As tropical forest cover is eliminated, there appear to be—despite earlier supposition to the contrary—a number of significant repercussions for climatic regimes, whether at local, regional, or even global, levels. These are manifested through disruptions of hydrological systems and precipitation patterns, through changes in albedo and associated evapotranspiration rates, and through contributions to the ‘greenhouse effect’. Certain of these processes are well established scientifically, whereas others remain speculative pending urgently-needed research.

This exploratory paper reviews some of the ecological linkages at work in the above super-serious circumstances. Further, it assesses the profound consequences that may arise for major development sectors such as agriculture, energy, and human settlements. It concludes with a short appraisal of some policy responses available, though here again choices for adoption should be based on the results of far more scientific research and allied investigation than has yet resulted in reliable knowledge.

The environment and natural resources of Estonia (area 45,000 km2, population c. 1.5 million) are described: Estonia is a flat country of which 40% is forested (managed on a sustained-yield basis), 20% is covered by peat bogs (widely cut for agricultural purposes and fuel), and 22% is under cultivation, often on drained land (largely growing grain for livestock). Rich deposits of oil-shale (used for fuel, etc.) and phosphorite (used for fertilizer, etc.) are exploited, especially in the north-east. Both of these resources are to a large extent strip-mined, causing enormous local surface disruption and more widespread water and air pollution— especially so in the case of the phosphorite extraction. Estonia has, however, recently been able to prevent a planned expansion of phosphorite exploitation.

About 3% of Estonia is set aside as Nature reserves, including some wetlands of international importance. Environmental protection is an important item on Estonia's agenda; the prognosis is quite favourable, not only because of a commendable population density, but also in large part (as there is considerable evidence to suggest) because the population has a keenly-developed Nature ethic of long standing.

Roadside bird mortality is a new environmental dimension in developing countries. With the recent increase in the number of high-speed cars and the simultaneous improvement of roads in India, bird-car strikes and the resultant bird mortality are becoming important. To know how many species frequent roads in Punjab and thus may be prone to be killed by fast vehicles, we censused birds along 420 km of roads of different widths and traffic volumes from a vehicle moving at 50–60 km per hour. We also counted birds along transects c. 1 km away from roads, for comparison.

In all, 35 species of birds were recorded on the road proper or within 3 m of either edge. Common Myna (Acridotheres trisitis) was the most abundant species (34.8% of all birds), followed by House Sparrow (Passer domesticus) (29.5%), Ring Dove (Streptopelia decaocto) (13.1%), and House Crow (Corvus splendens) (9.7%). These four species together accounted for c. 87% of the total of all bird species. The off-road community consisted of 68 species. The species-richness of granivorous, insectivorous, omnivorous, and some other birds, was less on or near roads than in the off-road transects, but within each community, species having different feeding habits were in similar proportions. About 93% of the total birds on or near roads (as against 66% off-road) were either granivorous or omnivorous.

Our results suggested that granivorous birds are attracted, but insectivorous and other birds are repelled, by roads. Omnivores were equally abundant on and off roads. Food (such as spilled grain) seemed to be the main factor attracting birds to roads. Species diversity and equitability of the bird community on roads (1.82 and 0.51, respectively) were less than those off-roads (3.11 and 0.74, respectively). Wider roads had lower species-diversity and equitability, probably because of the greater volume of traffic on them compared with narrower roads. Species richness and bird abundance seemed not to be affected by roadwidth. Bird mortality on roads is discussed, along with the possibility of roads acting as “ecological traps” for foraging birds.

Nomadic migration of cattle in the middle Niger valley is an age-old traditional method of raising cattle by pastoralism. However, this method of free-grazing of animals has been observed to affect some of the ecological balances of the savanna ecobiome. These ecological effects include denudation of the soil through excessive and repeated trampling by cattle on permanent routes, destruction of vegetational structure through uncontrolled burning and tree-lopping by pastorallists, dissemination of animal diseases due to long-distance trekking and unrestricted movement of cattle, and other social problems such as conflict with farmers when animals infiltrate into arable farmlands.

With increasing use of the limited land-resources for other human activities, the need to create grazing reserves and provide infrastructures to reduce the widespread movement of cattle is recommended. This will improve the productivity of cattle and check any unfavourable ecological repercussions resulting from their unrestricted movement.

With respect to environmental conservation at* the Prince Edward Islands, South Africa has not lagged behind other nations owning sub-Antarctic islands. Indeed, with respect to some aspects, it can claim to be in the forefront. The most serious environmental problems at the Prince Edward Islands have to do with the need for control or eradication of certain established alien species of both plants and animals, the prevention of the introduction of additional aliens, and the carrying out of environmental impact assessments prior to new developments or expansions of existing facilities and programmes. However, where South Africa has lagged behind is in the enunciation of a policy on, and the proclamation of legislation giving, formal status to environmental conservation at, and the implementation of a formal and effective management plan for, the Prince Edward Islands.

It is hoped that these shortcomings will be redressed in the near future. But if, for example, an aircraft landing strip were ever to be built on Marion Island, then the need for the proclamation of legislation and the implementation of a management plan would become even greater than at present. Prince Edward Island is so exceptionally special as an undisturbed sub-Antarctic island that it must never be subjected to any such development.

The island of Zákynthos, in western Greece, supports the most important nesting biotope of the endangered Loggerhead Sea-turtle (Caretta caretta) within Europe. The evaluation of the impacts of human activities, such as beach-use by people, lights, noise, and traffic, on its nesting habitats revealed that they are running out of time under the pressure of rapid and massive tourist development. It is therefore essential for the protection of this unique species to conserve its nesting biotope. This implies adequate, ecologically sound management, which might well be ensured through the establishment of a Marine Park.

The structure of the El Kala National Park, its aims, zonation scheme for conservation and development, and boundaries, are described. Those ecobiomes and ecosystems which merit the highest classification and protection within the National Park are described and evaluated along with the numerous sites of similar importance outside the Park. A summary evaluation table (Table III) of the habitats, the species, and the resources for sustainable utilization, is presented.

Three wetlands within the Park—Lake Oubeïra (perennial freshwater lake: a Ramsar Convention site important for wintering waterfowl), Lake Tonga (semi-perennial freshwater lake with surrounding marsh and earn a Ramsar Convention site with significant numbers of breeding waterbirds), and the Bou Redim marsh (freshwater carr with open water and a breeding colony of herons) are placed in the highest category of protection for the National Park. Four wetlands outside the National Park—the Mkhada marsh (8,900 ha of seasonally-flooded freshwater marsh), Lake Fetzara (15,000 ha freshwater lake now refilled with water in winter), Lac des Oiseaux (40 ha perennial freshwater lake), and the Cheffia Reservoir (3,000 ha)—are considered as important and consequently deserving of legislative protection. A marine section of the Park needs further study.

The highest level of protection is recommended for the coastal dunes, including alder carrs, within and outside the Park; for the pristine low-montane Cork Oak woodlands, including the last remnants of Pinus pinaster ssp. renoui in Algeria; for the rare Lusitanian Oak forests including the small and declining Algerian population of Barbary Deer (Cervus elephas barbarus); and for some of the last remaining riverine woodland in North Africa. In addition, the healthy and diverse population of raptors is noted. The megalithic and later archaeological remains are extensive, valuable, and little-known.M

Ecological improvements to Lakes Tonga and Fetzara, which were drained in the 1930s, have recently developed from the operation of the old sluices to hold water back in the lakes, although at Lake Tonga some of the marginal vegetation and alder forest appears to be suffering from the prolonged inundation. The construction of the large Mexanna Dam within the National Park will desiccate the Mkhada Marsh, and Lake Oubeïra may have its ecological character changed if it is used for regulatory storage. The dune ecosystems are being affected by agriculture, groundwater pumping, industrial forestry (including perhaps a pulp mill), and the new road which is being driven into the heart of the dunes. Fishing and aquaculture may further reduce the suitability of Lakes Oubeïra and Melah for wintering waterfowl, and deliberate fires continue to ravage the Cork Oak forests.

Exotic insect pests worldwide are many. They are accidental biotic contaminants. Classical biological control (CBC) agents can be considered as deliberately introduced biotic contaminants that, when successful, reduce the overall biomass of contamination and often bring considerable self-sustaining economic relief to farming communites.

Although the introduction of exotic agents would seem to be contrary to conservation philosophy, there are no quantified instances to date where the introduction of arthropod agents has been shown to have harmed a specific conservation programme or has been categorically damaging to native fauna. There is only limited anecdotal evidence that introduced parasitoids may have damaged certain specific native taxa. CBC in some cases actually assists conservation by reducing the level of exotic pests in nature reserves.

As CBC is an important socio-economic method of pest control, especially for tropical farmers, and as the taxonomic groups and life-histories of its targets are so different from those insects of endangered status, the two approaches are not in conflict. But as CBC is virtually irretrievable, it must continue to be carried out carefully and selectively only by truly responsible CBC agencies using appropriate quarantine facilities.

Tourists and general travellers pose a greater threat to native faunas than do the activities of such CBC agencies. It is well known that vertebrate agents and certain invertebrates, especially snails, can be devastating to certain native biotas. Additionally, and in view of the impending world-wide biotic diversity crisis, even traditional agents such as insect pathogens, insect parasitoids, and insect and mite predators, should be viewed with extreme caution—especially when oligophagous, and unquestionably when polyphagous.