2020, VOLUME 7 ISSUE 2Pages: 460-471
Floristic composition and natural regeneration status in Abhoypur reserve forest of Assam following Mikania micrantha Kunth. ex. H.B.K. invasion
Kuntala N. Barua* and Protul Hazarika
*Forest Ecology & Climate Change Division, Rain Forest Research Institute, Jorhat-785010, Assam, India
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Mikania micrantha is a fast growing perennial vine of Asteraceae family, native to Central and South America. Recently the open sunny patches of Abhoypur Reserve Forest of Upper Assam was severely infested by this invasive species. The present study was undertaken to assess the impact of M. micrantha on vegetation pattern and natural regeneration of trees in Abhoypur reserve forest. Survey was carried out randomly lined quadrats of 10 m × 10 m, and 5 m × 5 m and 1 m × 1 m for tree, shrubs and herbs, respectively, in Mikania infested and un-infested forest areas. Study on floristic pattern has recorded a total of 417 plant species distributed within 321 genera and 102 families and Euphorbiaceae as the dominant family with16 species followed by Lauraceae (14 species). In herbaceous strata of infested site, Mikania attained dominating position with IVI of 99.53 during the full growth period and causing displacement of a number of native species. Dipterocarpus retusus was the dominant species with IVI 22.21 followed by Artocarpus chama (IVI 20.82), Mesua ferrea (IVI 14.62) in un-infested site, whereas, in M. Micrantha infested site the upper canopy was dominated by Ficus hispida (IVI 17.21), Dysoxylum gotadhora (IVI 9.52), Macaranga peltata (IVI 9.14). Diversity index were relatively high in un-infested sites for all tree, shrub and herb communities (4.45, 3.23 and 2.53). Altogether 140 tree species were regenerated during the study period, of which, 101 species in un-infested and 58 species in infested forest sites. Invasion of Mikania promotes the recruitment of some light demanding deciduous species such as Alangium chinense, Bischofia javanica, Bombax ceiba, Mallotus ferrugineus, Balakata baccata other than evergreen species. The ‘none’ regeneration and ‘poor’ regeneration group contributed 15.52% and 24.13%, respectively, that gradually created instability among the tree species which need attention.