Sandstone quarry in relation to change in diversity, distribution and community organization of trees in sub-tropical forest of Mizoram, North east India
Publication Date : 19/04/2016
Mizoram is one of the 8 states fall under North East India. Sandstone quarryis prevalent in state, and it has great socio-economic value. On other hand, it is very detrimental to environment particularly, vegetation, water and soil of the area. In view of this, the present study has been carried out to assess the impact of sandstone quarry on diversity, distribution and community structure of trees in sub-tropical forests of Mizoram, north-east India.The study was conducted in forest standsin catchment area of Tlawngriver, situated nearby villages Sairangand Shimmuih, 26 km away from the state capital Aizawl in Mizoram. A total of four sampling sites were selected. Of these, three sites were selected in sandstone quarry affected areas with different ages of mining, representing undisturbed, mildly disturbed and highly disturbed sites. The fourth sampling site was selected in un-mined area representing reference site. The quadrat method was adopted for field data on vegetation to compute various phytosociological analyses, and diversity and distribution of plants.Altogether, a total of 49 tree species belonging to 41 genera and 25 families of angiosperms were recorded from all four selected study sites. The findings reveal that undisturbed stand harbors maximum number of species. There was shift in position of dominant species and families along disturbance gradient. The species common to all sites having high ecological amplitude. The disturbance leads to reduced girth classes from undisturbed to highly disturbed stand. Majority of species showed contagious distribution pattern and few random distribution. The diversity index decreased with increase in degree of disturbance. On the contrary, dominance index followed a reverse trend of result. Sorenson’s index of similarity indicate that mildly disturbed site was more similar with highly disturbed site. There is an ample scope of scientific method for quarry to minimize adverse effects of mining on vegetation. Phase-wise clearing of forest and re-vegetatingabandoned areas with suitable species especially soil binding plants may be more effective to minimize land deterioration. Moreover, environment awareness campaign should be launched for rural indigenous people to educate them for damage to the environment due to unscientific mining. It seems that integrated approach involving local people, NGOs and Government organizations could be an effective tool for proper management of abandoned mine areas.
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