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David Bly: Too many deer are hard on the environment

A deer was killed by a car not far from our home, and my grandchildren were delighted.

A deer was killed by a car not far from our home, and my grandchildren were delighted.

No, they didn鈥檛 rejoice at the death of a deer, but at the sight of the cleanup crew 鈥 a venue of vultures that would hop and flop a short distance away when cars drove past.

(Yes, 鈥渧enue鈥 is the collective noun for a group of vultures 鈥 I looked it up and couldn鈥檛 wait to use it.)

In a more urban setting, someone would have called the municipality to come and remove the deer carcass, but I鈥檓 glad that didn鈥檛 happen in this instance. That isn鈥檛 to recommend that deer carcasses be left to rot on the streets of Oak Bay or Victoria, but where possible and practical, we should let nature take its course.

The turkey vultures were efficient 鈥 before long, the only evidence left was a scattered pile of bones and a bit of hide. It was a bad day for the deer, but a good day for the vultures and an even better day for some kids who are intensely keen about nature in all its manifestations.

We enjoy the deer and have come to know several of them, especially the doe and two fawns who frequently saunter across our yard and down the driveway, and the buck whose rack of antlers grows larger daily.

But we also enjoy the birds and the native plants. I have spent many hours removing broom and Himalayan blackberries in an effort to facilitate the restoration of the natural landscape. Part of it is esthetics and a desire for a viable ecosystem, but let鈥檚 be honest 鈥 it鈥檚 a lot less work if you can get nature to be your landscaper. Never discount the motivational value of laziness.

Among the rewards has been the discovery of a clump of red columbine where last year I could see only blackberries and broom, and we have a few more fawn lilies and shooting stars. I discovered a decent patch of blue camas not far from our property, and I鈥檓 hoping to encourage their spread.

What does this have to do with a dead deer? Only that we could use a few more of them, and I don鈥檛 mean that in a vindictive way.

In a conversation with Peter Arcese, Forest Recovery B.C. chair of applied conservation biology at the University of British Columbia, I learned something of the effect deer can have on the environment, and it鈥檚 not all good.

Arcese has done extensive research on the interaction of plants and animals, and the restoration of natural areas. Using some of the Gulf Islands as laboratories, he and his colleagues have been able to gauge the effects of deer populations on the environments. Where there are no predators and where deer are flourishing, the plant life takes a beating.

鈥淒eer have a very eclectic and wide diet, and seldom eat just one plant,鈥 said Arcese.

鈥淚f there鈥檚 a richness of plants around, they won鈥檛 have an impact on one species.鈥 But when deer are uncontrolled by predators or hunting, plant species start to dwindle.

Some of the perennial plants that deer browse 鈥 such as mock orange, saskatoon and honeysuckle 鈥 were common historically, but are now hard to find on many Gulf Islands.

In some areas, an overabundance of deer also means a scarcity of blue camas, fawn lilies, trillium and other plant species. Browsing deer prevent a shrub called ocean spray from regenerating, and deer strip leaves from saplings of the threatened arbutus. If that pressure is maintained over the years, species disappear from affected areas.

Arcese says the optimum deer population is about one deer per 10 hectares. After that, biological diversity suffers.

In our neighbourhood, I鈥檓 sure the density is far above optimum, but there鈥檚 hope: A couple of months ago, a cougar killed a deer about a hundred metres from our house and dragged it deep into the nearby bushes to feed. The remains are still there.

There aren鈥檛 enough cougars to restore the imbalance we humans have created, but there鈥檚 some comfort in knowing that nature, in all its gritty glory, is still trying.