Testing Decision Rules for Categorizing Species’ Extinction Risk to Help Develop Quantitative Listing Criteria for the U.S. Endangered Species Act

Lack of guidance for interpreting the definitions of endangered and threatened in the U.S. Endangered Species Act (ESA) has resulted in case‐by‐case decision making leaving the process vulnerable to being considered arbitrary or capricious. Adopting quantitative decision rules would remedy this but requires the agency to specify the relative urgency concerning extinction events over time, cutoff risk values corresponding to different levels of protection, and the importance given to different types of listing errors. We tested the performance of 3 sets of decision rules that use alternative functions for weighting the relative urgency of future extinction events: a threshold rule set, which uses a decision rule of x% probability of extinction over y years; a concave rule set, where the relative importance of future extinction events declines exponentially over time; and a shoulder rule set that uses a sigmoid shape function, where relative importance declines slowly at first and then more rapidly. We obtained decision cutoffs by interviewing several biologists and then emulated the listing process with simulations that covered a range of extinction risks typical of ESA listing decisions. We evaluated performance of the decision rules under different data quantities and qualities on the basis of the relative importance of misclassification errors. Although there was little difference between the performance of alternative decision rules for correct listings, the distribution of misclassifications differed depending on the function used. Misclassifications for the threshold and concave listing criteria resulted in more overprotection errors, particularly as uncertainty increased, whereas errors for the shoulder listing criteria were more symmetrical. We developed and tested the framework for quantitative decision rules for listing species under the U.S. ESA. If policy values can be agreed on, use of this framework would improve the implementation of the ESA by increasing transparency and consistency. Evaluando Reglas de Decisión para Categorizar el Riesgo de Extinción de Especies con el Fin de Desarrollar de Criterios Cuantitativos de Alistamiento en el Acta de Especies en Peligro de los EE. UU.     

The Capacity of Australia's Protected‐Area System to Represent Threatened Species

Abstract: The acquisition or designation of new protected areas is usually based on criteria for representation of different ecosystems or land‐cover classes, and it is unclear how well‐threatened species are conserved within protected‐area networks. Here, we assessed how Australia's terrestrial protected‐area system (89 million ha, 11.6% of the continent) overlaps with the geographic distributions of threatened species and compared this overlap against a model that randomly placed protected areas across the continent and a spatially efficient model that placed protected areas across the continent to maximize threatened species’ representation within the protected‐area estate. We defined the minimum area needed to conserve each species on the basis of the species’ range size. We found that although the current configuration of protected areas met targets for representation of a given percentage of species’ ranges better than a random selection of areas, 166 (12.6%) threatened species occurred entirely outside protected areas and target levels of protection were met for only 259 (19.6%) species. Critically endangered species were among those with the least protection; 12 (21.1%) species occurred entirely outside protected areas. Reptiles and plants were the most poorly represented taxonomic groups, and amphibians the best represented. Spatial prioritization analyses revealed that an efficient protected‐area system of the same size as the current protected‐area system (11.6% of the area of Australia) could meet representation targets for 1272 (93.3%) threatened species. Moreover, the results of these prioritization analyses showed that by protecting 17.8% of Australia, all threatened species could reach target levels of representation, assuming all current protected areas are retained. Although this amount of area theoretically could be protected, existing land uses and the finite resources available for conservation mean land acquisition may not be possible or even effective for the recovery of threatened species. The optimal use of resources must balance acquisition of new protected areas, where processes that threaten native species are mitigated by the change in ownership or on‐ground management jurisdiction, and management of threatened species inside and outside the existing protected‐area system.     

Use of Ancient Sedimentary DNA as a Novel Conservation Tool for High‐Altitude Tropical Biodiversity

Conservation of biodiversity may in the future increasingly depend upon the availability of scientific information to set suitable restoration targets. In traditional paleoecology, sediment‐based pollen provides a means to define preanthropogenic impact conditions, but problems in establishing the exact provenance and ecologically meaningful levels of taxonomic resolution of the evidence are limiting. We explored the extent to which the use of sedimentary ancient DNA (sedaDNA) may complement pollen data in reconstructing past alpine environments in the tropics. We constructed a record of afro‐alpine plants retrieved from DNA preserved in sediment cores from 2 volcanic crater sites in the Albertine Rift, eastern Africa. The record extended well beyond the onset of substantial anthropogenic effects on tropical mountains. To ensure high‐quality taxonomic inference from the sedaDNA sequences, we built an extensive DNA reference library covering the majority of the afro‐alpine flora, by sequencing DNA from taxonomically verified specimens. Comparisons with pollen records from the same sediment cores showed that plant diversity recovered with sedaDNA improved vegetation reconstructions based on pollen records by revealing both additional taxa and providing increased taxonomic resolution. Furthermore, combining the 2 measures assisted in distinguishing vegetation change at different geographic scales; sedaDNA almost exclusively reflects local vegetation, whereas pollen can potentially originate from a wide area that in highlands in particular can span several ecozones. Our results suggest that sedaDNA may provide information on restoration targets and the nature and magnitude of human‐induced environmental changes, including in high conservation priority, biodiversity hotspots, where understanding of preanthropogenic impact (or reference) conditions is highly limited. Uso de ADN Sedimentario Antiguo como una Herramienta Novedosa de Conservación para la Biodiversidad Tropical de Grandes Altitudes     

Effect of Small‐Scale Heterogeneity of Prey and Hunter Distributions on the Sustainability of Bushmeat Hunting

Abstract: Bushmeat is the main source of protein and the most important source of income for rural people in the Congo Basin, but intensive hunting of bushmeat species is also a major concern for conservationists. Although spatial heterogeneity in hunting effort and in prey populations at the landscape level plays a key role in the sustainability of hunted populations, the role of small‐scale heterogeneity within a village hunting territory in the sustainability of hunting has remained understudied. We built a spatially explicit multiagent model to capture the dynamics of a system in which hunters and preys interact within a village hunting territory. We examined the case of hunting of bay duikers (Cephalophus dorsalis) in the village of Ntsiété, northeastern Gabon. The impact of hunting on prey populations depended on the spatial heterogeneity of hunting and prey distribution at small scales within a hunting area. Within a village territory, the existence of areas hunted throughout the year, areas hunted only during certain seasons, and unhunted areas contributed to the sustainability of the system. Prey abundance and offtake per hunter were particularly sensitive to the frequency and length of hunting sessions and to the number of hunters sharing an area. Some biological parameters of the prey species, such as dispersal rate and territory size, determined their spatial distribution in a hunting area, which in turn influenced the sustainability of hunting. Detailed knowledge of species ecology and behavior, and of hunting practices are crucial to understanding the distribution of potential sinks and sources in space and time. Given the recognized failure of simple biological models to assess maximum sustainable yields, multiagent models provide an innovative path toward new approaches for the assessment of hunting sustainability, provided further research is conducted to increase knowledge of prey species’ and hunter behavior.     

Biodiversity Consequences of Genetic Variation in Bark Characteristics within a Foundation Tree Species

Abstract: The developing field of community genetics has the potential to broaden the contribution of genetics to conservation biology by demonstrating that genetic variation within foundation plant species can act to structure associated communities of microorganisms, invertebrates, and vertebrates. We assessed the biodiversity consequences of natural patterns of intraspecific genetic variation within the widely distributed Australian forest tree, Eucalyptus globulus. We assessed genetic variation among geographic races of E. globulus (i.e., provenances, seed zones) in the characteristics of tree‐trunk bark in a 17‐year‐old common garden and the associated response of a dependent macroarthropod community. In total, 180 macroarthropod taxa were identified following a collection from 100 trees of five races. We found substantial genetically based variation within E. globulus in the quantity and type of decorticating bark. In the community of organisms associated with this bark, significant variation existed among trees of different races in composition, and there was a two‐fold difference in species richness (7–14 species) and abundance (22–55 individuals) among races. This community variation was tightly linked with genetically based variation in bark, with 60% of variation in community composition driven by bark characteristics. No detectable correlation was found, however, with neutral molecular markers. These community‐level effects of tree genetics are expected to extend to higher trophic levels because of the extensive use of tree trunks as foraging zones by birds and marsupials. Our results demonstrate the potential biodiversity benefits that may be gained through conservation of intraspecific genetic variation within broadly distributed foundation species. The opportunities for enhancing biodiversity values of forestry and restoration plantings are also highlighted because such planted forests are increasingly becoming the dominant forest type in many areas of the world.     

CO-OPERATION IN THE DEVELOPMENT OF SHARED WATER RESOURCES

This article examines the current status of and recent progress in co-operative arrangements for the development of water resources shared by two or more countries. Such arrangements may range from the simple exchange of data to the design and implementation of major projects and formal resolutions of disputes. Topics which are of growing concern to river-basin organizations include integrated development and management or shared water resources and dealing with the fresh water-maritime interface. The article indicates that optimum co-ordinated development, use and protection of shared water resources is still a distant goal, and that increased institutionalization of co-operation is required. Cet articles passe en reveu l'état actuel et les récents progrés réalisés dans le domaine de la coopération pour la mise en valeur des ressources en eau communes à deux ou plusieurs pays. Cette coopération peut ***revêtir plusieurs formes, allant du simple échange de données à la conception et la réalisation de projects importants ainsi qu'aux règlements officiels de disputes. Les sujets qui intéressent de plus en plus les agences de bassins comprennent la mise en valeur et la gestion intégrées des ressources en eau communes ainsi que les rapports entre les eaux douces et marines. L'article souligne que la meilleure coordination dans les domaines de la mise en valeur, l'utilisation et la sauvegarde des ressources en eau communes constituete encore un but très éloigné et qu'une réglementation accrue est nécessaire. Este articulo examina la situación actual de los acuerdos de cooperación para el desarrollo de recursos hídricos compartidos por dos o más países. Tales acuerdos pueden variar desde el simple intercambio de información al diseño y ejecución de grandes proyectos y la solución formal de disputas. Los asuntos de creciente importancia para las organizaciones encargadas del desarrollo de cuencas comunes incluyen el desarrollo y administración de los recursos compartidos y los problemas de contención de aguas salinas. El artículo indica que la óptima coordinación o utilización y protec-***     

Analysis of Feedstock Supply Costs for Wood-fired Electric Power Plants in Liberia, West Africa

In Liberia, as in many developing countries, electrification of towns and cities throughout the country has long been a major development goal. However, fuel expenditures by the Liberian Electricity Corporation (LEC) for its rural public stations represent a major and growing burden on the financially hard-pressed utility. In this paper we evaluate the economics of supplying wood to rural electric power plants utilizing different sources of feedstock. We also evaluate the cost implications of differences in wood supply requirements based on the use of steam or gasifier technology, and from variation in plant utilization level.
The wood supply we consider as sources are: (1) retired rubber trees; (2) the harvesting of secondary-growth forest just before the land is returned to temporary cultivation; (3) the establishment of commercial short-rotation wood energy plantations; and (4) adding to the system of shifting agriculture the planting of fast-growing wood species. The results indicate that wood can probably be supplied under a wide range of supply and demand conditions for US$1.00–1.70 per GJ. We estimate that wood steam plants can generate power for about $0.09-0.14 per kWh and gasifier plants for $0.10-0.18 per kWh. These costs are well below the present cost of oil-based rural electric power generation in Liberia (about $0.20–0.27 per kWh).     

Water Resources Development in Small Islands Perspectives and Needs*

The paper reviews the special problems of small islands in the field of water resources development. The mode of occurrence of surface and groundwater resources in the smaller Caribbean Islands is described along with the problems which arise from unfavourable hydrological conditions. A brief survey is given of the various types of water supply systems which have been developed to meet the requirements of the resident population and the tourist sector of the islands. Institutional deficiencies are discussed as they relate to the problems being experienced in the management of public water supply agencies and the conservation of water resources.     

Broadsided by broad traits: How to sink science in five dimensions or less

This paper is a conceptual and methodological critique of arguments advanced by Ones and Viswesvaran (1996, this issue) favoring ‘broad’ over ‘narrow’ personality traits for personnel selection and theoretical explanation. We agree with Ones and Viswesvaran that predictors should match criteria in terms of specificity. We depart from them, however, in our view of how traits should be chosen to obtain the best possible prediction and explanation of a complex overall job performance criterion. We argue that the best criterion-related validities will be attained if researchers use a construct-oriented approach to match specific traits (i.e. traits narrower than the Big Five) to those specific job performance dimensions that have been found to be job relevant. We further argue that researchers should focus on development of theories of job performance that incorporate constructs that are both specific and meaningful. If researchers seek to emphasize only overall job performance and personality traits greater than or equal to the Big Five in breadth, we will fail to acquire a great deal of important knowledge about the nature and causes of important aspects of work behavior.     

Managers' reactions to a corporate acquisition: A test of an integrative model

Drawing upon previous theoretical and empirical work on mergers and acquisitions, survivors' reactions to layoffs, organizational stress, and perceived personal control, we proposed a structural model of managers' reactions to the acquisition of their company. The model was evaluated on the basis of survey data collected from a sample of middle-level managers (N=91) whose company was acquired through a hostile takeover by another company. Both were Fortune 500 companies. Though most variables were measured 16 months after the initial implementation phase of the merger, manifest indicators of change in job control were measured twice: at the beginning of the implementation phase and 16 months later. Mixed latent/manifest variable structural equations analyses provided results that were generally consistent with the proposed model. Implications of the results as well as suggestions for future research are discussed.