Floristic diversity and correlates of naturalization of alien flora in urban green spaces of Srinagar city

Abstract

The sustainable management of green spaces in cities is crucial in achieving the challenging goal of urban sustainability. The common practice of cultivation of alien plants in urban green spaces is often associated with risk of naturalisation (i.e. escape into wild), which can have sometime adverse impacts on biodiversity and ecosystem services. To mitigate these risks, understanding patterns and processes of naturalisation of alien flora in urban green spaces becomes crucial. Here we report the floristic diversity of alien flora and correlates of its naturalisation in the green spaces of Srinagar city – one of the largest urban centres in the Himalaya. We documented 342 plant species belonging to 66 families from the green spaces of Srinagar, predominantly represented by 245 alien species (72%). Among the alien species pool, 133 species (54%) are exclusively under cultivation (non-escapes) and 112 species (46%) grow in the wild (cultivation escapes and accidentally introduced species); and of the latter, 51 were naturalised, 39 casual and 22 invasive. The cultivated alien species escaped into the wild belong to 27 families, and most prominently to the Asteraceae. Habitat-wise, plant dumping sites in the green spaces constituted the most dominant habitat of cultivation escapes. A significant relationship was revealed between the proportion of aliens under cultivation and species traits such as growth form, life span and residence time; and plant species with herbaceous growth form, annual life span and relatively longer residence time showed higher proportion of naturalisation. We found a significant correlation between abundance of the cultivation escapes and residence time (r = 0.507). The present study has generated policy-relevant data on urban green spaces of Srinagar, which can support policy regulations to steer the sustainable development of this rapidly urbanising Himalayan city.