Monash University, Science Alert 10 Nov 09;
A 15-year study across northern and central Victoria has shown that about two-thirds of bird species - including lorikeets, pardalotes, thornbills and honeyeaters - have declined dramatically in distribution and numbers.
A team of researchers, including ecologists from the Australian Centre for Biodiversity at Monash University, systematically monitored woodland bird populations at 560 sites in a 30,000 km2 region from St Arnaud to Chiltern, mostly in box and ironbark forests.
"Most worrying is that species thought to be secure, the red wattlebird, striated pardalote, grey shrike-thrush and musk lorikeet, have declined as much as or more than species already of conservation concern - those listed as threatened, vulnerable or endangered, such as the crested bellbird, black-chinned honeyeater and crested shrike-tit," Professor Mac Nally said.
"Many species were encountered 60 per cent less often in surveys, and their abundances were down by at least 40 per cent."
Professor Mac Nally said climate change and the provision of food such as nectar, insects and seeds had compounded the already serious effects of broad-scale habitat loss and fragmentation in the region since the 19th century.
"The region has been largely cleared and the remaining woodlands poorly managed over many decades, so that the system was vulnerable to effects of climate change and the severe drying we have seen since 1996," Professor Mac Nally said.
"There also seems to be much less breeding and lower breeding success in the past few years in remnant vegetation. We think that the recent plunge in numbers reflects a longer period of breeding failure, so that when adults die, there are few young to replace them," Professor Mac Nally said.
However, the research team reported some positives.
They found more breeding in relatively young replanted sites, especially on more fertile soils, suggesting that widespread replanting may be part of the solution to reversing the decline.
The results of the study, which also involved scientists from Deakin and Melbourne Universities, were published in the July issue of the international journal Diversity and Distributions.
