Hungry herbivores, fungal diseases and long hot summers are just a few of the challenges land managers face when attempting to re-introduce a threatened
plant species. But the biggest challenge of all may lie in calculating whether a reintroduction program has been successful.
“When we reintroduce a threatened plant species, we do so with the goal of creating a viable population that will be self-sustaining into the future,” says project leader Dr David Coates, from the Department of Parks and Wildlife, WA.
“The aim of our project [Project 4.3] is to examine the methods we use in our programs, in order to improve our success rates.”
Dr Coates and his team face a series of inter-related problems that begin with the challenges of propagation.
“Some of these species require unusual techniques to get them going, for example we need to use fire to extract the seeds from banksia cones.
“Sometimes seeds don’t propagate easily, either due to the specific soil mix or the difficulty of creating the right conditions. And other times we just don’t know why a particular species struggles to get going.
“We must always remain conscious that in the case of particularly rare species, we don’t have large amounts of seed to begin with, so we need to be very careful. Our margin for error is small.”
Even if the propagation is successful, the team must work to find a suitable habitat to reintroduce the young plants, and ensure there are no immediate threats.
“In Western Australia we are always on the lookout for dieback, which is an introduced pathogen and devastating soil-borne fungal disease. For the most part we can’t really combat it, other than by preventing access by people to affected areas to minimise its spread,” says Dr Coates.
“Both feral and native animal grazing are also threats, they are typically curious about our activities and have a taste for young seedlings. If we don’t fence them out, they will eat everything.
“We also need to keep an eye on the weather. Long hot summers can quickly undo all of our hard work and initial watering may be needed to assist establishment.”
In order to achieve the ultimate goal - a self-sustaining and viable population, a critical number of plants must survive to reproductive maturity.
“This will be a major focus of our research, looking at ways we can both measure and model levels of pollination, reproduction, recruitment and genetic variation. This will be challenging in some cases where the lifespan of a number of the shrubs and trees will usually outlast the lifespan of any given project.”
“We can then benchmark these results against natural populations.”
“It’s essentially a numbers game, where we need to discover how many plants need to be established in order to ensure a species’ survival. At the moment we aim for at least 250, but depending on the species, we may need many more.”
“Our research aims to provide the answers to these questions.”
Image: Lambertia orbifolia - Round-leaf Honeysuckle by Tatters/Flickr (CC BY-NC 2.0)
Many landscapes in Australia are fire-prone, and increasingly so. Altered fire regimes can have a serious negative impact on threatened plant species and ecological communities. A Threatened Species Recovery Hub project is working to better understand the effects of different fire regimes on threatened flora in order to improve fire management strategies and conservation outcomes.
Almost a quarter of Australia’s possums and gliders are listed as threatened under Australian environmental law, and many more are showing signs of decline. Dr Rochelle Steven from The University of Queensland believes people in the community can do a lot to support conservation, especially in urban areas.
The detection and monitoring of threatened species have been a strong area of research in the National Environmental Science Program and also the two national environmental research programs which preceded it. Hub Director Professor Brendan Wintle takes a look at what we’ve been achieving and why it is so important to the conservation of Australia’s threatened species.
In 2009, the Christmas Island blue-tailed skink and Lister’s gecko were headed for imminent extinction. Parks Australia acted quickly to collect remaining wild individuals in order to establish captive breeding programs on Christmas Island and at Taronga Zoo, Sydney, which have been highly successful. A Threatened Species Recovery Hub project team is working closely with Parks Australia to help secure a future for the two lizards beyond captivity.
The silver-headed antechinus and black-tailed dusky antechinus are carnivorous marsupials found in high-elevation forests in parts of central-eastern and south-eastern Queensland. They were only described in the past six years, but they are already listed as Endangered. Knowing where they occur is essential for effective conservation, but current distribution knowledge is patchy. To address this, PhD candidate Stephane Batista in partnership with the Queensland Herbarium and Queensland Department of Environment and Science is modelling the habitat where these threatened species are likely to occur, and is using detection dogs to rapidly survey these sites.