What we need now is to find the balance required between all types of space from the ecological point of view. A great danger for food production is being created by the expanding human settlements. As soon as commercial forms of energy and machines enter our settlements, they start to expand at a much greater rate than does the growth of the settlement's propulation and economy. As the growing settlements need to add a lot of industry and many big buildings, their expansion is not directed towards mountainous areas but occurs chiefly on the plains. It is here that the best soils usually lie: thus urban growth means profligate elimination of agricultural land.

This is not an immediate problem for tomorrow, in terms of days; but it is a very big problem in terms of years and decades, as agricultural land covers a very small percentage of the total global surface and we cannot afford to lose it. The danger is very great and we must act quickly if we are to avoid it.

This need for action has led me to classify twelve zones of land-use with the ultimate goal of reaching a Global Ecological Balance (G.E.B.) and the immediate goals of saving land for agriculture and food production, of conserving the environment, and of giving a boost to the dying flora and fauna.

Pacem in Maribus once again stressed that an ocean regime must encompass the oceans as a whole and be considered as a sub-system of the entire global system. Jurisdictional decisions, including those affecting the Exclusive Economic Zone (EEZ), must reflect that paramount concern. It is not a matter of geographical realignment or of partition; marine ecosystem do not correspond to political demarcations. Nor is mankind, for which the concept of the common heritage is prescribed, confined to coastal states or to the present generation.

In its discussions and studies, Pacem in Maribus has consistently stressed the significance of rapid scientific and technological developments which have radically changed the nature of many conventional uses of the sea and call for management as the only alternative to conflict and possible disasters. In its commitment to an Ocean Space Authority rather than to an International Sea-bed Authority, Pacem in Maribus contends that activities on the sea-bed cannot be dissociated from activities in the water-column, at the surface, and at the atmospheric interface; that the sea-bed must become part of an integrated management system for ocean space; and that claims to national jurisdiction carry a surrogate responsibility in that management.

Pacem in Maribus contends that any Law of the Sea which does not respect and embody these overriding considerations will prove to be ineffective if not inoperable.

The purpose of this study was to learn how ozone might affect the growth and reproduction of understorey species of the aspen community, and thereby influence its stability and composition. Plants of 14 species belonging to the aspen community were grown in greenhouse chambers and fumigated with ozone for 3 hours each day, 5 day per week, throughout their growing-seasons. The plants were exposed to 30 pphm (parts of ozone per hundred million parts of air), 15 pphm, ambient air reaching 5–7 pphm during about 2 hours each day, and filtered air.

Exposure to ambient air did not appear to cause a significant reduction of total plant-weight in any of the species investigated, while plant-weight of Achillea millefolium and Isatis tinctoria grown under such conditions was significantly greater than that of control plants grown in filtered air. At 15 pphm, growth of Isatis tinctoria, Madia glomerata, and Viola italica, was significantly reduced; on the other hand, growth of Ligusticum porteri and Polygonum aviculare was increased. At 30 pphm, growth was substantially suppressed in all plants except Chenopodium album and Phacelia heterophylla.

Black-fly (Simulium spp.) occurs practically through out the world. It poses biting problems wherever it is found. In Africa, black-fly carries a human disease called Onchocerciasis or river blindness. The World Health Organization has decided on a £50 million project, spreading over 20 years, to control this disease. They propose to apply, very extensively and protractedly, larvicides which are non-selective, reasonably persistent, and only mildly toxic to Man and other higher animals but fatally toxic to Simulium larvae (the target) and some other forms of aquatic life (non-target). This will result in the reduction of the already small quantities of fish available to the people. It will also put at risk the lives of the animals that constitute the major source of the scanty protein supply of the local populace, and hence conceivably jeopardize their own lives.

The decision to go ahead with the project was based on the grounds that chemical control of Simulium breeding is the only sure method of dealing with Onchocerciasis, and that the areas of West Africa to be affected are among the least developed. But foreseeable consequences of the project alone are considered serious enough to justify its reconsideration, while quite likely consequences are powerful enough in themselves to make such as review seem necessary.

Until such a time as the world is able to devise a universally acceptable method of controlling black-fly, the current method of treatment preventing Onchocerciasis from causing blindness should be extended to all areas where the disease is present.

The genus Sequoia has existed since Mesozoic times, and early Tertiary Redwoods occurred practically throughout the northern hemisphere. Today, the Coast Redwood (Sequoia sempervirens) is the only living species of the genus, and it is restricted to the coastal environments of California and the southern extremity of Oregon. Climatic factors determine the outer limits of Redwood distribution, while edaphic, biotic, and hydrologic, variables influence the occurrence of Redwood within the climatic range.

Human use of Redwood forests has altered the environmental conditions under which the Sequoia now grows. Logging has exposed the forest floor to increased light and higher temperatures, while in some places it has exposed the soil to accelerated erosion. Recent floods in the major watersheds of north-western California have been particularly disastrous in undercutting large trees along the river banks. Increased degradation rates on upper slopes have resulted in delivery of coarse sediments to floodplains, with possibly deleterious effects on living old-growth Redwoods.

Pb, Zn, and Mn, levels in sediment and common estuarine plants and animals colonizing dredge-spoil disposal areas were compared with levels occurring in the same materials from a natural salt-marsh. Finegrained dredge-spoil had considerabily higher levels of all three metals than did natural salt-marsh sediment, and large differences in the metals content of the spoil were observed, depending on sediment type.

Pb levels in the Grass Shrimp (Palaemonetes pugio), Mummichog (Fundulus heteroclitus), Common Reed (Phragmites communis), Saltmarsh Cordgrass (Spartina alterniflora), and Saltmeadow Hay (Spartina patens), from dredge-spoil areas, were significantly higher at the 0.01 confidence level than in these species from the natural salt-marsh. Zn concentrations were significantly higher at this confidence level in the three plant species growing in dredge-spoil compared with those from the natural marsh. Mn content in Grass Shrimp from ponds in dredge-spoil disposal areas was significantly higher (0.05 confidence level) than in those from the natural marsh. Thus, dredge-spoil containing heavy metals, even though disposed of in specially designed diked containment areas, may act as a source of certain heavy metals that are potentially toxic to the biota.

Data on the transfer of Pb and Mn in simple foodchains of the dredge-spoil pond ecosystem are presented and discussed in relation to feeding behaviour. Decreasing concentrations with increasing tropic level were observed for Pb and Mn, but no consistent pattern was noted with Zn.

A preliminary survey of thirteen Latin American nations indicated that both the number and rate of importations of wild hoofed animals from Europe, Asia, and Africa, has increased rapidly in recent years. This is especially true for Mexico, Argentina, and Chile. In nearly every instance reported, the original stock of hoofed game was held under fence and no importer intended that animals should escape from his control. From these and other instances around the world, it seems that eventual escapes of captive ungulates held under normal ranching conditions are a virtual certainty. As the full effects of imported species on the plants and animals in their new environment cannot be predicted with certainty, guideline principles to govern species introductions are sorely needed.

Systematic sampling of hoverflies, ichneumonid wasps, and butterflies, in a suburban garden at Leicester, England, has revealed a remarkable diversity of species. Suburban gardens, which support an enormous variety of plants, now cover at least a million acres (405,000 ha) of England and Wales (about 1/37 of the total land area), and if the diversity of insects found in one garden reflects the situation elsewhere, gardens are collectively the most important nature reserve in the country. They are, moreover, in no danger of disappearing; on the contrary they are spreading, yet their potential for conservation has been neglected.