Abstract
As a result of urbanisation, landscapes and land use patterns are changing the world over. This extreme form of land use alteration has affected species composition and abundance, moulding a few species to dominate the urban environment and a few others to extinction. Urbanisation occurs at different scales and the community composition of species gets affected accordingly. In this paper, we look into species richness and abundance of birds, and their variation along an urban-rural gradient at Tiruchirappalli, India. In Tiruchirappalli, bird species diversity increases from more to less urbanised centres. Though diversity is less in urban areas, the abundance of species occupying these areas is higher. During this study, the maximum recorded birds were omnivores. The most affected species is the House Sparrow, with a few populations residing in the urban environment. Along the urban-rural gradient, farmlands and wetlands are the most preferred landscapes of birds, and conservation measures need to be oriented in this direction to protect the most vulnerable species. Species diversity in urban areas is significantly contributed to by edge species that occupy the fringes of urban areas. Though urban landscapes are less species rich, they too play a significant role in biodiversity conservation as they are species abundant zones. City planners and urban foresters need to pay more attention towards preserving habitats not only in urban areas but along the urban fringes, as they provide suitable corridors for various activities of birds and their movement.References
Arnold, C.L. & C. Gibbons (1996): Impervious surface coverage: The emergence of a key environmental indicator. Journal of the American Planning Association 62(2): 243-258.
Beissinger, S.R. & D.R. Osborne (1982): Effects of urbanization on avian community organization. Condor 84: 75-83.
Bibby, C.J., N.D. Burgess, D.A. Hill & S. Mustoe (2000): Bird Census Techniques. 2nd edn. Academic Press, London. Pp. 325.
Blair, R.B. (1996): Land use and avian species diversity along an urban gradient. Ecol. Appl. 6: 506-519.
Blair, R.B. (2001): Birds and butterflies along urban gradients in two ecoregions of the United States: is urbanization creating a homogeneous fauna? Pp. 33-56. In: Lockwood, J.L. & M.L. McKinney (Eds): Biotic Homogenization: The Loss of Diversity through Invasion and Extinction. Kluwer Academic Publishers, Boston, MA.
Blair, R.B. (2004): The effects of urban sprawl on birds at multiple levels of biological organization. Ecol Soc 9(2): http://ww.ecologyandsociety.org/vol9/iss5/art2.
Bray, J.R. & J.T. Curtis (1957): An ordination of the upland forest communities of Southern Wisconsin. Ecol. Monographs 27: 325-349.
Brotons, L. & S. Herrando (2001): Reduced bird occurrence in pine forest fragments associated with road proximity in a Mediterranean agricultural area. Landscape and Urban Planning 57: 77-89.
Chace, J.F. & J.J. Walsh (2006): Urban effects on native avifauna: a review. Landscape and Urban Planning 74: 46-69.
Clergeau, R, J.P.L. Savard, G Mennechez & G. Falardeau (1998): Bird abundance and diversity along an urban-rural gradient: a comparative study between two cities on different continents. Condor 100: 413-425.
Crooks, K.R., A.V. Suarez & D.T. Bolger (2004): Avian assemblages along a gradient of urbanization in a highly fragmented landscape. Biological Conservation 115: 451-462.
Emlen, J.T. (1974): An urban bird community in Tuscon, Arizona: derivation, structure, regulation. Condor 76: 184-197.
Fraterrigo, J.M. & J.A. Wiens (2005): Bird communities of the Colorado Rocky Mountains along a gradient of exurban development. Landscape and Urban Planning 71: 263-275.
Friesen, L.E., P.F.J. Eagles & R.J. Mackay (1995): Effects of residential development on forest-dwelling neotropical migrant songbirds. Conservation Biology 9: 1408-1414.
Glennon, M.J. & W.F. Porter (2005): Effects of land use management on biotic integrity: an investigation of bird communities. Biological Conservation 126: 499-511.
Grimm, N.B., J.M. Grove, S.T.A. Pickett & C.L. Redman (2000): Integrated approaches to long-term studies of urban ecological systems. BioScience 50: 571-584.
Jackson, J.A. (2006): Ivory-billed woodpecker (Campephilus principalis): hope, and the interfaces of science, conservation, and politics. Auk 123: 1-15.
Jokimaki, J. & J. Suhonen (1993): Effects of urbanization on the breeding bird species richness in Finland: a biogeographical comparison. Ornis Fenn 70: 71-77.
Kluza, D.A., C.R. Griffin & R.M. Degraaf (2000): Housing developments in rural New England: effects on forest birds. Animal Conservation 3: 15-26.
Lancaster, R.K. & W.E. Rees (1979): Bird communities and the structure of urban habitats. Canadian Journal of Zoology 57: 2358-2368.
Machlis, G.E., J.E. Force & W.R. Burch Jr. (1997): The Human Ecosystem, Part I: The human ecosystem as an organizing concept in ecosystem management. Society and Natural Resources 10: 347-368.
Magurran, A.E. (2004): Measuring Biological Diversity, Blackwell. Pp. 260.
Mckinney, M.L. (2002): Urbanization, biodiversity, and conservation. BioScience 52: 883-890.
Mckinney, M.L. (2006): Urbanization as a major cause of biotic homogenization. Biological Conservation 127: 247-260.
Mckinney, M.L. & J.L. Lockwood (1999): Biotic homogenization: a few winners replacing many losers in the next mass extinction. Trends Ecol. Evol. 14: 450-453.
Miller, J.R. & R.J. Hobbs (2002): Conservation where people live and work. Conservation Biology 16(2): 330-337.
Mills, G.S., J.B. Dunning Jr. & J.M. Bates (1989): Effects of urbanization on breeding bird community structure in southwestern desert habitats. Condor 91: 416-428.
Morin, P.J. (1999): Community Ecology. Oxford University Press, Oxford, UK. Pp. 424.
Olden, J.D. (2006): Biotic homogenization: a new research agenda for conservation biogeography. J. Biogeogr. 33(12): 2027-2039.
Pacyna, J.M. & E.G. Pacyna (2001): An assessment of global and regional emissions of trace metals to the atmosphere from anthropogenic sources Worldwide Environmental Review 9: 269-298.
Palomino, D. & L.M. Carrascal (2006): Urban influence on birds at a regional scale: Acase study with the avifauna of northern Madrid province. Landscape and Urban Planning 77: 276-290.
Prentice, I.C. (2001): The carbon cycle and atmospheric carbon dioxide. Pp. 185-237. In: Houghton, J. & D. Yihui (Eds): Climate Change 2001: The Scientific Basis. Cambridge University Press, New York.
Shochat, E. (2004): Credit or debit? Resource input changes population dynamics of city-slicker birds. Oikos 106: 622-626.
Stratford, J.A. & W.D. Robinson (2005): Distribution of neotropical migratory bird species across an urbanizing landscape. Urban Ecosystem 8: 59-77.
Tratalos, J., R.A. Fuller, K.L. Evans, R.G. Davies, S.E. Newson, J.J.D. Greenwood & K.J. Gaston (2007): Bird densities are associated with household densities. Glob. Change Biol. 13: 1685-1695.
Turner, B.L., W.C. Clark, R.W. Kates, J.F. Richards, J.T. Mathews & W.B. Meyer (1991): The Earth as Transformed by Human Action: Global and Regional Changes in the Biosphere over the Past 300 Years. Cambridge University Press, Cambridge, UK.
Vitousek, P.M., H.A. Mooney, J. Lubchenko & J.M. Melillo (1997): Human domination of Earth’s ecosystems. Science 277: 494-499.