Pine beetle might be good on a sandwich though.
Beetle damage hits salmon runs, report says
The loss of forest cover over streams alters watershed ecology
Derrick Penner
Vancouver Sun
Wednesday, March 26, 2008
CREDIT: Mark van Manen, Vancouver Sun
Pine-beetle killed forests in northern B.C. The loss of tree cover over a stream makes the water warmer in summer, decreasing its suitability as a salmon run, according to a new report.
If rising water temperatures weren't enough of a danger to Pacific salmon, the effects of the mountain pine beetle infestation are adding to salmon's woes, scientists say.
Both events are related to global warming.
The grain-of-rice-sized beetles have chewed through Interior pine forests covering an area four-times the size of Vancouver Island, says a report released Tuesday by the federally funded Pacific Fisheries Resource Conservation Council.
Some 60 per cent of the Fraser River watershed is affected through the loss of forest cover over salmon streams that has led to numerous impacts that "significantly alter the watershed's ecology, threatening already stressed salmon runs."
Because the enormous pine forests are dead or dying, the tree boughs don't intercept snow and rain, or shade the forest floor to slow the spring snow-melt.
The result is bigger snow packs, more rapid snow melts leading to flash flooding and higher peak flows that erode streambeds.
Then rapid runoffs mean more summer droughts, combined with higher summer water temperatures, the report notes.
However, while the situation is dire, Gordon Ennis, managing director of the conservation council, said the intent of the report isn't to instill hopelessness.
The council wants to educate the public on the seriousness of the salmon's plight, but also highlight the importance of making changes that are within humans' control to help the salmon's survival.
"We would be very concerned if the message is so negative that people throw their hands up," Ennis said in an interview.
Instead, the council wants to encourage efforts such as more careful development, reforestation to put shade trees over important fish habitat and using hydro dams to release cooler water into streams that have dams and fish populations.
And there is evidence, in a report released by the provincial Ministry of Forests and Council of Forest Industries, that the pine-beetle infestation may have passed its peak.
On the public policy front, Ennis added that the B.C. Water Act needs to be updated with a mind to ensuring adequate water is left in streams for ecological purposes including nurturing fish.
Ennis said better care could be taken in agricultural irrigation practices. And the province could look at taking greater care with the salvage logging of pine-beetle-killed forests, treating it as an experimental practice to find the best ways to prevent rapid runoffs.
Some salmon stocks might become extinct because of climate change, Ennis added, but there have also been some encouraging developments.
Salmon have re-appeared in the Alouette River after decades of absence thanks to changes in flows from a hydroelectric dam, he said.
Ennis added that efforts are underway to re-establish salmon populations in the Coquitlam River.
"Given the fact there are changes occurring that you don't have much control over, it's important for those matters you do have control over that you do exert it so that [salmon], which are iconic to British Columbia, continue to thrive and survive.
In the meantime, the Ministry of Forests and Council of Forest Industry's (COFI) annual survey on the pine beetle's spread in 2007 seems to indicate that it is slowing, Doug Routledge, COFI's vice-president, said in an interview.
The survey shows that the pine beetle had infected 710 million cubic metres of lodgepole pine forests at the end of 2007, up from 582 million cubic metres at the end of 2006.
Routledge said that is an increase by a factor of 1.3, which is below the growth rate of 1.4 to 1.6 over the past five years leading officials to believe the beetle's spread is past its peak.
"The primary reason is that it has pretty much eaten itself out of house and home," Routledge added. "It's running out of food."
The growth rate was also stunted by a couple of severe cold snaps, Routledge said -- one in the early spring of 2007 and one this past January -- that killed off significant numbers of beetles, particularly on the east side of the Rocky Mountains in B.C.'s Peace River region and Northern Alberta.
Routledge added that this result was expected to occur at some point, and by the time the beetle's population collapses, it will have eaten its way through 80 per cent of B.C.'s lodgepole pine forests.
That is expected to happen by 2015.
depenner@png.canwest.com© The Vancouver Sun 2008
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Topic: Beetle damage hits salmon runs (Read 1659 times)