole habitat was estimated at UK£12, but the marginal value of a meter (based on our methods) could range between £0 and £40 or more.     

Effects of Two Amphibian Pathogens on the Developmental Stability of Green Frogs

Abstract: Developmental instability, measured as fluctuating asymmetry (FA), is often used as a tool to measure stress and the overall quality of organisms. Under FA, it is assumed that control of symmetry during development is costly and that under stress the trajectory of development is disturbed, resulting in asymmetric morphologies. Amphibian emergent infectious diseases (EIDs), such as Ranavirus and chytrid fungus, have been involved in several mortality events, which makes them stressors and allows for the study of FA. We analyzed nine populations of green frogs (Rana clamitans) for the presence or absence of Ranavirus and chytrid fungus. Individuals were measured to determine levels of FA in seven traits under the hypothesis that FA is more likely to be observed in individuals infected by the pathogens. Significantly higher levels of FA were found in individuals with Ranavirus compared with uninfected individuals among all populations and all traits. We did not observe FA in individuals infected with chytrid fungus for any of the traits measured. Additionally, we observed a significant association between Ranavirus infection and levels of FA in both males and females, which may indicate this viral disease is likely to affect both sexes during development. Altogether, our results indicate that some EIDs may have far‐reaching and nonlethal effects on individual development and populations harboring such diseases and that FA can be used as a conservation tool to identify populations subject to such a stress.     

The customer is not always right: customer aggression and emotion regulation of service employees

Research on work aggression or anger has typically focused on supervisors and co‐workers as the instigators of aggression; however, aggressive customers are also likely and may have unique consequences for the employee. We explore this phenomenon with a sample of 198 call center employees at two work sites. The employees reported that customer verbal aggression occurred 10 times a day, on average, though this varied by race and negative affectivity. Using LISREL, our data indicated that both the frequency and stress appraisal of customer aggression positively related to emotional exhaustion, and this burnout dimension mediated the relationship of stress appraisal with absences. Stress appraisal also influenced employees' emotion regulation strategies with their most recent hostile caller. Employees who felt more threatened by customer aggression used surface acting or vented emotions, while those who were less threatened used deep acting. Job autonomy helped explain who found these events more stressful, and implications of these results are discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

AGRICULTURE LAND‐USE EFFECTS ON NUTRIENT LOSSES IN WEST TIAOXI WATERSHED,CHINA1

ABSTRACT: Five types of land use/land covers in the West Tiaoxi watershed of China were studied for nutrient losses in artificial rainstorm runoff. A self‐designed rainfall simulator was used. In situ rainfall simulations were used to: (1) compare the concentrations of nitrogen and phosphorous in different land use/land covers and (2) evaluate the flux of nitrogen and phosphorous export from runoff and sediment in various types of land use/land covers. Three duplicated experiments were carried out under rain intensity of 2 mm/min, each lasting 32 minutes on a 3 m² plot. Characteristics of various species of nitrogen and phosphorous in runoff and sediment were investigated. The results showed that the concentrations of total nitrogen (TN) and total phosphorous (TP) were greatest in runoff from mulberry trees and smallest from pine forest. The TN and TP export was mainly from suspended particulate in runoff. TN and TP exports from the top 10 cm layer of five types of land use/land covers were estimated as high as 4.66 to 9.40 g/m² and 2.57 to 4.89 g/m², respectively, of which exports through sediment of runoff accounted for more than 90 percent and 97 percent. The rate of TN and TP exports ranged from 2.68 to approximately 14.48 and 0.45 to approximately 4.11 mg/m²/min in runoff; these rates were much lower than those of 100.01 to approximately 172.67 and 72.82 to approximately 135.96 mg/m²/min in the runoff sediment.     

The burning of fuelwood in South Africa: When is it sustainable?

Fuelwood harvesting is considered sustainable when consumption is equal to or less than production. An empirical model was developed to estimate potential fuelwood production from savannas. The model is based on the observation that in semiarid savannas, biomass production is linearly dependent on rainfall. Woody basal area is linked to mean annual precipitation, and aboveground woody biomass is proportional to basal area. Production averages 4% of standing woody biomass and is corrected to exclude stems that are too small for harvesting. The model assumes that the entire area consists of seminatural savanna. Corrections for the land lost as a result of land transformation and degradation would have to be included. Data on land loss can most effectively be obtained from satellite imagery, with appropriate ground calibration. The model is based on limited data sets but in most instances has been validated against independently collected data. The model yields a reasonable prediction at a national and regional level, but estimates for limited areas or specific points on the ground may differ substantially from the predicted values. Model results indicate a potential for sustainable fuelwood production at the national level, but specific regions are using fuelwood at nonsustainable levels.     

Book reviews

Common Property Economics: A General Theory and Land Use Applications

Glenn G. Stevenson

Cambridge, Cambridge University Press, 1992, XIV + 256pp., £35

Controversial Issues in Environmental Policy: Science vs Economics vs Politics

Kent E. Portney

London, Sage, 1992, 181 pp. £22.00 hb., £10.95 pb.

Economics of Natural Resources and the Environment

E. Kula

London, Chapman & Hall, 1992, 287 pp., £40

Policy Implications of Greenhouse Warming: Mitigation, Adaptation and the Science Base

Committee on Science, Engineering and Public Policy (US), Panel on Policy

Implications of Greenhouse Warming

Washington, DC, National Academy Press, 1992, xxiii + 918 pp., $89.95 hb.

Contemporary Rural Systems in Transition, Volume 1: Agriculture and Environment, Volume 2: Economy and Society

I. Bowler, C. Bryant & M.Nellis (Eds)

Wallingford, CAB International, 1992, 288 pp. + 336 pp., £35 + £40 (2 vols. £70) hb.

Third World Cities: Problems, Policies and Prospects

John Kasarda & Allan Parnell (Eds) London, Sage, 1993, 310 pp., £19.50 pb.

Pricing the European Environment

Stale Navrud (Ed)

Oxford, Oxford University Press/Scandinavian University Press, 1992, 288 pp., £30.00 hb.