spruce bark beetle alaska global warming

2006), and mountain pine beetle in high-elevation forests (Bentz and Schen-Langenheim 2007). Modeling cold tolerance in the mountain pine beetle, Stochastic simulation of daily air temperature and precipitation from monthly normals in North America north of Mexico, Empirical analyses of plant-climate relationships for the western United States, Mountain pine beetle-associated blue-stain fungi are differentially adapted to boreal temperatures. DL But many more remain standing, their spines still upright and looking as skeletal as ever. R Régnière Further, a study done by the Kenai Wildlife Refuge in Southcentral Alaska has found no significant relationship between beetle-related die-off and wildfire occurrence in Alaska; in other words, beetle outbreaks have occurred more frequently than fire historically, and the loss of trees to beetle kill does not necessarily result in widespread wildfires. MN The CRCM data was generated and supplied by Ouranos. These changes in climatic conditions over the next century will significantly affect the condition, composition, distribution, and productivity of multiple ecosystems (Easterling et al. Our assessment assumes no change in current tree distributions, and that thermal conditions conducive to bark beetle population success result in increased levels of tree mortality, although we do not explicitly model the impacts to forests. Wood Spruce beetle (Dendroctonus rufipennis Kirby) outbreaks are important disturbances affecting subalpine forests of Engelmann spruce (Picea engelmannii), subalpine fir (Abies lasiocarpa), and lodgepole pine (Pinus contorta) in the southern Rocky Mountains. Trees and shrubs are invading alpine tundra at a rate of up to 10 feet per year, and woody plants are barging in on ancient peat bogs. Jose F. Negrón is with the USDA Forest Service, Rocky Mountain Research Station, in Fort Collins, Colorado. Music I 2008). J MR C Their dry branches creak as they sway in the wind. . . Seybold K Balanyá NL Lee 2006), could cause an overall reduction in long-term spruce beetle impacts in that region. The ecological roles and temperature dependencies of the majority of bark beetle community associates are not well understood, which hampers full comprehension of the consequences of climate change on bark beetle population dynamics. KF Cold tolerance. forests on and near the Kenai Peninsula, The distribution of coniferous vegetation across western North America resulted from climatic shifts dating back millions of years (Brunsfeld et al. . Cronin Field When spruce beetles (Dendroctonus rufipennis) thin a forest canopy, surviving trees grow more rapidly for decades until the canopy closes and growth is suppressed through competition. Jorgensen Adult spruce beetles typically emerge from their host trees each spring when temperatures reach 60°F. BH Marland KF SA Although not all species have been investigated, diapause has been demonstrated or suggested to exist in five bark beetle species indigenous to western North America: (1) fir engraver, Scolytus ventralis LeConte (Scott and Berryman 1972); (2) spruce beetle (Hansen et al. This is particularly important because new research shows that trees that have better access to snowpack and snowmelt throughout the summer are better able to defend themselves from beetles during such outbreaks. SG Stephens 2007). This means reducing GHG emissions from a variety of sources … 2008). Bark beetles are currently responsible for killing an unprecedented number of trees in forests across Europe and North America. Bale Discussions with Robert Progar and John Lundquist and comments from Craig Allen and several anonymous reviewers greatly improved this article. When used in conjunction with quantitative models that are based on a mechanistic understanding of biological responses to temperature, results can provide insight into ecosystem responses to climate change. The Caribou Hills was the epicenter of a spruce bark beetle outbreak that eventually killed ~1 million acres of Sitka, white and Lutz spruce on the Kenai Peninsula from the mid-1980s through 1990s, sustained by consecutive summers of above-average temperatures. L 1, Climate extremes: Observations, modeling, and impacts, The effectiveness of vegetation management practices for prevention and control of bark beetle infestations in coniferous forests of the western and southern United States, Anatomical and chemical defenses of conifer bark against bark beetles and other pests, Physical effects of weather events on the abundance and diversity of insects in North American forests, Mountain Pine Beetle Impacts in High-Elevation Five-Needle Pines: Current Trends and Challenges, US Department of Agriculture Forest Service, Northern Region, Glacial vicariance in the Pacific Northwest: Evidence from a lodgepole pine mitochondrial DNA minisatellite for multiple genetically distinct and widely separated refugia. Figure 1. Changes in carbon assimilation will also alter within-plant allocation of carbohydrates available for growth, defense, and tissue repair, affecting the production of constitutive or inducible chemical defenses (Herms and Mattson 1992) and thus a tree's ability to respond to bark beetle invasions. We explore the potential effects of changing climate on bark beetle outbreak dynamics using two case studies: (1) spruce beetle and (2) mountain pine beetle. Oxford University Press is a department of the University of Oxford. Zhu Researchers Stephen Pacala and Robert Socolow at Princeton University have suggested one approach that they call "stabilization wedges." The right conditions simply aligned for the beetle to thrive. By Ivar Ekman. NPS Photo/A. Raupach Jenkins J Host-tree distribution. . Community associates. The potential for bark beetle outbreaks to affect communities and management paradigms in regions that historically have not experienced severe beetle outbreaks is perhaps an eventual outcome of climate warming during the 21st century. Little A 2016 aerial survey conducted by the Forest Service showed a roughly 35% increase in spruce beetle activity as compared with new activity in 2015. Dworschak K. (2013) Ecophysiology of the European spruce bark beetle (Ips typographus L.): ... Krokene P. et al (2011) Modelling the potential impact of global warming on Ips typographus voltinism and reproductive diapause. K If one does not believe in Global Warming and its effect, seeing Rehfeldt A new generation of trees and plants are beginning to emerge. T 2004), information is lacking on temperature-dependent physiological aspects of its life history that may be range limiting. Joe Romm Apr 30, 2012, 9:00 pm. Model output was masked using polygons that estimate the 20th-century locations of spruce (for spruce beetle) and pine (for mountain pine beetle) habitat in the United States and Canada (Little 1971). this devastation will open their eyes. The time required to complete a generation varies among bark beetle genera, species within a genus, populations within a species, and individuals within a population. EL In some places, these gray, skeletal trees seem to outnumber the trees that are alive. Logan We also used the cold tolerance model developed by Régnière and Bentz (2007) to predict the probability of annual survival given a one-year temperature regime. Trees smaller than six inches in diameter are spared because they produce enough pitch to suffocate mother beetles and their phloem layer is too tight for them. AP . 2001), in addition to more recent recolonization of deglaciated lands from multiple refugial populations (Godbout et al. Ojima DW 2006). Langor 2001, Werner et al. JG Ciais Page Currently, spruce beetles are affecting over 400,000 acres in the Matanuska-Susitna Valley, resulting in widespread mortality of spruce trees. While the spruce bark beetle is not a new arrival, it now poses a bigger threat because global warming is having a direct effect on the natural defenses against parasites. . Zogas Mattson Mountain pine beetle-killed whitebark pine on the Bridger Teton National Forest, Wyoming. Following aggregation and subsequent mating, adults lay eggs in the phloem, and larvae excavate feeding tunnels in this tissue or in the outer bark, depending on the beetle species—a process that eventually results in the mortality of the host tree. Despite uncertainty in forecasts of future climate parameters that have been downscaled to a forest landscape, predictions of trends in bark beetle population success as a function of the direct effects of temperature will be instrumental in development and application of strategies for management of future forests. Though the visible effects can be dramatic, this is part of a normal forest disturbance cycle. The insects have chewed up 4 million acres of spruce trees. Bentz Mendoza Hard Search for other works by this author on: Adaptation, migration or extirpation: Climate change outcomes for tree populations, Movement of outbreak populations of mountain pine beetle: Influences of spatiotemporal patterns and climate, Global genetic change tracks global climate warming in, Herbivory in global climate change research: Direct effects of rising temperature on insect herbivores, A rapid altitudinal range expansion in the pine processionary moth produced by the 2003 climatic anomaly, Ecology of mountain pine beetle cold hardening in the Intermountain West. M K Serra King Salmon, AK The potential for adaptive seasonality in central Canada decreases dramatically from the historical period to the end of this century, with high probability of population success restricted to northern provinces (figure 3a, 3b, 3c). Ebata 2008). The understory is becoming denser and more productive. DL Aukema public that the costs of warming will be VERY REAL and VERY expensive. Cold tolerance for these insects is therefore greatest during the winter months, and lowest during periods of glycerol synthesis and catabolism in autumn and spring, respectively, suggesting a direct correlation between increasing minimum temperatures associated with climate change and a reduction in cold-induced beetle mortality. But many more remain standing, their spines still upright and looking as skeletal as ever. The indirect negative effects of enhanced CO2 on bark beetle growth and survival are, at least in part, outweighed by other climate-change-induced effects on host trees, including reduced defenses. Stastny Based on projected warming, increases in thermal regimes conducive to population success are predicted for Dendroctonus rufipennis (Kirby) and Dendroctonus ponderosae Hopkins, although there is considerable spatial and temporal variability. Black Spruce trees killed by the Spruce Bark Beetle, near Portage glacier, Alaska. MS What Can We Do? . DL Are these trees a fire hazard? Other community associates and trophic interactions, including avian predators and insect parasitoids and predators (McCambridge and Knight 1972, Boone et al. Female beetles excavate galleries in which to lay eggs. 2010). Spruce beetle eggs normally hatch by August, then spend the winter, dormant, in larvae beneath the bark. Direct effects of climate change on bark beetles Of the hundreds of native bark beetle species in the western United States and Canada, few species (< 1%) attack and reproduce in live trees. WE ing biotic agents affecting forests globally (Anderegg et al. Host-tree physiology. Mountain pine beetle model results. By the end of the century, about 48% of the western US landscape is predicted to experience climate profiles with no contemporary analog to the current coniferous vegetation (Rehfeldt et al. T Predictions for mountain pine beetle in the southwestern United States, in particular, may differ as new developmental parameters are incorporated. Huang Although there are many possible avenues for atmospheric changes to influence phytophagous insect outbreaks, because of the direct link between insect population success and seasonal temperature (Danks 1987), outbreaks are predicted to be affected dramatically by global warming (Bale et al. Nowak For example, spruce beetles have specialized body structures to carry associated nematodes (Cardoza et al. Additional fitness parameters potentially affected include higher adult longevity and prolonged adult emergence and flight. In addition to directly affecting tree death through carbon starvation and cavitation of water columns within the xylem, climatic water stress can have profound effects on tree susceptibility to bark beetle attack. In Katmai’s forests, the spruce bark beetle population increased a whopping 300% from 2005 to 2006, accorrding to data from the US Forest Service. Diapause is a dynamic, endocrine-mediated and environmentally driven dormancy that occurs at a specific life stage. Further, a study done by the Kenai Wildlife Refuge. 1: Conifers and Important Hardwoods, US Department of Agriculture Miscellaneous Publication 1146, Model analysis of mountain pine beetle (Coleoptera: Scolytidae) seasonality, Herbivory in relation to plant nitrogen content, Factors affecting spruce beetles during a small outbreak. Although it appears that the northern extent of this bark beetle species, and others restricted to the southwestern United States and Mexico, is currently limited by climate and not host-tree availability (Salinas-Moreno et al. LaValle, PO Box 7 In the mountain pine beetle, for example, life stage-specific developmental thresholds aid in synchronizing adult emergence at appropriate times of the year (Powell and Logan 2005). Buffo These warm temperatures are fueling the largest tree-killing, bark beetle epidemic ever recorded throughout western North America. To avoid drought-induced hydraulic failure, plant stomates close to restrict transpiration. Climatic Change , 109, 695–718. Though the dramatic outbreak has slowed since then, nearly a decade later we are still feeling its effects. As Alaska continues to experience a warming climate recent studies also indicate that spruce bark beetle outbreaks may become more frequent. Model predictions suggest that during the historical period 1961–1990, the majority of spruce forests in Alaska, and those at high elevations in the contiguous western United States and northern latitudes of Canada, would have a moderate to low probability of spruce beetle populations developing in a single year (figure 1a, 1d). Chansler Schen-Langenheim Skov Temperature pattern throughout a life cycle is therefore critical to appropriate seasonality, and predicted rises in temperature could affect both developmental thresholds and rates in multiple life stages. VR Significant temporal and spatial variability in thermal suitability is predicted, however, emphasizing the complexity in both the thermal habitat and temperature-based physiological processes of these insects. BJ CH 2006), can reduce the resistance of surviving trees to bark beetle attack. 2008, Raffa et al. Bark beetles reproduce in the inner bark (living and dead phloem and cambium tissues) of trees.Many species, such as the mountain pine beetle (Dendroctonus ponderosae) attack and kill live trees.Most, however, live in dead, weakened, or dying hosts. Ayres Zheng N Developing mountain pine beetle larvae acquire vital nutrients not found in plant tissue by feeding on two fungi, Grosmannia clavigera and Ophiostoma montium, the hyphae of which spread throughout the phloem and sapwood following inoculation into the tree by attacking beetles. SM YJ CK Because bark beetle population survival and growth are highly sensitive to thermal conditions, and water stress can influence host-tree vigor, outbreaks have been correlated with shifts in temperature (Powell and Logan 2005) and precipitation (Berg et al. Raffa . Holliday None of these outbreaks was as intense as the 1990s outbreak, which has killed most of the large white and Sitka/Lutz spruce on the southern Kenai Peninsula. Nearly 70,000 trees were reported under attack that year. 2001); (3) Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (Ryan 1959); (4) eastern larch beetle, Dendroctonus simplex LeConte (Langor and Raske 1987); and (5) pine engraver, Ips pini (Say) (Birch 1974). AV 2008), undoubtedly will also be influenced by abiotic factors associated with climate change. LaValle BJ Probability values were linearized by logistic transformation before interpolation and before the maps were back transformed. JA Hicke Nealis . Nearly 70,000 trees were reported under attack that year. RA Fish species from warmer waters were showing up in fishing nets. Sullivan Stahl During the same period, the areas inhabited by ponderosa pine, Pinus ponderosa Laws., and Douglas-fir, Pseudotsuga menziesii Franco, hosts of several bark beetle species, are projected to increase by 11% and 7%, respectively (Rehfeldt et al. 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