Two isolated bandicoot populations are being linked by a passageway of restored vegetation.
AS SUBURBS ENCROACH on bushland, and as roads, agriculture and urban infrastructure bisect, fragment and disrupt the continuity of habitat, wildlife populations are always at risk of becoming isolated. When land is cleared of native vegetation, already vulnerable species can become stranded in small ‘islands’ where their numbers may not be sufficient to maintain genetic viability.
This has been the fate of two isolated populations of southern brown bandicoot ( Isoodon obesulus) confined to the 189ha Mark Oliphant Conservation Park and the 835ha Belair National Park, both in the Mt Lofty Ranges east of Adelaide, South Australia. Research by the University of Adelaide and South Australian Museum has confirmed that these populations are at risk of local extinction unless there is active intervention and habitat restoration. There were once seven bandicoot species found in SA. Today, southern browns are the only survivors, with fox-free Kangaroo Island being the last stronghold of the species in that state.
The two parks lie 5km away from each other. Without the protection of suitable habitat linking the two reserves, the bandicoots are vulnerable to predation by feral cats and foxes. But since 2016, conservation volunteers, in collaboration with 19 separate landowners, have been working on establishing a protective corridor between the reserves for the bandicoots to use.
It’s hoped the restored vegetation will encourage the populations to intermix and breed, strengthening the species’ gene pool and minimising the risk of adverse genetic effects caused by inbreeding.
Ironically, the usually beneficial clearing of invasive vegetation such as blackberries has in the past left the bandicoots exposed to feral attack. Weeding and revegetation are now being tackled as one seamless exercise.
With the incremental removal of dense infestations of blackberries matched to the establishment of adequate native vegetation cover, what has been dubbed a ‘bandicoot superhighway’ just might have a chance of saving two relict populations of endangered marsupials.
Southern brown bandicoot.