Phyto-Distribution of Alien Invasive Species in the Campus of Pune University by Using GPS Mapping and their Interaction

Abstract

The invasive plant species hamper crops, human activities and become part of dynamic ecosystems, which grow in varied habitats and harsh ecological conditions and often invade the new ecosystems. The campus of Pune University is highly rich in phytodiversity of native and invasive weeds, which interact with each other. The invasive weeds like Cassia uniflora Mill. non Spreng, Alternanthera tenella Colla., Synedrella nodiflora (L) Gaertn, S. vialis Gray and native weed species like Achyranthes are showing dominance in the campus. The GPS mapping indicated that C. uniflora, S. nodiflora, . tenella, Blainvillea acmella, Euphorbia geniculata, Triumfetta rhomboidea and C. obtusifolia were dominant and occasionally forming pure stands in the campus reducing the phytodiversity of natives by substitution. The results on weed-weed interactions indicated that major associations were between Cassia and Achyranthes, Cassia and Bidens . Synedrella population was forming monothickets. The studies on weed-weed associations and interactions at all the sites indicated that native plants were substituted by the encroachment of invasive weeds due to negative interactions. The negative influence of Cassia and Synedrella was prominent through out the campus. The strong positive and negative associations of native and alien weeds in the university campus predicted changing Phytodiversity and ecosystem dynamics. The aggressive nature and invasiveness of C.uniflora and S.nodiflora was confirmed by their respective abundance such as 25.83 and 24.80 as compared to native weeds like Achyranthes (12.93). The investigation clearly proved the declining phytodiversityof native plant species in the university campus, which has perturbed the ecological balance through the release of allelochemicals / ecochemicals in the habitat.