Impact of Invasive Ageratina Adenophora on Relative Performance of Woody Vegetation in Different Forest Ecosystems of Kumaun Himalaya,India

Invasive plant Ageratina adenophora (Sprengel) R. King H. Robinson has invaded majority of the temperate forests in Kumaun, Central Himalaya. Information on A. adenophora invaded forest types, their structural attributes, population demography and regeneration status are still at rudimentary level. Considering this, the present study was conducted to assess the impacts of A. adenophora on vegetational attributes and regeneration status of three forest types, viz., Oak (Quercus oblongata D. Don), Pine (Pinus roxburghii Sarg.) and Cypress (Cupressus torulosa D. Don). We selected three sites for each forest type and each site was further purposively stratified into paired sampling plots of 1 ha each i.e., A. adenophora invaded and uninvaded sites. Our results showed large densities of cut stumps or felled trees throughout invaded sites, but with fewer fire signs in comparison to uninvaded sites. In uninvaded sites, total density and basal area calculated for woody species were relatively higher than those in invaded sites, although results were insignificant (p>0.05). With the exception for Cypress forests, vegetation indices showed low woody species richness and diversity in invaded Oak and Pine forests. Also, regeneration of Q. oblongata, P. roxburghii and C. torulosa tree species did not differ significantly (p>0.05) between invaded and uninvaded sites. These insignificant differences clearly imply that A. adenophora’s presence has not entirely changed the perennial plant communities in terms of composition, structure and natural regeneration. However, tree species with poor or no regeneration status requires special attention and needs management strategies involving control of invasive species in forest ecosystems.