Invasive Weeds, Threat to the Biodiversity -
A Case Study from District Lakki Marwat, Northwest Pakistan

Ikramullah Khan and Khan Bahadar Marwat

Department of Weed Science, NWFP Agricultural University Peshawar, Pakistan
e-mail: ikramws@yahoo.co.uk

Abstract

Pakistan is rich in biodiversity of flora and fauna due to diversified climatic conditions. Besides many factors, affecting the biodiversity and environment, invasive species introduction is the devastating one. In this regard survey was conducted using a sample of 297 farmers from 99 villages of 33 union councils of district Lakki Marwat, during March 2002 to September 2003 regarding weeds. Eleven weeds reported as invasive of total 50 problematic weeds. These were Avena fatua, Carthamus oxyacantha, Prosopis juliflora, Eucalyptis camaldulensis, Phragmites austrailis, Xanthium strumarium, Galium aparine, Asphodelus tenuifolius, amaranthus viridis, Imperata cylindrica and Trianthema portulacastrum. Among these Prosopis juliflora and Eucalyptis camaldulensis were purposely introduced, while rest of the species were introduced accidentally or were present in the local flora, but due to ecotypic changes these became aggressive and suppressed the local flora.