Warmer streams threat to species

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Warmer streams threat to species Acid rain and air pollution were the initial focus of the study Scientists have warned of the threat to some wildlife in local streams from climate change, after a 25-year study. The Cardiff University research at 14 Carmarthenshire streams, began in the 1980s by looking at acid rain effects. But their findings also revealed a temperature increase of

1.4C-1.7C, not explainable by natural variations. They predict that if temperatures keep rising at this rate, the number of small stream animals could fall by up to 21% in spring for every 1C rise. The species monitored were stream macroinvertebrates - animals that can be seen with the naked eye such as crustaceans, snails and larval insects like stoneflies or mayflies. The variety of species in the streams studied at Llyn Brianne near Llandovery might also fall by 12 - 25% if trends continue during the next 50 years, the study found. Professor Steve Ormerod, of the Cardiff School of Biosciences, led the study with Dr Isabelle Durance. This would be absolutely critical for anything else that feeds on those insects such as fish and birds Prof Steve Ormerod "It is predicted that temperatures in Wales by 2050 will be somewhere between 2C- 3C higher than now" he said. "Based on the collection of data, if trends continue as they have so far, we will be looking at something like four to 10 species at risk of local extinction, within the streams we've looked at." That adds up to around 12% of the total number of species living around the streams in central Wales, according to Prof Ormerod, who added that rarer insects would be most at risk. No change in river flow - the other

main prediction of the affects of climate change - had been detected by the research. The research was carried out at streams at Llyn Brianne A drop of 21% in the number of animals in the streams in spring would have far reaching ecological implications, said Prof Ormerod. "This would be absolutely critical for anything else that feeds on those insects such as fish and birds that live along the river like the Dipper. "Anything that feed on things emerging from the stream would be affected because there would be less available." The data collected for the study is "fairly unique" globally, according to Prof

Ormerod because it had been collated over such a long period. He said the main conclusion was that upland streams, of which there are 20,000km across Wales, are very sensitive to climate change, probably because they are small. The paper detailing the results of the study is published in the May edition of the journal Global Change Biology. Peter H

 

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