Transformations of nitrogen at the interface between the topsoil and an impervious clay subsoil

Much work has been done on gaseous emissions and leaching of nitrogenous compounds from whole soil profiles and also from soil surface measurements which are assumed to be mainly due to topsoil activity. In soils with an impervious clay subsoil, the boundary between the topsoil and subsoil may provide an interface for microbial activity, including N transformations. In this study, we investigated movement and transformations of two reactive N species (nitrate and urea) at the subsoil interface using a series of replicate, intact soil blocks, under two contrasting watering regimes. We measured fluxes in both liquid and gaseous phases and demonstrated that nitrate reaching the subsoil interface does not necessarily leach into water systems, but may denitrify immediately and could, therefore, add to atmospheric pollution through N₂O production. On the other hand, ammonium reaching the subsoil interface either directly, or after mineralization, appears to be more mobile than expected and has the potential to pollute watercourses.     

Monitoring and modelling walking track impacts in the Tasmanian Wilderness World Heritage Area, Australia

A program has been developed for monitoring the condition of unimproved walking tracks on a 1000-km track system in Western Tasmania, and it has been used as the basis of an eight-year study of track-impact development. The monitoring technique involves measuring track depth and two track-width indicators at permanently marked and widely dispersed sites, each site comprising ten transects located at 2-m intervals. Sites have been 'typed' on the basis of track slope, drainage and substrate characteristics, and the typing scheme has been tested and refined by assessing the relationship between type-usage groups and observed impacts. Analysis reveals that track depth and rates of erosion are strongly influenced by track type and to a lesser extent by usage, while track width is influenced mainly by usage and track bogginess. The time-invariant variable 'usage gradient' was introduced to compensate for the fact that usage levels on most walking tracks in Western Tasmania have varied over time. Data derived from multiple inspections at 2-3 year intervals since 1994 from over 250 sites have been used to derive impact/time curves for different type-'usage gradient' groups. Each of the impact variables can be approximated by the formula m = alphatBeta, where m is the expected value of the impact variable, t is chronological time, and alpha and Beta are constants characteristic of the impact variable and type-'usage gradient' group in question. The typing scheme and impact-development model have the potential to be used for systematically describing and predicting impacts over extensive systems of 'typed' tracks. The implications of these findings for the ongoing monitoring, sitting and management of walking tracks are discussed.     

Contrasting nitrate adsorption in Andisols of two coffee plantations in Costa Rica

Fertilizer use in coffee plantations is a suspected cause of rising ground water nitrate concentrations in the ground water-dependent Central Valley of Costa Rica. Nitrate adsorption was evaluated beneath two coffee (Coffea arabica L.) plantations in the Central Valley. Previous work at one site had identified unsaturated zone nitrate retardation relative to a tritium tracer. Differences in nitrate adsorption were assessed in cores to 4 m depth in Andisols at this and one other plantation using differences in KCl- and water-extractable nitrate as an index. Significant adsorption was confirmed at the site of the previous tracer test, but not at the second site. Anion exchange capacity, X-ray diffraction data, extractable Al and Si, and soil pH in NaF corroborated that differences in adsorption characteristics were related to subtle differences in clay mineralogy. Soils at the site with significant nitrate adsorption showed an Al-rich allophane clay content compared with a more weathered, Si-rich allophane and halloysite clay mineral content at the site with negligible adsorption. At the site with significant nitrate adsorption, nitrate occupied less than 10% of the total anion adsorption capacity, suggesting that adsorption may provide long-term potential for mitigation or delay of nitrate leaching. Evaluation of nitrate sorption potential of soil at local and landscape scales would be useful in development of nitrogen management practices to reduce nitrate leaching to ground water.     

Pollution and Waste Production in Home-Based Enterprises in Developing Countries: Perceptions and Realities

Using mainly qualitative data from a four country case study, this paper describes the nature of home-based enterprises (HBEs) and the wastes that they produce. It finds that most only generate material similar to domestic wastes, but in greater quantities. While some are undoubtedly generating dangerous wastes, they are only a small proportion of all HBEs and tend to be aware of at least some of the problem and take mitigating steps. The paper argues that the encouragement of clean processes should replace the usual negative views about HBEs that are held by policy makers.     

Protection of biota on nonpark public lands: Examples from the US Department of Energy Oak Ridge Reservation

Security buffers of Department of Defense (DoD) and Department of Energy (DOE) reservations provide long-term habitat protection for many rare and endangered species. The importance of these government-owned reservations as nationally valuable resources has been relatively unrecognized. During the last 50 years, the DOE Oak Ridge Reservation (ORR) has been a relatively protected island in a region of rapidly expanding urbanization and land clearing. Consisting of the Oak Ridge National Environmental Research Park and associated lands surrounding DOE facilities at Oak Ridge Tennessee, the unique nature of the ORR in the surrounding landscape is clearly visible from the air and has been documented using remote sensing data. Although forests dominate much of other regions of eastern Tennessee, this 15,000-ha tract of mostly natural forest habitat is unique in the southern Ridge and Valley physiographic province, which is otherwise widely developed for pasture, marginal cropland, woodlot, and urban uses. Twenty state-listed and federal-candidate plant species are known to be present on the ORR. This richness of species, which are provided protection by state and federal laws, exceeds that of the Great Smoky Mountains National Park on a species area basis and is an index of the value of the ORR both regionally and nationally in conserving biodiversity. With the end of the Cold War, changing DoD and DOE missions combined with increasing development pressure contribute to uncertainty in the future management of security reservations.     

The classic environmental issue

Summary Environmental issues are rarely straightforward. The construction of the Tellico Dam not only proved to be an exceptionally complex environmental problem but also developed into a major political issue in its own right. Following the discovery of a previously unknown species of fish near the site of the nearly completed dam, environmentalists began a long legal battle to halt construction work and protect the habitat of the fish. The United States Supreme Court found in their favour, but local political interests, through a series of clever manoeuvres, succeeded in exempting the dam from all legislation to secure its completion. The blatant use of political expediency to resolve an environmental dilemma makes the Tellico Dam a classic case study for students of environmental policy and decision-making.Graham Bennett was born in London in 1948 and graduated from the School of Environmental Sciences at the University of East Anglia where he also completed his doctoral research. Since 1980 he has been working in The Netherlands as an Associate in the Department of Environmental Science at the Catholic University of Nijmegen. His research interests lie in the field of environmental management and he is currently involved in the study of environmental policy making in Britain and The Netherlands with particular reference to the control of pollution by local authorities.     

Evaluation of management effectiveness of protected areas in the Volta Basin,Ghana: perspectives on the methodology for evaluation,protected area financing and community participation

ABSTRACT

Protected areas are widely recognized as an important strategy for biodiversity conservation. Most of the sites are, however, poorly managed as resource exploitation by fringe communities and low government funding, among other things, threaten their management effectiveness. We used the World Commission on Protected Areas framework for designing management effectiveness evaluation systems, with the Rapid Assessment and Prioritization of Protected Areas Management (RAPPAM) methodology as a tool, to evaluate six components of the management cycle at six sites in Ghana for their management effectiveness. We examined the robustness of RAPPAM as an evaluation tool in the African context. The results showed that most of the sites evaluated are vulnerable and exposed to various degrees of pressure and threats, including poverty in the nearby communities, adjacent land-use and encroachment. On RAPPAM, we noted that apart from inconsistencies in some of the assessment scores due to the biases associated with the self-assessment approach of the methodology, the management effectiveness framework places little emphasis on financing and community participation, though both play major roles in the management process. We proposed a modification of the framework within the African context, to address effectively the underlying courses of pressure and threats facing Ghana’s protected areas.     

Lessons for ecological policy design: A case study of ecosystem management

This paper explores the prospects for combining elements of the ecological and policy sciences to form a substantive and effective science of ecological policy design. This exploration is made through a case study whose specific focus is the management problem posed by competition between man and an insect (the spruce budworm, Choristoneura fumiferana) for utilization of coniferous forests in the Canadian Province of New Brunswick. We used this case study as a practical testing ground in which we examined the relative strengths, weaknesses, and complementarities of various aspects of the policy design process. Where existing approaches proved wanting, we sought to develop alternatives and to test them in turn. In particular, we used a combination of simulation modeling and topological approaches to analyze the space-time dynamics of this ecosystem under a variety of natural and managed conditions. Explicit consideration was given to the development of invalidation tests for establishing the limits of model credibility. An array of economic, social, and environmental indicators was generated by the model, enabling managers and policy makers to evaluate meaningfully the performance of the system under a variety of management proposals. Simplified versions of the models were constructed to accomodate several optimization procedures, including dynamic programming, which produced trial policies for a range of possible objectives. These trial policies were tested in the more complex model versions and heuristically modified in dialogue with New Brunswick's forest managers. We explored the role of utility functions for simplifying and contrasting policy performance measures, paying special attention to questions of time preferences and discounting. Finally, the study was shaped by a commitment to transfer the various models and policy design capabilities from their original academic setting to the desks and minds of the practicing managers and politicians. An array of workshops, model gaming sessions, and nontraditional communication formats was developed and tested in pursuit of this goal.This paper reports some specific management policies developed, and some general lessons for ecological policy design learned in the course of the study.     

Implementing Sustainability: the Use of Natural Channel Design and Artificial Wetlands for Stormwater Management

Sustainability is a concept that has been widely embraced both politically and intellectually but has not been addressed in terms of practical application. In most resource sectors, the features of a sustainable future remain unclear and there are few examples that give practical expression to sustainability. This is especially true in the case of water resources management which has been conspicuous in its absence from the majority of the literature. This paper attempts to address this deficiency on two counts. First, it provides a discussion of sustainability and the application of the concept to the management of water resources. Second, the paper illustrates how the concept can be utilized for the management and planning of urban stormwater. The paper concludes by offering research opportunities to investigate the feasibility of adopting natural channel design and artificial wetlands for sustainable stormwater management.     

Environmental education in third world schools: Rhetoric or realism?

Summary Approaches to teaching about environmental concerns that have been successful either in Western schools or in non-formal Third World projects are unlikely to be effectively implemented in Third World schools. The perceptions of schooling in the Third World, together with the economic, political and social context in which it is conducted, present constraints that are very different. Unless these constraints are recognized, attempted reforms by environmental educators will, at best, remain only at the rhetorical level and, at worst, prove counter-productive. The paper discusses three broad categories of constraint: arising from the socio-political context of schooling, the educational system itself, and issues concerning school-village transfer. The argument is illustrated by reference to research in developing countries on similar educational reforms, such as community schooling, and with examples from the author's research in Papua New Guinea. The paper concludes with some positive lessons for those wishing to see a concern for environmental issues pervade the curriculum of schools in the Third World. The danger of making such reforms over-ambitious is stressed. To be successful, such work must be given high status in the eyes of students and teachers and examination reforms should be introduced to reinforce this.Dr Graham Vulliamy lectures in Sociology in the Department of Education at the University of York. Following field research trips to Papua New Guinea in 1979–1980, 1982 and 1986, he has a special interest in the implementation of educational reforms in developing countries. He is an executive editor of theBritish Journal of Sociology of Education and of theInternational Journal of Educational Development.