The New Nation - Internet Edition

Biodiversity is a popular way of describing the diversity of life on earth , it includes all life forms &the ecosystems of which they are a part. The biological resources of each & every country are important, but not all are equally endowed. In general ,a small number of countries lying with in the tropics &subtropics account for a very high percentage of world's biodiversity. Thus, biodiversity provides the raw materials, combinations of genes, that produce the plant varieties and animal breeds upon which agriculture depends.

Global warming is perhaps the most pervasive of the various threats to the planet's biodiversity. Unlike other threats also caused by Human development, it has the potential to influence all ecosystems, including those that are far from human populations and are still classified as wilderness. Unfortunately, despite this insidious nature, there have been few efforts to assess the potential effects of greenhouse warming on global ecosystems. The global warming effects on biodiversity are:- 1. Global warming has the potential to cause extinctions in a great majority of the world's especially valuable ecosystems. Losses of habitat types are predicted within the ecoregions and, based on species-area relationships, can be expected to result in losses of biodiversity.

. 2.Depending on species responses to the warming, especially their ability to migrate to new sites, habitat change in many ecoregions has the potential to result in catastrophic species loss.

. 3.The fact that certain ecoregions are of high value from a biodiversity perspective did little to protect them against the effects of global warming. Although some ecoregions were more vulnerable than others, on the whole they faired little better than random regions of the globe.

High required migration rates were not isolated occurrences within the ecoregions.. Future migration rates may need to be unprecedented if species are to keep up with climate change. It is safe to conclude that although some plants and animals will be able to keep up with the rates reported here, many others will not. Some species with low dispersal capabilities may fail to migrate at all. Global warming is likely to have a winnowing effect on the ecosystems within ecoregions, filtering out species that are not highly mobile and favoring a less diverse, more "weedy" vegetation and ecosystems that are dominated by pioneer species, invasive species, and others with high dispersal capabilities. The effects of global warming are influenced significantly by species geographic distributions and climatic tolerances.

Md. Mahbubur Rahman

Santosh, Tangail.