Topsoil is essential to abandoned mines and has to be stock-piled separately for post-mining land reclamation. If the storage period exceeds the 'shelf life' of the topsoil, it cannot be preserved by technical reclamation only. Opencast coal mining production in India is predicted to increase from the present level of 180 million tonnes per year to approximately 256 million tonnes per year by the year 2000. At that time about 60 km2 of land per year would be damaged by direct coal mines and 75 km2 per year would be affected by external overburden dumps and topsoil dumps. A large opencast coal mine was studied to evaluate the effect of stock-piling topsoil. Soil characteristics of soil dumps of six different ages (1, 3, 4, 6, 9 and 10 years old) were compared with those of surrounding unmined sites. Soil profiles were found to change greatly with age. Physico-chemical characteristics of soil dumps were found to deteriorate with respect to unmined soil. It was observed that, as the age of soil dumps increased from one to 10 years, the concentrations of suitable plant growth nutrients in soil gradually decreased and, after six years, the soils were found to be stagnant. This may be considered to be the 'shelf life' of topsoil. Biological reclamation must be adopted to preserve the topsoil if the storage period exceeds the shelf life period. The methodology provides guidelines for assessing the shelf life of topsoil in other areas.

Previous studies have inferred that the side effects of physical disturbance associated with bait-collecting for the sandprawn Callianassa kraussi are more deleterious than the actual removal of the prawns. The present study was specifically designed to disentangle the side-effects of trampling and disturbance associated with using suction pumps for bait-collecting. Separate areas were sucked over with a prawn pump at three different intensities, and the prawns collected from these areas subsequently returned to them. A parallel treatment involved trampling the sediment at levels comparable to the 'sucking' intensities, without removing the prawns. The responses of the meiofauna, macrofauna and microflora were assessed six weeks after this disturbance.

Prawn densities were depressed six weeks following both sucking and trampling but recovered by 32 weeks. The meiofauna responded positively to some of the disturbance treatments; macrofaunal numbers on the other hand, declined in most treatment areas, and similarity analysis and multidimensional scaling showed that macrofaunal community composition in the most-disturbed areas was distinct from that in other areas. Chlorophyll levels were reduced at the more intensely-disturbed sites.

The results corroborate the conclusion that trampling per se has almost the same effect as sucking for prawns, on both the prawns and on the associated biota. This has important implications in terms of managing the use of lagoonal and estuarine ecosystems.

Livestock depredation by the snow leopard, Uncia uncia, and the wolf, Canis lupus, has resulted in a human-wildlife conflict that hinders the conservation of these globally-threatened species throughout their range. This paper analyses the alleged economic loss due to livestock depredation by these carnivores, and the retaliatory responses of an agro-pastoral community around Kibber Wildlife Sanctuary in the Indian trans-Himalaya. The three villages studied (80 households) attributed a total of 189 livestock deaths (18% of the livestock holding) over a period of 18 months to wild predators, and this would amount to a loss per household equivalent to half the average annual per capita income. The financial compensation received by the villagers from the Government amounted to 3% of the perceived annual loss. Recent intensification of the conflict seems related to a 37.7% increase in livestock holding in the last decade. Villagers have been killing the wolf, though apparently not the snow leopard. A self-financed compensation scheme, and modification of existing livestock pens are suggested as area-specific short-term measures to reduce the conflict. The need to address the problem of increasing livestock holding in the long run is emphasized.

Despite direction by the Conservation Act (1987) to give effect to the principles of the Treaty of Waitangi, New Zealand's Department of Conservation has few formal collaborative management arrangements with Maori. Obstacles to establishing agreements that involve Maori in equitable conservation decision-making roles include divergent philosophies (preservation versus conservation for future use), institutional inertia, a lack of concrete models of co-management to evaluate success or otherwise to promote conservation, a lack of resources and opportunities for capacity building and scientific research amongst Maori, opposition and a lack of trust from conservation non-governmental organizations that are predominantly euro-centric in approach and membership, and a fundamental reluctance of some to share power with Maori. Recent examples of work towards co-management emphasize the need for innovative methods to build trust and explore common ground and differences. Meetings on marae (traditional Maori gathering places) have established guiding principles, lengthy dialogue, and a collective symbol as a metaphor for co-management. These were valuable steps towards building trust and understanding required for the restoration of coastal lakes and a river, and the potential joint management of two national parks on the west coast of the North Island. Establishment of a research project to assess the sustainability of a traditional harvest of a sea-bird (Puffinus griseus) by Rakiura Maori was facilitated by drawing up a 'cultural safety' contract. This contract underscored the role of Maori as directors of the research, protected their intellectual property rights to their traditional environmental knowledge, guaranteed continuity of the collaborative research project and regulated how results were to be communicated. The scientific ethics of a university ecological research team were safeguarded by the contract, which ensured that they could publish their inferences without erasure or interference. The New Zealand experience shows that even when legislation signals from the top down that the doorway is open for co-management with indigenous people, this by itself is unlikely to make it happen. Active facilitation by innovative middle-level agreements and the creation of new administrative structures are needed to govern co-management of a broad spectrum of resource issues. Bottom-up initiatives involving single, or very localized, resource uses may also trigger co-management. Models for successful co-management involving indigenous peoples must focus more strongly on issues of equity or power sharing, and therefore may be very different from models directed at a single conservation outcome.

There is increasing international concern about the environmental impacts of refugees on host areas, with governments calling for compensation for environmental damage, particularly concerning the loss of woodland resources as a result of demand for wood for fuel. In addition to an obvious increase in the population of host areas, concern about refugees' woodfuel-use centres on the notion that they are 'exceptional resource degraders'. Since they view their stay as temporary, it is argued, they therefore do not have any incentive to use resources in a way that is sustainable in the long term. This study examined refugee migration to the middle valley of the Senegal River, and compared woodfuel use by refugee and local populations. Drawing on a household survey and direct measurement of woodfuel use, little or no evidence is found to support the expectation that refugees use more wood for fuel than local people, or that they are more destructive in their collection or use of wood. This is important since it suggests that policy measures developed to reduce what is perceived as excess demand by refugees, notably through the introduction of fuel-efficient stoves, are unlikely to be successful. Reforestation schemes have been relatively unsuccessful in addressing supply or demand for wood.

Coastal ecosystems in the Arabian Gulf region are under increasing pressures from hostilities and other developmental activities; the region has a long history of crude-oil pollution. Because of the high ambient temperature, oil deposited along the coastline or inland evaporates, leaving a semi-solid tar. In Qatar, to clean up the polluted sites, the deposited tar is stripped off and dumped in the coastal marshes as confluent dome-shaped piles. Flowering plant colonization of tar-piles is described here as a chrono-sequence, ranging in age from 2 to 14 years. The successional patterns in vegetation, seed bank, species diversity and plant growth were predicted from tar-pile disturbances with different ages and tar content. The success of natural plant colonization and the establishment of plant communities on the tar-pile disturbances depend upon: (1) age of the tar-pile disturbances, (2) tar content of the piles and soil physico-chemical properties, (3) soil moisture content, (4) structure of plant communities in the surrounding landscape, (5) size of the disposal sites and the method of dumping, and (6) prevailing environmental conditions. A management and restoration framework is proposed to optimize the natural recolonization of tar-piles. To retain these ecosystems in a self-sustaining state, some native plant species might be used including: Aeloropus lagopoides, Aizoon canariense, Anabasis setifera, Fagonia indica, Mesembryanthemum nodiflorum, Reichardia tingitana, Salsola imbricata, Suaeda aegyptiaca, Senecio glaucus, Sporobolus arabicus, Zygophyllum quatarense, and Zygophyllum simplex. To clarify the biological and chemical aspects of the problem, further research on the chemistry of tar-polluted soil and its vegetation in relation to the food web is needed.

Although the Government of Indonesia has good data on forest cover and population, it does not have data on how many people live on state-claimed forest land. The objective of this study was to assess the extent of this deficiency and to develop a methodology for overcoming it, based on field research in the province of West Kalimantan. The project retrieved and combined government data on forests and people, analysed their significance in terms of numbers of forest-dwelling people, compared these results with government estimates and an empirical field-check, and sought to explain why knowledge of forest dwellers on state-forest lands is problematic. Results suggest that 20 to 30% of the population of West Kalimantan (approximately 650 000 to one million people) live on state-claimed forests. The main reason why it is difficult to determine how many people live on state-claimed forest lands is that a large number of villages remain unmapped and thus it is not possible to unite census data with forest boundaries in a spatially-precise manner. While the Indonesian Ministry of Forestry has not placed a high priority on determining how many people live on state-claimed forests, this study suggests that the lack of information on forest population densities is as much a consequence of the lack of information on village locations as it is a result of political or institutional interests.

Increasing human pressure has presumably led to a decrease in the cover and herbage yield of Kuwaiti desert vegetation, but, to date, there has been little detailed study on such human impacts. A study of Rhanterium epapposum (local name arfaj) and Haloxylon salicornicum (local name remeth) steppe was therefore effected to determine the seasonal variation in above-ground phytomass and percentage cover, and to investigate differences between protected and adjacent grazed areas.

An average seasonal precipitation of 90 mm supported a mean of 223 kg ha-1 in arfaj steppe in 1979–1989, whereas an average mean seasonal precipitation of 73 mm during 1983–1989 maintained a mean phytomass of 102 kg ha-1 in the remeth steppe. Annual forbs and perennial shrubs were the greatest producers of dry matter per kg of phytomass in the arfaj and remeth steppes, respectively. The seasonal production of dry matter was related directly to the seasonal precipitation in the arfaj steppe, whereas the remeth steppe did not show an obvious relationship to the precipitation. The plant cover was 83% and 70% less, and herbage production was 76% and 91% less in grazed areas than in protected areas in the arfaj and remeth steppes, respectively.

Despite steady injection of public funds by successive administrations, the Canadian fishery industry is characterized by resource depletion, vessel tie-ups, and overcapacity, which have led to plant closures and rising unemployment. This paper assesses the progress Canadian marine policies have been making towards rational use and conservation of fisheries and promotion of employment and economic development in fishing communities since 1977.

The analysis begins with the creation of the 200-mile exclusive economic zone (EEZ) and its rationale in the United Nations Convention on the Law of the Sea (UNCLOS), namely conservation. State subsidies for fleet upgrading, industry modernization, marketing, and the introduction of quota systems, such as the individual transferable quotas (ITQs) and enterprise quotas (EQs), are identified as the key policy initiatives which might realize an economically-viable fishing industry in the post-1977 period. These policies produced corporate expansion and prosperity in the mid-1980s, but there followed corporate losses because of Canadian over-dependence on American markets and sharp quota cuts.

With regard to conservation, shortcomings are identified in the virtual population analysis model (VPA), and the inability of the Department of Fisheries to monitor fishing effort by domestic and foreign vessels. The need for radical change in the future direction of marine policies is emphasized and arguments made which support the following objectives: elimination of ecologically-harmful fishing technologies; use of community quotas (with a modified individual quota system); strengthening of community management systems and development of co-management approaches to fisheries management, involving government and fishing communities.

Predicting the distribution of endangered species from habitat data is frequently perceived to be a useful technique. Models that predict the presence or absence of a species are normally judged by the number of prediction errors. These may be of two types: false positives and false negatives. Many of the prediction errors can be traced to ecological processes such as unsaturated habitat and species interactions. Consequently, if prediction errors are not placed in an ecological context the results of the model may be misleading. The simplest, and most widely used, measure of prediction accuracy is the number of correctly classified cases. There are other measures of prediction success that may be more appropriate. Strategies for assessing the causes and costs of these errors are discussed. A range of techniques for measuring error in presence/absence models, including some that are seldom used by ecologists (e.g. ROC plots and cost matrices), are described. A new approach to estimating prediction error, which is based on the spatial characteristics of the errors, is proposed. Thirteen recommendations are made to enable the objective selection of an error assessment technique for ecological presence/absence models.

Many sea-birds are dependent for breeding on islands free from both mammalian predators and high levels of human disturbance. Yet human use of small islands appears to be increasing in many parts of the world, including the >150 islands in the Gulf of California, México. For this reason, the frequency and activities of human visitors to San Pedro Mártir Island, one of the most important sea-bird nesting sites in México, were studied over the course of 14 months of field work between 1990 and 1992. On average >350 people per month visited the near-shore waters. The most important visitors were: (1) commercial fishers in small open boats called pangas; (2) commercial fishers in larger ships; (3) private sport-fishers; and (4) commercial environmental-tourism groups. Private sport-fishing boats were most frequently observed, but private sport-fishers rarely landed on shore and caused little apparent disturbance to nesting or roosting sea-birds or California sea-lions (Zalophus californicus). Commercial companies concerned with environmental tourism also caused little apparent disturbance to sea-birds or sea-lions, but only because the company that brought the majority of 'ecotourists' developed and followed guidelines to minimize disturbance. Disturbance caused by all tourists can be reduced at minimal cost to both tourists and protected-area managers. Commercial fishers were responsible for most of the apparent disturbances to sea-birds and sea-lions; decreasing this apparent impact will be more difficult. Most apparent human impact was found to be short term and localized. However, commercial fishers and scientific researchers have the potential to cause long-term changes to the terrestrial ecology of the island by introducing exotic species.

Given limited budgets to enforce access restrictions, protected area (PA) managers and non-governmental organizations (NGOs) in developing countries employ a range of policy instruments to conserve the area's natural resources. Natural characteristics of the PA combine with the managers' enforcement activities and other policy instruments to create a set of incentives to which local people respond in making decisions about extracting resources from the PA. The different management approaches employed in the Xishuangbanna Nature Reserve (XNR; China) and the Khao Yai National Park (KYNP; Thailand) and the reaction to the incentives which they create are compared. KYNP managers use policing and punishment mechanisms, in conjunction with limited NGO-supported income-generation projects, to deter resource use. In contrast, XNR managers rely on extensive cooperation with local people and trade-offs between current resource degradation and increased rural incomes.

As predicted by the economic enforcement literature, rural people respond to the threat of punishment, and its reduction of the expected benefit of an illegal activity, by reducing that activity, but may undertake socially-costly avoidance activities to avoid punishment. This literature also correctly predicts that XNR managers will concentrate less on pure enforcement than KYNP managers because, as a result of a difference in government mandates, the XNR managers consider the value of the extracted products and the non-PA productivity in their decisions while the KYNP managers do not. In both PAs, rural people's actions affect the quality of resource conservation. In KYNP, natural characteristics and the policing activities deter resource extraction and encroachment in the central core of the Park. Even NGO projects, however, have not controlled extraction, and even agricultural encroachment, in the outer third of the Park, which has caused over-extraction of some resources and has left a ring of highly-degraded land. In contrast, XNR's cooperative management approach has generated more control over the amount and the spatial configuration of resource degradation. XNR's control, however, comes at the cost of reduced area and level of current conservation.

The Western Australian system of protected areas (PAs) covers more than 15 million ha and is the second largest conservation estate of the Australian continent. An analysis of the history of the creation of PAs in Western Australia shows that the concept of nature conservation through reserves was slow to emerge. During the early decades of the century, reserves were mainly created for their recreation values. The lack of governmental interest in nature conservation led to a belated development of reserve coverage up to the 1950s, while vast areas of land were opened to farming and pastoralism. Following two scientifically-based reviews of the PA system, the number and coverage of PAs increased dramatically up to the late 1970s. The rationalization of the vesting and managerial responsibilities for PAs was only finalized in the 1980s. Since then, there has not been any large increase in PA area but a consolidation of the PA coverage. The development of the system of PAs has been impeded by the belated response of Western Australian governments to conservation concerns and a 'worthless' land approach to conservation as a land use. While large-scale land alienation for agriculture has now stopped, other types of land uses such as mining and other aspirations over land management and vesting, such as Aboriginal land claims and forestry are now constraining any large expansion of the PA system. Only an approach embracing the whole landscape can overcome the political and social limitations of the concept of PAs and the further degradation of developed land in Western Australia.

Sustainable development requires that population and consumption remain within the limits of carrying capacity, while preventing a decline in the carrying capacity of an area requires that productive systems implanted through development be sustainable. Zoning can be a valuable tool in influencing land-use decisions, but we cannot expect government decrees to be capable of causing the landscape to evolve toward the sustainable patterns which have been recommended through zoning. A prerequisite for influencing land-use change is understanding the social processes involved in land-use decisions, beginning with deforestation dynamics. Work to estimate carrying capacity needs to embrace the wide variety of production systems used and contemplated for Amazonia and to be able to interpret this information at scales ranging from local communities to the region as a whole. This will require not only studies of different land-use systems in rural areas, but also integration with studies of energy use and support limits of urban populations. Risks of environmental impacts must be quantified under different development scenarios, and limits of acceptable risk identified and integrated into analyses of carrying capacity.

Tapping the value of environmental services of standing forest represents a promising means of sustaining Amazonia's population over the long term, but numerous obstacles exist. These include halting deforestation before opportunities are lost and supporting the population in non-damaging ways while the institutional groundwork is laid for using the environmental services involved. Research is needed to quantify the magnitude of services and the appropriate monetary value per unit of service. Diplomatic agreement must be reached on these values, which can be expected to be quite different from estimates of the 'true' values based on research. A series of social arrangements must be proposed and implemented if the value derived from environmental services is to fulfil its dual role of maintaining both the forest and the human population in Amazonia.

The implications of world population growth for future fertilizer use and impact on the environment have scarcely been predicted. We investigated world protein production using a global nitrogen balance model. The model assumes that world population continues to grow and crop yield per unit area is closely related to nitrogen fertilizer use. About five times more cereal protein is needed to produce meat protein through farming. Advanced countries consume more meat than people in developing countries. Assuming the world's arable land remains constant in area in the next century, and if the meat consumption in advanced countries is matched by the rest of the world, the demand for fertilizer will increase and reach 220 Tg y-1 by the middle of the next century. This is approximately three times more fertilizer than is currently used, and would accelerate environmental deterioration. The world would be suffering from conflict between supplying sufficient protein and greater nitrogen pollution of the environment.

Estimates of population size have been essential for ecological theory and wildlife management, but they depend on spatial scales of observation. Reported aspects of study and interpretive design were tested to see if they could explain variation in puma (Puma concolor) density. Comparison of puma studies revealed information shortfalls and possible confounding effects in research trends. Vegetation descriptions and other biological and physical aspects of the study site explained none of the 30-fold range of variation in puma density, nor did sampling and estimation methods and other aspects of study and interpretive design. Most (78%) of the variation in puma density estimates can be explained by the spatial extent of study area. Given the effect of scale, puma density estimates have been inappropriately extrapolated to larger geographic areas for management purposes. Due to spatial shifting of local population clusters, conventional density estimates cannot contribute to assessments of puma population trend without study at multiple sites over longer periods of time. Field studies would contribute more to knowledge of puma by spanning larger areas, a greater variety of land uses and habitats, and more of puma's range of distribution.

Tropical forest destruction jeopardizes wildlife habitat. In many countries, hunting by low-income households also poses a direct threat to many species. This paper reports a study of the wildlife hunting practices of an indigenous cultural community in the Philippine province of Palawan. A survey of hunting practices was conducted among farmers living along the forest margin. The survey collected information on hunting frequency, hunting techniques, and species hunted. These data were combined with household income and demographic data to learn how socioeconomic factors influence hunting patterns and practices. Descriptive statistical procedures and regression analysis show that hunting pressure during the study period was typically greatest among resource-poor households. Poor households used the widest range of hunting implements, including modern implements such as air rifles, and low living standards were associated with greater hunting effort. Households with small farms were more likely to hunt, and were also more likely to expend greater hunting effort. Hunting was a supplementary source of food acquisition for most farmers and was found to be inferior to agricultural production, in the sense that households with large farms tended to hunt less often than households with small farms. Indirect evidence suggests that higher population pressure correlates positively with hunting pressure, and that non-agricultural employment negatively correlates with hunting probability and intensity.

Over the past two decades 'sustainable development' has grown from a term expressing concern for social and environmental problems to an international craze. The concept purportedly offers cures for the many and diverse problems afflicting modern society, and because it involves an integrated approach, the sustainable development fashion has resulted in much-needed collaboration between specialists from diverse backgrounds, to work on the complex problems involved in the interactions between society and environment. However, the term is rarely defined, and, being stylish and institutionalized, the 'sustainability movement' now directs the way much science and policy for biological conservation and development are designed, executed and evaluated. Occult, but basic, in nearly all discourses of sustainable development is the axiom of continual growth; and, in most cases, instead of offering a true solution to contemporary problems, the term is a source of confusion, contention and even deception. It is imperative that the use of this term, especially in multidisciplinary, international and scientific spheres, be based on clear understanding of its meaning, and that the issue of growth and the concept of limits be clearly incorporated into the core of the discussion.