Community structure and recolonization by earthworms in rehabilitated ecosystems in garhwal himalayas, India (original) (raw)
Forestry Research and Engineering: International Journal
Consequences of deforestation arise from site degradation leading to modification of soil properties this significantly affect both incidence and abundance of soil macro fauna. Earthworm communities are more directly altered by these changes. Endemic and exotic species co-existed in the study area following deforestation and intensive cultivation. That native species were dominant in the undisturbed sites and disturbance and degradations leads to invasion by the exotic species holds true in our study. The sites under study represented the degraded areas as none of the species reported from the present experimental plots were endemic to the region, all the species are either peregrine exotic or peregrine endemic to the area as many of the endemic species of this region probably exterminated during the last Quaternary Glaciation. The numbers of species present at our sites ranged between 2 to 5. The presence of litter layer and lower perturbation pressure resulted in the numerical dominance of Lennogaster pussilus in the Oak forest (OF) and the higher biomass of A. alexandri may be because of the larger size of the earthworm. B parvus, L. pussilus and P. excavatus are litter-associated taxa which were more directly affected by OF clearance and the resulting decrease in available litter, thus explaining their disappearance in the changed ecosystems, however improved soil moisture and temperature as well as input of organic matter in rehabilitated agricultural land (RAL) could probably be favourable factor for decolonization and dominance of L. pussilus. A. alexandri had wider ecological amplitude occurring under all land use types as reported in our studies, conversion of two other land use types resulted in lower species diversity. Our results show that the abandoned agriculture land (AAL) remains closer to the AL(T) than to the forest because in these land use types the overall vegetation diversity remains low corresponding to a low diversification of the organic resources thus explaining the similarity between the earthworm communities in land use types. Seasonal rhythmic pattern was exhibited by all the species identified.
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