Invasion and Impact of Non-native Species on Indigenous Flora in an Urban Ecosystem of India: A Case Study

Abstract

We quantified the urban vegetation through floristic inventory to assess the invasion risk and document the non-native flora of the study sites with their influence on indigenous flora. The present study was carried out in four different directions viz., east, west, north and south direction of Ambikapur of Sarguja district of Chhattisgarh. We found that most of the species recorded during investigation was non-native. A total of 52 floral species were recorded during the investigation out of which 38 species were non-native (73.08%). Out of 26 tree species 17 (65.38%) were non-native species, in shrub out of 8 species 7 (87.50%) were non-native species and in herb species out of 18 species 14 (77.78%) were non-native species. In case of non-native (tree species, shrub and herb) species total 16 families were recorded the dominant family was Fabaceae (18 species) followed by Asteraceae (7 species). While in case of native flora (tree, shrub and herb) a sum of 11 families were recorded and the dominant family was Fabaceae and Meliaceae (2 species each).The density of indigenous and non-native species were varied from 100-130 tree/ha and 40-110 tree/ha, respectively. It reflects that the density of non-native species were higher towards north direction (45.83%) among different sites. In present study regeneration percentage of tree species were 72.73% (east), 60% (west), 35.29% (north), 81.82% (south) were not regenerative, species with good regeneration were 9.09% (east), 40%(west), 29.41% (north), 18.18% (south), species with fair regeneration were 18.18% (east), 17.65% (north), species showing poor regeneration was 17.65% (north). The non-native species caused declined in the generation upto 20% in west direction, 29.41% in north direction whereas towards east direction no species was recorded having good regeneration potential and towards south similar value of good regenerating species (9.09%) were recorded for both native and non-native flora. The present findings were essential from the urban planning and development point to view and helpful towards checking the introduction of non-native species.