Our Woodland birds are still disappearing

By: Mark Kesby, Projects Officer

I’m sure that most of us (including me) didn’t realise that Monday last week (7th September) was National Threatened Species Day. However, this day has great significance in recent extinction history – it’s the day that the last Thylacine (Tasmanian Tiger) died in the Hobart Zoo in 1936.

While this event is considered significant, in reality it is just one of a multitude of extinctions that have occurred in the relatively short period of European settlement. Of the birds and animals species present in 1788, 56 are extinct (that we know about), 36 are listed as critically endangered, 134 endangered, 197 vulnerable and 3 conservation dependent. That’s a total of 426 species of animal that we have lost or are in danger of losing.

Alarmingly, 1324 species of plants and 46 ecological communities are also considered threatened and warrant protection.

Marine species are not immune, either. Dugong, whales, turtles, sharks, fishes, even corals are now endangered or critically endangered - globally.

Our plants and animals are under threat from a range of causes – introduced plants and animals and habitat loss being the most significant. In 200 years we have introduced around 28,000 plants –2800 of which have become a significant weed problem. Many threaten to displace our natural plants and disrupt the habitat of native animals. Lantana, Coolatai Grass and Bitou Bush are prime examples.

Habitat loss and fragmentation of remnants is a major problem – especially for species that have very particular habitat requirements and are reluctant to traverse our highly modified environment. Woodland birds are a good example of this.

Over the years many have written (including in this column) of the decline of our woodland birds throughout the slopes west of the Great Dividing Range from Victoria through to southern Queensland. It was hoped that, following recognition of the problem and extensive replanting of trees since the 1990’s, this decline would be reversed or at least halted.

Unfortunately, recent Victorian research has shown that the decline in woodland birds continues. Recently completed Land and Water Australia research has shown that both the number of woodland species and numbers of birds (across 240 sites) declined significantly between 2002 and 2007. This is thought to be due to the ongoing drought and a long term decline brought about by previous habitat loss and fragmentation. In other words, the effect of clearing can take years (even decades) to be fully felt by vulnerable species.

Overall, the studies have found that the species loss is greater where the landscape is highly cleared (less than 10% tree cover) and woodland patches are small. Isolated patches had a greater decline than those with connection to nearby remnants. Alarmingly, even areas of relatively high tree cover (greater than 30% ) also experienced decline. Riparian areas had the least decline. View the full report here.

While northern NSW has more tree cover (and consequently healthier populations of woodland birds) we cannot take them for granted. We are still losing areas of woodlands – often via tree aging and death. We need to protect our significant remnants and increase our rate of strategic replanting to increase their size and improve their connection.

This report should alarm us all. Urgent action is required to prevent further loss of our birds.

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