Tracy Menzies had been in a constant battle with slugs in her backyard garden, as they consistently outpaced her in harvesting, but this year marked a significant turnaround. The strawberries in her garden this season flourished beautifully.
The culprit behind the dwindling slug population seems to be the invasive European wall lizard, a formidable new predator rapidly expanding its presence in the area. These lizards, as experts report, are voracious eaters consuming a variety of creatures, including insects, spiders, and slugs.
Residing near the Gorge Waterway in Saanich, Menzies observed an increasing number of wall lizards darting through her garden and scurrying around her property in recent months. She noted a notable absence of slugs in her yard since the lizards’ arrival, suggesting they may be feasting on these pests.
According to Gavin Hanke, the curator of vertebrate zoology at the Royal B.C. Museum, estimates suggest a population of approximately 800,000 to a million European wall lizards in British Columbia, mainly concentrated on Vancouver Island. These lizards have expanded their territory as far north as Campbell River, 220 kilometers from Victoria, raising concerns about their potential environmental impact.
Hanke expressed apprehension over the rapid spread of the lizards and emphasized the need to adapt to coexist with them. The lizards’ predatory behavior poses a threat to invertebrate populations, with reports of them preying on baby garter snakes, impacting the local insect and spider populations on Vancouver Island.
Biologist Nicholas Wong from the Invasive Species Council of B.C. highlighted the lack of official management programs to control the lizards’ population growth. Wong emphasized that these invasive lizards compete with native species for resources, further complicating the ecosystem dynamics.
The proliferation of European wall lizards in B.C. traces back to an intentional release of 12 lizards in 1970 following the closure of a roadside zoo in Central Saanich. Their successful establishment can be attributed to the favorable climate of southern Vancouver Island, characterized by mild winters and warm summers, mirroring their native Italian habitat.
To contain the spread of these lizards, Hanke recommended maintaining a minimalist garden landscape, as they prefer environments with less vegetation. Attempting to eradicate them now is deemed impractical, considering their widespread presence since the early 1970s.
Hanke cautioned against relocating the lizards to new areas, as this could accelerate their spread to other regions. The responsibility for the invasive species’ presence ultimately falls on human actions, disrupting natural ecosystems and inadvertently facilitating their introduction.
With the irreversible establishment of European wall lizards in British Columbia, efforts to mitigate their impact must focus on coexistence and minimizing further spread. The need for collective action and responsible environmental stewardship is crucial to manage and adapt to the challenges posed by these invasive reptiles.