Impact of Coal Mining on Vegetation: A Case Study in Jaintia Hills ...

IMPACT OF COAL MINING ON VEGETATION: A CASE STUDY IN JAINTIA HILLS DISTRICT OF MEGHALAYA, INDIATable 4.2: Stand density as affected by mining in different zonesSpecies Control Zone-I Zone-II Zone-III Zone-IVTrees (individual/ha) 1040 561 515 603 647Shrubs (individual/m 2 ) 1 2 1 1 2Herbs (individual/m 2 ) 32 165 178 154 1574.1.3. Dominance PatternThe dominance were different for tree, shrub and herb component in mined and the unmined controlarea <strong>of</strong> the study area. In terms <strong>of</strong> importance value Pinus kesiya (IVI: 243.97-280.27) was thedominant tree species in the mining area and presented in all the zones, which was followed by theSchima wallichii (IVI: 10.05-46.36). In the control site Camelia caudata (IVI: 54.5), Castanopsispurpurella (IVI: 44.9) and Quercus griffithii (IVI: 30.7) were the dominant tree species.In the shrub layer, Eupatorium adenophorum (IVI: 22.78-53.74) and Melastoma nepalensis (IVI:23.36-48.86) were the two dominant species followed by Lantana camara (IVI: 23.93-49.44) indifferent zones <strong>of</strong> the mining area. Control site was dominated by Psychotria erratica (IVI: 16.13),Cassia floribunda (IVI: 14.52), Shutaria vestida (IVI: 14.52), and Plectranthus striantus (IVI: 14.52).Among herbaceous species Paspalum orbiculare (IVI: 68.42-95.47) dominated all the zones <strong>of</strong> themining area, which was followed by Isachne himalaica (IVI: 15.75-19.57). Globba clarkii (IVI:38.73), Selaginella semicordata (IVI: 29.52) and Panicum brevifolium (IVI: 24.13) were the dominantground species in the control site (Table 4.3).The high importance value <strong>of</strong> Pinus kesiya in mining areas suggesting its ability to grow in thedisturbed environments and its dominance in the harsh conditions. Higher importance value <strong>of</strong> Schimawallichii indicates the degraded environment. The higher importance value <strong>of</strong> Paspalum orbicularesuggests that it can multiply rapidly in the disturbed environments. This perennial grass by virtue <strong>of</strong> itsstolon and rooting at each node can bind the soil particles, making the soil more stable. The dominance<strong>of</strong> one or two species explain the low diversity and high dominance in the mined affected areas.Dominance-diversity curves have been used to interpret the dominance <strong>of</strong> species in the community inrelation to resource apportionment and niche space (Whittaker, 1975). The curves (Figure 4.1, Figure4.2, Figure 4.3) in the unmined sites resemble the log normal suggesting that there was more or less aneven apportionment <strong>of</strong> resources among the members <strong>of</strong> the important species. The curves for themined sites resemble with broken-stick series model (Poole, 1974). This could be attributed to thelesser number <strong>of</strong> species occurring in these areas and also represent a stress environment whereconditions were not favourable for plant growth. Species diversity was low on these stands, but thespecies that grow here appear to have developed tolerance that enable them to grow in such anenvironment.31