PhD Theses (SACON)

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Author: search.filters.author.Azeez, P ASubject: search.filters.subject.Ecology

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    A study of the ecology of select species of weeds in different vegetation types of Nilgiri Biosphere Reserve
    (SACON, 2000) Mahajan, Maya V; Azeez, P A
    Invasion by weedy species of plants has serious impact on natural and managed ecosystems. Weedy species invade agricultural lands, fallow lands, roadsides, disturbed forests and plantations. Invasion by such species modifies the ecosystem structure and function. Invading species may dominate and displace the native vegetation and cause extinction of certain native species, leading to alteration in the original biodiversity of an area. In recent years, biological invasion is being recognised as a serious threat to biodiversity conservation (Pimm and Gulpin 1989, Vitousek et al. 1996). In contrast to studies in agricultural fields, not much attention is given to plant invasion in natural ecosystems. Nevertheless, the colonisation of natural forest ecosystem by weedy species is growing as a threat. In recognition of the threats posed by plant invasions in natural vegetation and realising the scarcity of ecological information on various colonising plant species
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    Status and Ecology of House Sparrow Passer domesticus along an urban to rural gradient in Coimbatore, India
    (SACON, 2011) Dhanya, R; Azeez, P A
    In due course of the evolution of human civilisation, from their nomadic to the resident lifestyle, they were industrious agents of change. Their behaviours changed ecological processes in agglomerates of residences and trades, in cities and as well as in other areas (Vitousek et al. 1997). As the human population rise, infrastructure grows up; urbanisation spreads and increasingly affects biodiversity (Blair 2004). Human activities in the form of land use changes, urbanisation and infrastructure developments are considered major threats to biodiversity (Gontier 2008). This in turn results in the loss and fragmentation of natural habitats, thereby threatening populations of local species and ultimately biodiversity (Saunders et al. 1991). Urban development produces the greatest local extinction rates and eliminates the majority of the species (Vale and Vale 1976, Marzluff 2001, Czech et al. 2000). This replacement brings in the process of biotic Homogenisation that threatens to reduce the biological uniqueness of local ecosystems (Blair 2001). The loss and fragmentation of valuable habitats influences the long-term viability of species populations, which may ultimately become extinct at the local or regional scale