causes of biodiversity loss .

from a study of the history of life on earth through fossils records, we learn that large scale loss of species like the one we are currently witnessing have also happened earlier , even before humans appeared on the scene.

in general , loos of diversity may lead to

1. decline in plant production 
2. lowered resistance to environmental perturbation such as drought.
3. increases variability in certain ecosystem processes such as pkant productivity , water use and pest and diseases cycles.

the major causes of biodiversity are

1. habitat loss and fragmentation : this is the most important causes driving animals and plants to extinction . one covering more than than 14 percent of the earth land surface . these rain forest now cover no more than 6 percent . they are being destroyed fast. besides total loss, the degradation of many habitats by pollution also threatens the survival of many species. when large habitats are broken up in to small fragments due to various human activities , migratory birds are badly affected, leading to population declines.
2. over exploitation : humans have always depended on nature for food and shelter , but when " need" turns to " greed " . it leads to over exploitation of natural resource.presently many marine fish population around the world are over harvested , endangering the continued existence of some commercially important species.
3. alien species invasion : when alien species are introduced unintentionally or deliberately for whatever purposes , some of them turn invasive , and cause decline or extinction of indigenous species.
4. co extinction : when the species become extinct , the plant and animal associated with it in an obligatory way also become extinct.