Forest decline in the tropical zone of the world has provoked an enormous amount of concern but, so far, few if any panaceas. Leaving aside the pervasive impact of clearance for agriculture to focus for the time being exclusively on the role of timber extraction in the moist tropics, it appears that, in present circumstances at least, commercial logging is effectively incompatible with sustainable forest use. For this reason there is a developing interest in the potential which private-sector plantation forestry may have, in these areas, for significantly contributing to both local and export timber needs and so relieving pressure on the remaining area of natural forest. The peculiarly long-term character of investment in trees, and the capital-poor nature of the countries concerned mean, however, that financial incentives will almost certainly be necessary if plantations are to have real consequence.

It is in this context that the recent history of the forest programme in Ireland, the country with the lowest overall proportion of forest cover and the highest percentage of state (as opposed to private) forestry in the EC, may be relevant. Forestry incentives introduced in 1980, and aimed at landowners in the agriculturally disadvantaged western region, were initially ineffective, despite the region's comparative advantages for timber-growing. However, major additions to the level and range of support in the second half of the 1980s, led to an exponential increase in grant-uptake.

The very success of the above scheme in recent years has caused it to be critized for the loss of large areas of bogland which have considerable environmental value but low potential for timber production in any normal investment sense. In addition, plantations in all parts of the region are overwhelmingly coniferous. More generous, country-wide incentives for environmentally desirable broadleafed planting are too new for it to be known what effect they will have on the afforestation of the better land. It seems almost certain, however, that attempts to reconcile productive and environmental aims in private forestryprogrammes inevitably increase their complexity and cost: this has undesirable implications for the possible transfer of such schemes to developing countries in the tropics.

Representatives of national academies of science from throughout the world met in New Delhi, India, from 24 to 27 October 1993, in a ‘Science Summit’ on World Population. The conference grew out of two earlier meetings—one of the Royal Society of London and the United States National Academy of Sciences, and the other being an international conference organized by the Royal Swedish Academy of Sciences. Statements published by both groups expressed a sense of urgent concern about the expansion of the world's population and concluded that if current predictions of population growth prove accurate and patterns of human activity on the planet remain unchanged, science and technology may not be able to prevent irreversible degradation of the natural environment and continued poverty for much of the world.

The River Yamuna, originating in the Himalayas, is the largest tributary of the River Ganga (Ganges) into which it flows at Allahabad. Its drainage basin covers about 42% of the Ganga River basin and about 11% of India's total land area. The area of the Yamuna drainage basin is densely populated and under intensive agriculture, while industrial activity is also rapidly growing in it. Climatically, a large part of the basin is semi-arid, and the river-flow depends upon highly erratic monsoonal rains. Therefore, the River and its tributaries have been regulated for over a century by dams and barrages for domestic water-supply and irrigation.

Besides increased flow-regulation, the River's system has been under increasing anthropogenic stress from discharge of—mostly untreated—domestic and industrial wastewaters, and from other activities in the basin. River Yamuna is severely polluted by domestic and industrial effluents especially from Delhi down to Agra. Water extraction and consequently low flow has affected the selfpurification capacity of the River. The greater inflow of River Chambal helps River Yamuna to recover to some extent after their confluence near Etawah.

Studies of water quality and biota of the River Yamuna along its course during the past 30 years show rapid deterioration of water-quality, loss of fisheries, and significant changes in the biotic communities. In the manner of River Yamuna, its tributaries have also become increasingly polluted during the same period. There has, however, been little attention paid to the management of the River system and conservation of its resources, except for some efforts at the treatment of sewage effluents but emphasizing only water-quality. Ignoring the river-flood-plain interactions which play significant roles in the ecology of a river, most of the floodplain has been reclaimed by constructing high levees.

We emphasize that the Yamuna River basin should be treated as one ecocomplex in developing appropriate management strategies, and that the conservation of waterquality and biota can be achieved through protection and better management of floodplains than has been practised to date.

It has been increasingly accepted that park management policies in some countries should allow for limited access to park resources by the local people to meet their subsistence and cultural needs. However, too much access to the natural resources of a park may simply cause people to rely on the park resource and manage their own lands less intensively than hitherto.

The issue of illegal livestock-grazing and fodder-cutting in Royal Chitwan National Park (RCNP) by local people is examined. The study area was comprised of 16 village units having an estimated population of 148, 404 people in 21, 621 households. Despite the presence of a large number of armed guards, the data from interviews with farmers indicated that illegal livestock-grazing and fodder-cutting in RCNP were prevalent. In the spring season, grazing intensity on the Park was higher than in other seasons, whereas cutting of fodder was intense in both winter and spring seasons.

The actual monitoring of 11 patches (totalling 365 ha) of grasslands or savanna for a calendar year inside the Park but near its boundary, indicated that illegal grazing averaged 4.1 head per ha (3.0 cattle, 0.9 buffalo, and 0.2 sheep/goats). In addition, the livestock biomass was found to be increasing by 2.36% per annum in Park-adjoining villages. There is some evidence that villagers adapt their livestock practices in response to the availability (illegal) of grazing in, and fodder-removal from, the Park.

The pressures for illegal access to park resources will continue to grow and eventually will exceed the capacity of the resource to recover from harvest. The best approach to resolve this illegal livestock grazing issue is neither strict protection nor widely-expanded access. The Park should consistently work to induce a gradual behavioural change, on the part of the farmers, to stall-feed livestock from fodder originating from their own farms and/or from community plantation.

An investigation is in progress in Formentera, Balearic Islands, to see whether satisfactory growth-rates can be achieved for trees of certain species — using small quantities of highly saline irrigation water, but relying on winter rainfall alone for leaching, and at the same time avoiding detrimental long-term environmental effects. Climate and soils in Formentera are similar to those of many semi-arid portions of the Mediterranean region. Two species, Eucalyptus gomphocephala and Acacia saligna, were tested with four irrigation treatments: no water, best available water (less than IdS/m), and waters of 5 and 10 dS/m. At Site 1, sea-salt water was mixed with BAW to achieve the desired conductivities, and at Site 2, highly saline ground-water was used for mixing. Sodium absorption ratios (SARs) were 84.8 for 5dS/m mixes and 152.1 for 10dS/m mixes at Site 1, and 13.06 for 5dS/m and 23.2 for 10dS/m at Site 2.

Trees were raised from seed in a local nursery, and were planted out in a grid pattern at 1.5 × 2 m spacings. Water requirement was calculated from a balance between pan-evaporation and tensiometer readings. Soil samples were taken at the beginning and end of each irrigation season. Trees were watered by hand-held hosepipe for two seasons. Irrigation was then withdrawn from half of the sample-trees. The remaining half were watered for two further seasons. Thus it was possible to compare the performances of trees receiving two years and four years of irrigation. In the first two years the three irrigated classes did significantly better than the trees which had received no water, but there was no significant difference between the classes due to salinity. At four years of age, the trees receiving continuing irrigation had grown more than those which received only two years of irrigation, although the latter continued to grow at a slower rate. However, where soils were extremely shallow (Site 2), withdrawal of irrigation affected survival rates, especially among the eucalypt.

The Acacia survived better than the Eucalyptus, even on extremely shallow soils. At the end of the second season it was clear that the establishment and vigorous early growth of the trees had been successfully achieved. At the end of the fourth year, it was also clear that trees would continue to grow without continuing irrigation — with the proviso that, on extremely shallow soils (20 cm or less), the Acacia survived significantly better than the Eucalyptus.

Analyses show that the winter rain appears to be effectively leaching the soil. Exchangeable sodium percentages (ESPs) rise during the irrigation season and fall during the winter. All ESPs have fallen off considerably when irrigation has been withdrawn. It appears that satisfactory growth can be achieved, and environmental protection established, with these small quantities of water at a purely temporary environmental cost (the short-lived increase in soil salinity). So far, the experiment demonstrates a low cost and effective technique for rapid tree establishment with low-quality water. Monitoring continues of soil nutrients, organic matter, litter, and soil fauna, to determine the sustainability of benefits.

Increasingly, seabirds nesting on islands are exposed to tourists who view, photograph, and study, them for variable periods of time. The escalating frequency of human-seabird contacts on heretofore undisturbed nesting islands raises questions and concerns about the effects of human disturbance, and of the continued preservation of nesting colonies of marine birds. We examined short-term changes in behaviour of Masked (Sula dactylagra), Redfooted (S. sula), and Blue-footed (S. nebouxii), boobies when tourists walked by, and examined display station and nest placement as a function of distance from a regularlytraversed tourist path on Tower (Genovesa), Hood (Espanola), and North Seymour, Islands, Galápagos.

Whether displaying boobies walked, flew, or remained on their station, when tourists passed, was related to their distance from the trail. Boobies displaying at stations on or up to 2 m from the trail, walked or flew from their station 62 to 95% of the time, depending on the species. All species of boobies performed more head and body turns, and gave-out more calls, after tourists passed than before, while the rate of preening did not differ. All three species of boobies avoided nesting right along the trail, despite similarities of habitat.

These data suggest that boobies respond to tourists in subtle ways often related to their species, and that further studies should delineate impacts operating over longer periods—including reproductive success variation as a function of disturbance.

The discussion above sought to clarify some of the key aspects of the relationships among impoverishment, population, and environmental degradation, and to pose a conceptual framework for addressing the issue. At various times, impoverishment has been identified: as a root cause of environmental degradation; as a proximate cause; and as a contributing factor, merely reinforcing the linkage between environmental degradation and poverty often caused by wealth and greed. Despite an abundance of recent literature on the topic, it is not clear how environmental degradation and impoverishment are linked. What is apparent is that the relationship amongst these elements is complex, multidimensional, conditional and, at present, indeterminate. Although much of the evidence linking impoverishment and environmental degradation is anecdotal, it appears that the key issue is one of equity. Considerations of international equity, national equity, and intergenerational equity, must form the cornerstone of any strategy to confront the joint issues of environmental degradation and impoverishment.

Promoting equity as a key principle or strategy, however, does not reduce the complexity of the issue; equity has an economic dimension, a political dimension, and a social dimension; numerous case-studies can be found to illustrate these dimensions, and a few are noted in our above discussion. This framework is also tied to the goal of sustainable livelihood security, which recognizes that security has both political and environmental components. Despite the complexity of these issues, it is still possible to develop general recommendations to be used as a guide to the design of intervention strategies by agencies providing development assistance. Accordingly, five such recommendations are noted last above.

The conceptual framework developed in this paper sought to extend the work on the impoverishment, population, and environment, issue begun by Leonard (1989), Holmberg (1991), and others. It is clear, however, that much more study of these complex interrelationships is needed before the linkages amongst them are well identified and understood. In addition, it is not enough to accept the importance of equity as a key principle of sustainable livelihood security; development agencies must be willing to act on this principle, and to design intervention strategies which aim at reducing and eliminating the inequities which are a major cause of environmental degradation.

Extending over a year, all the birds that could be detected were counted on two transects which together sampled an area of 1.39 km2. Only 37 species were recorded during 82 surveys. Total bird density during the spring (March–June) was 43.0 birds/km2, and the density for the entire year was 26.7 birds/km2. The characteristic nesting birds were Western Meadowlark, Sage Sparrow, Burrowing Owl, Mourning Dove, Horned Lark, Long-billed Curlew, Lark Sparrow, and Loggerhead Shrike. Western Meadow-larks and Sage Sparrows were the most abundant nesting birds, having an average density of 11.2 and 7.8 birds/km2, respectively. Seasonal distribution of birds varied with species, but most species were present only from March to September.

Sixty-three per cent of the habitat surveyed was dominated by Big Sagebrush, 26% was dominated by Cheatgrass, and the remaining 11% was dominated by Spiny Hopsage. Big Sagebrush habitat supported a greater total bird density than the Cheatgrass or Hopsage habitats. Sage Sparrows were closely associated with Sagebrush habitats, while Western Meadowlarks showed no strong habitat affinities.

Extensive habitat modifications induced by more than a century of agriculture and livestock grazing have greatly depleted native Shrubsteppe habitat in the Columbia Basin. Over the past 40 years, the Hanford Site has served as a refugium for Shrubsteppe habitat that supports populations of native Shrubsteppe birds. The concept of the Hanford Site as a refugium for native Shrubsteppe habitat and Shrubsteppe nesting birds is favourably discussed.

Middens (i.e. persistent ‘dung-heaps’) produced by Rabbits (Oryctolagus cuniculus) on a limestone quarry-spoil bank in the process of reclamation were small areas of enhanced biological activity, initiated and maintained by Rabbits, that were probably beneficial, through recycling of nutrients, to those same Rabbits.

The soil of the middens, at a depth of 0–5 cm, was moister, richer in nutrients, of lower pH, and more humic, than elsewhere on the spoil. It probably owed these characteristics to the Rabbits' urine as well as dung.

Middens were ‘beneficial’ to the pioneer vegetation through the resultant of increased fertility and grazing; sown grasses were stimulated to produce local patches of sward on the spoil. The plants themselves were more intensely green, and richer in nitrogen, phosphorus, and potassium, than those in the surrounding area.

Associated with the soil surface of the middens was a rich invertebrate fauna, some members of which must be directly and entirely dependent on the dung. Overall the Rabbits were judged beneficial to the reclamation.

The management of many ocean wildlife species is left in an institutional void, yet certain species command considerable public attention and have burgeoning management problems. In this paper the non-consumptive recreational use of Killer Whales (Orcinus orca) on Canada's Pacific Ocean coast is used as an example of management difficulties that are associated with oceanic species. Problems associated with jurisdiction and institutional arrangements are coupled to significant levels of biological uncertainty and restricted management options, as well as to management concerns associated with the human domain. The case is conceptualized as an interaction between the human and more general ecological spheres, mediated by the history of the relationship between humans and the species in question. Two routes to regulation are presented, dealing respectively with the human and ecological aspects. Of particular significance is the idea that both types of information are necessary to maximize utility to both the human user and the Whales.

Results from an ongoing study of recreational use are presented to indicate some of the variables that have emerged. These are to be interpreted within current resource management infrastructure to create a tenuous situation. The unfortunate logic that results from this study is that if Killer Whales (a high-profile species) in Canada (a well-endowed nation) have not warranted more substantial protection, then the outlook for less well-known marine species in areas of the world where resource management priorities involve more direct survival concerns, is not optimistic.

Long-term climatic variations over the past 400,000 years, disclose a cyclical alternation of cold or glacial phases. At the present time, the world is experiencing one of its warmer climatic periods. Nevertheless, summer insolation has decreased sharply during the last 9,000 years and, apart from human influences, a gradual reduction in temperature might well be expected to occur during the next 50,000 years. On the other hand, if the human-induced ‘greenhouse effect’ manifests itself as is sometimes forecast, climatic changes will take place much faster, and temperatures could reach higher levels than in any of the post-Pleistocene interglacial phases. The future of the Sahara depends to a considerable extent upon which of these trends actually manifests itself.

Climatic change is not a new phenomenon, nor is it random, as most of the variation can be explained in terms of variations in the sunlight reaching the surface of the Earth. The solar energy reaching the surface is modified by the aerosols in the atmosphere, however, and that means primarily aerosols of volcanic origin.

The climatic history of the Earth is divided up into episodes with abrupt beginnings and ends. Rapid changes from one climatic state to another are normal. The fluctuations within this century do not appear to be unusual in any respect.

To the Author's knowledge there is no evidence that past climatic changes, including those of the last decades, are related to changes in carbon dioxide in the atmosphere—except perhaps for warmer nights in the North American mid-west. It is not possible to simulate past climates using carbon dioxide content as the main variable, but it is possible to do so using calculated solar radiation as modified by volcanic aerosols. This strongly suggests that forecasts of the climatic future based on carbon dioxide increases are suspect.

Computerized models of the climate that can simulate decadal and century-long variations of climate as well as variations on the millennium scale, suggest that the climate will not warm dramatically in the next fifty years, but will, rather soon after that, begin a rather rapid change towards the next glacial climate.

Changes in our global array of cultures, sufficient to affect the global climate in a way which we perceive as beneficial, probably are not possible within centuries without massive physical conflict. There are both winners and losers when the climate changes in a non-uniform pattern, as it always does. It is a well-known fact that a global change of 0.5°C in mean temperature, such as has happened in recent years, might produce some regions of 10°C change in either direction and some regions with no change at all, and additionally an array of rainfall changes of various magnitudes. Russians would welcome warming of their climate!

The problems with attempting to modify the global climate in a particular direction are enormous and would be incredibly costly. This is compounded by our not knowing what the climate would do without intervention. Only one thing is truly clear, and it is that the present knowledge of the climatic effect of changing carbon dioxide content of the atmosphere is totally inadequate as a basis for initiating any global attempt to change the climate.

The indicated action would appear to be to engage in some high-quality climatic research based on sound science before taking global risks greater than those that might arise from the putative ‘global warming’.

The protracted dispute over the fate of the Endau-Rompin rain-forest in southern Peninsular Malaysia is outlined. Attention is focused on why a proposal to create an Endau-Rompin national park was eventually abandoned, on what has been done of late to protect the wilderness region, and on what has been learned from the dispute. The main points are as follows:

1. Endau-Rompin is one of the last-remaining extensive tracts of largely undisturbed rain-forest in southern Peninsular Malaysia.

2. The Third Malaysia Plan 1976–1980 incorporated an earlier proposal to create a national park in the Endau-Rompin region.

3. A controversy erupted in 1977 when the state govern ment of Pahang approved a logging concession in the core area of the proposed park.

4. Logging ceased in 1978, but in spite of the preparation of a preliminary management plan and the passage of the National Parks Act (both in 1980), a national park was not created.

5. The 1985–6 ‘Malaysian Heritage and Scientific Expedition’ to Endau—Rompin focused a great deal of public attention on the wilderness region, but still a national park was not created.

6. In mid-1987 it was announced that there would be two adjoining state parks, not a national park, in the Endau-Rompin region.

7. The proposal to create a national park came to nothing because Pahang and Johor were unwilling to surrender their jurisdiction over their respective components of the required land to the Federal Government, and because the latter made no attempt to acquire the land in the national interest.

8. A state park has been established in the Johor part of the wilderness region, but the promised adjoining state park in Pahang has yet to be established. It would appear that the two parts of the protected area will be managed separately, with eco-tourism as an important focus.

9. For more than fifteen years the Malayan Nature Society has played a key role in the struggle to save the wilderness region.

10. The Endau-Rompin dispute revealed that NGOs such as the Malayan Nature Society can play a key role in the environmental arena, that ever-increasing competition for scarce natural resources makes it increasingly unlikely that new protected areas will be established, and that the protection and management of Malaysia's natural heritage is greatly confounded by the constitutional division of powers between the Federal and state governments.

Significant differences in embryonic mortality and occurrence of structural developmental defects between three separated populations of the Black-headed Gull were examined. Growth retardation was not studied.

Population ‘C’ (average 2.78 eggs per nest), living in Western Slovakia, exhibits in three-egg clutches relatively low mortality (7%) as well as a low occurrence of developmental defects (2.8%). In population ‘B’ (2.6 eggs per nest, living in Southern Moravia), breeding in a region that is intensively exploited for agriculture, the mortality is still very low (3%) but the proportion of malformed embryos increases to 15%. In population ‘A’ (2.6 eggs per nest, living in Southern Bohemia) the highest mortality was found (13%) but only 4.3% of embryos were malformed, though there was a broader spectrum of developmental defects. In this population the eggs were significantly smaller and had thinner shells.

In all the populations which were examined, the mortality and occurrence of developmental defects were higher in one-egg clutches, which were more frequent in populations ‘B’ and ‘A’ than in ‘C’.

Except for mercury, it does not seem that concentration of toxic substances in eggs could be responsible for the observed differences in reproductive success. An increase in embryonic mortality at locality ‘C’ is probably evoked by malnutrition in garbage specialists.