Assigning conservation value: a case study from India

Abstract

We assign conservation values to ecological zones, habitat types, and specific localities of the south Indian district of Uttara Kannada on the basis of occurrence of bird taxa. This is a two-step process, assigning values first to individual bird taxa and second to spatial elements based on the occurrence of birds. The attributes of bird taxa considered are geographical distribution at four levels, habitat preference, taxonomic position, and degree of endangerment. The criteria translating the attributes into values are based on the assumption that the rarer, more taxonomically unique, or more endangered the taxon, the more valuable it is. The conservation value of a given bird taxon is thus a point in a seven-dimensional space. We reduce this to three dimensions by using internal correlation and clumping of values. Each spatial element may then be assigned a conservation value based on number of taxa and the total and mean conservation value along the three dimensions. The total values are highly correlated with number of taxa, permitting a simplification of the problem at the level of spatial elements to four dimensions. The analysis provides a basis for assigning specific conservation values to five ecological zones of the district; to fifteen natural, quasinatural, and manmade habitat types; and to 107 specific localities. Our analysis shows that degraded evergreen forests, exotic tree plantations, and urban settlements have low conservation value; the other habitat types considered rank high along one or more dimension. We also identify 12 different sets of 20 localities each that would maximize either the diversity of bird taxa or conservation value along the different dimensions. We thus attempt to synthesize diversity and quality of taxa to generate conservation prescriptions, whereas the existing methods tend to emphasize either rare or endangered taxa or total diversity. Such prescriptions would be one useful input into working out an overall conservation strategy for a geographical region.