Relationship between distribution of Odonata species and environmental factors on the irrigation ponds in Awaji Island, central Japan, analyzing spatial autocorrelation

Abstract

  Dragonfly and damselfly (Odonata) species were surveyed from May to October 2002 on 38 small irrigation ponds in the north part of Awaji Island. The investigation was conducted nine times on each pond. Totally 1568 individuals of 28 species were recorded for six months. We selected nine species recorded more than 40 individuals and analyzed the relationships of individual number of these species with environmental factors, including conductivity, NO₂^-, NO₃^-, NH₄^-, PO₄^3-, COD, surrounding land uses within 50 meters from the edge of pond, the number of aquatic water plant species, and autocovariates explaining spatial autocorrelation, using Generalized Linear Models (GLM). The result showed that NO₃^-, COD, surrounding grassland, woodland and the number of water plant species were critical factors for the distribution of some Odonata species.