Barbara Bowen

It has been an exciting 12 months since the last update on the CPSM. Since that time there have been 3 PhD, 1 Masters and 3 Honours student completions. There have been new species of Phytophthora described from our native woodlands with many more waiting to be described, we have fished successfully for Phytophthora throughout Western Australian waterways, we've learnt how to eradicate P. cinnamomi from some of our native ecosystems across Australia, how some of our native plants respond to treatment to phosphite and how this treatment can be optimised, how satellite and airborne remote sensing technologies can be used to monitor and detect decline in tree health, the effect of Phytophthora on our remarkable fauna, and how P. cinnamomi appears to survive in black gravel soils of bauxite mines. Newly initiated projects will lead to exciting discoveries, including the sequencing of the entire P. cinnamomi genome, the interaction between P. cinnamomi and woylies and bandicoots, the potential spread of P. cinnamomi by feral pigs, the susceptibility of Australian native plants to P. ramorum, the biology, ecology and management of Phytophthora spp. in nurseries, and the mechanisms of survival of P. cinnamomi in a range of different soils in our natural ecosystems. Finally, the CPSM was instrumental in a successful bid for the State Centre of Excellence for Climate Change and Woodland and Forest Health with 27 national and international collaborating partners and this will be hosted by Murdoch University and have a close alliance with the CPSM. This talk will give a brief overview of some of these exciting research developments.

Eucalyptus gomphocephala (Tuart) is an iconic woodland canopy tree, endemic to the Swan Coastal Plain of Western Australia, and one of few eucalypts able to dominate on calcareous soils. Unfortunately, less than one third of the original E. gomphocephala woodland ecosystem remains today (Government of Western Australia 2003), largely as a result of clearing for urbanisation, agriculture and industry. Equally disturbing is a decline of complex and unknown cause(s) within the Yalgorup region, south of Mandurah, 50 km south of the capital city of Perth. The decline and death of mature trees has been occurring within Yalgorup for approximately 15 years with the majority of the region affected and up to 1 00% mortality of E. gomphocephala in some locations.

Eucalyptus gomphocephala (Tuart) is an iconic woodland canopy tree, endemic to the Swan Coastal Plain of Western Australia, and one of few eucalypts able to dominate calcareous soils. Unfortunately, less than one third of the original E. gomphocephala woodland ecosystem remains today (Government of Western Australia 2003), largely as a result of clearing for urbanisation, agriculture and industry. Equally disturbing is a decline of complex and unknown cause(s) within Yalgorup region, south of Mandurah, 50 km south of the capital city of Perth. The decline and death of mature trees has been occurring within Yalgorup for approximately 15 years with the majority of the region affected and up to 100% mortality of E. gomphocephala in some locations.

Introduction: The Stirling Range National Park (SRNP), Western Australia, is a place of international importance with regard to its extremely high degree of floral biodiversity and endemism. The introduced root pathogen Phytophthora cinnamorni is having a devastating impact on the native plant communities of the SRNP and is regarded as a biological disaster of global significance for the conservation of high biodiversity areas (Shearer et al. 2007). Inappropriate fire regimes have also driven species declines in some communities, Little is known of the effects of fire on root-rotting fungi such as Phytophthora spp. Fire has been proposed as a tool to control root disease pathogens in Australian ecosystems, having the potential to reduce susceptible hosts of P. cinnamomi (Robinson and Bougher 2003). Fires of high intensity may temporarily reduce fungal populations by causing a change in fungal microbial balance, but fire may have indirect effects on P. cinnamomi by changing environmental conditions (Podger and Brown 1989). This paper reports on the first major investigation of its kind in Western Australia into the interaction of fire and P. cinnamomi in plant communities in the SRNP. The aim of the study was to determine whether there were significant differences in species composition, abundance, richness and plant health in sites burnt more recently compared with paired longer unburnt sites where P. cinnamomi was present.

Mycosphaerella cryptica is one of the most destructive foliar pathogens of eucalypts in plantations in southern Australia. The majority of research on this pathogen has been conducted in plantations, with little focus on its distribution and impact on eucalypts in native forest. Tuart (Eucalyptus gomphocephala) is magnificent woodland tree endemic to Western Australia. With almost 75% of its original area cleared and concerns for the health of those remaining, the recruitment of tuart is highly important. The study of pathogens and pests that pose a threat to seedling survival will contribute to ensuring the regeneration of the remaining woodlands. Mycosphaerella cryptica has been recorded on E.marginata (Jarrah), E. diversicolor (Karri) and E. patens (Blackbutt) in native forests. In the present study we carried out surveys of regenerating stands of tuart between 2003 and 2005, confirming the presence of M. cryptica throughout all stands surveyed, and in some cases contributing to mortality of seedlings. These findings are somewhat surprising given M. cryptica has not previously been recorded from tuart in native forests. In addition to these surveys, trials were established in Yalgorup N.P. in the native forest to investigate how the presence/absence of ashbeds and competition with midstorey (mainly Agonis flexuosa) affects the survival and growth of planted seedlings. These trials were assessed seasonally over a 14 month period for phytophagous insect attack and fungal pathogen damage. Initial assessments at 12 weeks confirmed the presence of M. cryptica associated with leaf lesions (also known as Crinkle Leaf). Over the subsequent 12 month period the severity of Crinkle Leaf increased across the trial and in some cases resulted in seedling mortality. In comparison to phytophagous insect damage, at the final assessment Crinkle Leaf was by for the most dominant category of damage. Comparisons were made between the climatic conditions, seasonal growth patterns, and severity of Crinkle Leaf at the study site and in eastern Victoria where previous studies on M. cryptica have been conducted. Seasonal periods of infection by M. cryptica differed between the two sites. We propose that this is due to optimal conditions for spread and infection of the pathogen, and growth of the seedlings occurring in winter in Yalgorup N .P. compared with summer in eastern Victoria. Knowledge gained in this study provides important information for disease management and will benefit restoration/regeneration initiatives of this threatened species of eucalypt.

Tuart is a magnificent woodland tree endemic to the Swan Coastal Plain of Western Australia, and is one of the few eucalypts that is adapted to calcareous soil profiles (1). Prior to European settlement there were more than 111,600 ha of tuart woodlands (2) but this has been reduced to 30,311 mostly as a result of clearing for urban development and agriculture (3). In the early 1990’s the decline of tuart woodlands in Yalgorup National Park (YNP), 1.5 hours south of Perth, became severe causing public awareness and concern. At present, the majority of the 13,000 hectares of this park is affected. A large research group was established in 2003 to investigate the cause(s) of this decline, conducting research on a range of abiotic and biotic factors, including water relations and hydrology, environmental correlates, fire and competition, mycorrhizae and nutrition, fungal pathogens and insect pests. The collaborative, integrated and adaptive approach to the research, and the latest findings of the group will be presented.

Phytophthora cinnamomi causes extensive damage to some Australian native forests and is a major concern for conservation. Disease impacts include: the mass collapse of susceptible species, substantial changes to vegetation and floristic characteristics, decreases in leaf litter and transpiration, an increase in sunlight reaching the soil, and the invasion of field-resistant plant species into diseased areas. Although the effect of P. cinnamomi on vegetation communities is well documented, similar studies measuring the response of small mammal populations to this disease is limited. A possible association between P cinnamomi and a reduction in the abundance and diversity of small mammals is proposed. Small mammals have vital roles in ecosystem processes and landscape development, and if they are absent from the landscape, ecosystem processes may be disrupted. To test this hypothesis a study was undertaken to assess the functional roles of small mammals through mycophagy, nectarivory and soil development in diseased and healthy ecosystems in SW Australia. The long-term acquisition of this data will be useful for setting conservation strategies for small mammal populations and ecosystem health.