The examples discussed here show how closely connected are purely natural biogeochemical processes with the consequences of Man's impact on Nature in the present-day biosphere—especially if this impact takes the form of deforestation, largearea irrigation without drainage, or massive introduction into the biosphere of complex compounds utilized in industry, farming, and other branches of economy and life. Reconstruction of Man's economic activities on a planned scientific basis is becoming imperative now. We need implementation of the principles of science-based, waste-free technology, maximum reutilization and recycling of the rejects and by-products, and adoption of an extremely delicate approach to Nature and its links. Regular observations of the status of Nature (monitoring) at suitable biospheric stations are necessary. This means that a lot of various technological, field, and laboratory studies, with experiments and modelling, have to be done. They will help us to unravel further the mysteries of the biosphere-man system, and to use with greater effect all available mineral wealth, energy, soils, water, plants, and other natural resources. Then we shall better understand the aridization and other depletion phenomena with which we are confronted, and be able to devise methods of fighting them and of multiplying the productivity of land and water.

Our environment and natural resources should be used and controlled in such a way as to maintain normal biospheric functions and efficiently prevent cases of functional disorganization of this complicated system. We must also try to reduce the possible negative after-effects of any disruptive processes in order to protect Man and his health and also Nature.

We have to preserve the biosphere of our beautiful and unique planet Earth for ourselves and for future generations.

Taiwan has the highest population density in the world today. The population growth-rate has been decreasing linearly since 1951, but the present growthrate of 2% is still much too high to lessen the population pressure. With the area of agricultural land severly limited, the agricultural sector of Taiwan can no longer absorb extra farm labourers without sacrificing the productivity of each farm labourer.

In order to feed the growing population, the high productivity of a rice paddy has been maintained by applying ever-increasing amounts of chemical fertilizers and pesticides, which in turn cause many pollution problems. Moreover the rapid growth of industries, which are mainly financed by outside capital, causes the expansion and congestion of the cities along with all sorts of pollution problems (air pollution of cities, water pollution of rivers, harbours, coastal waters, etc.)

The heavy dependence on imported energy (70% of the total energy consumption) and on trade with Japan and the United States, puts Taiwan in a vulnerable position with regard to fluctuations in the world economy. The ever-increasing population density, and the demands of a higher per caput consumption on the limited natural resources, risk leading to economic inadequacy and ecological degradation. Such a situation could endanger our industrial civilization more widely.

The rehabilitation plan for a surface-mined area should be in detail and prepared as part of the mining plan. The area to be disturbed should be identified as to its vegetation-types and potential for rapid and complete restoration. The rehabilitation plan should show, by means of topographic maps or three-dimensional maps prepared before the advent of mining, the general lay of the terrain and the reconfiguration after mining. Such maps will indicate how soil-slope regulations are being met, how aesthetic acceptability can be evaluated, and how ecological response-units for revegetation can be characterized.

In order to prepare a detailed revegetation plan before mining, the following maps and information are needed: (1) a topographic map, (2) a soil-series map, (3) a vegetation-cover map, and details concerning (4) the wildlife that inhabits the area, (5) the prevailing climatic conditions such as wind and the amount and form of precipitation, and (6) the character of each geological stratum that lies above the coal-seams or whatever is to be mined—including its structure, depth, and possible toxicity.

The detailed revegetation plan should identify where the topsoil or other plant-growth medium will be obtained, so that it can be stockpiled to be redistributed over the spoil material. Fine sandy loams, silty clay soils, and soils that are high in toxic elements or low in organic matter, should be avoided. It is recommended that topsoil material be redistributed over the spoil material to a minimum depth of 18 to 24 inches (457 to 610 mm), in order to furnish adequate depth for root concentration and for storage of reserve moisture following the spring snow-melt. The seedbed should be firm and free from competitive weeds. On harsh sites, water-holding basins or contour trenches should be constructed.

The method of seeding should include either drilling or broadcasting the seed, with due provisions for seed coverage by soil, and the addition of fertilizers and mulches where appropriate. The selection of species should include both native and introduced species that are adapted to the site. A wide diversity of life-forms and species should be included, to ensure stabilization of the area and furnish the wildlife habitat requirements. The season of seeding should be the period prior to the incidence of the most dependable precipitation in the area. The quantities of different seeds in the mixture and the overall amount employed will vary from site to site and with the method of planting. Generally speaking, poorer sites require more seed than favourable sites, and broadcasting requires about twice as much seed as does drilling.

Direct on-site costs for reclamation may vary from $250 to as much as $2,750 per acre (0.405 ha), depending upon saving and distributing the topsoil, shaping the overburden, seed-bed preparation, planting, fertilization, drainage control, mulching, and irrigation.

Spartina alterniflora salt-marsh has been established from seed and transplants on dredged materials and sandy shorelines along the North Carolina coast. Transplants were more successful than seeding over a greater portion of the intertidal range and under more rigorous environmental conditions, but seeding was successful in the upper half of protected sites. Seeding at the rate of 100 viable seeds per square metre from April through May can result in complete vegetational coverage by the end of the first growing-season. At the end of the second growing-season, above-ground biomass accumulation from seeding approached that produced by transplants which had originally been planted on a 0.9-metre centre. Both above-ground and below-ground production of planted marsh compared well with values for these components in natural marshes. There were no differences in production by epiphytes between planted and natural S. alterniflora marsh at two different locations. Faunal production in the upper 13 cm of sediment was significantly less in planted than in natural marsh, and where marsh plants accumulated sediments, faunal numbers and biomass were less in planted than in unplanted areas. Sediment carbon content indicated that 4 to 25 years might be required for a newly-planted marsh to resemble a natural marsh.

Based on our studies, the techniques developed to plant S. alterniflora on dredged material and along sandy shorelines can be employed to initiate new and functional salt-marsh where none existed previously. The length of time required for man-initiated marsh to resemble natural marsh depends upon how closely the new substrate resembles natural marsh in the type of sediment accumulated, in the elevation of the new substrate, in the natural sedimentation rate in the area, and in the relative maturity of the natural marsh system.

In spite of a relatively pollution-free ground- and surface-water system in the Ljubljana region of Yugoslavia, large public investments are planned for waste-water treatment systems. This is due to a high level of public awareness of pollution dangers and to particular characteristics of the decentralized economic and political institutional framework of the Yugoslav self-management system. The decentralized framework leads to a trend towards parsimonious decisionmaking—that is, adoption of the simplest solutions to otherwise complex policy-problems.

The new ‘water self-management communities’ in Slovenia may potentially become the instruments for regional basin-wide planning, but face four major existing problems: (1) the proliferation of local wastewater facilities throughout the region; (2) without consideration of their cost-effectiveness, the major policy goal is simply to provide sewers for 90% of the population, and not optimization of water-quality or investments; (3) the fragmentation of water management institutions hinders a comprehensive basinwide approach; and finally (4) the system of waterquality monitoring is not related to the planning process, while discharge standards and stream classifications are not based on utilization of in-stream assimilative capacity.

Three alternative systems of waste-water treatment and disposal are considered: decentralization, regionalization, and the present trend towards local communal treatment facilities but with a centralized system. Even taking into account scale economies, regionalization is probably the most costly because of the low-density urban pattern in the region, and the last-mentioned trend should be the least costly in terms of short-run capital outlays. The study could have wide implications as an example.

The present bacteriological pollution of chlorinated drinking-water supplies in many regions of Jordan gives cause for considerable alarm, especially as it has been ascertained in the work described in this paper that faecal coliform Bacteria have already polluted 37% of the underground wells in the Amman–Zarqa area. Intensive efforts should be launched in order to prevent further pollution of ground-water in Jordan.

Current trends in the utilization of wildlife in China continue a tradition of satisfying material needs for meat, apparel, and medicinal and other products. Wild animals have been hunted to bolster income from agriculture and to supply the industrial sector of the economy with material goods. Decisions about conserving or protecting animals are therefore based largely upon utilitarian premises. If they decrease agricultural productivity or are harmful to humans, predatory animals are heavily persecuted.

Chinese biologists have followed initiatives, begun in the Soviet Union, of introducing alien animals to areas where they can multiply and be cropped for commercial purposes. Research also continues to be focused on the possible relocation of faunal elements within China, to develop the market for meat and skins.

However, there appears to be a growing concern for preserving certain rare, unusual, and threatened, species because they are unique to China or have beneficial or symbolic value. This concern is likely to increase as studies in animal behaviour, migration, and ecology, demonstrate that significant declines have occurred in the populations of many ‘useful’ birds and mammals.

The environmental impact statement requirement under NEPA has resulted in a proliferation of techniques for environmental impact assessment. These may be classified according to their function into the three main categories of impact identification, impact valuation, and impact comparison. For each of these categories, some problems relating to measurement techniques are identified and discussed, and a few prominent examples of techniques in the category are reviewed. Impact identification techniques must consider how the issues should be organized, how the material is to be presented, what geographical and other boundaries should be fixed to keep the analysis at a manageable size, and what descriptive criteria should be included. Sorensen's system of ‘linear graphs’ and the Saratoga Associates' matrix approach are discussed with respect to these points.

Impact evaluation techniques, in addition to idenfying the impacts of a project, place a numerical value on their significance. For some impacts, a physical measurement scale may not be appropriate without modification; for others, no objective physical scale exists. In both cases, it is necessary to resort to subjective judgements to quantify the true seriousness of an impact. These judgements should be made systematically and, where possible, in such a manner that the resulting values form an interval- or ratio-scale rather than merely an ordinal scale. The matrix procedure devised by Leopold et al. (1971) is discussed as an example of impact evaluation techniques.

Impact comparison techniques, in addition to impact evaluation, weight the relative importance of each impact and combine the impacts for an overall assessment of the project and any alternatives to it. A major problem here is the lack of comparability between different types of impact; interdependence between impacts also makes the combination of factors difficult. Again, subjective judgements are needed, and proper use of scaling techniques can provide some basis for comparison. Techniques suggested by McHarg (1968), by Peterson et al. (1974), and by Dee (1972), are reviewed in this section.

Although EIS preparation raises several of the thorniest problems that occur in planning for decisionmaking, these are problems that must be faced, not evaded. Whereas the techniques suggested by no means solve all the problems that have been raised, they do provide partial answers. People involved in environmental impact assessment can only gain by thinking systematically about exactly what tasks are to be accomplished, and by making an appropriate choice of techniques for undertaking these tasks.

Rapid development for the exploration and extraction of mineral and petroleum resources in the cold-dominated arctic tundra and subarctic taiga regions of the world has resulted in a series of unexpected potential impacts on the environment, wildlife, and human health and safety.

Surface transportation, especially over low wet-tundra areas in summer, causes long-term changes in vegetation through reduction of insulation to the underlying permafrost. The number of passes over the same track, ground pressure of the vehicle, and speed of travel, affect the degree of degradation. For permanent roads, gravel removed from adjacent stream-beds or hillsides and laid directly on the tundra mat, has provided the most suitable road-bed. These roads, and the removal of gravel, however cause aesthetic and practical problems such as spreading of dust, impoundment of water, behavioural barricading of animals, alteration of river channels, and siltation of streams.

Anadromous fishes constitute a major food resource; alteration of stream channels or siltation of rivers can affect their movement and reproductive success. Oil-spills in aquatic systems, especially in rivers, are harder to control and clean up than terrestrial ones. Recovery of ponds in which oil has been spilled takes several years. The oil-rich outer-continental shelves in the Beaufort, Chukchi, and Bering Seas, now under exploration for oil, are especially sensitive, as they are highly productive and contain unique populations of marine mammals and birds.

Human habitation of the Arctic requires transport of food, fuel, and construction materials for lodging, and disposal of refuse and human wastes which, due to the permafrost-underlain vegetative mat, is difficult in arctic areas. Heating by fossil fuels results in ice-fogs in winter and accumulation of atmospheric pollutants at ground-level during thermal inversions at all seasons.

Perhaps the greatest impact on arctic ecosystems is simply the increased intervention of the human population. Where native people were previously only sparsely settled or nomadic in the tundra, and on coasts where they tended to congregate, now the economic need for resources has resulted in increased pressure overall which will result in decreasing habitats for wildlife, destruction of wilderness areas, and increased access to humans for further exploration and recreation.

Most of the large cities of the world are in trouble, and yet in the decades to come a vast additional number of people will live in cities. Enormous population increase produces the steep graphs we are familiar with, yet the graphs showing urbanization are even steeper, due to the migration from country to city.