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The squeeze is on for BC’s big cats

July 16th 2009

Island Tides
Chris Genovali
July 16-29, 2009

A recent cougar attack in Squamish has brought to the fore BC’s failure to manage these top-level predators. Reports that BC has 4-6,000 cougars have no scientific basis. In fact, since little or no effort has been made to study BC’s cougars, there is no reliable method to assess cougar numbers.

A preliminary BC cougar-management plan drafted in 1980 discussed habitat issues and cautioned that provincial cougar populations would likely fall in the near future as a result of habitat loss and prey population decline and recommending cougar conservation through protection of cougar and prey habitat – 30-year-old advice that the provincial government has yet to take.

According to Raincoast Conservation’s senior scientist, large carnivore expert Dr Paul Paquet, ‘the distribution of cougars was once the largest of any land mammal in the western hemisphere.

However, the historic North American range has been reduced by 50%. Three subspecies are found in western Canada: the Vancouver Island cougar, the Coastal cougar and the Rocky Mountains cougar. Owing to extirpation elsewhere, BC harbours most of the remaining cougar population in Canada.’

Deer on Vancouver Island -the main prey species for cougars- have dropped from 200,000 to around 55,000 in the last 20 years.
A major factor behind the decline is the loss of old-growth forest, an important habitat for Blacktail deer. Out of 91 primary watersheds over 5,000 hectares, only six are left intact; not one watershed on eastern Vancouver Island remains intact or is protected-and 75% of the Island’s productive ancient forests have been logged.

As prey decreases, so do its predators: the Ministry of Environment estimates that Vancouver Island’s cougar population has fallen from approximately 750 in 1995 to around 350.

Settlement Encroachment

It has been confounding to read comments of a provincial conservation officer dismissing the role of development in the upsurge in sightings and cougar-human interactions. Even the mother of the toddler who experienced the cougar encounter in Squamish agrees that rampant development is at the root of increasing conflicts with the big cats.

Leading cougar researchers Ken Logan and Linda Sweanor have written that habitat loss due to human development is the single greatest threat to cougar conservation in North America. Cougars require habitat for prey availability, hunting and feeding cover, as well as nurseries and bedding sites.

In BC, continuing settlement encroachment on wildlife habitat has lead to a predominantly ‘shoot-first-ask-questions-later’ method of large carnivore management. Trophy hunting of cougars continues unabated, without even the pretense of scientific management. The government has also promoted lethal predator control in connection with endangered Vancouver Island marmots and mountain caribou recovery.

Predator control has negative effects on individual cougars, cougar populations, kittens, prey, and entire ecosystems. Any contemplation of cougar control should include the understanding that ecosystems are extremely complex and that reliable scientific data is generally limited.

The Paradox of Gulf Islands’ Deer

On the Gulf Islands deer populations are unchecked by any naturalpredator. Cougars occasionally appear on the islands, where they might be ecologically welcomed, given the ubiquity of deer and lack of predators. Instead, the appearance of a cougar typically results in the swift removal of the animal.

This is unfortunate as the predator-prey imbalance in the Gulf Islands is evident in the severely over-browsed understory of the region’s remaining forested lands. Sustained over-browsing by deer alters the natural succession of vegetation in forested landscapes, reduces plant cover and diversity, alters nutrient and carbon cycling- and is difficult to reverse.Over-browsing affect the growth and survival of many herb, shrub, and tree species; modifying patterns of relative abundance and vegetation dynamics; and redirecting the forest structure. This has cascading effects on insects, birds, and other
mammals. Deer overpopulation also contributes to the spread of Lyme disease.

Chris Genovali is the Executive Director of Raincoast Conservation. Later this year, Raincoast Conservation will publish a report providing a comprehensive assessment and framework for a cougar conservation
plan.

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