Impact of global warming on biodiversity
Box 2 | Responses to global warming
Adaptation strategies will not be limited to the efforts of human societies; some species may already be adapting – and evolving – in response to global warming. Climate change has probably always played a role in evolution, although scientists debate the nature of that role. At least some of the data are inconclusive: studies of beetles during the Quaternary Period (the last 2 million years or so), for example, show that beetles survived climate change in the past mainly by dispersing to new environments – that is, by following their climatic envelopes.
Evolutionary responses
But Australian scientists have detected what they think is an evolutionary response to rapid climate change amongst the fruitfly Drosophila – a species that has often been used in genetic experiments. This insect carries a gene called Adh; a variation of this gene, called Adhs , is thought to help the insect survive arid conditions. Usually Adhs is more common in northern Australia, which is hotter and drier, but scientists at La Trobe University in Melbourne have discovered that the distribution of the gene has moved 400 kilometres to the south – presumably in response to rising temperatures and decreasing rainfall.
Behavioural responses
Scientists who study the relationship between the seasons and biological phenomena have looked at long-term records of the indicators of change from one season to another, such as temperature, rainfalls and the number of hours of sunlight. They found that global warming has changed the timing of the seasons – spring arrives earlier and autumn lasts longer – and that wildlife is adapting to the change by altering its behaviour. Scientists found that a number of plants are consistently forming buds and flowering earlier in spring, and that the migration and breeding times of birds has also changed.
Box
Box 1. Giant problem for pygmy possum
Related sites
Climate change – ecosystems (World Wildlife Fund)
Changing times (Australian Broadcasting Corporation)
Climate change alters genes on the fly (BioEd Online, USA)
Global warming shows up in fly genes (1 September 2006, Scientific American)
Page updated October 2006.