Patterns of invasion by crofton weed (Ageratina adenophora) in Kailash sacred landscape region of western Himalaya (India)

Invasion of alien species in high altitude ecosystems is a potent threat to the species diversity as well as it can cause severe environmental and economic issues. The invasion of alien plant species can be facilitated by many eco-climatic factors. The present study was conducted to assess patterns and trends of invasion by Ageratina adenophora in major land use and land cover types; in Gokerneshwergad watershed of Kailash Sacred Landscape (KSL) in western Himalaya. Extensive surveys were conducted to map the species in each season and habitat type. Sites with high biotic pressure and open forest canopy were the most suitable habitats for its growth. A negative correlation was found between distribution and altitude. The highest invasion was recorded in between 1700 – 1800m elevation gradient, between 20° and 30° slope positions and at North (33.33%), whereas, the lowest invasion was recorded between 700 – 800m in South-East directions (3.70%). Several other parameters such as distance from the disturbance site such as road, villages or settlements, drainage and soil texture were also found to be affecting the distribution pattern of this species. Interestingly results reveal that the alien plants also start competing among themselves after reaching their threshold level.