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Butterfly behaviour signals climate change

Canada
Edmonton Sun
12/07/2010

They may look like lightweights, but in a biological sense butterflies are heavy hitters when it comes to protecting species threatened by climate change. As the world warmed, a butterfly called Ediths Checkerspot was the first organism to show a documented range shift, said Camille Parmesan, an associate professor of biology at the University of Texas at Austin. Ediths Checkerspot has been dying out in northern Mexico but is doing well in Canada, Parmesan said this week while in Edmonton, during a break from the sixth International Conference on the Biology of Butterflies. It is also dying out at lower elevations but is flourishing in the Sierra Nevadas highest elevations.

Parmesan and some colleagues did a study of 57 European species that showed two-thirds of them were moving north. Research shows many species move north because of changes in the growth pattern of plants that the butterfly relies on for food.

People think of changes in timing as not important; at least a lot of the general public do. Who cares if a plant is flowering two weeks earlier Parmesan asked. But research on the Ediths Checkerspot showed its host plant was drying up too quickly, making it inedible to the species larvae and causing local extinctions.

As long as the host plant grows further north, where its still cooler, and the butterfly can make its way to those spots through connected habitat patches, the butterfly could shift north.

Butterflies that already live at high altitudes or in northerly sites are the most likely to be in serious trouble, Parmesan said.

What were seeing at the highest elevations is the species with nowhere to go are essentially evaporating off the tops of those mountains, and were losing those species, said Jeremy Kerr, associate professor of biology at the University of Ottawa, who has also studied the insects.

Butterflies are this kind of canary in the coal mine that may be useful guides for what other species will eventually do, and the pressures that other species, or species groups, may face, he said. Whether those species respond the same way or not, the pressures that those species are confronted with may be comparable.

Humans have been paying close attention to butterflies for centuries.

Data on butterflies go back to 1760 in the United Kingdom, Sweden and Finland, Parmesan said. In Canada, they go back to the 1860s, said Kerr.

Kerr has used this data and models to show that butterflies have responded as expected to the changing climate and landscape. Generalist species such as the common roadside butterflies that everybody sees are expanding their ranges and becoming more common, he said. And they are doing so essentially at the expense of the specialist species the things that really distinguish the regions of Canada from one another biologically, the species that are relatively uncommon and specialize on narrower sets of floral hosts. These species are slowly fading away from our landscapes.

Kerr said every single observation of an endangered butterfly species in the country is likely to reside in southern Canada, as predicted by models. But, he said, this is also the area where human activities have their deepest footprints. Kerr said this means we cant rely on protected parks alone to conserve biological diversity, adding that parks actually dont protect species as well as randomly selected areas in some places. What we need to do is change the way we use landscapes. Simply leaving unused margins or fields in agricultural areas unmowed would go a long way to protecting biodiversity, he said. Allowing native prairies to take root in the margins would also be good for lots of birds, all kinds of insects, including pollinators, and wildflowers. And Kerr said we need to anticipate the changes that climate change will bring.

The trick here in terms of climate change is not to think about where we are today, but to think about where the puck is going. And the puck is going to be moving in roughly a northern direction here, he said. We need to be thinking about conserving areas that are the kind of frontiers for the near future. Parmesan agrees. Canada will become increasingly important for preserving North American biodiversity because a lot of the U.S. species that are even common species, as theyre moving up into Canada, theyre dying out in the U.S.A., she said. We need to be thinking more continental-scale in terms of conservation, not just country-scale. In other words, the U.S. should be partnering with Canada to try to preserve species that are moving into Canada.

El contenido de las noticias que se presentan en esta sección es responsabilidad directa de las agencias emisoras de noticias y no necesariamente reflejan la posición del Gobierno de México en este u otros temas relacionados.

    

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