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

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 regalarly leads to dramatic changes in both the structural and the floristic characteristics ofthese 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 fioristics was not reflected in different abundances of ground-dwelling invertebrates.

Patterns of tree dieback in Queensland, Australia: the importance of drought stress and the role of resistance to cavitation

“…Using scientific records and historical accounts, the occurrence of dieback has been related to the severe droughts Australia has experienced periodically during the last 150 years (Fensham and Holman 1999). These El Niño drought events have had a significant effect on Australian savanna structure and composition (Newell 1998;Weste et al 2002) as well as the fauna associated with these habitats (Newell 1997;Ford et al 2001). Some researchers have questioned the primary role of drought as the factor initiating dieback (Podger 1981;Landsberg 1985).…”

Effects of tree mortality caused by a bark beetle outbreak on the ant community in theSanBernardinoNationalForest

“…Other studies have examined the effect of natural disturbances such as the formation of tree‐fall gaps (Feener & Schupp, ) on ants, and many studies have examined the effect of fire (e.g., Parr et al ., ; Gunawardene & Majer, ; Ratchford et al ., ; Arnan et al ., ; Lafleur et al ., ; Gibb & Hjältén, ; Kutt, ). Perhaps because large‐scale biotic disturbances are less common, few studies have investigated the effects of such disturbances on ants, although one study examined the impact of an outbreak of cinnamon fungus ( Phytophthora cinnamomi Ronds) on ground‐dwelling invertebrates (Newell, ). Because the response of ant communities to a disturbance has been examined in the context of many habitats and many types of disturbance, there exists a fairly rich database to which the effects of the large‐scale tree mortality now occurring in North America may be compared.…”

Distribution of Phytophthora cinnamomi at different spatial scales: When can a negative result be considered positively?

“…Under appropriate conditions P. cinnamomi can cause large-scale ecological damage. Studies in Victoria (Kennedy & Weste 1986;Weste & Marks 1987), Tasmania (Barker & Wardlaw 1995), Western Australia (Shearer & Dillon 1996), South Australia (Davison 1970;Davison & Brumbieris 1973) and Queensland (Brown 1999) have all demonstrated devastating effects of P. cinnamomi on the ecology and conservation of native flora (Gadek 1999) and fauna (Er 1997;Newell 1997). Phytophthora cinnamomi was recognized by the Australian Federal Government as one of only five key threatening processes originally listed under Schedule 3 of the Endangered Species Protection Act 1992 (Environment Australia 1999).…”