Welcome to the first edition of the Invasive Species Council’s ebulletin Double Trouble for 2010.
To kick off the year we’ve covered 15 scientific papers focusing on different aspects of the growing interactions between climate change and invasive species.
We look at how climate change is likely to be a boon for particular invasive species, including a snail in Australia, a crayfish in the US, and weeds in India and Europe.
We also cover studies showing that some invasive species can substantially increase or decrease greenhouse gas emissions. These impacts need to be much better understood to allow countries to monitor and manage changes in carbon stocks in forests.
A highly invasive snail found in Australia’s Murray-Darling Basin is expected to become more dominant under climate change because of its greater tolerance for higher temperatures than a native snail it seems to be replacing.
Invasive crayfish could become more harmful to native crayfish because of their greater tolerance of climatic disturbance, new research suggests.
Worldwide, crayfish are among the most threatened of organisms, mainly because of invasive crayfish.
Exotic species from warm climates are increasingly invading the cooler regions to which they have been introduced, with more than 100 examples documented in a review by 29 European researchers.
By reducing the competitiveness of some invasive species, climate change may create opportunities for habitat restoration, which should be planned for in advance.
Substantial changes are expected to the north-eastern forests of North America, as climate change affects the pathogens, insects and weeds that affect forest structure and function.
Weeds can dramatically and rapidly alter ecosystem carbon dynamics. Shrub invasion of grasslands has been shown to reduce carbon storage. Now, in the reverse situation, Elizabeth Wolkovich and colleagues have found that grass invasion of a shrubland can turn it from a carbon source to a sink by increasing carbon storage.
Invasive insects can turn forests from carbon sinks into carbon sources, with new research finding that 20% defoliation in one forest reduced carbon sequestration by more than 40%.
In another example of an exotic grass altering carbon storage, Japanese stiltgrass (Microstegium vimineum), which is invading many US forests, has been found to reduce soil carbon stores, probably by stimulating higher rates of decomposition in the soil.
Indirect impacts of invasive species on carbon stocks in forests are often greater than the direct impacts. This is one finding of Dave Peltzer and colleagues, in a review of how different types of invaders can change carbon dynamics in forests under climate change. Much more about this needs to be understood to allow countries to manage and monitor changes in carbon stocks in forests, as required under international agreements.
Climate change can expose species to novel climates, which means that bioclimatic models relying wholly on data about their native distribution and abundance will fail to accurately predict the new ranges of invasive species.
Global warming may have assisted an Asian clam to invade rivers in the northern hemisphere, but future warming may be less than beneficial.
Invasions of native savannah snake species into rainforest in Cameroon due to human disturbance may be fast-tracked by higher temperatures, but inhibited by the increased rainfall predicted under climate change.
Carbon dioxide enrichment is likely to benefit two serious weeds in Indian dry tropical forests, increasing their invasiveness and making management more difficult.
Swiss researchers have found that temperature and urbanisation best explain patterns of exotic plant distribution since 1500 in their country.
Climate change highlights the limitations of protecting nature through static networks of nature reserves, with native species potentially migrating out and invasive species moving in.