Assisted Colonization: A VERY Sharp, Double Edged Tool?

A team of researchers, led by biologists at Durham and York Universities, has shown that translocation to climatically-suitable areas can work and that butterflies can survive beyond their northern ranges if they're given a 'helping hand' to get to suitable new habitats.

The research, funded by NERC, aimed to examine the implications of climate change for the conservation and management of biodiversity by looking at the distribution of butterflies.

The research team ran a series of climate-change models to identify areas in northern England where, as a result of the climate warming of recent decades, butterflies found further south might thrive but which they had not yet reached. Researchers then transported Marbled White and Small Skipper butterflies to two of these climatically-suitable sites that were well beyond the butterflies' northern range boundaries.

Between 1999 and 2000, free flying individuals were collected from sites in North Yorkshire and translocated, using soft cages, to release sites in disused quarries in County Durham and Northumberland. These sites had ample suitable breeding habitat for the butterflies, and were chosen after careful discussion with local experts. After release, the introduced populations were monitored over the following 8 years.

The research, published in Conservation Letters, involved Durham University, the University of York, the University of Leeds, the Centre for Ecology and Hydrology, and Butterfly Conservation. The team's modelling shows that there is a lag between climate change and distribution change, and the practical results prove that butterflies can flourish in habitats that they might not normally be able to reach.

This is a topic that has caused some ecologists to be very, very concerned. The idea of transplanting an organism from one locale to another may cause a very nasty, if inadvertent invasive species problem: taken out of ecological context the organism may run wild causing harm to other organisms in its new habitat. It will be interesting to see if this technique is actually used much.

That said, it should be noted that even without help that the ecologies are changing: trees are 'marching' north and have been, off and on (mostly on) since the end of the last glacial cycle. 10k years ago (+/-) Canada was originally a wasteland. The ecologies there are very, very YOUNG.

The world is not a static entity, even without people.