Future Looks Bleak for Spotted Owls
Protecting more old-growth forest habitat will do little to increase British Columbia's spotted owl population within the next decade.
But if current management approaches continue, habitat will decline and there may not be enough left for a recovering owl population in future.
Scientists say that changes to forest management need to occur now in order for enough suitable habitat to become available for the owls in fifty years time. While the types of forests used by spotted owls vary across their BC range, forests must be below 1100 m elevation with trees at least 100 years old and over 24 m tall.
More immediate to avoiding extirpating spotted owls from BC is increasing survival rates of both adults and young. Projections of owl populations in the province show numbers declining to less than 25 birds within 50 years, down from the 33 nesting pairs estimated in 2002. This assumes that owl survival is better than it has been in the last 15 years.
Once there are fewer than 70 birds around, the population is so small that random and unforeseen environmental events can shatter its chances of surviving. This, along with insufficient data on ages and breeding status of the owls presently out there, produces a large amount of uncertainty around forecasting owl population trends.
The owl population and forest management predictions were developed with an integrated collection of models for timber supply, owl habitat and owl population dynamics that mapped the results. The modelling indicates little hope exists that BC's spotted owls will recover in number on their own.
G.D. Sutherland, D.T. O'Brien, S.A. Fall, F.L. Waterhouse, A.S. Harestad and J.B. Buchanan. 2007. A Framework to Support Landscape Analyses of Habitat Supply and Effects on Populations of Forest-dwelling Species: A Case Study Based on the Northern Spotted Owl. Technical Report 038. BC Ministry of Forests and Range, Research Branch. Victoria, BC.