(a) Alien species invasion
When alien species are introduced unintentionally / deliberately for whatever purpose , some of them turn invasive and cause decline / extinction of indigenous species eg.
- the introduction of African catfish / Clarias gariepinus (for aquaculture purpose) poses a threat to indigenous catfishes in our rivers
- The Nile perch introduced into lake Victoria in East Africa led to the extinction of more than 200 species of Cichlid fish in the lake
- Carrot grass / Parthenium , Lantana , Water hyacinth / Eichhornia poses a threat to
indigenous species
Fragmentation
When large habitats are broken up into small fragments due to various human activities
- mammals / birds requiring large territories and certain animals with migratory habits are badly affected
Habitat Loss
The Amazon rain forest is being cut and cleared for cultivating soyabeans / conversion to grasslands for raising cattle
(b) (i) Provides information of extinction of species
(ii) Regions with very high levels of species richness , high degree of endemism / species confined to that region and not found anywhere else are identified which need to be conserve all priority basis.