Are human beings edging out all other life forms?

Are human beings edging out all other life forms?

Northeast India occupies 8 per cent of the country's geographic area, and supports 3.8 per cent of India's total population (2001 census figures). The average population density of the Northeast is 149 persons per square kilometre (sq km), a figure far below India's population density (324 persons per sq km). The state of Assam has the highest population density in the region (340 persons per sq km), while Arunachal Pradesh has the lowest (13 persons per sq km). The population density for this region registered a growth of 44.7 per cent from 1981 to 2001. This is still far below the Indian average of 55.8 per cent.

But what do these figures imply for the 'biodiversity hotspot' that Indo-Burma is? Well, although the population density of the Northeast is lower than that of India as a whole, it is higher than the average population density of biodiversity hotspots (73 persons per sq km), and more than 3.5 times that of the world as a whole (42 persons per sq km). The population density in major tropical wilderness areas, in fact, was recorded as 8 persons per sq km. The population density and growth rate in the Northeast are also much higher than the rest of the Indo-Burma biodiversity hotspot. If population numbers are observed in isolation, Assam and Tripura are most at risk. They show the highest human population density in the region. Population alone, though, is not an adequate indicator of the dangers that a biodiversity hotspot is in. To begin with, lower rates of population growth in high population density areas add more individuals to an ecosystem.

It is in this context that one must factor in the culture and life-style influences on resource utilisation patterns. Expanding human population has resulted in changes in the land-use pattern. This causes fragmentation of habitats, ecosystems and landscapes in most parts of the world.

Habitat fragmentation, in fact, is a leading cause of biodiversity loss. The rate of species loss would be 14,000 to 40,000 species per year, or 2 to 5 species per hour. S L Pimm and P Raven had predicted that even if all remaining habitat in hotspots were saved, some 18 per cent of their species would be lost. However, if only currently protected areas are saved, we will see a 40 per cent species loss. As ecosystems dominated by humans expand, one of the most biologically diverse terrains in the world finds itself threatened.

H Birkumar Singh is scientist-in-charge, Manipur substation, regional research laboratory of the Council of Scientific and Industrial Research at Jorhat