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Posted 25 February 2009

By Dr Carol Booth, Invasive Species Council Policy Officer

Considered in isolation, invasive species and climate change will both have dire impacts on Australian biodiversity. In combination, the consequences could be catastrophic.

As farmers well know, droughts and floods often trigger massive weed invasions. Extreme weather events destroy native vegetation, creating ideal openings for weeds and other pests.

Healthy ecosystems resist invasion by pests, but under climate change habitats will lose their resilience and become more vulnerable to invasion.

No other environmental problem, including habitat loss, salinity, pollution and over-harvesting,  is expected to worsen as much under climate change as invasive species.

This was highlighted by Australian Government adviser Professor Ross Garnaut in the Garnaut Climate Change Review:

“The ultimate outcomes are expected to be declines in biodiversity favouring weed and pest species (a few native, most introduced) at the expense of the rich variety that has occurred naturally across Australia.”
- Garnaut Climate Change Review, Section 7.3

Double Trouble: Pests and Climate Change

Through our Double Trouble: Pests and Climate Change project the Invasive Species Council will campaign for better policies to deal with the deadly combination of climate change and invasive species.

As part of that project we will publish a regular climate change and invasive species bulletin, called Double Trouble, to alert decision-makers and opinion-makers to the need to consider these two great threats in combination.

The bulletin will have its own website, and will be sent out as a free ebulletin to subscribers six times a year. To receive your copy, email doubletrouble@invasives.org.au, and make sure you put ‘subscribe’ in the subject line and include your name and address.

Understanding the threats posed by climate change and invasive species

The problem can be understood by analogy to the human body. A healthy person who catches the flu will survive. But for someone already weakened by some other disease, that same flu virus can prove fatal.

In much the same way, invasive species render ecosystems more vulnerable to climate change, and vice versa.

Climate change will also directly and indirectly benefit many invasive species. More pests have already been noted in the Australian Alps as warming extends their range upward.

We need a much better understanding of how climate change and invasive species will interact with each other. The Invasive Species Council will be advocating better integrated policies to manage the problems. We welcome your contributions to this.