The important role of predators in BC’s Gulf Islands

Healthy ecosystems require a full suite of species distributed across a hierarchy of levels on the food chain. If a link is removed, changes in the numbers and types of species will follow.

‘Mesopredator release’ is a phenomenon that occurs when top predators are removed from ecosystems. It allows smaller, mid-level predators to increase in numbers and consume prey at higher rates. This can lead to extreme reductions or even extinctions of species at lower levels on the food chain.

BC’s Gulf Islands Archipelago is an excellent place to study ‘mesopredator release’. As a PhD student at the University of Victoria working with Raincoast, I am examining how the loss of wolves, cougars and bears has allowed smaller invasive predators, specifically raccoons, to flourish. When raccoons arrive on islands where they are not native, considerable changes can occur to songbird populations and intertidal animals. By comparing islands with and without raccoons, we hope to understand the effect that unnaturally high raccoon numbers have on local biodiversity, a result that should translate to other places where wolves, cougars and bears have disappeared.

A lack of top predators doesn’t just affect raccoon numbers. Research suggests that fear of predators alone can change an animal’s behaviour. With no fear, each animal does more of what it likes; namely eat and breed. Understanding how raccoons behave with and without large carnivores present is key to understanding the effects of predator loss.

Ideally, the raccoon mesopredator project will inform conservation and park management in the southern Gulf Islands. I am extremely excited to be joining the Raincoast team and look forward to the opportunity to help protect BC’s rich biological heritage.

Justin
by Justin Suraci, biologist and UVic PhD student

PS – Raincoast has a leveraged external funding for most of this project. Our part is only $6,000 which we need to secure by the end of August. Your support will help us meet our fundraising goal.

MASKED BANDIT?

Or mesopredator release? A new study examines the impact of unnaturally high numbers of raccoons in Canada’s Gulf Islands.

AN UNBALANCED DIET As Gulf Islanders know, the lack of predators has also allowed deer numbers to explode, dramatically impacting native plant life. These imbalances underscore the importance of wolves, bears and cougars to ecosystem health.

Raincoast will soon be announcing dates forGroundswell and the Art for an Oil Free Coast Exhibition. Stay tuned.About Raincoast.

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Raincoast’s in-house scientists, collaborating graduate students, postdoctoral fellows, and professors make us unique among conservation groups. We work with First Nations, academic institutions, government, and other NGOs to build support and inform decisions that protect aquatic and terrestrial ecosystems, and the wildlife that depend on them. We conduct ethically applied, process-oriented, and hypothesis-driven research that has immediate and relevant utility for conservation deliberations and the collective body of scientific knowledge.

We investigate to understand coastal species and processes. We inform by bringing science to decision-makers and communities. We inspire action to protect wildlife and wildlife habitats.