Climate change and the outbreak ranges of two North American bark beetles

Abstract

1 One expected effect of global climate change on insect populations is a shift in geographical distributions toward higher latitudes and higher elevations. Southern pine beetle Dendroctonus frontalis and mountain pine beetle Dendroctonus ponderosae undergo regional outbreaks that result in large-scale disturbances to pine forests in the south-eastern and western United States, respectively. 2 Our objective was to investigate potential range shifts under climate change of outbreak areas for both bark beetle species and the areas of occurrence of the forest types susceptible to them. 3 To project range changes, we used discriminant function models that incorporated climatic variables. Models to project bark beetle ranges employed changed forest distributions as well as changes in climatic variables. 4 Projected outbreak areas for southern pine beetle increased with higher temperatures and generally shifted northward, as did the distributions of the southern pine forests. 5 Projected outbreak areas for mountain pine beetle decreased with increasing temperature and shifted toward higher elevation. That trend was mirrored in the projected distributions of pine forests in the region of the western U.S. encompassed by the study. 6 Projected outbreak areas for the two bark beetle species and the area of occurrence of western pine forests increased with more precipitation and decreased with less precipitation, whereas the area of occurrence of southern pine forests decreased slightly with increasing precipitation. 7 Predicted shifts of outbreak ranges for both bark beetle species followed general expectations for the effects of global climate change and reflected the underlying long-term distributional shifts of their host forests.

Effect of Water Stress and Fungal Inoculation on Monoterpene Emission from an Historical and a New Pine Host of the Mountain Pine Beetle

“…Global climate change might allow MPB to expand its range into formerly unoccupied lodgepole pine habitat and also enable further eastward invasion of jack pine (Williams and Liebhold, 2002). Climate change is expected to produce longer and more frequent droughts in many regions of the world (Breshears et al, 2009) that may influence the ability of trees to defend themselves against invading insects and diseases (reviewed in Franceschi et al, 2005).…”

Modelling bark beetle disturbances in a large scale forest scenario model to assess climate change impacts and evaluate adaptive management strategies

“…Thus, an increase in temperature is expected to increase the reproductive capacity and number of completed life cycles per year of important biotic disturbance agents such as bark beetles (Bale et al 2002). Moreover, climate change is likely to cause shifts in outbreak ranges of insect species (e.g., Parmesan et al 1999;Williams and Liebhold 2002). Due to the wide latitudinal and altitudinal distribution of the main European tree species the spatial distribution of important insect herbivores is in many cases limited by harsh environmental conditions rather than host availability.…”

Land Use and Climate Change

“…Numerous studies find that increases in temperature affect pest populations and migrations. Rising temperatures are also predicted to increase forest pests, crop pesticide usage costs, and wildfire risk (e.g., Chen and McCarl 2001;Williams and Liebhold 2002;Taylor et al 2007;Hicke and Jenkins 2008;Robinet and Roques 2010;Walther et al 2009;Gan 2004Gan , 2005.…”

“…Williams and Liebhold (2002) In terms of agriculture, crops are negatively affected by insect and disease pest outbreaks. Chen and McCarl (2001) find that increases in rainfall raise pesticide usage costs for corn, cotton, potatoes, soybeans, and wheat, while hotter weather increases pesticide costs for all crops except wheat.…”