GLOBAL BIODIVERSITY

The 1992 conversion on biological diversity defines biodiversity as the variability among living organisms for all sources, inter alia, terrestrial, marine and other aquatic ecosystems in the ecological complexes of which they are part. This includes diversity within species (genetic diversity), between species (species diversity) and of ecosystems. Recent estimate of the number of species worldwide is 13million but 1.6 million are described.

Mairéad (2007) put the estimate at 5-100 million with 1.75million described. Pandey (2007) also put the estimated figure of described and known species at between 1.7 and 1.8 million with total number between 30-50million.

Biodiversity hot spots on the globe show exceptional concentrations of species with high levels of endemism and rapid rate of depletion e.g. tropical forests, coral reefs and Mediterranean ecosystems.   

Major threats to biodiversity include:

i.    Habitat alteration and loss

ii.   Over-harvesting

iii.  Chemical pollution

iv.   Invasive species

v.    Increasing population pressure

Biodiversity hot spots are areas that are unusually rich in species, most of which are endemic (confined) and are under a constant threat of overexploitation (Pandey, 2007) e.g. reptiles, amphibians, angiosperms, Swallow-tailed butterflies endemic in the Eastern  Himalasyas and Western Gats of India.

Climate change may modify and enhance local anthropogenic disturbances. The rates of habitat modification are currently so high and protected areas may become ecological islands in surrounding ‘oceans’ of habitat.

Fragmentation and isolation process- concepts of island biogeographic theory is predicted to lead directly or indirectly to accelerated species extinction at both local and global scales thus reducing the world’s biodiversity at all levels. 

Biodiversity loss threatens ecosystem integrity as well as ultimate human existence.

References

Pandey, B.P 2007: The Economic Botany, 525-557.

Mairéad, S. 2007: The Effects of Climate Change on Biodiversity. Submission Paper to the Dublin City Council policy Paper on Climate Change. 10pp

UNCED, 1992: United Nations Conference on Environment and Development. Convention on Biological Diversity.1-33