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Whence The Forests Biodiversity? : Review with reference to Forest of Manipur
Dr. B. Manihar Sharma Due emphasis on these aspects were given in the PT, CT and UM sections of the program. Researches on the areas again gained momentum with the undertaking of the global multidisciplinary Man and Biosphere (MAB) program by UNESCO since 1974. The main objectives of MAB
has been to investigate the impact of man's activities on different ecosystems (projects 1 to 6) and
finding out ways and means of protecting the plants and animals on the verge of extinction (project 8). The awareness campaigns among the public mass on the profound roles of the conservation of the species in keeping the ecological balance grew more intensive after the UN Conference on Environmental Development (UNCED) held in Rio during June 1992. The need for conservation and sustainable utilization of plants and animals as well as successful utilization of potential resources of Renewable Energy from biomass have been included in agenda 21 of the Earth Chapter of the Rio Conference. We are aware of the fact that restoration of forests and conservation of forest biodiversity with modest endeavor would help mankind to a great extent in keeping ecological balance in the fragile environmental complex of to day. It has been estimated that the world population of 5.4 billion in 1995 and 6.00 billion in 2000 A. D. would reach 8.5 billion in 2035 A.D. The global grain production fell sharply from 1,800 million tons in 1985 to 1,400 million tons by the end of 1988 and the global grain area has also fallen gradually by about 7% since 1981 (World Watch Institute, 1989). At the same time, our environment has become much polluted nowadays due to the activities of man, which directly or indirectly is responsible for the environmental disasters. The enormous emissions of carbon monoxide and carbon dioxide into the atmosphere is estimated at 7.1 billion tons per annum of which 5.5 billion tons are produced by the burning of fossil fuels and 1.6 billion tons are liberated due to deforestations involving massive burning of forest vegetations. Now the concentration of carbon dioxide in he atmosphere is gradually increased at rate of 4% annually. This has produced the Green House Effects or the warming up of the earth. Due to the heavy destruction as well as massive removal of the forests in the world especially in the tropical and sub-tropical regions , the liberation of oxygen from the vegetations is curtailed to a extent and hence the excessive liberation of carbon from the factories can no longer be counterbalanced by the amount of oxygen present in the air . At the same time other catastrophes in the nature such as soil
erosion, salinization, desertification and floods occur quite often in the world today. Such
catastrophes are attributed to the combined effects of a number of factors, which are all interrelated. One of the potent factors is the depletion of forests causing an upset in the hydrological and nutrient cycles of the earth. Forest destructions have been taking place at an accelerated manner during the last 3-4 decades. In many countries 50-70% of the forest resources have been lost due to destructions. In Europe and Latin America repercussions of deforestation are the extinction of the rare and endemic species, increase in carbon production with the consequences of carbon dioxide induced climatic change, increase in the sedimentation rates in the major systems and disturbance in the hydrological cycle. Another consequence is the degradation of land. Water run-off will be increased whereas water infiltration into the sub-surface will decrease. The resulting reduction in soil moisture and ground water supplies worsens the effects of drought while the increase in the rate or run-off exacerbates flooding. Burning of forests also release 1.6 billion tons of carbon annually, which represents 22.5% of the total liberation of carbon (7.1 billion tons) into atmosphere.
It can be noted that in the midst of heavy removal of the forests in the world today, tree-planting measures are also being undertaken in many countries of the world. It will be of interest to compare the rates of forestation in the face of deforestation going on in the environmentally sensitive regions of the world. The relative rates are given below: Successful strategies should be worked out to solve the critical problem so that the forests are saved in time. It has been observed that pristine areas around the world are lost at unprecedented rate, which are mainly attributed to the pressures of the expanding human populations. Recently, studies had been directed analyzing anthropogenic threats to biodiversity based on species distribution, species habitat use, forest loss and human demographic trends. Forest loss index of the countries of the world and forest loss ranks have been worked out by a number of workers (Myers, 1990, Thomas, et al., 1994, Samson and Knopf, 1996). The countries having high forest loss index have been designated as the regions requiring critical conditions and some of important regions of critical concern (Table 1) are Philippines, Nicaragua, Columbia, Costa Rica, New Zealand, Thailand, Angola, Ghana, India, China, and Bhutan. On analyzing a number
of characters responsible for the threats to biodiversity such as forest loss index, presence of " hot spots " etc. some of the countries of high critical concern need top priority towards undertaking conservational measures. These countries have been listed in Table 2. Among these countries special mention may be made for India, Philippines, Taiwan, Thailand, Costa Rica, Columbia, Angola, Ghana and Nigeria as they have been included in both Global and
Continental categories of " critical concern '. In addition to the inclusion in both levels of critical concern, a few countries (Colombia, India, Philippines) have also got mega diversity and regional " hot spots". But Satellite photographs and remote sensing data have clearly indicated that 40 million hectares of forest area have been degraded and hence the forest coverage stands at 35 million hectares representing hardly 11 % of the total geographical area. The forest area decreased from 54 million hectares in 1972 to 46 million hectares by 1981 and in 1988-1998 the area was reduced to 35 million hectares only. The quantity of fuel wood that can annually be produced from our forest on a sustained basis is 40 million cu m only. As the present demand for fuel wood in the country stands at 235 million cu m, there occurs a deficit of 195 million cu m on an annual basis (Lal, 1992). Deforestation as well as overgrazing has led to extensive land degradations in India. Almost all the forests (90%) of the middle mountain ranges of Indian Himalayas have been deforested in the last four decades. The result is the fantastically high sedimentation rate in the Ganges and Brahmaputra where 3000 million tons of sediments are deposited annually and obviously this has become the highest rate of sedimentation in the world (World watch institute, 1989). Deforestation has resulted to excessive drainage of water in run- off thereby causing significant decrease in the amount of water in the ground water reserves. Of the total amount of annual precipitation in the country (400 million ha m), as much as 180 million ha m is lost from the ecosystem as runoff. The estimated amount of water available in the aquifer is reportedly decreased from 55 million ha m in 1985 in 1985 to 45 million ha m by 1996 (The Hindu, 1996). Hence in India, water tables are falling down gradually in the last 3 decades and severe shortages in water resources occurred. In UP water shortage increased from 17,000 villages in 1960 to about 70,000 villages by 1985. Similar cases also happened in MP and Gujarat. In contrast to the high of deforestation, afforestation measures taken up by the Government of India are far from satisfactory. During 1990s the Government has aimed at a projected planting of trees over 1.9 million hectares. Of the various regions in India, Madhya Pradesh, Maharashtra, Orissa and the NorthEast have recorded very high rates of forest removal i.e. over 500 sq Km per annum (Table 3). In the various regions of India, afforestation measures have also been taken. Comparatively higher rates of annual afforestation have been noticed in Gujarat, Haryana, Karnataka, Madhya Pradesh, Orissa, West Bengal and Rajasthan (90-524 sq Km per annum). In the present context, it is worthwhile to study the rates of afforestation in relation to those of deforestation so that we may be able to see if there is any positive outcome of the measures so far undertaken. In line with the computations of FAO, the afforestations by deforestations ratios have been worked out for the forest of India (Table 3). In some states like Maharashtra, Bihar, Himachal Pradesh, Manipur, Meghalaya, Arunachal Pradesh, Mizoram, Nagaland and Orissa, high ratios crossing the world ratio of 1:10, indicate that immediate remedial measures are badly needed. The annual forest loss index calculated by comparing the loss data of the state with that of country (Table3) reveal that Gujarat, Bihar, Madhya Pradesh, Maharashtra, Orissa and the North East regions have higher forest loss index above 0.04. As these states fall under ' critical concern areas' (Table 4 0), immediate measures of conservation is imperative. Many of these states are also characterized by high percentages of Jhum practice, low inclusion of forests under Reserve and Protected legal classes and lack of proper management practices as ' working plans' are not formulated significantly. Hence, 'problem forests ' suffering from one or more of these threats have been found in the following states and territories of India: The total area under jhum is estimated at 4,905 sq. km (8% of total jhum land of India) and the largest area cleared for the practice is 1,400 sq km Senapati District, which is followed successively by 1200,710 and 675 sq km at Churachandpur, Ukhrul and Tamenglong respectively. We are aware of the various dire consequences of Jhuming viz. flash floods, soil and land degradation, loss of topsoil, ecological catastrophes etc. The annual removal of forest for jhum is estimated at 900-950 sq km. An immediate ecologically safe cultivation practice to replace Jhum is called for before the present jhum cycle of 3 is further reduced to 1 or even 0. Massive burning practiced during the ' slash and burn' process of jhum is the major cause of the depletion of the important tree species like pine, teak phoebe (Uningthou), Juglans (Heijuga) etc. Besides, a number of important shrubs, bamboos, canes, aromatic and medicinal plants (some of which are endemic in the State) are also vanishing from the forest. Such plants, which are presently under the threat of extinction, have been assessed under the present study. The list, which is provisional and not a comprehensive one, is presented in Table 5. The degree of threat for the species is also been specified following the different categories of rare plants (endangered, vulnerable, rare) as recognized by the IUCN (Melville, 1970). In this regard increase in the plantation area of locally suited economical trees, restocking of trees as well as proper management by including more areas in the 'working plan' may be helpful in replenishing the forests and their resources. Table –1: Threatened forests of the World (compiled from Thomas, et al 1994, Samson and Knopf 1996)
Table-2: Priority areas of conservation of Biodiversity (compiled from Myers 1990, Thomas et al. 1994, Samson and Knopf 1996
Table 3: Annual rates of Deforestation and afforestation in the Forests of India.
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