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.     

Legitimizing Fluvial Ecosystems as Users of Water: An Overview

We suggest that fluvial ecosystems are legitimate users of water and that there are basic ecological principles guiding the maintenance of long-term ecological vitality. This article articulates some fundamental relationships between physical and ecological processes, presents basic principles for maintaining the vitality of fluvial ecosystems, identifies several major scientific challenges and opportunities for effective implementation of the basic ecological principles, and acts as an introduction to three specific articles to follow on biodiversity, biogeochemistry, and riparian communities. All the objectives, by necessity, link climate, land, and fresh water. The basic principles proposed are: (1) the natural flow regime shapes the evolution of aquatic biota and ecological processes, (2) every river has a characteristic flow regime and an associated biotic community, and (3) aquatic ecosystems are topographically unique in occupying the lowest position in the landscape, thereby integrating catchment-scale processes. Scientific challenges for the immediate future relate to quantifying cumulative effects, linking multidisciplinary knowledge and models, and formulating effective monitoring and assessment procedures. Additionally, forecasting the ecological consequences of changing water regimes is a fundamental challenge for science, especially as environmental issues related to fresh waters escalate in the next two to three decades.     

Defining Critical Habitats of Threatened and Endemic Reef Fishes with a Multivariate Approach

Understanding critical habitats of threatened and endemic animals is essential for mitigating extinction risks, developing recovery plans, and siting reserves, but assessment methods are generally lacking. We evaluated critical habitats of 8 threatened or endemic fish species on coral and rocky reefs of subtropical eastern Australia, by measuring physical and substratum‐type variables of habitats at fish sightings. We used nonmetric and metric multidimensional scaling (nMDS, mMDS), Analysis of similarities (ANOSIM), similarity percentages analysis (SIMPER), permutational analysis of multivariate dispersions (PERMDISP), and other multivariate tools to distinguish critical habitats. Niche breadth was widest for 2 endemic wrasses, and reef inclination was important for several species, often found in relatively deep microhabitats. Critical habitats of mainland reef species included small caves or habitat‐forming hosts such as gorgonian corals and black coral trees. Hard corals appeared important for reef fishes at Lord Howe Island, and red algae for mainland reef fishes. A wide range of habitat variables are required to assess critical habitats owing to varied affinities of species to different habitat features. We advocate assessments of critical habitats matched to the spatial scale used by the animals and a combination of multivariate methods. Our multivariate approach furnishes a general template for assessing the critical habitats of species, understanding how these vary among species, and determining differences in the degree of habitat specificity. Definición de Hábitats Críticos para Peces Arrecifales Amenazados y Endémicos Mediante un Método Multivariado     

Positive and Negative Effects of a Threatened Parrotfish on Reef Ecosystems

Species that are strong interactors play disproportionately important roles in the dynamics of natural ecosystems. It has been proposed that their presence is necessary for positively shaping the structure and functioning of ecosystems. We evaluated this hypothesis using the case of the world's largest parrotfish (Bolbometopon muricatum), a globally imperiled species. We used direct observation, animal tracking, and computer simulations to examine the diverse routes through which B. muricatum affects the diversity, dispersal, relative abundance, and survival of the corals that comprise the foundation of reef ecosystems. Our results suggest that this species can influence reef building corals in both positive and negative ways. Field observation and simulation outputs indicated that B. muricatum reduced the abundance of macroalgae that can outcompete corals, but they also feed directly on corals, decreasing coral abundance, diversity, and colony size. B. muricatum appeared to facilitate coral advancement by mechanically dispersing coral fragments and opening up bare space for coral settlement, but they also damaged adult corals and remobilized a large volume of potentially stressful carbonate sediment. The impacts this species has on reefs appears to be regulated in part by its abundance—the effects of B. muricatum were more intense in simulation scenarios populated with high densities of these fish. Observations conducted in regions with high and low predator (e.g., sharks) abundance generated results that are consistent with the hypothesis that these predators of B. muricatum may play a role in governing their abundance; thus, predation may modulate the intensity of the effects they have on reef dynamics. Overall our results illustrate that functionally unique and threatened species may not have universally positive impacts on ecosystems and that it may be necessary for environmental managers to consider the diverse effects of such species and the forces that mediate the strength of their influence. Efectos Positivos y Negativos de un Pez Loro Amenazado Sobre Ecosistemas Arrecifales     

How Many Plants Feed the World?

Abstract: FAO food supply data for 146 countries were analyzed to identify the plant commodities that account for the top 90% of each country's per capita supply of food plants by weighs calories, protein, and fat. The plant commodities were divided into two groups: species commodities, such as "cabbages," that can be attributed to particular species; and general commodities, such as "hydrogenated oils," whose species composition is not known. A total of 82 species commodities and 28 general commodities contribute 90% of national per capita supplies of food plants. The 82 species commodities consist of 103 species. Fifty-six of these commodities, comprising 75 species, individually account for 5% or more of at least one county's supply of a nutritional category (plant weight, plant calories, plant protein, plant fag. These figures are several times higher than previous findings that very few (7–30) plant species feed the world. The new figures are considered more accurate because they derive from national supply rather than global production data and from several separate measures of the importance of a food commodity rather than one. The results suggest that (1) plant species diversity remains a significant factor for world food supply; and (2) a conservation priority is to maintain both this wider away of species and the diversity of genetic variants that comprise each species.