|
Environment & ForestsBiodiversity HotspotsBIODIVERSITY Extinction is the gravest aspect of the biodiversity crisis: it is irreversible. While extinction is a natural process, human impacts have elevated the rate of extinction by at least a thousand, possibly several thousand, times the natural rate. Mass extinctions of this magnitude have only occurred five times in the history of our planet; the last brought the end of the dinosaur age. âBIODIVERSITY HOTSPOTâ defined The concept of biodiversity hotspots was penned by British ecologist Norman Myers in 1988 as a means to address the dilemma of identifying the areas most important for preserving species. Myers recognized thatâdespite their relatively small sizesâcertain ecosystems account for a high percentage of global biodiversity. Many of these same areas face tremendous pressure from logging, agriculture, hunting, and climate change, scientists say. Myers reasoned that a prudent conservation strategy would be to target dollars and research at those regions where these threats are greatest to the greatest number of species. A seminal paper by Norman Myers in 1988 first identified ten tropical forest âhotspotsâ characterized both by exceptional levels of plant endemism and by serious levels of habitat loss. Conservation International adopted Myersâ hotspots as its institutional blueprint in 1989, and in 1996, the organization made the decision to undertake a reassessment of the hotspots concept, including an examination of whether key areas had been overlooked. Three years later an extensive global review was undertaken, which ironed out a formula for hotspot designation. To qualify as a hotspot, a region must meet two strict criteria: 1. It must contain at least 1,500 species of vascular plants (> 0.5 percent of the worldâs total) as endemics, and 2. It has to have lost at least 70 percent of its original habitat.
North and Central America South America 10. Caucasus Africa Asia-Pacific
In total, an updated analysis reveals the existence of 34 biodiversity hotspots, each holding at least 1,500 endemic plant species, and having lost at least 70 percent of its original habitat extent. Overall, the 34 hotspots once covered 15.7 percent of the Earthâs land surface. In all, 86 percent of the hotspotsâ habitat has already been destroyed, such that the intact remnants of the hotspots now cover only 2.3 percent of the Earthâs land surface. Between them, the hotspots hold at least 150,000 plant species as endemics, 50 percent of the worldâs total. The total number of terrestrial vertebrates endemic to the hotspots is 11,980, representing 42 percent of all terrestrial vertebrate species. Reptiles and amphibians, are more prone to hotspot endemism than are the more wide-ranging mammals and birds, but the overall similarity between taxonomic groups is remarkable. Overall, 22,022 terrestrial vertebrate species call the hotpots home, 77 percent of the world's total. With rapid increases in data quality and synthesis, we can now derive species lists for each hotspot, above and beyond estimated species numbers. The current analysis also includes the first assessment of inland fishes across all hotspots. Although most current statistics are likely underestimates -- because almost 200 freshwater fish species are discovered each year -- the hotpots already hold 29 percent of the world's freshwater fish species as endemics, with 55 percent of species occurring.
Three major conclusions emerge from hotspots analysis: 1. It is clear that the hotspots concept is solidifying. The new update results in few major modifications to the broad global picture of hotspots. 2. Second, the amount of biodiversity contained in the hotspots is extremely high. More than half of the planetâs species are endemic to only 16 percent of its land area. Based on the evidence from terrestrial vertebrates, it seems that the overall number of species occurring in the hotspots is much greater âapproaching four-fifths. If we consider only the extent of remaining habitat â2.3 percent of the planetâs land surfaceâ these numbers are even more remarkable. 3. Finally, and most importantly, hotspots provide us with the real measure of the conservation challenge. Unless we succeed in conserving this small fraction of the planetâs land area, we will lose more than half of our natural heritage. THE WESTERN GHATS Forest cover decline in the Western Ghats Hotspot Original Extent (km2) :189,611
The threats to this eco-region's natural habitats and biodiversity are manifold. Some of the major threats include: Conversion of forests The Nilgiri and Cardamom hills in particular harbor high levels of richness and endemism as well as some of the most important populations of elephants and tigers. These areas are especially affected by the tea, coffee, and rubber plantations. Shifting cultivation has begun to clear patches of old-growth forest (Kendrick 1989). In the Anamalais, fig trees from the sholas are felled or lopped to feed camp elephants. Because many of these species are dioecious, this affects the sexual selection among trees and causes reproductive isolation. Fig trees are also keystone food resources for several species (from giant squirrels to hornbills), and their removal results in cascading ecological effects on the frugivore community. The mountains, especially in the south, are mineral-rich. Therefore, mining is a potential future threat that should be addressed with preemptive measures. Mining Damage to the environment is mainly done by the reject dumps, pumping out of muddy waters from the working pits including those where the mining operations have gone below the water table, and slimes from the beneficiation plant. The damage is more evidenced during monsoon where the rain water carries the washed out material from the waste dumps to the adjoining low-lying agricultural fields and water streams. Population: |
From the Discussion Forumcrooks governing Goa Sep 16, 08 | viriato_fernandes TRUE PATRIOTISM Oct 18, 08 | sachinbhat Incorporate Roman Konkani Script Sep 27, 08 | ARWIN Garbage disposal/collection system Jan 20, 08 | sugarnspice CALL TO ACTION – Goa’s Identity. Mar 20, 08 | ARWIN
|
into tea, coffee, potato, teak, Eucalyptus, and cardamom plantations, as well as road construction, tourism pressures, and livestock grazing (Rodgers and Panwar 1988; WII 1999). Illegal taking of timber is high and is considered a major threat to the remaining forests. Many people own guns for crop protection that they also use for poaching.
for iron ore production has been the most important economic activity contributing significantly to the State revenue of Goa. However, mining and associated activities over a sizable area has had considerable adverse impacts on environment and natural resources. Open pit mining operations have left an indelible mark on the region: hills have been flattened, forests razed, and fields blanketed in silt run-off from waste sites and processing plants.
Recent studies have shown that the hotspots have a higher population density than expected when compared to the global average. Coastal Asian hotspots with major cities are suffering the worst from overpopulation in hotpots with the Philippines, Japan, and Western Ghats and Sri Lanka all having over 250 people per km², in comparison to the global average of 42 people per km²