Local-scale turnover of pond insects: Intra-pond habitat quality and inter-pond geometry are both important

The distributions of larvae of seven species of pond insect were recorded from 30 small, adjacent temporary ponds over the course of three years. Incidences were modelled using logistic regression to compare the effectiveness of measures of intra-patch habitat or inter-patch geometry as predictors of distribution. Incidence, extinction and colonisation were modelled separately against systematic environmental variation (e.g. length of dry phase), temporal change (e.g. year) and individual pond characteristics as predictors of presence or absence. Models of incidence created for all species were dominated by negative correlations to the length of preceding summer's dry-phase, positive correlations with length of flood links between ponds and species-specific changes with year. Models of colonisation and extinction events suggested that colonisation and extinction may be driven by different factors. The results suggest that both intra-pond habitat and inter-pond geometry affect the distribution of pond insects. The conservation of pond invertebrates will require strategic policy attentive to both aspects of pond invertebrates' ecology, rather than relying on ad hoc, site by site interventions.