Showing papers on "Diversity index published in 1991"

Note on biological diversity, evenness, and homogeneity measures

Abstract: This paper is concerned with measurement of diversity of a biological or ecological sample of individuals belonging to various species.Using the cocept of statistical odds, an alternative diversity measure with an appealing interpretation is formulated as a simple modification of the popular Simpson index

Diversity of stream-living insects in northwestern Panama

Abstract: Data on species richness and diversity of aquatic insects are presented for 42 streams from four drainage areas in northwestern Panama. 189 taxa were collected, many of which are undescribed species. Nearly 45% of the taxa were found in only one of the drainage areas. Diversities, as measured by alpha of the log series, and similarities, measured by number of expected species shared (NESS), were calculated for 25 sites in the four drainages. Diversities varied widely between streams and broadly overlap alpha diversities found in temperate streams. There was no significant correlation between insect diversity and altitude in the Panamanian streams. Similarity of Ephemeroptera faunas among streams showed two patterns: a relatively homogeneous mountain stream fauna in localities above 300 m elevation, and a much more heterogeneous fauna in lowland streams below this altitude. These patterns were less clear for other aquatic insect orders. The results suggest that variation among streams within a tropical reg...

Diversity of indigenous Bradyrhizobium japonicum in North Carolina soils

Abstract: The diversity of Bradyrhizobium japonicum in agricultural fields has not been well characterized. Therefore a study was conducted to determine the serotypic diversity of B. japonicum both within and among six fields in the Coastal Plain and Piedmont of North Carolina where soybeans [Glycine max (L.) Merr.] are grown. Nodule samples were collected from non-inoculated standing soybean crops. Both nodules and isolates were typed by the enzyme-linked immunosorbent assay (ELISA) technique. Serotypes and their proportions varied both within and among locations. Common serotypes in order of abundance across all sites were 76, M1 (multiple reaction beyween 31 and 94), 94, 24, and 122, and together accounted for over 66% of the typable reactions. No cultivar effect on serotype distribution was observed. Unknown types ranged from 4 to 24%. Based on the total number of serotypes identified and the Shannon diversity index (H′), the mean population diversity was 0.76 for the Piedmont sites and 0.91 for the Coastal Plain sites.

Assessing diversity in plant communities: The importance of within-species variation

Abstract: While the measurement of plant species diversity continues to play a central role in ecology and conservation, few formal attempts have been made at defining the concept of diversity, and, specifically, at evaluating the utility of taxonomic species as units for diversity indices. Ecological diversity is defined here as a measure of the degree of biotic and/or abiotic dissimilitude within a community that is perceivable and utilizable by organisms. Although indices based merely on ‘species' may be useful for cataloging taxonomic diversity in communities, plant taxa are generally unreliable units for quantifying the ecological diversity perceived and utilized by most organisms in communities. Recent research highlights the shortcomings of the unit of species for characterizing ecological diversity, and we advocate the further exploration of alternative diversity classes with which to describe plant communities.

Relationships between water quality, morphological factors in river basins, the diversity index and the biotic index

Abstract: The relationships among water quality, the morphological factors in river basins, the Diversity Index, and the Pollution Index were analyzed by the principal component, using the data obtained from the rivers in Kumamoto Prefecture from 1984 through 1988. The value of the Pollution Index, which was used as a biotic index, correlates with both water quality and morphological factors.