| Abstract: | The horizontal and vertical distribution of dolichopodid flies in a deciduous woodland ecosystem was investigated by means of white-water traps during a nearly 8-month period. Eighteen traps were installed along a light intensity/soil humidity gradient (three zones) and from 0 to 80cm high (six levels). Six environmental features were recorded on several occasions. The dolichopodid data were analysed by means of two multivariate techniques, detrended correspondence analysis (DCA) and two-way indicator species analysis (TWINSPAN). The DCA revealed four distinct species groups, which also proved to be clearly different on a broader ecological basis. The horizontal distributions in many species could be explained by the different environmental conditions in the zones. Although nearly all species were unequally distributed over the traps, their stratification patterns generally showed no significant correlation with the recorded biotic and abiotic features. It is therefore suggested that the observed vertical distributions are the results of a combination of specific and environmental characteristics. |
