UBC Undergraduate Research

Woodpeckers as a potential barrier to the mountain pine beetle (Dendroctonus ponderosae Hopkins) east of the Rocky Mountains Sunter, Emily


Insect pest outbreaks have become substantial problems for forest managers as climate change and intensive land management practices affect the landscape. Woodpeckers have been suggested as a natural regulator of insect pest populations and outbreaks in combination with other management practices. The purpose of this study was to investigate the possibility of woodpeckers acting as a barrier to the invasive mountain pine beetle in the pine forests of Alberta. I hypothesized that woodpeckers would have the greatest effect on bark beetles where other food sources were abundant, such as wood borers, where nest sites were available, and where trees were larger and older. I also predicated feeding activity would differ by forest type. Where mountain pine beetle mass attacks were found, I predicated that woodpeckers would function as efficient predators and mortality agents. In four Alberta pine stands, two jack pine and two lodgepole pine stands, bark beetle population surveys were completed, along with the collection of prism cruise data and woodpecker foraging activity on bark beetle attacked trees. A binary logistic regression was used to determine which trees were most likely to have woodpecker foraging activity present, and Fisher’s exact test was used to determine whether woodpeckers fed on mountain pine beetle mass attacked trees preferentially over other trees containing other species of bark beetles. The results of the binary logistic regression indicate that wood borer presence, bordering coniferous forest, and large diameter are the most influential factors in determining whether woodpeckers feed on a tree with bark beetle activity. Tree species and nest site availability were not part of the final model but experimental set-up may have affected these results. Fisher’s Exact test results indicate woodpeckers do feed preferentially on mass attacked trees. These data along with supporting literature indicate woodpeckers could act as a potential barrier to mountain pine beetle expansion and future epidemics east of the Rocky Mountains. In order to promote woodpecker presence in a stand, timber management practices will have to manage for woodpecker habitat characteristics such as food sources during non-outbreak periods, nest sites, and habitat heterogeneity.

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