Population pressures are major sources of environmental degradation. Population numbers, fertility rates, and the age composition of populations, interact with natural resources, ecological processes, and life-support systems.

The International Tropical Timber Organization (ITTO), an increasing number of citizens and foresters, and the vast majority of environmentalists, must surely realize that most current use of tropical moist forest is unsustainable. The environmental services of tropical forest, and the biodiversity which it harbours — the world's richest source — is being lost so rapidly that consumer boycotts and other trade constraints aim to reduce the rate of irreversible damage but have so far proved little-effective. On one hand, tropical moist deforestation benefits exceedingly few people, and then only ephemerally. On the other hand, such deforestation permanently impoverishes, deracinates, or sickens, millions of people, impairs local or global environmental services, and exacerbates global environmental risks. The World Resources Institute ranks logging as one of the top causes leading to deforestation.

The need for an integrated approach to ecological conservation and natural resource development is becoming widely recognized as environmental and social problems become more and more acute with human population pressures and depletion of resources. While a number of academic programmes addressing environmental problems have been operating for several decades, comprehensive approaches that integrate conservation with development issues are only just beginning to occur. These innovative, cross-disciplinary problem-solving approaches still face a number of traditional constraints to successful programme development. Obstacles occur in every major aspect of academia — including structure, communication, reward systems, research, curriculum, and evaluation.

Lake Naivasha is an important freshwater resource for Kenya's foreign-currency-earning agriculture and tourism, and for water-supply. It has always experienced extensive water-level fluctuations as a consequence of irregular rainfall patterns that are affected by continental-scale climatic events, and its communities — particularly of aquatic plants — were adapted to these changes.

Mathematical models predict that a nuclear war could cause widespread reductions in light intensity and temperature. To assess the possible impact of these reductions on lowland tropical rain-forests, we exposed seedlings of three species of the family Moraceae to various combinations of day and night conditions under reduced light. The species represent three stages in tropical rain-forest succession: Cecropia obtusifolia is an early-successional pioneer, Trichospermum mexicanum is a mid-successional tree, and Brosimum alicastrum is a late-successional tree of mature-phase forests.

The ability of global agricultural systems to supply sufficient food for our rapidly-growing human population is becoming constrained by physical and economic limits to traditional means of agricultural expansion. Pests consume or ruin a staggering proportion of crops and, in general, have not been satisfactorily controlled through the ‘broadcast’ application of pesticides.

The mountainous Kaokoveld of northwestern Namibia contains numerous endemic plants and animals whose ranges, in many cases, extend into the Etosha National Park, an area extremely rich in game. Etosha Pan, the most striking feature of the Park, is bordered on the South by natural springs and artificial waterholes. These provide drinking places for the animals which congregate in large numbers and cause overgrazing and browsing pressure in the area. Migration to regions beyond the Park boundary is prevented by an 850 km-long game-proof fence. The main factors affecting animal populations are anthrax and poaching. Even so, the culling of Elephants becomes necessary from time to time, and the sale of ivory and other products helps to finance the operation of the Park.