Climate influences on whitebark pine mortality from mountain pine beetle in the Greater Yellowstone Ecosystem

A survey of parasitoid wasps (Hymenoptera: Braconidae) in Grand Teton National Park reveals undiscovered (but not unexpected) diversity, as well as changes in diversity associated with the bark beetle epidemic and the unusually warm, dry year. Our 2012 survey found nearly the same number of Braconidae subfamilies (18 vs 19) as a 2002 survey (Shaw 2002); a remarkable amount of diversity given that the 2002 survey was based upon five times as many specimens. Eleven species found in this study are new distribution records for the Greater Yellowstone Ecosystem (GYE), which points to much undiscovered local diversity. Differences from previous studies are possibly due to the unusual warmth and dryness of spring 2012, along with some influence from beetle kill. We provide a list of parasitoids and predators associated with mountain pine beetle (Dendroctonus ponderosae Hopkins) in the Greater Yellowstone Ecosystem (GYE), a stepping stone for further research to determine the role of natural enemies in bark beetle outbreak dynamics in the GYE.

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Interactions of White Pine Blister Rust and Mountain Pine Beetle in Whitebark Pine Ecosystems in the Southern Greater Yellowstone Area

Natural Areas Journal ◽

10.3375/043.032.0105 ◽

2012 ◽

Vol 32 (1) ◽

pp. 31-40 ◽

Cited By ~ 25

Author(s):

Nancy K. Bockino ◽

Daniel B. Tinker

Keyword(s):

Mountain Pine Beetle ◽

Whitebark Pine ◽

White Pine Blister Rust ◽

White Pine ◽

Blister Rust ◽

Mountain Pine ◽

Greater Yellowstone Area ◽

Pine Beetle ◽

Greater Yellowstone

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Climatic Correlates of White Pine Blister Rust Infection in Whitebark Pine in the Greater Yellowstone Ecosystem

Forests ◽

10.3390/f10080666 ◽

2019 ◽

Vol 10 (8) ◽

pp. 666 ◽

Cited By ~ 1

Author(s):

David P. Thoma ◽

Erin K. Shanahan ◽

Kathryn M. Irvine

Keyword(s):

Mountain Pine Beetle ◽

Greater Yellowstone Ecosystem ◽

Whitebark Pine ◽

White Pine Blister Rust ◽

White Pine ◽

Climate Conditions ◽

Rust Infection ◽

Blister Rust ◽

Mountain Pine ◽

Greater Yellowstone

Whitebark pine, a foundation species at tree line in the Western U.S. and Canada, has declined due to native mountain pine beetle epidemics, wildfire, and white pine blister rust. These declines are concerning for the multitude of ecosystem and human benefits provided by this species. An understanding of the climatic correlates associated with spread is needed to successfully manage impacts from forest pathogens. Since 2000 mountain pine beetles have killed 75% of the mature cone-bearing trees in the Greater Yellowstone Ecosystem, and 40.9% of monitored trees have been infected with white pine blister rust. We identified models of white pine blister rust infection which indicated that an August and September interaction between relative humidity and temperature are better predictors of white pine blister rust infection in whitebark pine than location and site characteristics in the Greater Yellowstone Ecosystem. The climate conditions conducive to white pine blister rust occur throughout the ecosystem, but larger trees in relatively warm and humid conditions were more likely to be infected between 2000 and 2018. We mapped the infection probability over the past two decades to identify coarse-scale patterns of climate conditions associated with white pine blister rust infection in whitebark pine.

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Landscape Topoedaphic Features Create Refugia from Drought and Insect Disturbance in a Lodgepole and Whitebark Pine Forest

Forests ◽

10.3390/f9110715 ◽

2018 ◽

Vol 9 (11) ◽

pp. 715 ◽

Cited By ~ 5

Author(s):

Jennifer Cartwright

Keyword(s):

Climate Change ◽

Mountain Pine Beetle ◽

Pine Forest ◽

Boosted Regression Trees ◽

Pine Forests ◽

Whitebark Pine ◽

Insect Outbreaks ◽

Landscape Characteristics ◽

Mountain Pine ◽

Pine Beetle

Droughts and insect outbreaks are primary disturbance processes linking climate change to tree mortality in western North America. Refugia from these disturbances—locations where impacts are less severe relative to the surrounding landscape—may be priorities for conservation, restoration, and monitoring. In this study, hypotheses concerning physical and biological processes supporting refugia were investigated by modelling the landscape controls on disturbance refugia that were identified using remotely sensed vegetation indicators. Refugia were identified at 30-m resolution using anomalies of Landsat-derived Normalized Difference Moisture Index in lodgepole and whitebark pine forests in southern Oregon, USA, in 2001 (a single-year drought with no insect outbreak) and 2009 (during a multi-year drought and severe outbreak of mountain pine beetle). Landscape controls on refugia (topographic, soil, and forest characteristics) were modeled using boosted regression trees. Landscape characteristics better explained and predicted refugia locations in 2009, when forest impacts were greater, than in 2001. Refugia in lodgepole and whitebark pine forests were generally associated with topographically shaded slopes, convergent environments such as valleys, areas of relatively low soil bulk density, and in thinner forest stands. In whitebark pine forest, refugia were associated with riparian areas along headwater streams. Spatial patterns in evapotranspiration, snowmelt dynamics, soil water storage, and drought-tolerance and insect-resistance abilities may help create refugia from drought and mountain pine beetle. Identification of the landscape characteristics supporting refugia can help forest managers target conservation resources in an era of climate-change exacerbation of droughts and insect outbreaks.

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Verbenone and Green-Leaf Volatiles Reduce Whitebark Pine Mortality in a Northern Range-Expanding Mountain Pine Beetle Outbreak

Canadian Journal of Forest Research ◽

10.1139/cjfr-2021-0120 ◽

2021 ◽

Author(s):

Etienne Cardinal ◽

Brenda Shepherd ◽

Jodie Krakowski ◽

Carl James Schwarz ◽

John Stirrett-Wood

Keyword(s):

Mountain Pine Beetle ◽

Green Leaf Volatiles ◽

Green Leaf ◽

Whitebark Pine ◽

White Pine Blister Rust ◽

Leaf Volatiles ◽

Disease Resistant ◽

Mountain Pine ◽

Pine Beetle ◽

Pine Trees

This is the first study testing effectiveness of semiochemical treatments to protect individual trees from a range-expanding mountain pine beetle (MPB, Dendroctonus ponderosae Hopkins) attack into newly exposed host populations of endangered whitebark pine (Pinus albicaulis Engelmann). We investigated the effectiveness of a combination of verbenone and Green-Leaf Volatiles (GLV) to protect rare and valuable disease-resistant trees during a MPB epidemic from 2015 to 2018 in Jasper National Park, Canada. Treatments reduced the proportion of trees attacked by MPB for all diameter classes, across all stands, from 46 to 60%. We also evaluated the effect of the exotic disease white pine blister rust (caused by the fungus Cronartium ribicola J.C. Fisch), the species’ other main regional threat. MPB were less likely to attack large, rust infected trees than healthy trees, emphasizing the value of the semiochemical treatment. Protecting large, cone-bearing disease-resistant whitebark pine trees is fundamental to whitebark pine recovery. Maintaining reproductive trees on the landscape increases the frequency and diversity of rust-resistant genotypes more effectively than just planting seedlings to replace MPB-killed trees, because this slow-growing species takes over 80 years to reproduce. Our study confirmed protecting large rust-resistant trees with verbenone and GLV is a proactive and effective treatment against MPB for whitebark pine in naïve populations.

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