Invasion of Parthenium hysterophorus in the twin cities

Abstract

Islamabad – the capital of Pakistan and its twin city Rawalpindi shows a great susceptibility to invasive species which are now threatening the native flora. A phytosociological survey was carried out to estimate the floristic composition of the two cities and to evaluate the extent of infestation by the invasive weed – Parthenium hysterophorus. The results were analyzed using TWINSPAN - an appropriate technique for hierarchical classification of community data, which resulted into formulation of six major and six minor communities. These communities were further merged to develop three overlapping vegetation zones, among which zone I governed completely by Parthenium hysterophorus, represented almost one-third of the entire vegetation of the study area.  Parthenium with certain other invasive species as Broussonetia payrifera, Lantana camara etc. imparts serious threat to the native flora and demands immediate mitigation through integrated weed management.