Mountain pine beetle host-range expansion threatens the boreal forest
TL;DR: It is shown for the first time successful MPB attack in natural jack pine stands at the leading edge of the epidemic, and a panel of microsatellite loci optimized for both species to classify lodgepole pine, jack pine and their hybrids using simulated data is tested.
Abstract: The current epidemic of the mountain pine beetle (MPB), an indigenous pest of western North American pine, has resulted in significant losses of lodgepole pine. The leading edge has reached Alberta where forest composition shifts from lodgepole to jack pine through a hybrid zone. The susceptibility of jack pine to MPB is a major concern, but there has been no evidence of host-range expansion, in part due to the difficulty in distinguishing the parentals and their hybrids. We tested the utility of a panel of microsatellite loci optimized for both species to classify lodgepole pine, jack pine and their hybrids using simulated data. We were able to accurately classify simulated individuals, and hence applied these markers to identify the ancestry of attacked trees. Here we show for the first time successful MPB attack in natural jack pine stands at the leading edge of the epidemic. This once unsuitable habitat is now a novel environment for MPB to exploit, a potential risk which could be exacerbated by further climate change. The consequences of host-range expansion for the vast boreal ecosystem could be significant.
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Princeton University1, University of Idaho2, National Center for Atmospheric Research3, United States Geological Survey4, University of California, Santa Barbara5, United States Forest Service6, University of Montana7, University of Florida8, University of Arizona9, Los Alamos National Laboratory10, University of Wisconsin-Madison11, Macquarie University12
TL;DR: Using data sets from the western USA and associated studies, a framework is presented for determining the relative contribution of drought stress, insect attack, and their interactions, critical for modeling mortality in future climates.
Abstract: Climate change is expected to drive increased tree mortality through drought, heat stress, and insect attacks, with manifold impacts on forest ecosystems. Yet, climate-induced tree mortality and biotic disturbance agents are largely absent from process-based ecosystem models. Using data sets from the western USA and associated studies, we present a framework for determining the relative contribution of drought stress, insect attack, and their interactions, which is critical for modeling mortality in future climates. We outline a simple approach that identifies the mechanisms associated with two guilds of insects - bark beetles and defoliators - which are responsible for substantial tree mortality. We then discuss cross-biome patterns of insect-driven tree mortality and draw upon available evidence contrasting the prevalence of insect outbreaks in temperate and tropical regions. We conclude with an overview of tools and promising avenues to address major challenges. Ultimately, a multitrophic approach that captures tree physiology, insect populations, and tree-insect interactions will better inform projections of forest ecosystem responses to climate change.
602 citations
Cites background from "Mountain pine beetle host-range exp..."
...Warming has also allowed the mountain pine beetle’s northward expansion intoCanadian jack pine (Cullingham et al., 2011) and enhanced beetle survival in western high-elevation pine forests (Bentz et al., 2013), in the absence of any major drought effects (Fig....
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TL;DR: In this article, a hydraulic corollary to Darcy's law is used to predict the characteristics of plants that will survive during drought in a warmer climate, which indicates that forest trees will need to be shorter and more drought-tolerant to survive in the future.
Abstract: A hydraulic corollary to Darcy’s law is used to predict the characteristics of plants that will survive during drought in a warmer climate. This indicates that forest trees will need to be shorter and more drought-tolerant to survive in the future.
508 citations
TL;DR: The boreal woodlands and forests cover approximately 3.09 × 106 km2 in Canada and are characterized by cool summers and long cold winters as discussed by the authors, and have been warm since the 1850s.
Abstract: Canadian boreal woodlands and forests cover approximately 3.09 × 106 km2, located within a larger boreal zone characterized by cool summers and long cold winters. Warming since the 1850s, increases...
429 citations
Cites background from "Mountain pine beetle host-range exp..."
...6a), which is also susceptible to MPB (Cullingham et al. 2011)....
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TL;DR: The understanding of these processes can be only achieved by the exploration of the complex 'ecosystem microbiome' and its functioning using focused, integrative microbiological and ecological research performed across multiple habitats.
Abstract: Globally, forests represent highly productive ecosystems that act as carbon sinks where soil organic matter is formed from residuals after biomass decomposition as well as from rhizodeposited carbon. Forests exhibit a high level of spatial heterogeneity and the importance of trees, the dominant primary producers, for their structure and functioning. Fungi, bacteria and archaea inhabit various forest habitats: foliage, the wood of living trees, the bark surface, ground vegetation, roots and the rhizosphere, litter, soil, deadwood, rock surfaces, invertebrates, wetlands or the atmosphere, each of which has its own specific features, such as nutrient availability or temporal dynamicy and specific drivers that affect microbial abundance, the level of dominance of bacteria or fungi as well as the composition of their communities. However, several microorganisms, and in particular fungi, inhabit or even connect multiple habitats, and most ecosystem processes affect multiple habitats. Forests are dynamic on a broad temporal scale with processes ranging from short-term events over seasonal ecosystem dynamics to long-term stand development after disturbances such as fires or insect outbreaks. The understanding of these processes can be only achieved by the exploration of the complex 'ecosystem microbiome' and its functioning using focused, integrative microbiological and ecological research performed across multiple habitats.
399 citations
Cites background from "Mountain pine beetle host-range exp..."
...Both defoliators and bark beetles can kill virtually all mature trees within large areas and represent an excellent example of processes affecting multiple forest habitats (Table 2) (Cullingham et al. 2011; Štursová et al. 2014)....
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...Based on Cullingham et al. (2011), Bässler et al. (2016), Kaňa, Tahovská and Kopáček (2012), Kaňa et al. (2015), Karst et al. (2015), Mikkelson, Lozupone and Sharp (2016), Oulehle et al. (2013) and Štursová et al. (2014)....
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Duke University1, University of Wisconsin-Madison2, Michigan State University3, Arizona State University4, University of Washington5, University of Maryland, College Park6, University of Texas at Austin7, Brown University8, Florida International University9, University of Notre Dame10, University of New Hampshire11, University of Alaska Fairbanks12, National Ecological Observatory Network13, Harvard University14, National Oceanic and Atmospheric Administration15, University of Delaware16, Institute of Ecosystem Studies17
TL;DR: MacroSystems ecology is the study of diverse ecological phenomena at the scale of regions to continents and their interactions with phenomena at other scales as mentioned in this paper, which addresses ecological questions and environmental problems at these broad scales.
Abstract: Macrosystems ecology is the study of diverse ecological phenomena at the scale of regions to continents and their interactions with phenomena at other scales. This emerging subdiscipline addresses ecological questions and environmental problems at these broad scales. Here, we describe this new field, show how it relates to modern ecological study, and highlight opportunities that stem from taking a macrosystems perspective. We present a hierarchical framework for investigating macrosystems at any level of ecological organization and in relation to broader and finer scales. Building on well-established theory and concepts from other subdisci- plines of ecology, we identify feedbacks, linkages among distant regions, and interactions that cross scales of space and time as the most likely sources of unexpected and novel behaviors in macrosystems. We present three examples that highlight the importance of this multiscaled systems perspective for understanding the ecology of regions to continents.
290 citations
Cites background from "Mountain pine beetle host-range exp..."
...Range expansion enabled pine beetles to attack naïve trees, leading to more successful infestations (Raffa et al. 2008; Cullingham et al. 2011)....
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References
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TL;DR: Pritch et al. as discussed by the authors proposed a model-based clustering method for using multilocus genotype data to infer population structure and assign individuals to populations, which can be applied to most of the commonly used genetic markers, provided that they are not closely linked.
Abstract: We describe a model-based clustering method for using multilocus genotype data to infer population structure and assign individuals to populations. We assume a model in which there are K populations (where K may be unknown), each of which is characterized by a set of allele frequencies at each locus. Individuals in the sample are assigned (probabilistically) to populations, or jointly to two or more populations if their genotypes indicate that they are admixed. Our model does not assume a particular mutation process, and it can be applied to most of the commonly used genetic markers, provided that they are not closely linked. Applications of our method include demonstrating the presence of population structure, assigning individuals to populations, studying hybrid zones, and identifying migrants and admixed individuals. We show that the method can produce highly accurate assignments using modest numbers of loci— e.g. , seven microsatellite loci in an example using genotype data from an endangered bird species. The software used for this article is available from http://www.stats.ox.ac.uk/~pritch/home.html.
27,454 citations
TL;DR: The purpose of this discussion is to offer some unity to various estimation formulae and to point out that correlations of genes in structured populations, with which F-statistics are concerned, are expressed very conveniently with a set of parameters treated by Cockerham (1 969, 1973).
Abstract: This journal frequently contains papers that report values of F-statistics estimated from genetic data collected from several populations. These parameters, FST, FIT, and FIS, were introduced by Wright (1951), and offer a convenient means of summarizing population structure. While there is some disagreement about the interpretation of the quantities, there is considerably more disagreement on the method of evaluating them. Different authors make different assumptions about sample sizes or numbers of populations and handle the difficulties of multiple alleles and unequal sample sizes in different ways. Wright himself, for example, did not consider the effects of finite sample size. The purpose of this discussion is to offer some unity to various estimation formulae and to point out that correlations of genes in structured populations, with which F-statistics are concerned, are expressed very conveniently with a set of parameters treated by Cockerham (1 969, 1973). We start with the parameters and construct appropriate estimators for them, rather than beginning the discussion with various data functions. The extension of Cockerham's work to multiple alleles and loci will be made explicit, and the use of jackknife procedures for estimating variances will be advocated. All of this may be regarded as an extension of a recent treatment of estimating the coancestry coefficient to serve as a mea-
17,890 citations
"Mountain pine beetle host-range exp..." refers background in this paper
...Due to the level of differentiation described between these species (FST = 0.108, Wheeler & Guries 1987; GST = 0.247, Ye et al. 2002) we expected accurate resolution of first and second generation hybrids, however, we anticipated diminishing power with advanced generations of backcrossing given…...
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...Seed and cone morphometry are the current criteria for distinguishing species (Wheeler & Guries 1987); however, considerable morphological variation in the hybrid zone makes positive identification difficult (Rweyongeza et al. 2007)....
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...…including chemical profiles, allozymes, organellar DNA, random amplified polymorphism and restriction fragment length polymorphisms (Pollack & Dancik 1985; Wheeler & Guries 1987; Dong & Wagner 1993; Yang et al. 2007) have also been ineffective in resolving hybrids from parents in the hybrid zone....
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TL;DR: Genalex is a user-friendly cross-platform package that runs within Microsoft Excel, enabling population genetic analyses of codominant, haploid and binary data.
Abstract: genalex is a user-friendly cross-platform package that runs within Microsoft Excel, enabling population genetic analyses of codominant, haploid and binary data. Allele frequency-based analyses include heterozygosity, F statistics, Nei's genetic distance, population assignment, probabilities of identity and pairwise relatedness. Distance-based calculations include amova, principal coordinates analysis (PCA), Mantel tests, multivariate and 2D spatial autocorrelation and twogener. More than 20 different graphs summarize data and aid exploration. Sequence and genotype data can be imported from automated sequencers, and exported to other software. Initially designed as tool for teaching, genalex 6 now offers features for researchers as well. Documentation and the program are available at http://www.anu.edu.au/BoZo/GenAlEx/
15,786 citations
15,729 citations
TL;DR: Technique non parametrique pour la signification statistique de tables de tests utilisees dans les etudes sur l'evolution notamment.
Abstract: Technique non parametrique pour la signification statistique de tables de tests utilisees dans les etudes sur l'evolution notamment
14,666 citations
"Mountain pine beetle host-range exp..." refers methods in this paper
...Significance was assessed using Bonferroni corrected alpha values for multiple comparisons (a = 0.05, Rice 1989)....
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