Changes in understory vegetation including invasive weeds following mountain pine beetle outbreaks

Trees, Forests and People

卷:2

Christopher J. Fettig¹  Stephen R. McKelvey²  Jackson P. Audley³  Carl L. Jørgensen⁴  Kenneth E. Gibson⁴  Leif A. Mortenson⁵  Joel D. McMillin⁶  Jose F. Negrón⁶  Jared A. Trilling⁶  Brytten E. Steed⁷  Justin B. Runyon⁸  A. Steven Munson⁸ 

[1] Corresponding author.;

[2] Forest Health Protection, USDA Forest Service, 1249 South Vinnell Way, Suite 200, Boise, ID 83709, USA;

[3] Forest Health Protection, USDA Forest Service, 2500 South Pine Knoll Drive, Flagstaff, AZ 86001, USA;

[4] Forest Health Protection, USDA Forest Service, 26 Fort Missoula, Missoula, MT 59804, USA;

[5] Forest Health Protection, USDA Forest Service, 4746 South 1900 East, Ogden, UT 84403, USA;

[6] Pacific Southwest Research Station, USDA Forest Service, 1731 Research Park Drive, Davis, CA 95618, USA;

[7] Pacific Southwest Research Station, USDA Forest Service, 2480 Carson Road, Placerville, CA 95667, USA;

[8] Rocky Mountain Research Station, USDA Forest Service, 1648 South 7th Avenue, Bozeman, MT 59717, USA;

关键词: Bark beetles;    Dendroctonus ponderosae;    Disturbance;    Invasive plants;    Literature review;    Pinus contorta;   

DOI  :  

来源: DOAJ

【 摘 要 】

Bark beetle outbreaks alter forests in many ways including stand structure, fuels and fire behavior, wildlife habitat, and aesthetic value. Less understood are the effects outbreaks have on understory vegetation, despite the importance for overstory succession, nutrient cycling, water quality, soil erosion, and wildlife. Beetle outbreaks also change forests in ways that could promote invasion by nonnative weeds, but this is rarely studied. We assessed changes in cover of understory vegetation and presence/abundance of weeds in lodgepole pine forests in Colorado, Idaho, Montana, Utah and Wyoming, USA following recent mountain pine beetle outbreaks. Incipient beetle populations began in 2004, peaked around 2008, and returned to endemic levels by 2012. Understory vegetation was sampled in 2010, 2012, 2014 and 2018. Total understory cover and cover of shrubs and graminoids remained unchanged, while cover of forbs generally increased. Forb cover was negatively correlated with shrub and canopy cover. Approximately 20% of plots contained weeds and weed abundance increased over time. Presence of weeds was negatively correlated with graminoid cover and positively correlated with tree mortality and snag fall. By 2018, weed abundance was only positively correlated with snag fall. Localized soil disturbance created when snags uproot and fall appears to act as sites of weed invasion and proliferation. Lastly, we provide a global review of the effects of bark beetle outbreaks on understory vegetation which reveals a prevailing short-term increase following outbreaks, but the magnitude of response and cover type affected varies with beetle species/forest type and time since outbreak.

【 授权许可】

Unknown