Effects of Herbivory, Pathogens and Habitat Types on Invasive Alien Plant Species in Chobhar, Kathmandu, Nepal

Abstract

Invasive alien plant species (IAPS) in Nepal have become a great problem. They are responsible to cause severe damages to our ecosystem and contribute a huge amount of economic loss. It has been considered that the invasive species spreads rapidly because they are comparatively less damaged by herbivores and pathogens in the invaded range. This study aims to understand effects of herbivores, pathogens and habitats on invasive species Ageratina adenophora, Ageratum conyzoides, Bidens pilosa, Parthenium hysterophorus in Chobhar area of Kathmandu, Nepal. Additionally, the study compared density, frequency and coverge of these species. Ecological parameters were measured by sampling quadrats of size (1×1 m vi

2 ) in fallow land, forest and along road towards north and south aspects of the study area. Herbivory damages assessment was conducted by sampling plants from the quadrats sampled. Results showed that the herbivory damage differs among the IAPS and it depends on habitat type. In branches, B. pilosa was greately damaged in fallow land, A. adenophora in the forest, A. conyzoides in the road towards north aspect and P. hysterophorus in road towards south aspect. Similarly, in case of leaves, the highest damage was found in B. pilosa from sites fallowland and Road towards north aspects. In A. conyzoides and A. adenophora damages were found maximum in the road towards north aspect but in P. hysterophorus the damage was severe in road towards south aspect. Moreover, a total of 13 fungi were isolated from the infected leaves of IAPS and identified. Further studies are recommended for additional information in herbivory damages and fungal identification. This work might be helpful to know the current status of herbivory damages on selected IAPS in Nepal.

Key-words: Biological control, fungal species, habitat, herbivory damages, IAPS.