Tracy Menzies had been struggling against slugs in her backyard garden for years, but this season, her strawberries flourished beautifully. The reason for the slugs’ decline seems to be the rise of the invasive European wall lizard, rapidly spreading and devouring various prey in its path, including slugs.
Living near the Gorge Waterway in Saanich, Menzies observed a surge in lizard numbers in her yard a few months back, actively preying on the slugs. Gavin Hanke, a vertebrate zoology curator at the Royal B.C. Museum, estimated a population of 800,000 to a million European wall lizards in British Columbia, mainly concentrated on Vancouver Island, with sightings as far north as Campbell River.
Hanke expressed concerns about the lizards’ impact on the ecosystem, particularly on invertebrate populations and native species like garter snakes. Nicholas Wong, a biologist with the Invasive Species Council of B.C., highlighted the competition for food and space between the invasive and native lizards.
The European wall lizard’s origin in B.C. dates back to a deliberate release of 12 lizards in 1970 following the closure of a roadside zoo in Central Saanich. The lizards’ adaptation to the climatic conditions of Southern Vancouver Island has facilitated their rapid spread, advancing about 100 meters annually and hitchhiking on vehicles and materials.
While the lizards’ diet includes a variety of insects, spiders, and invertebrates, they also consume fruits like figs. Menzies, despite benefiting from their impact on slugs, expressed concerns about their unchecked spread. Hanke suggested maintaining a plain, well-manicured garden to deter the lizards, emphasizing the need for collective efforts to control their proliferation.
Hanke emphasized the impossibility of eradicating the lizards due to their widespread presence and urged against relocating them to prevent further expansion. He underscored human responsibility for introducing and enabling the invasive species, warning of potential southward spread if not contained.
