Tracy Menzies had been in constant battle with slugs in her backyard garden, often losing the harvest to them. However, this year, her strawberries thrived beautifully. The reason behind the slug decline seems to be the rise of the invasive European wall lizard, known for rapidly spreading and consuming various creatures, including slugs.
Living near the Gorge Waterway in Saanich, Menzies observed a surge in the number of wall lizards in her yard recently, actively preying on slugs. These lizards, ranging from a few inches to larger sizes, have become a common sight in her area. Gavin Hanke, a vertebrate zoology curator, estimated a population of 800,000 to a million wall lizards in British Columbia, mainly concentrated on Vancouver Island and expanding up to Campbell River.
With concerns about the environmental impact of the lizards’ rapid spread, experts fear their presence could disrupt the native ecosystem. Nicholas Wong, a biologist, highlighted the absence of official management programs to control the lizard population, which competes with indigenous lizards for resources and habitat.
Originating from a deliberate release in 1970 on southern Vancouver Island, the lizards found a favorable environment due to the region’s climatic conditions. Their spread, typically at a rate of 100 meters annually, can be accelerated by hitchhiking on vehicles or materials. While the lizards play a role in pest control by consuming insects and spiders, their diet also includes baby garter snakes and various invertebrates.
While the wall lizards have proven beneficial in Menzies’ garden by safeguarding her strawberries, she remains wary of their unchecked proliferation. Hanke emphasized the need for a collective effort to manage the lizard population effectively, suggesting maintaining uninviting habitats to deter their presence.
However, Hanke acknowledged that eradicating the lizards now is impractical due to past human actions leading to ecosystem disruptions. He cautioned against relocating the lizards, as it could unintentionally facilitate their spread to new territories. The curator predicted a potential invasion of Washington state by the lizards in the coming years, underscoring the irreversible consequences of introducing invasive species into new environments.