Abstract
Morni Hills of Panchkula district, Haryana harbor floristically important tropical dry deciduous forests and are quite enriched with the phytodiversity of medicinally important plant species. But these forests are under huge pressure due to anthropogenic activities facilitating the establishment and spread of invasive plant species. So, the present study was conducted in the forests of Morni Hills to understand the ecology of invasive alien plant species growing there. During the study, the area was colonized by many invasive alien plant species, such as Ageratum conyzoides L., A. haustonianum Mill., Chromolaena odorata (L.) R.M. King & H. Rob., Lantana camara L., etc. In terms of longevity, the annual growth form dominated over the perennial. The family Asteraceae was dominant with 11 species, followed by Malvaceae and others. The biological spectrum showed that the dominant life form was therophytes followed by phanerophytes and others, indicating vegetation disturbance while during flowering phenology assessment, maximum plant species were found to be flowering throughout the year. Using the data of flowering (presence or absence), a hierarchical cluster analysis was carried out and a heatmap was prepared. The diversity of invasive plants was calculated along an altitudinal gradient and was found to be changing along with rising altitude in a hump-shaped pattern. The invasive alien plant species cause severe threats to the forest ecosystems. Hence, by policy planning and adopting appropriate management strategies in the forests of Morni Hills, the growth of invasive alien plant species should be controlled to retain the natural ecology of the area.