TY - JOUR
T1 - Multiyear weather anomalies associated with range shifts by the mountain pine beetle preceding large epidemics
AU - Sambaraju, Kishan R.
AU - Carroll, Allan L.
AU - Aukema, Brian H.
N1 - Publisher Copyright:
© 2019
PY - 2019/4/15
Y1 - 2019/4/15
N2 - The recent range expansion of the mountain pine beetle, Dendroctonus ponderosae Hopk. (Coleoptera: Curculionidae), into evolutionarily naïve lodgepole and jack pine forests of northwestern Canada has triggered concern that continued eastward expansion through the boreal forest will threaten other pine species native to eastern North America. This unprecedented breach of a historic geoclimatic barrier was precipitated by a “hyperepidemic” west of the Rocky Mountains comprising the largest mountain pine beetle eruption in recorded history. We assessed climate-related latitudinal shifts of pre-outbreak populations of mountain pine beetle in western Canada over a 26-year period preceding the hyperepidemic, as movements of pre-outbreak populations determine, in part, the extent of subsequent outbreaks. We used digitized records of annual aerial overview surveys (1965–1979, 1986–1996) of tree-killing activity, comprising > 122,000 individual infestation polygons, and temperature and aridity data to associate trends in deviations of weather variables from historical averages with latitudinal shifts by the insect. Overall, we found that seasonal and multiyear weather phenomena such as anomalous temperature increases in a stable aridity regime, or vice-versa, and warmer-than-normal winter temperatures explained small but significant variation in northward annual range shifts after factoring out spatial and temporal variation. The numbers of discrete, tree-killing infestations increased rapidly during 1965–1979, and northward range shifts of 300 km in the early 1970s coincided with abnormally dry conditions. Mountain pine beetle populations advanced northward by 391 km from 1965 to 1996. Consistently high infestation levels of the mountain pine beetle occurred simultaneously with above-average temperatures that extended for nearly a decade immediately preceding the hyperepidemic. Climate-associated range shifts can provide gateways to rapid range expansions, and evoke concern with regard to future impacts of other bark beetle species inhabiting regions likely to experience multiyear droughts and/or temperature increases under climate change.
AB - The recent range expansion of the mountain pine beetle, Dendroctonus ponderosae Hopk. (Coleoptera: Curculionidae), into evolutionarily naïve lodgepole and jack pine forests of northwestern Canada has triggered concern that continued eastward expansion through the boreal forest will threaten other pine species native to eastern North America. This unprecedented breach of a historic geoclimatic barrier was precipitated by a “hyperepidemic” west of the Rocky Mountains comprising the largest mountain pine beetle eruption in recorded history. We assessed climate-related latitudinal shifts of pre-outbreak populations of mountain pine beetle in western Canada over a 26-year period preceding the hyperepidemic, as movements of pre-outbreak populations determine, in part, the extent of subsequent outbreaks. We used digitized records of annual aerial overview surveys (1965–1979, 1986–1996) of tree-killing activity, comprising > 122,000 individual infestation polygons, and temperature and aridity data to associate trends in deviations of weather variables from historical averages with latitudinal shifts by the insect. Overall, we found that seasonal and multiyear weather phenomena such as anomalous temperature increases in a stable aridity regime, or vice-versa, and warmer-than-normal winter temperatures explained small but significant variation in northward annual range shifts after factoring out spatial and temporal variation. The numbers of discrete, tree-killing infestations increased rapidly during 1965–1979, and northward range shifts of 300 km in the early 1970s coincided with abnormally dry conditions. Mountain pine beetle populations advanced northward by 391 km from 1965 to 1996. Consistently high infestation levels of the mountain pine beetle occurred simultaneously with above-average temperatures that extended for nearly a decade immediately preceding the hyperepidemic. Climate-associated range shifts can provide gateways to rapid range expansions, and evoke concern with regard to future impacts of other bark beetle species inhabiting regions likely to experience multiyear droughts and/or temperature increases under climate change.
KW - Climate change
KW - Dendroctonus ponderosae
KW - Drought
KW - Hyperepidemic
KW - Latitude
KW - Lodgepole pine
KW - Temperature
UR - http://www.scopus.com/inward/record.url?scp=85061443871&partnerID=8YFLogxK
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U2 - 10.1016/j.foreco.2019.02.011
DO - 10.1016/j.foreco.2019.02.011
M3 - Article
AN - SCOPUS:85061443871
SN - 0378-1127
VL - 438
SP - 86
EP - 95
JO - Forest Ecology and Management
JF - Forest Ecology and Management
ER -