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3 documents found tagged diversity indices [X]
  • Title
    Zooplankton diversity of Loktak Lake, Manipur, India
    Type
    Journal Article
    Description
    Zooplankton communities of Loktak Lake showed rich and speciose biocoenosis (162 and 142 species), high monthly richness (91 plus or minus 13 and 80 plus or minus 10 species) and by higher similarities (51.1-82.0 and 51.8-78.3 %) and peak richness during winter and autumn over two years of study. Zooplankton (267 plus or minus 41 n/l) formed a significant quantitative component (56.0 plus or minus 6.3 %) of net plankton and showed annual peak abundance during winter. Rotifera and Cladocera are dominant quantitative groups while Copepoda and Rhizopoda are sub-dominant groups. We observed significant annual and monthly variations of zooplankton richness and abundance. This study showed limited influence of individual abiotic factors on zooplankton, with richness showing a significant inverse correlation with water hardness and chloride, and abundance inversely correlated with nitrate. Multiple regressions indicated higher cumulative effects of 15 abiotic factors on richness and abundance. Our results exhibited no definite periodicity of richness and abundance of zooplankton and their constituent groups during two annual cycles. Zooplankton is characterized by highest species diversity (4.172 plus or minus 0.237), higher evenness and lower dominance.
    Attribution
    Sharma B.K., Sharma S. (2011). Journal of Threatened Taxa 5(3) pp. 1745-1755; doi:10.11609/JoTT.o2457.1745-55
  • Title
    Comparison of avifaunal diversity in and around Neora Valley National Park, West Bengal, India
    Type
    Journal Article
    Description
    Anthropogenic intervention has led to conversion of much of the global diversity by means of habitat alterations. The present study was carried out to investigate the importance of habitat quality and habitat heterogeneity for the diversity, distribution and abundance of avifauna in and around Neora Valley National Park (NVNP) during April-May 2010. A total of 73 bird species belonging to 25 families were recorded during the present study applying a modified point count method. Forest edges were found to be most diverse with a total count of 54 bird species having an abundance of 172.53 number of birds ha-1. Study areas with human settlements was represented by a total species count of 24 with an abundance of 130.39 number of birds ha-1 while a total species count of 22 with an abundance of 69.32 number of birds ha-1 was recorded from thick vegetation assemblage with close canopy cover. This site specific occurrence pattern for avifauna was reflected in the study of diversity indices. The highest Shannon-Wiener general diversity score of 3.77 was recorded for bird species from forest edges. Study areas with dense canopy closure were found to support more habitat specialist bird species while areas having human settlements harboured more opportunistic bird species. An overall negative influence of human settlements on bird diversity, distribution and abundance was evidenced from the present study and needs further investigation. Moreover, intensive studies will certainly enrich our knowledge of avian diversity and distribution pattern from the present study location.
    Attribution
    Roy U.S., Pal A., Banerjee P., Mukhopadhyay S.K. (2011). Journal of Threatened Taxa 10(3) pp. 2136-2142; doi:10.11609/JoTT.o2542.2136-42
  • Title
    Fish diversity studies of two rivers of the northeastern Godavari basin, India
    Type
    Journal Article
    Description
    Fish diversity was explored in two rivers of the northeastern Godavari basin: the Adan, tributary of the Painganga, and the Kathani, tributary of the Wainganga. Both rivers are part of the same basin but present different ecological, climatic and anthropogenic settings. Six sites were sampled in each river system over three years using gill nets, cast nets and locally available nets; the ‘catch per unit effort’ criterion was used for sampling. Forty-seven species of fish were identified. Species richness (Jackknife 1 and rarefaction) and diversity measures (Shannon and Simpson) were calculated and their values clearly show that the Kathani is a more diverse ecosystem in terms of fish diversity than the Adan. This difference is mainly due to anthropogenic influences upon the Adan.
    Attribution
    Heda N.K. (2009). Journal of Threatened Taxa 10(1) pp. 514-518; doi:10.11609/JoTT.o1764.514-8