Abstracts in Order of Presentation
Introduction to Biodiversity of the North
In many regions of northern Australia fire is little managed, resulting in extensive wildfires late in the dry season. In the contemporary era, on average greater than 350,000 km2 (~20%) of Australia’s 1.9 million km2 tropical savannas, or six times the size of Tasmania, are affected each year, mostly in the late dry season. The implications of contemporary fire regimes for north Australian savanna biodiversity, soils, greenhouse emissions, pastoral production, and broader social issues are increasingly well documented and understood. For example, frequent late dry season fires are recognised as having very significant impacts on regional savanna ecosystem and biodiversity values, particularly in less pastorally productive and higher rainfall regions of the Kimberley, Top End and Arnhem Land, and western Cape York Peninsula. The well-documented impacts of cane toads on various biodiversity components are in addition to impacts associated with contemporary fire regimes and pastoralism.
A major challenge therefore is to develop economically and ecologically sustainable fire management initiatives which address chronic limited infrastructure and resourcing issues, and an attendant very sparse population base. A particular challenge involves the engagement of, and developing employment opportunities for, remote Aboriginal communities; over half the north Australian population outside of regional centres is indigenous, with this component growing much faster than the non-indigenous population.
The Western Arnhem Land Fire Abatement (WALFA) project provides a novel illustration of how such a sustainable program might be developed. Through re-introduction of regional fire management incorporating traditional Aboriginal knowledge, western science and contemporary best-practice, WALFA implements a strategic burning program focused on the early-mid dry season which aims to deliver (1) significant greenhouse gas emissions abatement under a commercial offset arrangement to a major energy corporate, as well as providing (2) biodiversity and (3) regional employment benefits. WALFA has had singular success in meeting all its targets since inception of the program in 2005.
While the current national and international greenhouse and climate change policy environment evidently is in flux, nationally there has been strong bipartisan support to date for the development of greenhouse emission abatement opportunities through savanna burning. In the future, and as proposed by Professor Ross Garnaut in his national climate change review, those opportunities might realistically be broadened to include management of carbon stocks in native vegetation—such schemes are already financially supported by the Australian Government in Indonesia and Papua New Guinea. A final challenge therefore is for north Australians to become actively involved in informing debate concerning the development of sustainable greenhouse and land management opportunities and policies relevant to our region.
This study is a Masters project conducted through Macquarie University Sydney, with the assistance of Kimberley Specialists and the Kimberley Toad Busters volunteer group. The project aimed to determine the impacts Bufo marinus may have on the small reptile fauna of the Kimberley region, focusing on the Western Australian border region and the frontline of toad migration. Using a presence/absence study design of trapping and sampling, a species composition and abundance investigation was undertaken in areas inhabited by toads, and similar habitats where toads had not yet reached. Species diversity was found to significantly decrease with the presence of toads, along the edges of permanent water where toads congregate. Furthermore three species of skink, Ctenotus inornatus, Carlia munda and Carlia amax increased dramatically in abundance in these areas, indicating resilience to the presence of toads, or a reaction to the decline in less common species. Gut contents of Cane Toads from a sample of various habitats were analysed in order to infer what composition of prey items were being consumed. A strong correlation between habitat type and composition was found, with large disparities between pastoral land and natural vegetation. This has implications for the importance of competition with small reptiles, and the pressure placed on the vital population of dung beetles in cattle-grazing landholdings. Finally, observations of larger reptile species such as pythons and Keelback snakes indicate rapid changes to behaviour, clearly illustrating the disruptive effect of the Cane Toad on other faunal groups.
The results of this study will help understand the interactions and impacts this invasive species will have on the reptile communities found in the Kimberley region. In conjunction with the research into the impacts of the Cane Toad, trapping and visual observations of various localities within the region were underway to further understand the seasonal variations, distributions and species inventories of remote ecosystems within the Kimberley.
Jonathan K. Webb1, David Pearson2, Stephanie O’Donnell1 and Richard Shine1
We used ecological data (geographic range size, diet, population size, habitat) to identify mammalian predators potentially at risk from cane toads. In the laboratory, we offered small, non-lethal sized toads to mammals to determine their propensity to attack cane toads, and their ability to learn to avoid cane toads as prey. Most small mammals did not attack or consume toads, and hence, are unlikely to be at risk of toad poisoning. Small dasyurids (dunnarts, planigales) rapidly learnt to avoid cane toads as food. Remarkably, two rodent species Melomys burtoni and Rattus tunneyi readily attacked toads and showed no ill effects from ingesting multiple toads. Australian rodents appear to have high resistance to cane toad toxins, most likely from of co-evolving with plants that contain cardioglycosides that are pharmacologically similar in their effects to toad bufotoxins. Overall, our analysis suggests that cane toads may threaten populations of two species of dasyurid predators – the brush-tailed phascogale Phascogale tapoatafa and the endangered northern quoll Dasyurus hallucatus. Our preliminary laboratory and field trials suggest that we may be able to mitigate toad impacts on northern quolls. We discuss these results and explain how our novel method could be used to help mitigate toad impact on northern quolls and other predators.
J. Sean Doody
Invasive and toxic cane toads are well-known for lethally poisoning predators that try to eat them, including birds, mammals, and reptiles. However, robust (multi-year) evidence for population-level impacts is limited to a single study demonstrating major effects on three species of goannas, contrasting with no effect on freshwater crocodile populations, despite some dead (poisoned) crocodiles in the Daly River system. Thus, dead animals cannot be generalised into population-level impacts. Other studies documenting mass mortality of radio-telemetred goannas and quolls are also indicative of major population-level impacts on those species. A second study apparently demonstrating population-level effects across months on populations of freshwater crocodiles in the Victoria River system indicates a lack of generality across river systems for that species. There have been no species extinctions; although population extinctions may have occurred, particularly in quolls, based on decades of ‘no-sightings’ in much of Queensland. Despite reports to the contrary, there is no solid evidence of recovery of predator populations in the years following toad arrival. This is due to the lack of pre-toad baselines of predator abundance in Queensland, and a short post-toad time interval in areas with baselines (Northern Territory, Western Australia) in these longer-lived species. Meanwhile, realistic and effective large-scale toad control options remain elusive. Smaller-scale approaches are proving useful in reducing and potentially eradicating local toad populations, educating stakeholders on toad issues, and bringing together communities. However, because an encounter with one toad is sufficient to kill a predator, the persistence of just a few toads in a population of predators would lead to an encounter probability of 100%, meaning that anything short of eradication is unlikely to save predator populations from imminent declines. Thus, local control would need to be comprehensive and sustained indefinitely to prevent major impacts. Moreover, using control as an effective conservation tool requires follow-up studies to demonstrate the persistence of predator populations, although this requires substantial resources. I discuss a rare opportunity for local control that may be both effective and sustainable due to site-specific geomorphology, scale, and logistics.
The introduced cane toad (Chaunus marinus) was first detected in the Northern Territory in 1984 and has since spread and colonised significant areas of the top end. The spread has allowed the cane toad to interact with a wide range of fauna in Australia, mostly with unknown consequences. In 2001, surveys were commenced along the middle to lower Daly river in the Northern Territory in an attempt to quantify the impact of cane toads on native predators (Doody et al. 2009). The results identified significant declines in three species of predators associated with the arrival of cane toads.
Rick Shine and Team Bufo,
The high reproductive output of cane toads makes it difficult to reduce their numbers on any long-term basis by methods such as hand-collecting and trapping. Ideally, we need new approaches that are based on a detailed understanding of the toad’s biology in Australia. Some of the promising current lines of research involve (a) manipulating habitat characteristics around ponds to discourage toad-breeding; (b) deploying toad-specific pheromones that can be used to kill or attract toad tadpoles without influencing native tadpoles; (c) deploying a nematode lungworm that was brought to Australia with the toad, and is relatively host-specific (i.e., infects and affects toads rather than frogs); and (d) using existing natural enemies (such as meat ants) to help control numbers of metamorphosing toadlets. In this talk, I will briefly summarise recent progress on each of these projects.
Research has shown that under laboratory conditions, infection with the lungworm parasite, Rhabdias Pseudosphaerocephala, reduces survival, growth rates, locomotor capacity, and feeding rates of metamorph cane toads, Chaunus [Bufo] marinus. Even if the cane toads are infected with a single parasite, this can have an impact when the cane toad is stressed. Migration of the lungworm parasite is shown after 3 periods of sample collection (March 2008, March 2009 and January 2010). In 2008, the parasite frontline was still behind the cane toad frontline, in 2009 the parasite frontline was found in the back of the cane toad frontline and in 2010 the parasite frontline is almost in the front of the cane toad frontline. The parasite densities in the cane toad population are building up rapidly as well. The closer the cane toads are to the westerly invading frontline, the lower the incidence and intensity of the parasite in the cane toad is. If you go more further east behind the parasite frontline, the densities and intensities are higher, and building up quicker.
If you were to put high density infected cane toads with a healthy cane toad population at the frontline, you could accelerate the whole process of infecting frontline cane toads. Lungworm parasites have a declining effect on cane toad population and could be used to decrease the number of cane toads in Australia.
The Cane Toad, Bufo marinus, is one of Australia’s greatest environmental menaces, and is one of the “World’s 100 Worst Invader Species”. Toads are a major threat to Australia’s unique biodiversity, threatening native wildlife both directly and indirectly. Attempts to develop biological control agents for the toad have been hindered by the lack of knowledge about its genes and proteins and an inability to identify target molecules that would not be shared with native amphibia.
The strategy of seeking a biocontrol agent for Bufo marinus where this species is not present, but bioclimatically suited, was applied to a published CLIMEX modeling study for the species. Northern Argentina is identified as a region fitting this criteria and worthy of investigation. It is proposed that a search for a biocontrol agent for B. marinus be undertaken in this region utilizing captive B. marinus sourced from a neighbouring South American country and exposing them to local pathogen sources such as aquatic leeches and mosquitoes. Trypanosoma cruzi is recognized as a protozoa that has experimentally caused B. marinus mortality and hence anuran trypanosomes are considered worthy of special consideration as a potential pathogen. Factors such as a reported vectoring by a number of invertebrates, significant host specificity and absence from Australian B. marinus, is suggestive of the potential value of anuran trypanosomes as biocontrol agents. Identification of a non-pathogenic B. marinus or Bufo specific trypanosome may provide an agent worthy of consideration for genetic modification into a B. marinus biocontrol agent. This genetic approach is proposed to have further application to other pest species reported to host a species- or genus-specific trypanosome. This biocontrol strategy is supported by the recent establishment of the Rhabdias lungworm, the only parasite in Australia causing significant (juvenile) toad mortality, as being a South American parasite.
A J Peacock
The Australian Government has released a draft Threat Abatement Plan for cane toads, inviting public comments for three months. The Threat Abatement Plan provides leadership for addressing priority issues, which are:-
Quantitative knowledge of the wider impacts of cane toads on wildlife populations and trophic structure due to resource competition and change in predator prey relationships is relatively unknown. Knowledge does exist for the impact of cane toads for some key predators, however factors including time lag and the high variability of habitats in northern Australia, has prevented quantification of indirect impacts. This is instead largely left to anecdotal and local observations. The ‘What’s in your Backyard?’ program educates community on wildlife, the known direct impacts of cane toads and encourages community to participate in observational baseline survey to contribute to greater understanding of changes in wildlife populations and the indirect impacts of cane toads. The program has received excellent interest from schools, tourism operators, Ranger groups and the general public during the first months of operation. Survey programs suitable for interest groups are developed with a focus on frequency of survey and correct identification of species. Results to date include discovery of species outside their previously known ranges and persistence of species in cane toad areas. There is significant interest from the community in providing information for science to aid in conservation of biodiversity in the Kimberley. We are looking to build strong relationships with science at the beginning of a long-term monitoring program across the Kimberley.
As toads have spread towards the Western Australian border, they have been subject to an unprecedented control effort. Two community groups, and the WA Government have, over the last five years, collectively removed around 500,000 adult toads (and a large uncounted number of tadpoles and metamorphs) from the landscape. The majority of these animals have been removed or caught by hand. Despite this massive effort, the toads have continued to advance. How effective has this manual control effort been at slowing the spread of toads? How rapidly will toads spread if this control effort falters or stops? When will toads conquer all of northern Australia? Such questions are difficult to answer with precision. Recent advances in statistical modelling do, however, render such questions tractable. Here I show how such a statistical model might work, and show how we intend to use it to answer these questions.
Ruchira Somaweera, Jonathan K. Webb, and Richard Shine
Cane toads recently started colonising the eastern bank of Lake Argyle, which harbor one of the largest populations of Australian Freshwater crocodiles (Crocodylus johnstoni) anywhere in Australia. Freshwater crocodiles have low physiological resistance to cane toad toxins, and consequently, some individuals can die following the ingestion of large cane toads. The severity of the impact has shown to be different among studied lotic water bodies and may vary from trivial to very high. However, the absence of impact studies in a large, permanent and stagnant water body hinders predicting the plausible impact from toads on crocodiles at Lake Argyle. The intensity of toad impact conceivably relates to cane toad densities, availability of alternative prey, prey-preference of crocodiles, genetic resistance and the innate ability to learn in crocodiles. These factors are being investigated through field and laboratory studies and may give insight to the level of impact and how soon populations may recover after the invasion.
Bluetongue lizards (Tiliqua scincoides) are abundant across much of Australia, and have such an iconic status in Australian culture that beers and wines have been named after them. Although bluetongues have not traditionally been viewed as victims of cane toad invasion, we recorded a dramatic decline and virtual disappearance of bluetongues at our study site near Darwin. Laboratory studies suggest that this decline is directly attributable to lethal toxic ingestion of toads by bluetongues; and hence, these iconic lizards should be included as priority species in any management plan to mitigate toad impact.
Britton, E.K., Belford, A. and Britton, A.R.C.
The Australian Freshwater Crocodile (Crocodylus johnstoni) is present in a variety of freshwater and tidal habitats. The most upstream populations, typically associated with rocky escarpment, are significantly smaller in size compared with downstream populations due to limited resources. As freshwater crocodiles are known to be susceptible to bufotoxins from ingested cane toads, we hypothesized that these smaller upstream populations would be more significantly impacted by the appearance of toads compared with downstream populations. Results from a population of escarpment crocodiles before and after the arrival of cane toads are documented.
Two key programs have been started: radio telemetry of large predators (large snakes and goannas) which has been ongoing for 2 years and the east Kimberley biodiversity surveys which started in 2009. Corrin Everitt the program coordinator of the State Cane Toad Initiative will provide an overview of these two programs with mention of some of the interesting results so far.
Cane toads resemble native frogs in many ways, and thus we might expect toads to affect frog populations. However, previous research has suggested that – somewhat surprisingly – frog populations tend not to be greatly affected by toad invasion. To clarify reasons for this paradox, I conducted experimental studies on the risks that toads pose to frogs – especially by poisoning them, when the frog tries to eat the toad. Mortality rates differ among frog species, and sometimes are high immediately after toad invasion, but fall rapidly thereafter because frogs soon learn that toads are toxic and hence, cease attempting to consume them. A capacity for rapid aversion learning thus plays a part – but only a part – in determining the impacts of toad invasion on frogs.
History of the knowledge of the frog fauna of the Kimberley
R. Dobbs1, R. Cossart2 & C. Taylor2,
Over the past five years, there has been an increase in government planning and scientific research into water management in the Kimberley region of north-western Western Australia. Whilst this is developing our understanding of freshwater ecosystems at an academic and management level, it is important that these processes are complemented by broader community involvement. With this challenge in mind The University of Western Australia (UWA) and the Department of Water (DoW) have developed, trialled, and are currently implementing an on-ground waterways education program for the Kimberley.
Extensive consultation was necessary to develop a program applicable to stakeholder and community needs rather than implementing a program that provided little on-ground applicability or relevance. This flexibility in delivery models, including the recognition of skill levels, knowledge and needs, also allowed for a range of different objectives to be achieved from each of the partners, i.e. language and cultural outcomes, caring for country outcomes, education and waterways health outcomes.
Using this approach we have been able to strengthen the delivery and effectiveness of our education program and allow communities to contribute their knowledge towards waterway conservation through on-ground activities. This collaborative approach strengthening future research and management in the Kimberley.
One of the underpinning positions of community engagement is that it builds on the strength of social networks while also providing opportunities to exchange information with specific or broad population groups. Community engagement can therefore be viewed as a process to bring about a change in attitude, behaviour, policy or practice, which is fostered through the development and maintenance of relationships, partnerships and coalitions. Such an approach to working with communities places significant emphasis on locally driven ideas, activities and energy and allows local residents to address issues that impact most on their lives. Fundamentally, quality community engagement processes allow ideas to ‘bubble up’ from a grass roots level. This presentation reports on the findings of a PhD research project in the Ord River Irrigation Area, which indicate that applying the principles of community engagement to the management of biosecurity may be a far more effective in raising biosecurity awareness and bringing about social change and transformation that is relevant, meaningful and authentic to communities and its members.
Paul Mocks irrigation property is located near Ord River at Ivanhoe Crossing. An area of remnant vegetation exists, including many introduced plants. In this area he has managed to keep fire out for the last 22 years. The area has a unique biodiversity including a healthy population of Brown Bandicoots. When many other small to medium mammals are in decline across the Kimberley, this is a remarkable population.
Paul has been exploring the Kimberley by air, his observations of the devastation occurring to habitats and ideas for community to assist in fire suppression are echoed by many others in the East Kimberley.
The Kimberley and northern Australia are currently undergoing a biodiversity crisis associated with declines in small and medium sized mammals. These species, which include bandicoots, quolls, rodents, small wallabies and possums, have been the group most prone to extinction since European settlement throughout Australia, but this process is still continuing in northern Australia. Declines are partially thought to be the result of fire regimes being dominated by severe late season fires across the region. DEC is currently undertaking research to determine how much influence fire regimes have on small and medium mammals. Research is being conducted in the Mitchell Falls area located in the north Kimberley region, and also locally at Mirima National Park, Carlton Hill Station and MG reserves. The aim of this work has been to test first, whether fire events have direct impacts on mammal abundance, and second, to test whether there are differences in impacts of early cool mosaic fire versus hot late season fires. Research was conducted by trapping mammals in standard elliot trap grids. Grids were located in areas with different times since the most recent fire. Grids were also distributed between areas usually burnt in large dry season fires versus areas burnt in smaller scale management fires with areas of unburnt habitat nearby. Other features of the sites were measured, including food resources and habitat/vegetation structure, to give us information on what mammals might be reacting to in the environment in relation to fire. We found that abundance of mammals was very low in woodlands and relatively high in sandstone environments in the north Kimberley. We found that in a fine scale managed fire mosaic on sandstone, mammals (and associated fauna) had both positive and negative responses to fires, but usually very little response at all. However, in areas burnt by large dry season fires, in other words in a coarse-scale mosaic (patches >5000 ha), common mammal species were often missing. This data supports the benefits of fine scale prescribed burning which leaves significant areas (25-100 ha) unburnt. It also supports the role of large scale dry season fires in declines of mammals in the Kimberley.
Lee Scott-Virtue1 and Ju Ju ‘Burriwee’ Wilson2
In examining factors that impact on rock art and other Aboriginal heritage sites it was found that fire is the major destructive factor. Burning practices have substantially altered post European settlement. Changed vegetation resulting from introduced grasses and middle storey vegetation combined with a government mind-set and an increasing permanent and transient population partially explain why burning practices have increased. The introduction of European technology and insufficient knowledge on Traditional Aboriginal burning practices determines how burning is being conducted, resulting in increased intensity and frequency.
Open ground sites are affected throughout the region with the impact on rock art somewhat dependent on protected locations (although becoming scarcer) and the type of rock structure. The study concludes that there are an increasing number of parties involved in burning, that burning practices have changed and that the approach is uncoordinated and ill informed. The study also concludes that a unified research approach needs to be undertaken in order to implement procedures to protect rock art and other archaeological sites.
The Kimberley is a biodiversity hotspot, supporting many rare and endemic species. On a national (and indeed international) scale, the landscapes of the Kimberley are considered to be relatively intact, having sustained only minor development pressure, and this intactness is the basis for a thriving tourist industry. By virtue of this intactness, the Kimberley should be a haven for many species that have declined elsewhere across northern Australia. Unfortunately, this is not necessarily true: pervasive impacts of fire, grazing, and the invasion of exotic species pose serious threats to biodiversity in the Kimberley. In particular, changed fire regimes across northern Australia are a serious problem. Across northern Australia, a fire regime shifted towards extensive, late dry season fires has contributed to the decline of many species, including such icons as the Gouldian Finch. These fire regimes also reduce pastoral productivity, lead to poorer soils, damage cultural sites and result in higher greenhouse gas emissions. The Australian Wildlife Conservancy’s EcoFire program aims to promote biodiversity by shifting the fire regime back towards cooler, less extensive early dry season fires. This program works in partnership with local landholders and indigenous communities to simultaneously meet landuse needs and promote biodiversity. EcoFire now operates across 13 properties and covers approximately five million hectares of the Kimberley. Since its inception in 2007, EcoFire has dramatically decreased the extent of late dry season fires in its area, and has become a model program for fire management in the Kimberley.
Mary Anne and her family has been part of Kimberley Toad Busters for 5 years. Her work has included education of indigenous communities on the impact of cane toads and how to control cane toads in their communities.
The Gooniyardi Rangers formed last year after Thomas heard of the other ranger groups that had started. Thomas wanted to support the younger generation of the Bayulu community and ensure they have opportunities in training in looking after their land.
Over the last year the group has been involved in repairing fences along the Fitzroy River on Go Go Station, field guides and assistants for TRaCK research project looking at river health, assistants in a second TRaCK project looking at bush tucker and toadbusting with Kimberley Toad Busters.
The ranger group is growing in size and now includes 3 girls in addition to 11 boys. The group remains self funded. The group is highly motivated to learn how to protect and care for their country, and keep language and culture strong.
What it’s like to be a junior toadbuster
Biodiversity is declining worldwide. Many wildlife species are already in decline in the Kimberley. It is now 76 years after the introduction of cane toads to the Australian environment the impact of cane toads on wildlife is relatively unknown. Arrival of cane toads will change the ‘Kimberley Food Web’ in three major ways; by killing predator species, consumption of prey species and resource competition with other species that eat invertebrates. Little to no data exists for wildlife that will be indirectly impacted by loss of food resources due to the huge amount of invertebrates cane toads consume. Scientists have stated due to the variability inherent in Northern Australia they need a minimum of 1,000 sites before they can prove species abundance has significantly decreased. Scientists alone cannot achieve this level of monitoring, the community needs to become involved.
What’s in Your Backyard? is a program to empower community to record changes in wildlife abundance. The program focuses on encouraging the same site to be sampled frequently, once each season as a minimum. In some cases, participants are monitoring specific families or species (eg Water Monitors, Kingfishers, Common Bandicoot). Data sheets and educational material including species ID cards are available online to ensure consistency in recording and naming species. Participants can lodge data with Kimberley Toad Busters electronically or by returning data sheets. This data is entered into the What’s in Your Backyard? Access database. This data is freely available to any individual or organization interested in analysis of data. Participants are provided with a species list or recording chart to assist in frequent future surveys.
Already community data is providing interesting results, with at least three species found outside their previously known ranges. The program is proving popular with tourism operators, families, schools, toad busting groups and general public.
Wildlife in the Kimberley are disappearing due to a great variety of reasons: loss of habitat due to fires and land clearing; predation by feral cats; death on the roads and from now on from the impact of the cane toad. During my 20 years as a Vet in Kununurra I have seen a massive reduction in the variety of species that we treat, and a huge reduction in the numbers of individuals that are presented to us for care. I truly believe that if we do not protect the creatures that we have left, that in the next 10 to 15 years we will lose the little remaining wildlife that we have. Then what will be left for our children to appreciate? Come and learn how YOU can contribute, even in small ways, to protecting the wildlife in our region.
Kimberley Wildlife Rescue (KWR) is a small but dedicated group of volunteers who care for a great variety of orphaned and injured wildlife. Being a wildlife carer is a very rewarding, and sometimes challenging job, which allows us to learn a great variety of skills. It is a way in which people can contribute to protecting the wildlife that we have left, and enables us to educate people about the pressing need to protect the animals and birds that are a part of our unique environment. It is a job that can help us teach our children how to respect and care for animals, and to encourage them to think about, and become involved in, the needs of our environment. Could you become a wildlife carer?
Reptiles are becoming an increasing popular pet, especially in the East Kimberley. If you have your own reptiles or have considered keeping reptiles, join Bob and some of his pets, a collection of non-venomous pythons, to learn about how you can care for reptiles as pets. Bob will cover all aspects of reptile care including husbandry, reptile health, safety and housing. There will be time for all your questions to be answered by Bob.
Bob will also provide a display for correct reptile handling, come along to learn how to handle pythons. Everyone will have a chance to hold a LIVE non-venomous python.
Live cane toads will be used to demonstrate the key differences between cane toads and our native frogs. Safe techniques for handling cane toads will also be demonstrated.
The effort by volunteers over the last 5 years to combat cane toads before their arrival in the Kimberley has been described as a ‘social phenomenon.’ Ben will provide an overview of toadbusting, and other community driven control methods including eradication of cane toad breeding. Ben will also provide some practical tips on how to protect your land from cane toads. The community development aspect of Kimberley Toad Busters has been phenomenal, everyone can be a Kimberley Toad Buster.
Control by the community of an invasive species has never occurred on this scale in Australia. There are many challenges faced by a community group. John will provide an overview on some of the current ongoing issues including: methods for euthanasia of tadpoles, metamorphs and adult cane toads; access to national parks and future funding. One issue of a different kind is maintaining the energy of volunteers, and employees of Kimberley Toad Busters.
Mike Tyler will provide an assessment of a variety of euthanasia methods based on experience and common sense. These methods include decapitation, deep-freezing, pithing (decerebration followed by spinalisation) and use of anaesthetic agents. This session will leave everyone informed regarding appropriate methods of euthanasia for cane toads.
FrogWatch research projects since 2004 has involved a combination of trapping, shooting, toadBusting and fencing to test various strategies for eradicating cane toads or minimising their impact in certain areas.We have been researching elements of the control ideas and trialling field strategies as well. Our most recent research projects have included: NHT funded project “Cane Toad Population Dynamics and Control in Tropical Savannas of the TopEnd of the Northern Territory” 2006-07, Caring For Our Country funded project “Controlling Cane Toads in Tropical Savannas” 2008-09, and the Envirofund funded project “Toad Blocks” project 2008-09.
We also have some case studies we will present from the research and our ongoing project, the Community Cane Toad Control initiative. We have found that a combination of strategies gives the best results but that exclusion fencing is the single most effective control method, where it can be deployed. Exclusion fencing is the most effective and quickest way to eradicate cane toads from a location. We can locally eradicate a cane toad population, during the dry season, in as little as 5 days with exclusion fencing and research conducted by Dr Mike Letnic and his team has scientifically verified the results from the field trials of the previous 3 years. This has significant implications for eradicating toads from places like islands and places of significance like National Parks, and also looks to have the potential to push the southern extent of the toad population’s range back by hundreds of kilometres in the NT and WA. It may also mean we can remove cane toads from the channel country and other areas of the country that has extended dry periods.
Shooting toads with a gas powered repeating air rifle can yield cull rates of over 230 toads per person hr of effort and solves problems such as difficult terrain, steep and dangerous banks, dangers such a salt water crocodiles and toads in water where they cannot easily be reached for hand collection. A single operator can cull over 1000 toads in a night with this technique.
Manual toadBusting by hand collection is enhanced by fences. ToadBusting averages about 60 toads per hour but rates of over 100 toads per hour are achievable with trained personnel and high toad densities. Fencing increases the effectiveness and can double the collection rate to over 200 toads per hour.
Full reports are available from the funding body websites or the FrogWatch Website http://www.frogwatch.org.au