The threats facing the survival of the Tasmanian devil in the wild have much wider implications for the Tasmanian landscape. Many of the Program's contingencies rely on the reintroduction of devils back into a functional landscape. The Tasmanian devil plays a vital role in the landscape, potentially including the suppression of other fauna such as feral cats, foxes and other introduced carnivores. This relationship could be due to the interplay of a number of factors: direct predation of individuals, especially young, competition for food and resources, or the active exclusion from habitat.
We are all aware of the potential that foxes, if left unmanaged, have to devastate our native fauna. Anecdotally, reports of feral cat numbers also appear to be on the increase, especially in area of DFTD. Apart from predation of native animals, the secondary impacts from feral cats include the increased prevalence of toxoplasmosis. This disease is spread by cats throughout the environment and the ingestion of toxoplasmosis leads to infection in native mammals, livestock and is quite hazardous to humans, particularly with exposure in the womb.
This has major economic implications for the livestock industry, with a marked increase in the percentage of sheep samples testing positive to toxoplasmosis by the Department of Primary Industry, Parks, Water and Environment's (DPIPWE) Animal Health Laboratory. Combined with the presence of foxes, and without the suppression effects of devils, many of the favourable attributes of the Tasmanian farming landscape could change irreversibly.
As Tasmania's largest extant marsupial carnivore, changes to the local populations of Devil's are bound to have significant impacts on the ecology of an area. It has been estimated that the loss of devil numbers throughout the state has resulted in 50-100 tonnes of food being left available each night, with other predators able to fill the void. What is clear is that Devils play a vital role in the resilience of the Tasmanian environment.
To better understand these impacts and to help guide informed management decisions, the Save the Tasmanian Devil Program established the Ecological Impacts Unit. Like the Program itself, the Ecosystem Impacts Unit covers a wide range of disciplines and supporting institutions. Several current PhD projects supported by the Program are specifically designed to answer fundamental questions such as changes in landscape ecology with respect to emergence of DFTD and impacts on other native meso-predators and small mammals.
The main focus of the Unit is to gain a better understanding of these impacts by the initiation of targeted monitoring programs and by adding to the current monitoring programs carried out by the agency. The Unit is currently in the process of designing and implementing systematic monitoring initiatives. The benefits of these types of surveys are highlighted by the success of the state-wide spotlighting surveys. Though not designed specifically to meet these aims, the spotlight surveys conducted by the agency were the first crucial means of detecting the population impacts of DFTD. These surveys indicated that devil abundance had declined by up to 80% in areas where disease was well established. The survey design has been expanded to include a greater coverage and sample effort in non diseased areas; helping answer further questions regarding the impacts of the loss of devils.
Augmentation of existing programs, such as calibrating results from camera trapping used for disease monitoring, standardised transects for repeatedly driven routes, assessing the ecological impacts in areas of disease suppression, expansion of data collected for roadkill surveys, targeted carnivore surveys and seasonal raven and raptor counts are also being trialed.
Other areas of investigation include the impacts of potential island translocations of devils. The option of putting devils on offshore Islands is being strongly considered as part of the Program's management strategy. Island translocations of dasyurids have been successfully achieved in other areas of Australia, though prior to any introduction a comprehensive baseline monitoring program looking at impacts on island ecology will be conducted. These also present unique opportunities to look at the impacts that devils have within the environment, gaining valuable information on how devils will respond upon release into the landscape.
The threats facing the survival of the Tasmanian devil in the wild have much wider implications for the Tasmanian landscape. Many of the Program's contingencies rely on the reintroduction of devils back into a functional landscape. The Tasmanian devil plays a vital role in the landscape, potentially including the suppression of other fauna such as feral cats, foxes and other introduced carnivores. This relationship could be due to the interplay of a number of factors: direct predation of individuals, especially young, competition for food and resources, or the active exclusion from habitat.
