Six problems faced by the developed and developing worlds are discussed and possible solutions are considered. Given its relatively stable populations and adequate food supplies, the developed world must be prepared both to pay for and to encourage efforts to control pollution of the environment. Its comparative over-consumption of energy must be countered by the development of new energy sources, bearing in mind the risks involved in the use of nuclear energy. Also, great efforts must be made to assist the developing world by improving the quality and quantity of aid and by voluntary changes in world trade patterns.

The developing world's most serious problem is its exploding population which can be slowed by birth control and improved standards of living. Population growth puts pressure on cities, and makes it imperative that new sources of food be found and new agricultural techniques be developed. Population also exacerbates the difficulties of providing education in the developing world.

Hope for the future rests on Man's capacity to foresee problems and to solve them.

The Crown-of-thorns Starfish (Acanthaster planci) was perceived to be a threat to coral reefs of the Indo–West Pacific region partly as a consequence of new technology, in the form of SCUBA diving, becoming generally available. It took some years, however, for field practices to be developed which employed the new technology effectively in sampling such a phenomenon over large areas.

In Australia an emotional environmental campaign followed the publication of a report to the Queensland Government in 1969, which claimed that the Starfish was a major threat to the Great Barrier Reef, that it was probably Man-induced, and that it could be controlled. The report was neither adopted nor rejected in the period of more than a year which elapsed between its submission and its publication. As the public campaign gained momentum, official inquiries reviewed and questioned the data-base of the initial report but no attempt was made to devise, test, or implement, a more acceptable sampling procedure until 1973. In retrospect it is suggested that an early practical initiative to assess and remedy claimed defects of the initial sampling programme, would have removed the element of speculation which led to considerable heat in the Crown-of-thorns debate in Australia.

The recommendation of the official inquiries resulted in the establishment of a trust fund to give special support to research into the problem. The research thus conducted materially increased understanding of the phenomenon, but it has been claimed that vital areas of investigation were omitted, and the value of such special support has been questioned. It is suggested here that the special problems and expense of research into the ecology of remote reefs would have precluded almost all research into the Crown-of-thorns Starfish and its effects without such ad hoc support. However, it is further suggested that more direct management of the programme would have coordinated research effort and made more effective use of the facilities and support available.

An oil-spill by the ocean cruise liner Statendam, in Hamilton Harbour, Bermuda, on 2 August 1976, was pursued in the courts, the Captain of the ship being prosecuted successfully because of strong circumstantial evidence—including chemical analysis by gas chromatography which matched the ship's fuel-oil with a sample taken from the harbour immediately after the spill.

The conviction was upheld on appeal. The Chief Justice's decision set a strong precedent for absolute liability when oil is discharged in contaminated ballast.

A similar case of a spill off the Florida Keys, by the M. V. Garbis in 1975, was identified by gas chromatography and other chemical methods, but did not result in conviction because of lack of jurisdiction over the waters in which the spill occurred. The Statendam case appears to be the first in which chemical analysis played an important role in establishing a conviction for oil pollution.

Europeans began introducing plants into southeastern Florida during the 16th century, and by the middle of the 18th century several of these were already naturalized. Few of these events have been recorded, but we know that the Guava, Papaya, and oranges, were among the early immigrants. American settlement in the middle 1800s began another phase of plant movement which continues to the present. H. M. Flagler, Henry Nehrling, John C. Gifford, and others, brought plants in for landscaping or other uses. Among those brought in by the United States Department of Agriculture were the Sisal, introduced by Henry Perrine, and the many food and ornamental plants sent by David Fairchild to the Miami Introduction Station. Many of the plants brought to Florida have become important as ornamentals or foods; however, some of the exotics have escaped and now present problems to the native ecosystems and to Man.

Over 170 species of ferns and flowering plants are naturalized in southeastern Florida. Hundreds of other exotic plants have been introduced into the region and the potential exists for others to escape. Species such as Melaleuca quinquenervia are invading wet habitats and decreasing diversity; the Australian Pine (Casuarina equisetifolia) has become so abundant on some beaches that it interferes with nesting seaturtles and American Crocodiles, as well as contributing to dune erosion. Water-hyacinth (Eichhornia crassipes) and Florida Elodea (Hydrilla verticillata) clog natural and artificial lakes, ponds, and canals, blocking boat traffic and slowing water movement. Several grasses that were introduced as pasture plants are now considered pests. Even human health is being threatened by exotic plants such as the Melaleuca and Pepper-tree (Schinus terebinthifolius), which cause respiratory allergies and contact dermatitis.

The watershed of the River Euphrates lies within the boundaries of the present-day states of Turkey, Syria, Iraq, and Saudi Arabia. Almost 90% of the runoff from the basin is generated within the highlands of eastern Turkey as the result of snow-melt occurring during late spring and early summer. At this time, flood levels are usually reached along the whole length of the River.

The former inhabitants of the floodplain lands of Iraq utilized the waters of the River Euphrates for at least 6,000 years. By so doing, empires dependent upon irrigated agriculture flourished and then decayed, leaving behind spectacular ruins practically throughout Mesopotamia. Until the time of the Second World War, Iraq was the only country within the Euphrates basin that made large demands on the water resources of the River. Since that time, Iraq's demand has continued to increase, resulting in average water withdrawals of over 16,000 million m3/year during the 1960s. This figure represents about 45% of the average annual discharge of the Euphrates into Iraq.

Since the mid-1960s, both Syria and Turkey have planned major dam schemes to utilize the waters of the Euphrates. The Tabqa Dam in Syria, and the Keban Dam in Turkey, have already been constructed, and Turkey has planned other major hydraulic works along its section of the River. When the irrigation projects associated with these schemes are in full operation towards the end of the century, it seems that the likely demand for water will be in excess of the available flow of the River.

The country which is likely to suffer most as a result of this is Iraq, owing to its situation in the lowest part of the basin. Already, diplomatic relationships between Syria and Iraq have been severely strained as the result of disagreements about the allocation of the water resources of the River Euphrates. In future, it seems possible that such disputes will continue to occur, and perhaps also to become of increasing severity as both Turkey and Syria begin to use large proportions of the available riverflow for irrigation. The only permanent solution to the problem would seem to be the establishment of an international body to supervise the just allocation of the water resources of the Euphrates between Turkey, Syria, and Iraq. At present it seems unlikely that a lasting agreement will be reached between the three countries.

Maps prepared for the United Nations Conference on Desertification are critically reviewed and parts of selected maps are illustrated.

The World Map of Desertification, called for by the United Nations General Assembly, delineates areas at risk of desertification as determined by bioclimatic stress, the inherent vulnerability of the land, and pressure of land-use. Areas of very high desertification hazard are shown to be those arid and semiarid regions with very heavy pressure of land-use. The threat of desertification is shown to be highest beyond the margins of the full deserts, but the risk extends wherever drought marks the seasonal or periodic extension of aridity. The term ‘drylands’ is used to define areas in which this risk occurs.

Alternative maps at global scale include the Climate Aridity Index map based on the Budyko Ratio, which is the ratio between annual net radiation and mean annual precipitation. This allows a more sensitive depiction of aridity gradients and reveals that larger areas are under drought-stress than were previously recognized.

The map of Experimental World Scheme of Aridity and Drought Probability uses soil features as an integrative record of past and present environmental conditions, including ‘land aridity’, but is constrained by the concept of soil zonality, without sufficient consideration of topographic and inherited factors which determine soil properties.

The map of the Status of Desertification in the Hot Arid Regions shows the existing degree of desertification as judged by the difference between former (in the pristine state) and existing productivity. This is revealed as increasing outwards from the desert cores into the semi-arid lands, but the map does not extend into the sub-humid zone. However, it usefully depicts desertification as an expression of human impact on the land. Only very restricted areas are shown as having undergone very serious or irreversible desertification.

Global maps are too generalized to depict actual desertification in quantitative terms, but the continental scale of the unpublished Desertification Hazards Map of Africa North of the Equator allows this to be done, in addition to depiction of the degree of vulnerability to desertification. Areas shown as already degraded occur mainly in the arid zone, whereas those of very high vulnerability lie mainly in the semi-arid zones.

The U.N. Conference on Desertification recommended the compilation of an atlas of desertification to depict the state of the world's drylands and to serve as a cartographic basis for planning combative programmes. Regional maps of this kind, as exemplified in the synoptic maps accompanying the Case Studies of Desertification presented to the Conference, range in scale from 1:1,000,000 to 1:100,000—depending on the type of desertification portrayed—with the smaller scales for pastoral lands and more detailed scales for irrigation projects.

Landscape ecology is concerned with the interrelations between the Total Human Ecosystem—integrating natural ecosystems and human techno-ecosystems —and its concrete, spatial landscape units. It deals not only with natural and semi-natural landscapes but also with cultural–rural and urban–industrial landscapes and their inputs of fossil energy, artefacts, and cultural information and control. As an emerging branch of human ecosystem science with an interdisciplinary outlook on modern land-uses, it could play an important role in developing countries. Here, one of its greatest challenges is to find a compromise between the needs for conservation or reconstitution of open landscapes and the socio-economic needs of society. This can be achieved by transforming the noneconomic richness of the local ecosystem into workable parameters for the land-use planners and decisionmakers.

As an example of such an attempt, the development and improvement of non-tillable Mediterranean uplands is presented by a model of multiple-use ecosystem management strategies and their benefits. Highest overall benefit for nature conservation, wildlife and recreation amenities, protection of environmental quality as well as livestock, forestry production, and water yields, can be expected by multiple-purpose reafforestation and revegetation.

For the assessment of compatibility of these different land-use factors and their mutual influences, a cybernetic sensitivity model is proposed and the most active and critical variables—foresty, livestock production, and recreation—and the most passive one— water yields—are determined.

In order to make possible cost-benefit analyses and achieve optimization for dynamic planning, these relative values should be replaced by actual quantitative ecological, economic, and socio-ecological, parameters —to be implemented on a national level as parts of comprehensive landscape master-plans.