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)
New Hub research has quantified the extent of predation by cats on Australia’s birds and identified the species and types of birds most vulnerable to cats. The team found that cats kill over 1 million birds per day in Australia. The total is made up of an estimated 316 million birds killed by feral cats and 61 million killed by pet cats each year.
Sound recorders have been installed across farm land in south-western Victoria and on Kangaroo Island in research to help threatened glossy black-cockatoos and south-eastern red-tailed black-cockatoos, by learning more about their breeding.
As cats and foxes have spread across Australia, islands have prevented the extinctions of several mammals like the boodie. Associate Professor Sarah Legge discusses the importance of safe havens and also summarizes the highlights of a recent 'safe-haven' symposium held at the International Mammalogy Congress in Perth.
The TSR Hub is one of six National Environmental Science Programme hubs and each is making its own important contribution to the national effort to recover our threatened species. Hub Director Brendan Wintle takes a look beyond the TSR Hub to highlight the good work being done on threatened species by our sister hubs.
On sub-Antarctic Macquarie Island a multi-million dollar eradication program removed cats in 2000 and rabbits, rats and mice in 2013. In the aftermath of this effort, beautiful things are emerging. Dr Justine Shaw is leading a TSR Hub project to learn from this experience and monitor how ecosystems respond.