Alien flora of Doon Valley, Northwest Himalaya

摘要

this communication is an attempt to prepare an up-to-date account of alien/exotic flora of the Doon Valley. Both herbaceous and woody species are considered and their origin, habit, and families are investigated along with the socio-economic and ecological relevance of a few species. During this study, 308 woody and 128 herbaceous exotic species were identified and enlisted from various localities and 37.61% of these are of American origin. Interestingly, the statistical ratio of alien species was 45.69% for woody flora, while it was investigated 19.4% for herbaceous species. This relative proportion of exotic and native elements is irrespective of 28.8% endemic dicot species in Indian Himalaya and 40% exotics in the entire Indian flora. However, the occurrence of the present share of alien species and their naturalization cannot be considered safe for native and endemic flora. This is especially true of Doon Valley, which is part of the mega Himalayan 'hotspot, belt and is globally designated for priority of conservational activities in India.