Veerle's blog

Planning a trip to Australia? Think twice if spiders aren’t your best friends… The number of spiders in Australia, including potentially deadly redbacks, is exploding as scientists suspect global warming is wreaking havoc in wildlife populations. They said the migration patterns of birds were in disarray, and the status and distribution of many animals was undergoing fundamental change…

Queensland Museum arachnologist Robert Raven said many spiders that bred usually just once a year would breed three or four times this year. “Everything is cranking up a lot earlier,” Dr Raven said. “Spiders which should be juveniles at this time of year are already adults. We’re looking at some spiders doubling their lifespan.” He said the redback spider was expanding its range, becoming more common and even growing in size. “Redbacks are just exploding everywhere.”

While experts note that Australia’s climate is historically volatile, evidence is mounting that global warming due to greenhouse gas emissions may be at play. In southeast Queensland, birds that are usually strict summer visitors, such as white-throated nightjars and little bronze cuckoos, are staying over winter; and birds such as forest kingfishers, which normally breed once a year, are raising two broods. Other birds, such as noisy pittas, which leave their mountain forest haunts in winter to look for food in warmer lowlands, are staying put all year. “There’s some really weird stuff going on, it’s bizarre,” said leading Brisbane naturalist Rick Nattrass. “Things are happening that we’ve never heard of before.”

CSIRO visiting scientist Julian Reid said torresian (tropical and subtropical) birds, such as figbirds and scrub turkeys, were increasingly spreading south. “It is a very pervasive trend involving lots of species; I’m confident there’s been a strong push south over the last 20 years,” Mr Reid said. In Victoria, the resident population of 20,000 grey-headed flying foxes in the Mallacoota area ballooned to 80,000 this year.

In northern NSW and southern Queensland, grey-headed flying foxes were abundant 10 years ago, and their tropical cousin, the black flying fox, was rare. These days, the black species is numerous and the grey-headed is uncommon. Hugh Ford, professor of environmental sciences at New England University, said birds were breeding earlier and returning earlier from wintering in Europe, suggesting changes might be global. Professor Ford said temperature rises might seriously affect high-altitude species such as flame robins and corroboree frogs, while longer dry spells between wet years could reduce waterbird populations.