Short essay on Endemism and ‘Hot-Spots’ of Biological Diversity



Endemic species can be defined as those species which are confined only to a particular locality. Such organisms are very important from the point of view of conversation as their disappearance means extinction of the species as they are not found anywhere else.

No doubt endemism represents a unique step in the process of evolution which could be perpetuated and sustained only in the locality concerned by imperfectly understood attributes of environmental quality. The diversity of life forms which we see around us has essentially evolved by a method of trial and error. In the process of natural selection, changes which confer some disadvantage to the organism are eliminated while those changes which are advantageous are retained.

It is the environment only which is instrumental in the operation of the process of natural selection. This makes the habitats in which endemic species thrive very important. The importance of the habitat or locality is further highlighted by the fact that in most of the cases such localities possess a number of endemic species distributed in several taxonomic categories or groups. The endemism in a particular taxonomic category is usually matched by more or less similar degree of endemism in other taxonomic groups.

Naturally the endemic species and the habitats which are likely to be lost forever should receive urgent conservation attention. Based on the degree of endemism in species composition, Myers (1988) has identified 12 such localities in tropical regions of world which require urgent conservation attention.

These areas are spread over 292,000 sq. kms only and represent barely 0.2% of the earth's total land surface. Of the world's 8.34 million sq. kms of primary forests, these hot-spots of biological diversity represent only 3.5%. However, they possess 34,400 endemic plant species which is about 27% of all tropical forest species or 13% of the total plant species found on earth. In 1990, Myers identified another eight hot-spots of endemic species diversity in other climatic regions of the world. These are:

1. California, Western Floral Province

2. Central Chile.

3. Ivory coast

4. Cape Floral Province, Africa

5. Western Ghats, India.

6. Sri Lanka.

7. South-west Australia.

8. Eastern Arc Province, Tanzania.

These eight hot spots of biodiversity cover 454,400 sq. kms or only 0.3% of world's total land surface but possess 15,555 endemic species of plants representing 6% of the total number of species of plants world-wide. Thus about 49,955 endemic species of plants occur in an area barely 786,400 sq. kms or only 0.5% of the world's total land area.

On worldwide basis about 4.9% of earth's lam surface has been set aside as nationally protected areas. However, much of earth's hot-spots of biodiversity which comprise only one tenth of this area are not protected at all. Instead of badly managed 5% properly managed 0.5% of earth's land surface on which stand these hot-spots of biodiversity, could serve the purpose of conservation efforts in a much better way.