The abundance of ground‐dwelling invertebrates in a Victorian forest affected by ‘dieback’(Phytophthora cinnamomi) disease

Abstract

Abstract Phytophthora cinnamomi (cinnamon fungus) is a pathogenic soil fungus that infects plant communities along the southeastern coast of Australia and the southwestern corner of Western Australia. Infection of native plant communities with P. cinnamomi regularly leads to dramatic changes in both the structural and the floristic characteristics of these communities. This study aimed to assess the effect of P. cinnamomi induced changes in plant community attributes upon the abundance and diversity of invertebrates in an area of open forest in the Brisbane Ranges, Victoria. Pitfall trapping was conducted continuously for 1 week within each season over a 3 year period. Invertebrates were sorted to order level, and abundances were compared between times (season and year) and infection status for taxa with normalized distributions (Coleoptera, Collembola, Dermaptera and ants). Non‐parametric comparisons were made for other groups (Aranae, Blattodea, Diptera, Hemiptera, Orthoptera, ant ‘morpho‐species’ and unidentified larvae) to assess differences on the basis of infection status. Significant differences on the basis of infection were uncommon and, where identified, elevated abundances were more commonly observed at sites infected by P. cinnamomi. Consistent temporal effects (season and year) were observed in normalized data sets. Abundances both within individual taxa and from pooled counts were generally weakly associated with ground‐level habitat features. Overall, the impact of P. cinnamomi on vegetative structure and floristics was not reflected in different abundances of ground‐dwelling invertebrates.