| Summary: | <p>The effects of landscape modification on the diversity of three contrasting groups of organisms - trees, birds and macrofungi that are biologically and ecologically different - are presented in this study. Three competing heuristic frameworks - island biogeography, metapopulation theory and landscape ecology - which have been advanced to study the fragmented landscapes, are discussed. The most suitable framework for studying biodiversity of the three groups of organisms in landscapes that are modified but not fragmented, is determined. Two contrasting approaches to biodiversity conservation - strict protection, and community-based conservation - are assessed and the conditions where they are suitable are determined.</p><p>Methods were used for rapid assessment of biodiversity and evaluation of landscape structure in Kodagu district, in the Western Ghats of India, where few data are available on the distributions of trees, birds and macrofungi and where detailed spatial information is not easily accessible. The comparisons of diversity across the three groups of organisms were made based a maximum value that permitted calculation of rarefied species richness for all samples. The shaded coffee cultivation in the study area has been instrumental in maintaining a continuous cover of native trees, despite longterm management by humans. As an ecological consequence of high tree cover, recognised landscape measures such as patch area and isolation are inadequate for explaining the patterns of diversity in Kodagu, unlike in many other insularised fragmented landscapes. A slight climatic gradient and an increasing degree of human disturbance in patches farther from the contiguous forest reserve influence tree diversity, in addition to the isolation of the patches from the reserve. The intervening matrix of coffee plantations is not a strong barrier to the movements of many forestdwelling birds. The influence of landscape structure on moisture content of the air affects sporocarp production of macrofungi. The integrity of the surrounding landscape matrix has an influence on diversity of birds and macrofungi within patches.</p><p>There is no congruence in diversity of the three groups of organisms studied. It is inferred that their differences in biological and ecological characteristics as well as their ranges of dispersal are responsible for the distinct patterns of distribution in the landscape. It is proposed that the strategy for biodiversity conservation should consider landscape-level conservation in order to capture the range of biodiversity that exists outside the formal reserve network in Kodagu. While maintaining the integrity of the strictly protected forest reserve; of traditionally conserved sacred forests; and of privately owned coffee plantations is essential, conservation practice should emphasise the involvement of local communities in management of landscape rather than imposing biodiversity conservation by force.</p>
|
|---|