Lizard Invasion

Manuscript, published in

June 06, 2005
Victoria, Vancouver Island, British Columbia, Canada

Lizard Invasion
Scientists ponder the implications as a species native to Europe appears to be thriving on the south Island


CREDIT: Ray Smith, Times Colonist
MAKING THEMSELVES AT HOME: European wall lizards, a species not native to this area, have apparently found the Saanich Peninsula to their liking. This pair was found on Richard Hebda's Durrance Lake Road property.

They're sunning themselves at the Saanich Fairground and scampering on the walls of Wilkinson Road jail.
They're scurrying past Stelly's Cross Road and scaling Triangle Mountain.
Thousands of European wall lizards, a non-native species, are making this part of the world their home. It has left biologists wondering what effects they are having on B.C.'s native alligator lizard.
"We have great and grave concerns over exotic species" said Richard Hebda, curator of botany and Earth history at the Royal B.C. Museum. "It's a great challenge when it comes to climate change. Exotic species are poised to take over the niche abandoned by native species."
European wall lizards were introduced to Greater Victoria in the late 1970s when Rudy's Pet Park Zoo on Durrance Road closed. A few wall lizards either escaped or were released into the wilds of Central Saanich. The amphibians survived, living in rock walls and slowly spreading through the gardens and forests of the Saanich Peninsula.
Hebda remembers spotting a few tiny green and black-flecked creatures in a broken concrete wall on his property about 1988. A few years later, they were quite abundant, he said.
"They're delightful creatures. But there were never as many as we see now. Their numbers have gone way up. At first they were a curiosity, now they're just everywhere," he said.
The lizards -- which are about 10 centimetres long not including their tail -- no longer inhabit just the warm cracks in rock walls at his home, they also dash around the garden, said Hebda.
University of Victoria biology professor Pat Gregory first heard about the European wall lizards in 1990 and immediately went to see them.
"I was impressed by their numbers," said the herpetologist. "I don't know how many we saw that day."
He thought about the possibilities they offered for future research studies.
"Any introduced species is interesting and you have to take them quite seriously," said Gregory. "It's interesting to see how they fit into an entirely different system from their native one. It's interesting to know whether they pose a threat to native species."
A study by a master's student on the interaction between the European wall lizard and alligator lizard shows they
didn't get along too badly, said Gregory.
"The student found the alligator lizards were reluctant to go under the same cover as the wall lizards. But she didn't find any aggressive behaviour."
However, more research needs to be done on the population ecology of alligator lizards in places where wall lizards have been introduced, said Gregory.
"Just because we haven't observed a depressing effect on the population of the alligator lizard doesn't mean it isn't happening. There's nothing really obvious in terms of their negative effects, but there might be some less obvious effects."
Hebda has already heard tales of people who grew up in Central Saanich capturing wall lizards and releasing them in their suburban neighbourhoods -- a practice he frowns on.
"I think biologically we have enough challenges already. Gray squirrels are the most recent arrival on Vancouver Island. While they're cute, they're an ecological scourge." Getting rid of them would be impossible because there are far too many of them, said Gregory. And gardeners would probably object.
"They're small and numerous and people seem to like them," he said.

© Times Colonist (Victoria) 2005

Note: The lizards described in this article are Podarcis muralis maculiventris,
originating from the northern Apennin slope in Italy
(DEICHSEL G. & S. SCHWEIGER 2004: Podarcis muralis. Herp. Rev. 35(3)289-290)