ABSTRACT
Biodiversity refers to the number, variety and variability of living organisms. Biological diversity came into prominence with publications that appeared in 1980. Lovejoy used the term first in 1980, essentially to denote the number of species present. Norse and McManus employed it to include two related concepts viz., genetic diversity and ecological diversity. Norse et al., in 1986 expanded this usage to refer unequivocally to biological diversity at three levels viz., genetic (within species), species (species numbers) and ecological (community) diversity. Rosen coined the constricted term “biodiversity’’ in the first planning conference on National Forum on Biodiversity convened in Washington D.C. in September 1986. The proceedings of that forum edited by Wilson in 1988 under the title “Biodiversity’’ launched the word into general use. The Global Biodiversity Assessment defines biodiversity as the total diversity and variability of the living things and of the systems of which they are a part. This encompasses the total range of variation in and variability among systems and organisms at the bioregional, landscape, ecosystem and habitat levels, at the various organism levels down to species, populations and individuals, and at the level of population and genes (UNEP, 1995). It also embraces complex sets of structural and functional relationships within and between these different levels of organizations including human action and their origin and evolution in space and time. The multifaceted nature of biodiversity is reflected in the many definitions that have been propounded so far. Jutro has recorded 14 definitions of biodiversity. The three levels of biodiversity are hierarchical in nature and overlap with one another. They are covered by three major disciplines of biology viz., ecology, genetics and taxonomy. The species is the basic unit of classification and the most practical and commonly used currency while referring to biodiversity. Species is defined as a group of similar organisms that interbreed or share a common lineage of descent. Species do not occur in isolation but exist in a very wide array of ecological groupings, which we can recognize as distinct. These
together with the physical environment form the main eco-regions and biomes of the world. For practical purposes, the term biodiversity is synonymous with biological diversity as defined by Norse et al., in 1986. This is reinforced by the official definition of the Convention on Biological Diversity (CBD) ratified by 159 nations in the Earth Summit held at Rio in 1992. The broad scope of the CBD is illustrated in its Article 1, that includes “conservation of biological diversity, sustainable use of its components and fair and equitable sharing of benefits arising out of the utilization of genetic resources.’’ Resolving biodiversity into three levels viz., genetic, species and ecosystem diversity is not without its difficulties as they are inextricably interlinked and actions at any one level will have impact on other levels of the hierarchy. However biodiversity as a unifying concept brings together people from different disciplines and interests with a common goal of understanding of conservation and wise use of biological resources. Several attempts to unite the components into a universal paradigm have been made. A DIVERSITAS Programme has been designed and launched as a multi-level and multi-scale endeavour looking at the interactions and the integration of the different disciplines involved; this programme provides an acceptable framework or leitmotif for exchange of information across the globe (di Castri and Younes, 1996).
