The total population of Indus Dolphins, numbering perhaps 500 individuals, is subdivided by barrages into five or six subpopulations. At least two of these are so small (fewer than 20 animals) that they have little chance of survival past the next few decades. If dispersal occurs at all, because of barrages it will apparently only be downstream, causing a net loss to upstream subpopulations. The subpopulation in Sindh Dolphin Reserve, between Sukkur and Guddu barrages, is relatively large and apparently well-protected. However, the small size of the Reserve, its geographical position near the downstream end of the species range, and the political and economic instability of the area, taken together, mean that this subpopulation is at considerable risk. The need for additional reserves upstream of Guddu Barrage, to improve the prospects of the species' survival, is clear.

The subpopulation downstream of Taunsa and Panjnad barrages is unquestionably the largest in Punjab, and its protection should be a high priority of the Punjab Government. Apart from the obvious need to prevent both direct capturing and accidental killing, the Dolphins' aquatic habitat must be carefully safeguarded. Any additional withdrawal of water from the Indus and its tributaries, whether for agriculture or industry, would be inimical to Dolphin conservation. Moreover, any project involving changes to the river system's hydrography and water-quality, even if expected to have no net effect on discharge levels in the main channels, should be evaluated critically for the potential impact on Dolphins.

It is important to emphasize that responsibility for the fate of Indus Dolphins and the many other organisms affected by major water-development schemes, is shared by a number of countries in addition to Pakistan. We hope that foreign governments, in their efforts to support Pakistan's economic development and relieve poverty in the subcontinent by assisting in the planning and financing of water megaprojects, do not in the process contribute to the impoverishment of the client country's, and in turn the world's, ecological heritage.

Ecologists and environmentalists have long been at odds with economists over whether economic theory and practice helps or hinders environmental protection and improvement. This paper suggests that the specific field of environmental economics has contributed a great deal to the potential for environmental improvement, particularly with recent improvements in techniques which attempt to value environmental goods. The basic tenets of environmental economics are reviewed, including the tradable emissions-permits approach, and then specific recent applications of the permit system in the United States of America are presented.

The two basic valuation techniques, travel cost and the contingent valuation method (CVM), are briefly discussed, along with the shortcoming of the travel cost approach in obtaining ‘intrinsic’ values for environmental goods. This paper describes results from experimental economics which support the use of the CVM in estimating intrinsic values for environmental resources. In a new study, subjects in a laboratory experiment pay to prevent the destruction of a plant. This finding should appeal to the environmentalist and ecologist. Lastly, recent developments in macroeconomics and general equilibrium models which incorporate pollution and resource degradation variables, are shown to contribute positively to the goal of global environmental improvement.

Remote sensing is being widely used in the fields of resource management, planning, and wildlife habitat evaluation. Canopy cover-type mapping has been done in most of the bioclimatic zones of India and widely abroad, using aerial photointerpretation techniques. In the present study an attempt has been made to develop a methodology for mapping understorey vegetation in part of Kanha National Park, using 1:10,000-scale black-and-white aerial photographs.

The Park, one of the best for Tiger (Felis tigris) visibility and observation of other large carnivores and herbivores, has been mapped, with subdivision into 11 vegetation cover-classes and four density-classes, using aerial photographs, and each class has been visited in the field for understorey information concerning different physiographic units. Each category of canopy-cover was sampled in the field, and tree base-cover per hectare has been estimated.

Vertical profiles have also been drawn in the main vegetation classes in order to understand the occurrence of understorey vegetation. It was found that a physiographic analysis coupled with canopy-cover type and density, with appropriate sampling in the individual vegetation strata, have together proved indicative of understorey vegetationtype. When the relationship between understorey vegetation and canopy-cover type is established, one can directly depict understorey limits spatially in conjunction with the main vegetation cover. Such an approach of mapping understorey vegetation using aerial photographs could be of immense value for wildlife habitat evaluation and park management.

The growing interest in environmental impacts of agriculture calls for effective agricultural policies to confront the expanding use of chemical fertilizers. Environmental policies in agriculture should be based on evidence concerning the factors influencing fertilizer usage.

A hierarchical loglinear analysis of some social and economic factors showed that age, education, farm size, and employment status, all exert an independent effect on fertilizer usage. In addition, age and education exert a joint effect on fertilizer usage. It is found that the categories most likely to use high rates of application of fertilizer, at least in Greece, are full-time farmers 56 to 65 years old, well-educated or with small-sized holdings.

The EEC's socio-structural policy for agriculture is examined in the light of the above findings. It is concluded that the policy could form the core for an effective environmental policy in agriculture. However, areas are pointed out for the formulation of improved policy with avoidance of mistakes.

In September 1988, more than 300 participants attended the First International Forum on the Future of the Beluga, held in Tadoussac, Quebec, Canada. This Forum, organized by the ‘Fondation pour la Sauvegarde des Espèces Menacées’ (FOSEM), was intended to contribute to the development and the implementation of a survival strategy for the endangered St Lawrence population of the White Whale or Beluga (Delphinapterus leucas) by bringing together representatives of all the parties concerned. Exceeding all expectations, this event caught the attention of the press and the general public in such a way that the White Whale of the St Lawrence became a prominent symbol of our growing concern for environment in eastern Canada.

This paper is intended to present an overview of the facts and efforts that contributed to the success of the First International Forum on the Future of the Beluga as a casestudy showing how contributions from NGOs and the general public can help to improve the situation of an endangered species and the prospect of stabilization of that part of the human environment of which it has formed a prominent feature from time immemorial.

This paper addresses current and future concerns regarding the air-pollution situation in China, and focuses on reduction of particulates', SO2, and CO2, emissions in China's electric power-generation sector. Technical aspects of control methods include an assessment of innovative approaches such as enhanced oil recovery (EOR). Suggestions are made pertaining to the technical planning and management aspects of air-pollutant control.

In a technological context, improving coal-use efficiency, increasing the proportion of coal pretreatment, and using EOR technology, should be considered; these measures have proven effective and relatively economical elsewhere. If the measures could be adopted in China's electric power-generation sector, as much as about 50% of the particulates, 34% of the SO2, and 95% of the CO2, emitted from power-plants, could be removed. If fully engaged, these actions would improve China's air environment significantly.

In a planning and management context, five suggestions are made with respect to air quality regulations: administrative measures, coal prices, developing ‘clean’ energy systems, reforestation, and transferring to new energy-saving and pollution-controlling technologies. In addition to domestic efforts, active engagement in international cooperation would be extremely beneficial to China.

Although most of the lowland endemic forests of the mountainous Indian Ocean island of La Réunion have been converted by Man to other land-uses, relatively intact ecosystems still survive at higher elevations. Given the particular conservational value of these remnants of primary forest, detailed knowledge of the threats faced by these native ecosystems was urgently needed. Accordingly we conducted field surveys through the various plant communities on the island in order to answer particular questions regarding the vulnerability of native vegetation remnants to invasive, introduced plant species.

Our results indicated that most invaders colonize human-disturbed sites most successfully. However, such alien plants are also frequent in the Réunion primary forest remnants, with at least 62 species penetrating into areas which have experienced no or little human disturbance. Nevertheless, the forest remnants were still mainly dominated by indigenous or endemic plant species and maintain what is, presumably, their original vegetational structure.

The most threatening plant invaders are the trees Psidium cattleianum and Ligustrum robustwn, the bramble Rubus alceifolius, the shrubs Fuchsia magellanica and Lantana camara, and the herbaceous Hedychium gardnerianum, Boehmeria macrophylla, and Boehmeria penduliflora.

We found the early stages of primary succession on young volcanic sites to be dominated by aggressively expanding populations of alien species. It appears very unlikely that native species will replace the invaders as the succession proceeds, and furthermore the survival of many indigenous species probably hinges on the active control of alien species.

In order for alien plant management efforts to be successful, we propose a priority ranking based on the current and potential future extent of specific infestation, the rate of spread, the difficulty with which a species can be controlled, and its ecological impact on the areas invaded.

Finally, the long-term survival of the Réunion ecosystems depends largely upon the drawing up and implementation of an adequate overall conservation policy regarding human-caused invasions by alien plants in the native vegetation.

The nutrient removal-capacity of four chosen aquatic macrophytes was tested in both natural and laboratory conditions. Laboratory experiments were performed under controlled conditions using ‘microcosm’ methods wherein the plants were grown in three different nutrient concentrations. For field experiments, three ponds were selected that had different levels of plant nutrient concentrations and accordingly were treated as polluted, moderately polluted, and relatively unpolluted, respectively, the object being to study the nutrient removal-capacity of chosen aquatic macrophytes living in ‘natural’ conditions. For the present investigation, four common and widespread aquatic plants growing in all three ponds were chosen: Water-hyacinth (Eichhornia crassipes [Mart.] Solms), Water-lettuce (Pistia stratiotes L.), Round-leafed Water-fern (Salvinia rotundifolia Willd.), and Lesser Duckweed (Lemna minor L.). These plants were selected also because of their frequent presence in aquatic bodies in the region and their high reproductive capacity.

From the results it is revealed that, during the summer and rainy seasons, the highest content of nitrogen was removed by the Eichhornia, followed by the Pistia > Lemna > Salvinia, while during winter the highest content of nitrogen was removed by the Eichhornia followed by the Lemna > Pistia > Salvinia. Higher phosphorus removal was found in summer than in the rainy or the winter season. Phosphorus removal by the macrophytes was in the order of the Eichhornia > Pistia > Lemna > Salvinia, during the summer and rainy seasons, whereas the highest content of phosphorus was removed by Lemna in the winter months.

The nutrient removal-capacity was rated to be highest by the Water-hyacinth, followed by the Pistia, then the Lemna, and lowest by the Salvinia. It was also evident that the nutrient removal increased with increasing nutrient concentration in the wastewater. The removal of nitrate by the selected macrophytes ranged from 42.0% to 96.2%, while phosphate removal ranged from 36.3% to 70.2%. A positive and significant correlation was obtained between the concentration of nitrate and phosphate in the waters and plant tissues that were studied, and it is thought that a useful strategy to employ might be to grow the Eichhornia and the Lemna together at least where winter temperatures were likely to be low enough to favour the Lemna at that season, though at other times it is apt to be a nuisance.

Historically, remote islands and marine resources have been free for those willing to venture into their areas. Until recent years, many such islands have been effectively managed by their remote locations and any native humans. But nowadays, under-use is turning into destructive over-fishing and plundering, because there is no surveillance. Many marine parks in South-east Asia are facing the same problems as Tubbataha (White, 1989; Arquiza, 1990). Sustainable management in these areas is a challenge, especially where there are no local authorities or communities to take immediate control.

Field surveys at Tubbataha Reef in 1984 and 1989 have revealed a dramatic decline in the coral-reef quality from the incidence of dynamite fishing, the use of sodium cyanide for the aquarium and live-food fish trades, and the dropping of large anchors. Sea-turtles and seabirds are also endangered.

Solutions in areas such as Tubbataha will require organization beyond the grasp of local residents in the islands, who have traditionally had little formal government. Although they are aware of the problem, they are faced with outsiders and intruders who do not respect their conservatism. National government and/or nongovernment organizations can play a role in management, while being careful not to alienate the positive force and management control of the local communities (White, 1988a). Such issues require sensitive planning and community-based approaches that are directed at education, organization, and the involvement and building of local responsibility.

The management plan for Tubbataha Reef National Marine Park should have three thrusts and concomitant strategies: (1) to curtail immediate resource-destruction through the deployment of a team of educators, community organizers, and law-enforcement officers; (2) to articulate and implement a Park zonation plan which includes traditional fishing areas, sanctuaries, and buoys for anchoring; and (3) to implement a community development programme which will systematically integrate the adjacent fishing community into the Park management efforts and give the fishermen due responsibility in this process.

Climate issues reach far beyond the atmospheric and oceanic sciences, affecting every aspect of life on this planet. The issues are increasingly pivotal in determining future environmental and economic well-being. Variations of climate have profound effects on natural and managed systems, the economies of nations, and the wellbeing of people everywhere. A clear scientific consensus has emerged on estimates of the range of global warming which can be expected during the 21 st century. If the increase of concentrations of ‘greenhouse’ gases is not limited, the predicted climate change would place stresses on natural and social systems unprecedented in the past 10,000 years.

At the First World Climate Conference, in 1979, nations were urged ‘to foresee and to prevent potential man-made changes in climate that might be adverse to the well-being of humanity’. The Second World Climate Conference concludes that, notwithstanding scientific and economic uncertainties, nations should now take steps towards reducing sources and increasing sinks of ‘greenhouse’ gases through national and regional actions, with due negotiation of a global convention on climate change and related legal instruments. The long-term goal should be to halt the build-up of ‘greenhouse’ gases at a level that minimizes risks to society and natural ecosystems. The remaining uncertainties must not be the basis for deferring societal responses to these risks. Many of the actions that would reduce risk are also desirable on other grounds.

A major international observational and research effort will be essential to strengthen the knowledge-base on climate processes and human interactions, and to provide the basis for operational climate monitoring and prediction.

Sections of coastline of Heard and Macquarie Islands were surveyed for marine debris in the summer of 1987–88 and 1989, respectively. These surveys were carried out at the same sites as previous surveys in 1986–87 at Heard Island, and in 1988 at Macquarie Island. The minimum rate of artefact accumulation was 13 objects per km of shoreline per year for Heard Island, and 90 objects per km of shoreline per year for Macquarie Island. Drift-cards, released from known locations and collected on the two islands, show a similar artefact catchment area.

Plastic litter was a major component of the debris at both islands. Fisheries-related debris accounted for 40% of all artefacts on Heard Island, compared with 29% on Macquarie Island. Entanglement of Fur Seals appears to be more common at Heard Island, while plastic ingestion by seabirds appears to be more common at Macquarie Island.

In this paper, it is argued that the Norwegian Government must tackle the problems related to the conservation of coniferous forests more seriously and urgently than hitherto, and not let this important task be governed by commercial interests. A national plan based on political, non-scientific motives will not safeguard these ecocomplexes and their component ecosystems and the endangered species found in them.

A practical way to solve the time-consuming disagreements between environmental authorities and forest owners would be to guarantee full compensation, and to start paying for sites of high conservation interest immediately. This compensation must ensure that the forest owners can fulfil such financial commitments as they already have. An alternative would be the exchange of privately-owned forest for public forest land, including forests owned by ‘The Educational Fund’.

The Ministries involved must learn to cooperate in such work. If they do not, Norway's credibility in environmental matters may suffer. Solutions must be reached which do not put sectorial interests before national or international environmental values, and which guarantee the protection of a representative selection of coniferous forests according to scientific principles.

In this report we describe a method of examining the tolerance of birds to humans, namely by measuring the distance to which birds will allow a person to approach them before flying off (flush distance). We studied the tolerance of Indian birds to approaching people by recording the flush distance for 925 individuals of 138 species of residents (birds breeding in India) and migrants (birds that are not known to breed in India). Over 20% of the variance in flush distance was accounted for by the number of people situated within 50 m, the distance to the closest person, the bird's migratory status, the number of people approaching, the time of day, and the bird's total body-length (including tail).

For migratory species, 43% of the variability in flush distance was accounted for by distance to the closest other person, time of day, number of people originally within 50 m, number of people approaching, flock size, and species size. For resident species, only 18% of the variance was accounted for by distance to the closest other person, number of people within 50 m, and number of people approaching. Migrants were thus more responsive to the effect of humans, and their response was also influenced by their own size (body length) and flock size. Migratory species were less tolerant of people, flushing sooner than residents, and being more sensitive to the number of approaching people.

We suggest that resident birds in North India have become habituated to the non-violent protective behaviour of the Hindu people towards birds, whereas migrants from farther north are more wary. Alternatively migrants, being less familiar than residents with the local predators and hiding places, may be more wary than residents on their home territory. Enhanced wariness results in more time spent alert or fleeing, with resultant greater energy-demand and decreased time for feeding.