Shannon Dundas

Under ‘Western Shield’, the Western Australian Department of Environment and Conservation have aerially deployed 1080 meat baits seasonally over the last 15 years, covering almost 3.5 million hectares. Supplementary hand baiting is also carried out at high conservation significance sites (e.g. swamps harbouring threatened quokka populations). Previous bait uptake studies have predominantly focussed on unbaited areas, with foxes taking large percentages of baits. Few studies have investigated bait uptake under established baiting programs. We monitored 1080 bait uptake at 7 monthly hand-baited sites (baited over 14 years to protect known quokka populations). Our study shows that very few baits are taken by target pest species (i.e. <10% of baits were taken by foxes, cats or feral pigs), with non-target species, including quokkas (~45% of baits monitored), western grey kangaroos, bandicoots, brush tail possums, and mardo, frequently consuming baits. Baits were out for an average of 4 days after deployment; the longest duration monitored was 30 days. This study indicates that only a small proportion of baits are being taken by target feral species. The large uptake by non-target species, particularly native species that are already of conservation importance, suggests that greater focus needs to be placed on bait delivery mechanisms.

Worldwide Phytophthora diseases have significant direct and indirect impact on flora and fauna. In south-west Western Australia approximately 41% of the 5710 described plant species across a large number of plant families are susceptible to P. cinnamomi a pathogen listed as ‘a key threatening process’ to Australia’s biodiversity by the Commonwealth Government. P. cinnamomi in Western Australia is considered a ‘Biologial Bulldozer’ because of its ability to permanently change the structure and function of plant communities and the species they support. Through anthroprogenic activities this introduced exotic pathogen and related species are now widely distributed and many unique plant community types are now infested or threatened. Concerted effort is now spent on mapping its occurrence, identifying areas that are pathogen-free, considered protectable in the medium to long-term and have high conservation value. This presentation will discuss the biology of Phytophthora as a genus and what makes them such devastating plant pathogens, the methods used to diagnose and map their occurrence and the procedures used to select ‘protectable’ communities of high value. Case studies will be used to discuss the impact of the pathogen on plant communities in terms of floristics and habitat change and how this in turn impacts on native fauna and ecosystem function. Control strategies including communication, hygiene implementation measures, the aerial application of phosphite and the use of eradication techniques for spot infestations will be also be discussed with regards to their benefits and possible detrimental effects to native plant communities.

Conducting population studies on elusive species can be challenging. Despite intensive sampling effort, individuals can vary markedly in their trappability. These differences in detection probabilities are problematic for population estimates, where models incorporate assumptions that, if they are present within an area, all animals have an equal probability of being trapped. This study investigates the use of remote cameras to estimate detectability of a medium-sized macropod. We conducted intensive monitoring of quokkas (Setonix brachyurus) at four riparian sites in southwest Western Australia. Quokkas were trapped (seasonally over 18 months) and marked. Camera traps were placed out for 12 months in the vicinity of the trapping area. Camera trap events were reviewed and animals were classified as marked or not-marked. Animals were identified from photos as adult or juvenile and sexed (presence of pouch young, head size) where possible. Cameras indicated the presence of trap-shy animals which had not been marked during the course of the 18 months trapping, and allowed the estimation of detection probabilities for different cohorts. We conclude that camera trapping can enhance the robustness of population estimates of these elusive animals.

The quokka is a medium sized macropod endemic to southwest WA and two islands: Rottnest and Bald. Quokkas were once ‘commonly observed’ in swamps, although few surveys were conducted to establish historical presence. Quokkas suffered a major decline in the 1930s; by the 1950s, the quokka was thought to be extinct on the mainland. Fox predation was highlighted as an ongoing threat and fox baiting began in the mid-1990s targeting protection of this species (and other native fauna). Post-fox control monitoring at eight sites in the northern jarrah forest (1998-2000; Hayward and colleagues) identified small, fragmented populations, but no detectable response to fox baiting. The aim of our research was to establish the current status of quokka populations at these sites (7 of the 8 sites were suitable). Seasonal trapping during 2010-2011 indicated that these populations have increased over the last decade: trap success of the present study (9.4 new individuals/100 trap nights; 85 individuals over 900 trap nights) was substantially higher than previously (0.3 new individuals/100 trap nights; 71 individuals over 21,287 trap nights). Viable quokka populations were found in six of the seven sites surveyed, including two where quokkas had been pronounced ‘locally extinct’. Unlike a number of other native mammal species, and contrary to predictions of further decline, northern jarrah forest quokka populations have increased over the past decade. The quokka may be one ‘good news story’ for native species recovery in WA.

Since the 1970s, there has been a decreasing trend in annual rainfall coupled with increasing temperatures in southwest Western Australia. Over the last decade, this region has experienced three drought years. Models of future groundwater levels in the northern jarrah forest show decreasing groundwater availability, which is particularly apparent within riparian zones. These changes will affect vegetation assemblages present and the fauna which rely on this habitat. The quokka, a Vulnerable medium-sized macropod relies on dense riparian assemblages for food and refuge. This study presents data predicting potential impacts of ongoing reductions in water availability and potential forest management options in a drying climate. These management options will have direct impacts on quokkas, based on their known habitat preferences, and will potentially influence survival of the already fragmented populations of these iconic animals.

The quokka (Setonix brachyurus) is a 2.5 – 5kg macropod endemic to southwest Western Australia, where small mainland populations are restricted to dense riparian vegetation. The quokka is threatened by introduced predators (direct predation by foxes and possibly cats and habitat destruction by feral pigs). In WA, broad scale seasonal aerial 1080 baiting (Western Shield) is conducted to control foxes. Additionally, selected populations of quokkas are protected by more intensive monthly 1080 baiting. Previous research conducted in 1998-2000 by Hayward suggested quokkas in the northern jarrah forest were collapsing and demonstrated little response to 6 years of intensive 1080 baiting to control foxes. A decade later, the situation has changed. We have conducted subsequent trapping at Hayward’s sites following 16 years of baiting. In conjunction with trapping, we are monitoring feral predator presence (foxes, feral cats and feral pigs) with a range of non-invasive techniques including remote sensor cameras, PVC tubes for collection of hair for DNA analysis, track plates and bait stations. Preliminary results show viable quokka populations exist in areas where quokkas were believed to be going extinct. We will discuss our most recent quokka trapping results and outline the use of non-invasive techniques to detect feral predators and quokkas.

The honey possum is a unique species which feeds exclusively on nectar and pollen. Given their dependence on floristic diversity, the honey possum is thought to be especially vulnerable in habitats affected by Phytophthora cinnamomi. Honey possum habitat preferences were determined via radio tracking. Honey possums generally showed a preference for locations with attributes consistent with unaffected vegetation (ta11 and dense) although radio tracking showed they utilised both P. cinnamomi affected and unaffected areas. Honey possum food plants were determined from identification of pollen collected from captured honey possums. Honey possums had a particular affinity for Banksia plumosa subsp. plumosa which is utilised for year round nectar and pollen as well as refuge. Banksia plumosa subsp. plumosa is common throughout unaffected areas but is susceptible to P. cinnamomi. Honey possums were shown to be capable of moving relatively large distances and can utilise a range of flowering plants. Further spread of P. cinnamomi however could potentially result in food resources being so dispersed that they will be insufficient to support honey possum populations.

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.