Unmodified natural ecosystems as well as those ecosystems that have been changed to differing extents through human activity, may be expected to Play an important role in the future development of environmental biology. The unmodified ecosystems constitute a kind of protected areas and characteristically contain a rich variety of organisms some of which can serve as reliable indicators of disturbance in the system. As a consequence of increase tampering of nature by man, natural reserves are greatly dwindling and are becoming the main sanctuaries for wild plants and animals.
It has been Proposed that adequate examples of all important and representative biomes be protected and conserved. A world-wide network of such protected ecosystems is extremely important for ecological research pertinent to rational use conservation of the biosphere. The MAB programme visualizes an intensive study of the basic processes in ecosystems with a view to understanding how they function normally and under stress. It is an interdisciplinary programme of research and emphasizes an ecological approach to the study of interrelations between man and the environment. It intends to encourage comparative studies of undisturbed ecosystems and those that have been artificially disturbed to various extents through such activities or agents as fire, grazing, deforestation, silting and over-fertilizing, etc. By these methods and by the use of systems analysis and mathematical modelling, much useful information concerning such aspects as successional stages, regeneration or recovery rates, carrying capacity, productivity, etc.
, may be obtained. The Programme also aims at securing the continued existence of a wide range of genetically heterogeneous populations of various taxa in keeping with the diversity of conditions in which the species occurs. The continuing existence of wild biota is also necessary for long-term conservation of genetic diversity for future breeding purposes. The major objective of such conservation is to safeguard the continued existence of the largest possible number of the present-day species, varieties and strains of living organisms. In fact, wildlife is often a reliable indicator of the state of health of an environment. In addition to conservation of natural ecosystems, man is also greatly concerned with as much preservation of environmental quality as is reasonably possible. It is only within the last two decades that it has been realized that man is capable of inducing significant alterations in the environment either intentionally or inadvertently.
He possesses the potential or actual capacity to alter the basic functioning of the atmosphere, hydrosphere, lithosphere and the whole biosphere. The most essential basic attribute of most environments is that they are multidimensional systems of complex interrelationships in a continuing state of change. It is also generally recognized that the loss of life caused by such calamities as floods, droughts, cyclones and earthquakes, is largely a consequence both of the quality of natural environments as well as mankind’s misdeeds. The link between conservation and quality of human environment has also been duly emphasized by Cragg (1970).
Cragg advocates a study of the biogeochemical cycles disturbed by man and has pointed out many hazards arising from the recent marked increases in the CO2 content of the atmosphere and similar decreases in oxygen level of natural water bodies. He lists the following basic arguments for conservation: (a) maintenance and perpetuation of environmental quality; (b) aesthetic considerations; (c) food production; (d) preservation of gene-pools and germplasms; and (e) ecological diversity.