Prioritising invasive animal control to save the Lake Eyre Basin’s biodiversity

Bioregions of the Lake Eyre Basin
Bioregions of the Lake Eyre Basin

Australia’s Lake Eyre Basin (LEB) is amongst the largest internally draining systems in the world, covering 120 million ha (the size of Germany, France and Italy combined). This huge area of the outback has a rich and thriving indigenous culture stretching back tens of thousands of years, with indigenous people making up 40-90% of the population.

The LEB contains natural and cultural assets such as Lake Eyre, Uluru, Coongie Lakes and other internationally important Ramsar listed wetlands, and the threatened ecological community of “mound springs” (EPBC Act 1999) that provides refuge for at least 13 plant species and 65 animal species that occur nowhere else on earth. The Basin is also home to many other unique, rare, threatened species such as the greater bilby, yellow-footed rock wallaby, night parrot, grey falcon and letter-winged kite.

A significant threat to the natural systems of the LEB is the establishment and spread of exotic animals and plants. Climate change is also a major concern as it is altering the habitat suitability for many native species and may increase the severity of other threats, such as invasive species. Management across such a large area like the Basin is expensive, so smart decisions are necessary to make sure resources are used as efficiently as possible. Given limited money and time to spend in the Basin, how should we best choose which invasive animals or plants to manage? And how should we change our approach as the climate changes?

In a study funded by the Invasive Animals CRC, we combined local knowledge, scientific data and analyses to develop an efficient and rational set of strategies for managing the negative impacts of invasive species on the threatened flora and fauna of the LEB.

First, we determined which strategies would give the greatest improvement in species persistence per dollar spent managing invasive animals. We evaluated the cost-effectiveness of 11 invasive animal management strategies drawn from the collective experience and knowledge of 34 experts and stakeholders (participants) representing scientists, federal, state and local governments, indigenous landholders, pastoralists, non-government organizations, and members of the LEB advisory committees. For each strategy, participants estimated costs, feasibilities and benefits for improving the persistence of 148 threatened native flora and fauna species. We considered the effectiveness of each strategy not just under current conditions but also with projected regional changes in climate over the next 50 years.

The most cost-effective strategy is the management of feral pigs in specific locations across the region. Photo: Angus Emmott;
The most cost-effective strategy is the management of feral pigs in specific locations across the region. Photo: Angus Emmott

Our analysis found that managing feral pigs is the most cost-effective strategy, as pigs impact many different native flora and fauna species. Experts estimated that pig control would have the highest uptake, a moderate cost and one of the highest benefits for threatened species. Managing feral predators such as cats, dogs and foxes was the most cost-effective strategy for protecting mammals of the LEB. Threatened native species in the LEB are less likely to persist under future climate conditions, with 29 species at risk of being lost from the region over the next 50 years without effective threat management.

Invasive animals also impact on agriculture so managing them for biodiversity increases agricultural productivity. Implementing the recommended strategies for predators (cats, dogs and foxes), goats and rabbits, were estimated to result in a potential increase of 10%-30% in agricultural productivity depending on the strategy.

Efficiently responding to the threat of invasive animals is crucial for successfully meeting the challenge of protecting Australia’s biodiversity and presents significant agricultural side-benefits.

The priority threat management approach can help decision makers allocate scarce resources for the management of invasive animals across diverse management units to best protect biodiversity now and into the future.

Author Jennifer Firn (1,2), Ramona Maggini (3), Iadine Chadès (1,3), Sam Nicol (1,3), Belinda Walters (1), Andy Reeson (4) , Tara G Martin (1,3), Hugh P Possingham (3), Jean-Baptiste Pichancourt (1), Rocio Ponce-Reyes (1), and Josie Carwardine (1,3)
Year 2015
Notes 1. CSIRO Land and Water, Ecosciences Precinct, Brisbane
2. Queensland University of Technology, School of Earth, Environmental and Biological Sciences, Brisbane
3. ARC Centre of Excellence for Environmental Decisions, NERP Environmental Decisions Hub, Centre for Biodiversity & Conservation Science, University of Queensland, Brisbane
4. CSIRO Digital Productivity, Canberra