Infestation Of Weed Vegetation Parthenium hysterophorus L. In Tehri Garhwal Himalaya, Uttarakhand, India

Parthenium hysterophorus L. is a weed of global significance causing severe economic, environmental, agricultural, biodiversity, livestock, and human health problems. It is a highly noxious, invasive plant species of subtropical America and quickly spreads almost in all climatic conditions of the world. The weed has been spread almost in every part of every state of India including Uttarakhand. P. hysterophorus was observed to spread from sub-tropical climatic conditions to the temperate region up to 2200 m asl in Tehri Garhwal, Uttarakhand. It has severely affected the habitats of native plant species. P. hysterophorus is an annual herb that starts to grow during March-April and remains till last of the November-December. The infestation of Parthenium has been maximum during the summer and abolished during the winter season. Regular field visits and surveys were made during the growing season (2018- 19) from foothills to higher ridges of the study areas. The highest density value (729000 ind ha-1 ) for P. hysterophorus was recorded at the Chauras site followed by Rishikesh (554000 ind ha-1 ) and the Badshahithaul site (417000 ind ha1 ) whereas, the lowest density value for this weed was recorded at the Ranichauri site (61000 ind ha-1 ). P. hysterophorus was determined to be the dominating plant species in most of the survey sites based on density, basal cover, and the Importance Value Index (IVI). However, the dominance of P. hysterophorus in most of the study sites is a signal of probable threat to the associated species. Plant species degradation caused by high anthropogenic pressure would provide appropriate circumstances for Parthenium weed to invade, presenting a major threat to the ecological balance of the region. The aim of present study to investigate infestation of Parthenium weed with altitudes wise in Tehri Garhwal, Uttarakhand, India.