10 June 2014
By Zoe Gough
Reporter, BBC Nature
Island wolves' seafood diets differentiate them from their mainland relatives who prefer land-based animals
Two distinct populations of grey wolves have been found living side-by-side in British Columbia, Canada.
The research built on the knowledge of indigenous people who
had distinguished between the mainland "timber wolf" and island "coastal
wolf." Scientists compared DNA from wolf faeces to determine if the two groups were different. They say their findings show that different environments can influence genetic changes. The team, based at the University of Victoria, reported their research in the journal
BMC Ecology.
The wolves' diverse habitats are thought to be responsible for the genetic changes. The study focused on an area of the central coast of British
Columbia known as Bella Bella, which includes a mainland landmass
separated from five islands by water.
The researchers collaborated with people from the indigenous
Heiltsuk First Nation who have studied the wolves for nearly a decade. Team member Dr Chris Darimont, Hakai-Raincoast professor at
the University of Victoria, said discussions with Heiltsuk elder Chester
Starr led to the prediction on which their work was based. "He (Mr Starr) asked if we were going to study the 'timber
wolves' of the mainland or the 'coastal wolves of the islands'," Dr
Darimont said. "I thought that was peculiar
because the state of science at the time told us that there really
shouldn't be differences within wildlife populations across such a short
distance, especially as wolves are fantastic swimmers."Chester explained that timber wolves are creatures of the
mainland, who liked the more mountainous habitat and the plentiful deer
and other terrestrial foods, but the island wolves were smaller seafood
lovers. He knew they were different."
But the elder's idea did not fit well with the current understanding of wolf biology and the researchers initially dismissed it. Since then, evidence has shown genetic differences within
closely-occurring populations of sea turtles, fish and mammals,
including wolves. The team went on to study 116 individual grey wolves living
in the Bella, Bella area and identified a genetic difference between
mainland and island wolves.
"As scientists we should be
sceptical, not dismissive. Earlier in my career, I had assumed that
ecological knowledge could only come from science. I was wrong, and it's
exciting to learn from this and similar experiences with indigenous
colleagues," Dr Darimont said.
The scientists believe the extreme differences between the
mainland and island habitats are responsible for the changes in
genetics. Their data suggests that island wolves are now more likely to
breed with other island wolves than neighbouring mainland wolves. "The findings add to an emerging literature that suggests ecology can drive genetic differences," Dr Darimont said. "What is special here is that the gradient exists over such
short distances, a few hundred metres to a couple of kilometres, which
is easily swimmable. However the ecological differences are sharp and
that's what set in motion this genetic cline."
The team say their findings present opportunities for further
research and could help conservation attempts by offering detailed
information about the habitats of animals in neighbouring areas.
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