Climate Change & Species Migration

On a recent visit to Northern NSW, I had a discussion with a grower about climate change. Global warming is a topic I have avoided over the years owing to a range of divergent views; even though 97% of scientists agree climate change is occurring. The skeptics argue that the climate models are unreliable or that human activity is playing a relatively minimal role in global warming. Given the number of catastrophic weather events in recent times, I was interested in what the grower had to say. I quickly came to realise that climate change is more than just about changing weather patterns.

He told me that the geophyte, Crinum pedunculatum or Swamp Lily, native to the area, flowered in mid-winter last year instead of summer. He added that it is eaten by the native grub, Spodoptera picta, in summer, which is resistant to the plant’s poison. The night moth form of the insect lays its eggs on the underside of the lily in summer. Once hatched, the grubs can demolish and kill the plant in a couple of days. The grower said the grubs appeared mid last winter and again this winter.

He also noted that Australian bird life is on the move, including the native galah. Usually found west of the Great Divide, it is now a frequent visitor to the region. He also said that snakes have not hibernated the last few winters. Since moving to the area 14 years ago, he has observed that their hibernation period has become shorter and shorter, until last year when he believes they did not hibernate at all.

In Queensland, Australia’s most iconic bird, the kookaburra, is in strife in some areas as are willy wagtails and peewees. Populations of hollow-nesting birds like kookaburras are down in a coastal strip from southeast Queensland to Victoria, while rainforest species like paradise riflebirds appear to be increasing. Other species in trouble are the double-barred finch, peaceful dove, black-faced cuckoo-shrike, brown honeyeater and spangled drongo.

According to a recent report in the Courier Mail, Brisbane and the southeast are suffering from a loss of previously common species, especially insectivorous birds like swallows and swifts. Another in trouble is the beautiful rainbow bee eater and even some magpie populations are not doing well. Raptors like falcons, owls and eagles in the dry interior, which help regulate rat, mice and snake plagues, are also decreasing in Queensland, the NT, WA and SA, says the BirdLife Australia ‘State of Australia’s Birds’ report (http://birdlife.org.au/).

According to the CSIRO, little is known about the effect of climate change on Australia’s bird life, although the impact could be significant. Potential impacts include geographic change, movement patterns and abundance, as well as physiology, morphology changes and habitat factors. It is thought vegetation clearing and the isolation of bushland patches were also behind losses. If you think birds will fly elsewhere when vegetation is cleared, then you are wrong. Many bird species are sedentary with specialised feeding and breeding requirements.

Although we are unable to control species migration, maintaining flora and fauna habitat is an issue that growers should keep in mind when planning and developing their growing operations. Ω

September 2015 / Issue 159


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