Distributional pattern of Asteraceae along a spatial gradient in urban and suburban areas of Lahore City, Pakistan.

Ecological significance of Asteraceae in response to common colonizers due to the fast pace of urbanization in Lahore District was determined. The species are natural colonizers in this area. In order to gauge the response, sites from both urban and suburban areas were selected. A total of 28 species under 22 genera of the family Asteraceae were collected and identified. The results reveal that members of Asteraceae have highest diversity in suburban having richness of 18 species, followed by urban having only four species. The diversity index indicates that highest diversity was in suburban and rural wastelands of Raiwind. In comparison with the previous record, only 60% species of Asteraceae previously reported were found, out of which 50% species were present in suburban and rural and only 10% in urban areas. It appears that decline in the species number was due to the excessive growth of population, urbanization, industrialization, and invasive exotics like Parthenium hysterophorus and Pantanema vestitum.   Key words: Urbanization, colonizers, diversity index, wastelands, exotics.