The vegetational landscape of north-eastern Terai region at the foot hills of Central Himalayas is a mosaic of grassland, old-field, wasteland, and forest ecosystems. Like many other parts of the country, this region is also infested with alien intruders which not only interfere with the growth and production of food crops but also exercise adverse effects on the biodiversity of native species. The present study attempts to catalogue the invasive alien species of the terrestrial vegetation of north-eastern Uttar Pradesh especially with reference to their habit, taxonomic position, and nativity. A total of 1135 plant species within 580 genera under 119 families are so far known to occur in the region. Of these, only 149 species within 100 genera under 41 families have been found to be invasive aliens as evident from their center of origin, past history, nature of aggregation, and invasion observed under field conditions. About 80% of these invaders have been introduced from neotropics. Out of 173 invasive plants across India, this region shares 149 species, out of which 66% of species have come from Tropical America, 14% from African continent, and the rest from other countries. A better planning in the form of early identification and reporting of infestation and spread of noxious weeds is needed for their control. 1. Introduction Invasion of alien plant species in recent times has been recognized as the second worst threat after habitat destruction [1]. The International Union for Conservation of Nature and Natural Resources (IUCN) defines “alien invasive species” as an alien species which becomes established in natural or seminatural ecosystems or habitat as agent of change and threatens native biological diversity. Identifying the processes that determine the distribution and diversity of exotic species is a major area of research in ecology because exotics impose significant economic, social, and environmental costs, including human health [2]. Biological invasion may be considered as a form of biological pollution and the significant component of anthropogenic changes leading to extinction of native species. The ecological approach to plant invasion has been mostly based on (a) biological and ecological features promoting the invasion success of particular species [3, 4] and (b) the character and invasibility of invaded communities [5]. Recently, both approaches are treated as complementary [6, 7]. The phytogeographical and floristic approaches are important for research on alien plants [8]. A number of workers have studied and provided catalogues
References
[1]
C . B. D, “Invasive Alien species,” Convention on Biological Diversity, 2005, http://www.biodiv.org/programmes/cross-cuttings/Alien.
[2]
D. S. Wilcove, D. Rothstein, J. Dubow, A. Phillips, and E. Losos, “Quantifying threats to imperiled species in the U. S.,” BioScience, vol. 48, no. 8, pp. 607–615, 1998.
[3]
A. E. Newsome and I. R. Noble, “Ecological and physiological characters of invading species,” in Ecology of Biological Invasions: An Australian Perspective, R. H. Groves and J. J. Burdon, Eds., pp. 1–20, Australian Academy of Sciences, Canberra, Australia, 1986.
[4]
M. Rejmánek, “What makes a species invasive?” in Plant Invasions: General Aspects and Special Problems, P. Pysek, K. Prach, M. Rejmánek, and M. Wade, Eds., pp. 3–13, SPB Academic, Amsterdam, The Netherlands, 1995.
[5]
M. Rejmánek, “Invasibility of plant communities,” in Biological Invasions: A Global Perspective, J. A. Drake, H. A. Mooney, F. di Castri et al., Eds., pp. 369–388, John Wiley & Sons, Chichester, UK, 1989.
[6]
D. M. Lodge, “Biological invasions: lessons for ecology,” Trends in Ecology and Evolution, vol. 8, no. 4, pp. 133–137, 1993.
[7]
R. J. Hobbs and L. F. Huenneke, “Disturbance, diversity, and invasion: implications for conservation,” Conservation Biology, vol. 6, no. 3, pp. 324–337, 1992.
[8]
J. A. McNeely, H. A. Mooney, L. E. Neville, P. Schei, and J. K. Waage, “A global strategy on invasive Alien species,” in Collaboration With the Global Invasive Species Programme, IUCN, Gland, Switzerland, 2001.
[9]
J. A. Drake, H. A. Mooney, F. di Castri et al., Biological Invasions: A Global Perspective, John Wiley & Sons, New York, NY, USA, 1989.
[10]
M. Williamson, Biological Invasions, Chapman & Hall, New York, NY, USA, 1996.
[11]
J. R. Carey, P. Moyle, M. Rejmánek, and G. Vermeij, “Invasion biology,” Biological Conservation, vol. 78, pp. 1–214, 1996.
[12]
P. Pysek, M. Chytry, J. Pergll, J. Sadloland, and J. Wild, “Plant invasions in the Czech Republic: current state, introduction dynamics, invasive species and invaded habitats,” Preslia, vol. 84, pp. 575–629, 2012.
[13]
D. M. Richardson, P. Py？ek, M. Rejmánek, M. G. Barbour, F. Dane Panetta, and C. J. West, “Naturalization and invasion of Alien plants: concepts and definitions,” Diversity and Distributions, vol. 6, no. 2, pp. 93–107, 2000.
[14]
P. Py？ek, J. Sádlo, and B. Mandák, “Catalogue of Alien plants of the Czech Republic,” Preslia, vol. 74, no. 2, pp. 97–186, 2002.
[15]
M. B. Raizada, “Recently introduced or otherwise imperfectly known plants from the upper gangetic plain,” Journal of Indian Botanical Society, vol. 14, pp. 339–348, 1935.
[16]
M. B. Raizada, “Recently introduced or otherwise imperfectly known plants from the upper gangetic plain,” Journal of Indian Botanical Society, vol. 15, pp. 149–167, 1936.
[17]
J. K. Maheshwari, “Studies on the naturalized Flora of India,” in Proceedings of the Summer School of Botany, pp. 156–170, New Delhi, India.
[18]
K. M. Matthew, “Alien flora of Kodai Kanal and Palni Hills,” Records of Botanical Survey of India, vol. 20, pp. 1–241, 1969.
[19]
G. Singh and B. Misri, “Some exotic ornamentals of Kashmir,” Indian Journal of Horticulture, vol. 31, p. 834, 1974.
[20]
G. Singh and P. Kachroo, “Exotic trees and shrubs of Kashmir,” Indian Forester, vol. 109, pp. 60–76, 1983.
[21]
J. K. Maheswari and S. R. Paul, “The Alien flora of Ranchi,” Journal of the Bombay Natural History Society, vol. 72, pp. 158–188, 1975.
[22]
P. K. Hajra and B. K. Das, “Vegetation of gangtok with special reference to Alien plants,” India Forums, vol. 107, pp. 554–566, 1982.
[23]
B. D. Sharma, Exotic Flora of Allahabad, Botanical Survey of India, Dehra Dun, India, 1984.
[24]
R. P. Pandey and P. J. Parmar, “The exotic flora of Rajasthan,” Journal of Economic and Taxonomic Botany, vol. 18, pp. 105–121, 1994.
[25]
S. R. Kshirsagar, “Origin, present status and distribution of exotic plants in South Gujarat,” Indian Journal of Forestry, vol. 28, pp. 136–143, 2005.
[26]
P. S. Negi and P. K. Hajra, “Alien flora of Doon Valley, Northwest Himalaya,” Current Science, vol. 92, no. 7, pp. 968–978, 2007.
[27]
H. A. Mooney and J. A. Drake, “The ecology of biological invasions,” Environment, vol. 29, no. 5, pp. 10–37, 1987.
[28]
C. M. D'Antonio and P. M. Vitousek, “Biological invasions by exotic grasses, the grass/fire cycle, and global change,” Annual Review of Ecology and Systematics, vol. 23, no. 1, pp. 63–87, 1992.
[29]
P. T. Jenkins, “Trade and exotic species introductions,” in Invasive Species and Biodiversity Management, O. T. Sandlund and P. Schei, Eds., pp. 229–235, Kluwer Academic, Dodrecht, The Netherlands, 1999.
[30]
H. A. Mooney and R. J. Hobbs, Invasive Species in a Changing World, Island Press, Washington, DC, USA, 2000.
[31]
C. S. Elton, The Ecology of Invasions by Animals and Plants, University of Chicago Press, Chicago, Ill, USA, 2000.
[32]
R. Cowie, “Does the Public care about Species loss? A Glimpse into the Public's thinking,” Conservation Biology in Practice, vol. 2, pp. 28–29, 2001.
[33]
E. Wasson, Complete Encyclopedia of Trees and Shrubs: Descriptions, Cultivation Requirements, Pruning, Planting, Thunder Bay Press, San Diego, Calif, USA, 2003.
[34]
C. S. Reddy, G. Bagyanarayana, K. N. Reddy, and V. S. Raju, “Invasive Alien Flora of India,” National Biological Information Infrastructure, USGS, USA, 2008, http://www.isws.in/invasive-plants-of-india.php.
[35]
M. A. McGeoch, S. H. M. Butchart, D. Spear et al., “Global indicators of biological invasion: species numbers, biodiversity impact and policy responses,” Diversity and Distributions, vol. 16, no. 1, pp. 95–108, 2010.
[36]
A. S. Raghubanshi, L. C. Rai, J. P. Gaur, and J. S. Singh, “Invasive Alien species and biodiversity in India,” Current Science, vol. 88, no. 4, pp. 539–540, 2005.
[37]
Y. H. Sujay, H. N. Sattagi, and R. K. Patil, “Invasive Alien insects and their impact on agroecosystem,” Karnataka Journal of Agricultural Sciences, vol. 23, pp. 26–34, 2010.
[38]
P. Singh, “Lantana Weed and Lantana Lace bug,” Indian Forester, vol. 102, pp. 474–478, 1976.
[39]
P. M. Sinha, “Studies on the use of some Weedicides on Lantana camara,” Indian Forester, vol. 102, pp. 298–305, 1976.
[40]
V. B. Sawarker, “Lantana camara on wildlife habitats with special reference to the melaghat tiger reserve,” Cheetal, vol. 26, pp. 24–38, 1984.
[41]
K. P. Singh, A. N. Shukla, and J. S. Singh, “State-level inventory of invasive Alien plants, their source regions and use potential,” Current Science, vol. 99, no. 1, pp. 107–114, 2010.
[42]
C. S. Reddy, “Catalogue of invasive Alien flora of India,” Life Science Journal, vol. 5, no. 2, pp. 84–89, 2008.
[43]
K. C. Sekar, “Invasive Alien plants of Indian Himalayan region—diversity and implication,” American Journal of Plant Science, vol. 3, pp. 177–184, 2012.
[44]
S. H. Wu, C. F. Hsieh, and M. Rejmánek, “Catalogue of the naturalized flora of Taiwan,” Taiwania, vol. 49, pp. 16–31, 2004.
[45]
Q. Q. Huang, J. M. Wu, Y. Y. Bai, L. Zhou, and G. X. Wang, “Identifying the most noxious invasive plants in China: role of geographical origin, life form and means of introduction,” Biodiversity and Conservation, vol. 18, no. 2, pp. 305–316, 2009.
[46]
S. Tripathi and R. P. Shukla, “Effect of clipping and grazing on various vegetational parameters of grassland communities of Gorakhpur, Uttar Pradesh,” Tropical Ecology, vol. 48, no. 1, pp. 61–70, 2007.
[47]
K. S. Dogra, R. K. Kohli, and S. K. Sood, “An assessment and impact of three invasive species in the Sivalik Hills of Himanchal Pradesh, India,” International Journal of Biodiversity Conservation, vol. 1, pp. 4–10, 2009.
[48]
K. G. Saxena, “Biological invasion in the Indian sub-continent: review of invasion by plants,” in Ecology of Biological Invasion in the Tropics, P. S. Ramakrishnan, Ed., pp. 53–73, International Scientific Publications, New Delhi, India, 1991.
[49]
S. Tripathi, Plant diversity of grassland of north-eastern U.P. with emphasis on population of Parthenium hysterophorus L. [Ph.D. thesis], Gorakhpur University, Gorakhpur, India, 1999.
[50]
S. K. Sood, S. Kumar, K. S. Dogra, and R. Sharma, “Alien plants distribution and ecology in the temple-courtyards of Himachal Pradesh, North-West Himalaya,” Himachal Pradesh University Journal, pp. 1–11, 2011.
[51]
C. H. Chou, “Allelopathic researches in the subtropical vegetation in Taiwan,” Comparative Physiology and Ecology, vol. 5, pp. 222–234, 1980.
[52]
P. S. Ramakrishnan, Ecology of Biological Invasions in the Tropics, International Scientific, New Delhi, India, 1991.
[53]
K. G. Saxena and P. S. Ramakrishnan, “Partitioning of biomass and nutrients in the secondary successional herbaceous population subsequent to Slash and Burn,” Proceedings’of the Indian National Science Academy, vol. 8, pp. 807–818, 1982.
