Abstract
Mountain pine beetle (MPB) outbreaks have caused major economic losses and ecological consequences in North American pine forests. Ecological and environmental factors impacting MPB life-history and stands susceptibility can help with the detection of MPB infested trees and thereby, improve control. Temperatures, water stress, host characteristics, and beetle pressure are among those ecological and environmental factors. They play different roles on MPB population dynamics at the various stages of an outbreak and these roles can be affected by intensive management. However, to make detailed connections between ecological and environmental variables and MPB outbreak phases, a deeper quantitative analysis on local scales is needed. Here, we used logistic regressions on a highly-detailed and georeferenced data set to determine the factors driving MPB infestations for the different phases of the current isolated MPB outbreak in Cypress Hills. While we showed that the roles of ecological and environmental factors in a forest intensively controlled for MPB are consistent with the literature for uncontrolled forests, we determined how these factors shifted through onset, peak, and collapse phases of the intensively controlled forest. MPB presence mostly depends on nearby beetle pressure, notably for the outbreak peak. However additional weather and host variables are necessary to achieve high predictive ability for MPB outbreak locations. Our results can help managers make appropriate decisions on where and how to focus their effort, depending on which phase the outbreak is in.
Highlights
Mountain pine beetle (MPB) outbreaks have caused major economic losses and ecological consequences in North American pine forests
Our study aims to 1) develop a model to determine the local ecological and environmental factors driving MPB presence for the different phases of an outbreak in a forest intensively managed for MPB, 2) assess the degree to which the models predict MPB presence for each outbreak phase, and 3) show how selected factors have differing impacts on MPB presence depending on the outbreak phase
The selected models have high AUROC indicating a high level of predictive ability (AUROCbest,onset = 0.739, AUROCbest,peak = 0.890, and AUROCbest,collapse = 0.934; Tables 2 to 4)
Summary
Mountain pine beetle (MPB) outbreaks have caused major economic losses and ecological consequences in North American pine forests. Temperatures, water stress, host characteristics, and beetle pressure are among those ecological and environmental factors They play different roles on MPB population dynamics at the various stages of an outbreak and these roles can be affected by intensive management. Managers, tracking the rise and fall in numbers of infested trees may not be able to identify the endemic or early incipient-epidemic phase. This leads to an alternative categorization based on infested tree numbers, which we describe here and use in this paper: onset (increasing number of infested trees; typically late incipient-epidemic and early epidemic), peak (high and constant number of infested trees; late epidemic) and collapse (decreasing number of infested trees; post-epidemic). An outbreak usually lasts several years if sufficient host pines are present, with an average of approximately 10 years in British Columbia[10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
