Epidemics of infectious diseases often occur in predictable limit cycles. Theory suggests these cycles can be disrupted by high amplitude seasonal fluctuations in transmission rates, resulting in deterministic chaos. However, persistent deterministic chaos has never been observed, in part because sufficiently large oscillations in transmission rates are uncommon. Where they do occur, the resulting deep epidemic troughs break the chain of transmission, leading to epidemic extinction, even in large cities. Here we demonstrate a new path to locally persistent chaotic epidemics via subtle shifts in seasonal patterns of transmission, rather than through high-amplitude fluctuations in transmission rates. We base our analysis on a comparison of measles incidence in 80 major cities in the prevaccination era United States and United Kingdom. Unlike the regular limit cycles seen in the UK, measles cycles in US cities consistently exhibit spontaneous shifts in epidemic periodicity resulting in chaotic patterns. We show that these patterns were driven by small systematic differences between countries in the duration of the summer period of low transmission. This example demonstrates empirically that small perturbations in disease transmission patterns can fundamentally alter the regularity and spatiotemporal coherence of epidemics. Measles epidemics continue to pose a significant public health risk wherever vaccination coverage is low. In such populations transmission rates tend to fluctuate seasonally, mirroring patterns of human aggregation, due to the timing of school terms, and/or the migration of workers and their families. Here we show empirically that slight changes in the seasonal pattern of measles transmission can lead to massive shifts in the complexity of measles dynamics, in some cases driving epidemic patterns that resemble deterministic chaos. Our analysis is based on a comparison of 20-year biweekly measles incidence time series in 80 major cities in the prevaccination era United States and United Kingdom. The results are important in two ways: first, in contrast to previous theory, we show that subtle shifts in seasonal patterns of transmission can cause deterministic chaos in the epidemic dynamics of acute immunizing infections; second, we demonstrate that this new route to deterministic chaos is significantly more robust to stochastic extinction compared with previous chaotic models, suggesting chaotic dynamics may be more common in natural populations than previously thought. Acute immunizing infections remain a leading cause of death worldwide, and have accounted for a significant portion of all morbidity and mortality throughout human history, especially among children and in countries without adequate vaccination coverage –4. UnderEpidemics of acute immunizing infections often occur in predictable cycles–10. The The most intensively studied incidence patterns for measles are from Europe—notably the UK—during the prevaccination era and are characterized by stable limit cycles  with annual or biennial periods ,11,15,16In contrast, recent analyses of measles in western Africa—notably Niger—have revealed complex dynamics, featuring episodic epidemics with highly variable amplitudes. These are primarily caused by sharp seasonal increases in population density driven by collective migration  resultinPrevious case studies, therefore, suggest an impossible tension with respect to chaos in real world epidemics. Despite its mathematical plausibility –23, the We take a comparative approach, analyzing 20-year biweekly time series data on measles incidence in 80 major cities, 40 in the US and 40 in England and Wales (UK). To compare these contexts, we fit a Time-series Susceptible Infected Removed (TSIR) model to the measles incidence data for each of the 80 cities ,6,11. Tht by It, the concurrent number of susceptible individuals by St, and the population size by Nt, the TSIR model is given byE[.] is the expected value and βt represents seasonally fluctuating transmission rate in each city. The mixing parameter α, usually set at slightly less than unity, accounts for latent inhomogeneity in contact patterns between susceptible and infected individuals  and dispersion parameter It, so that the variance in It+1 is given by E[It+1] + E[It+1]2/It. To study the deterministic skeleton of the dynamics, we model It+1= E[It+1] in place of Eq . Secular variation in susceptible recruitment is a well-known driver of variation in measles periodicity [Susceptible dynamics are modeled asiodicity  that we iodicity ,11 that We assembled biweekly time series of measles incidence in US cities using the Project Tycho database  and tookWe used data for the 40 US cities in the Project Tycho database with the most records of measles incidence, which included most major US cities. While the Project Tycho database has measles incidence data from 1903 to 1953, data coverage was uniformly high for these 40 cities between 1920 and 1940, so we used that period in the analysis. For the England and Wales measles data we used the city of London plus the largest 39 cities that were more than 50km from London to prevent a “borough effect” where UK cities in the greater London area are entrained to its dynamics.Due to limitations on data availability, the US measles data we used extends from 1920–1940, whereas the England and Wales measles data extends from 1944 to 1964. Our analysis accounts for demographic differences associated with the changing time window between the US and the England and Wales data, including differences in birth rates over time among cities and countries. Consequently, the temporal mismatch between the US and UK data does not drive the observed epidemic patterns—evidence from other sources clearly shows that measles epidemics in London, UK and other major UK cities remained predominantly biennial and non-chaotic in the period covered by the US data , because the deterministic skeleton of these dynamics falls on an attractor that is globally less stable . Similarper se, but predictions for the impact of chaos on metapopulation dynamics have been somewhat equivocal, as epidemic chaos has its own complex relationship with persistence. Specifically, spatial decorrelation, such as that seen among US cities, can improve disease persistence in a metapopulation context, as subpopulations that experience local extinctions may be more likely to be rescued by connected subpopulations that have not experienced a fadeout—the metapopulation “rescue effect” [Although not conclusive, analysis of cross correlation in measles incidence across cities suggests that US cities may have had less synchronized epidemics at regional and country-wide scales Fig B in . The lev effect” –45. Howe effect” . The newOur analysis demonstrates the impacts of chaos on the metapopulation dynamics of cities, showing that the network consequences of complex epidemic patterns depend on the origins of the complexity. On one hand, if complex cycles emerge via high amplitude fluctuations in transmission rates, then local populations will be more likely to experience synchronous fadeouts, and metapopulation rescue effects will not considerably improve local persistence,40. On tIn conclusion, the emergence of persistent chaotic epidemics in the prevaccination US from small shifts in seasonal transmission patterns reveals a novel and potentially widespread route to chaos in population dynamics,46,47. MS1 Text(DOCX)Click here for additional data file.S1 Table(CSV)Click here for additional data file.


In the domestication and breeding of tree species that suffer from inbreeding depression (ID), the long-term performance of different breeding strategies is poorly known. Therefore, seven tree breeding strategies including single population, subline, selfing, and nucleus breeding were simulated using a multi-locus model with additive, partial, and complete dominance allele effects, and with intermediate, U-shaped, and major allele distributions. The strategies were compared for genetic gain, inbreeding accumulation, capacity to show ID, the frequencies and fixations of unfavorable alleles, and genetic variances in breeding and production populations. Measured by genetic gain of production population, the nucleus breeding and the single breeding population with mass selection strategies were equal or superior to subline and single breeding population with within-family selection strategies in all simulated scenarios, in spite of their higher inbreeding coefficients. Inbreeding and cross-breeding effectively decreased ID and could in some scenarios produce genetic gains during the first few generations. However, in all scenarios, considerable fixation of unfavorable alleles rendered the purging performance of selfing and cross-breeding strategies ineffective, and resulted in substantial inferiority in comparison to the other strategies in the long-term. Recurrent selection has been the principal method for the improvement of tree species  for intensive breeding, testing, and selection. The main tier contains the other candidates and a selection that were selected at lower intensities to avoid inbreeding and maintain genetic diversity, thus ensuring sustainable genetic gains in the long-term. Gamete transfer is allowed between these two tiers to bring gain and diversity. Several tree breeding programs have used this scheme (Zea mays L.) hybrids, selfing and subsequent cross-breeding has been a main breeding method for the improvement of many agronomic species  and long-term (15–20 generations) genetic consequences of their implementation. Such comparative studies can only be done through simulation approaches, of which the generally used infinitesimal model does not allow the tracing of purged unfavorable alleles and cannot realistically emulate how recessive/dominant alleles would induce ID. Only locus-based models have the capability to track the behavior of individual alleles under a nonadditive situation and emulate more complex phenomena such as linkage disequilibrium  two single breeding population strategies (SBP), ii) one subline strategy (SUBL), iii) two nucleus strategies (NUC), and iv) two selfing and cross-breeding strategies (SELF). All strategies comprised a founder population of 192 unrelated individuals and in each generation a total of 9600 progenies were generated, of which 192 individuals again were phenotypically selected for further breeding. Single pair-mating with random allocation of parents was used for all strategies except for selfing strategies and for the main tier of nucleus strategies where open pollination was simulated (a random set of selected fathers were mated to each mother). Details of the different breeding strategy designs can be seen in We compared seven breeding strategies ordered within four main categories : i) two e.g., traditional Swedish tree breeding strategy, For the purpose of our study, we used the single breeding population and mass selection (SBPM) as a reference strategy. This was compared to an alternative single breeding population strategy where selection was performed only within-family (SBPW) which produces equal contributions among families and implicitly limits the mating of related individuals  were selected.For breeding populations (BP), an overall selection intensity of 2% at each generation was applied. However, to easily compare breeding strategies with respect to output performance we also simulated the generation of a PP by selecting and mating a total of 24 elite trees from BPs at each generation . Elite selections for the PP were evenly distributed among BPs, except for the nucleus strategies where selections were made only from the nucleus, and SELFL where only the best 24 inbred lines (http://www.igv.fi.cnr.it/noveltree). The initial software was adapted to the study of breeding strategies dealing with adverse genetic correlations .A locus-based simulation software (Metagene) using a finite loci model was previously developed at INRA (B and b) affecting a trait of our interest. ID of varying severities was simulated by regulating the degree of dominant allele action at each of the 100 loci. In principle, three different scenarios were investigated which comprised: i) allelic effects of a purely additive nature  thus emulating the complete absence of ID, ii) partially dominant allele effects  leading to a relatively mild ID, and iii) completely dominant allele effects  implying severe ID. All loci were set to be physically unlinked  and no epistatic interactions were simulated. In addition to the 100 loci controlling the trait, an equal number of multi-allelic neutral loci were incorporated in the framework. For those loci, each founder was given a unique set of alleles thereby enabling the calculation of probabilities by descent and thus the inbreeding level (F) of individuals and populations. Virtual individuals and breeding populations  were created with respect to the designed genomic framework and breeding strategies. Phenotype values were created by adding randomly sampled environmental deviates to the genotypic values. Environmental deviates were sampled from a normal distribution with zero mean and variance calibrated to produce an initially narrow sense heritability (2h) of 0.3 for the total founder population. Genetic gain accumulated for a given population at generation t was calculated as the increase of average population genotypic value at generation t compared to the mean value of the founders.The virtual tree genomic framework was designed to comprise 100 biallelic loci  at locus j or not (H = 0). Assuming the absence of epistasis, linkage disequilibrium (LD), and any directed selection the theoretically expected ID capacity  frequency for locus I, respectively. Initial settings for the different genomic scenarios are summarized in The degree of ID is a dynamic property dependent on allele and genotypic frequencies as well as the degree of dominant allele action. Consequently, in order to continuously monitor the capacity of a population to express ID at any given time and situation, we calculated µcapacity  is:E(μD)F, which is frequently estimated and reported in empirical inbreeding studies (D/µF= 0). Consequently, these estimates are easily divisible with the percentage additive genetic coefficient of variation (ACV = 100 × σA/µF= 0) producing an estimate of the ID capacity per unit additive genetic standard deviation (µD/σA) fully comparable to corresponding values for the genomic scenarios of this study (see E(µD)/σA in ACV estimates from the meta-analysis of e.g., 10% for height and diameter growth and 20% volume). Thus, the initial ID capacities used in our simulations could be compared to empirical observations made for forest trees and the realism of the ID severity for the simulated genomic scenarios could be assessed.Notably, the ID capacity is theoretically equivalent to the linear regression coefficient of average phenotype on  studies . By seara = 1) on the trait of interest and that the founder population would have intermediate allele frequencies (E(ip) = 0.5). However, to test the robustness of the results with respect to allele frequencies, an alternative setup was designed where initial allele frequencies were set to follow a neutral model (U-shaped) distribution adjusted to an effective population size equal to the number of founders  than the other 80 loci . In this scenario, dominance effects were only assigned to the 20 major loci emulating a situation where the effects of ID origins only form a limited but influential part of the genome.The standard setting for the virtual genomic framework comprised all 100 loci exerting equally small additive effects , which is paramount for the success of phenotypic selection. Therefore, in order to be able to compare breeding strategies and scenarios at equal initial conditions, all resultant parameters were scaled to correspond to an initial σA2 at 50 for the founder generation . Simulations were run 500 times and averages of these are reported.One should note that variation in parameters such as allele effects and frequencies, set by choice or as a result of random sampling, will affect the initial additive genetic variance  is deposited at http://www.upsc.se/resources/databases-a-software.html and can be downloaded from file folder “genomic simulation” for execution.No experimental raw data were used or generated. The simulation software (F) of the BPs was plotted for the seven breeding strategies  accumulated inbreeding quicker than the corresponding main tiers, the differences in F were not very large and decreased by time. This indicates that nucleus strategy transfers are effective in keeping inbreeding low and maintaining genetic diversity in the nucleus population. The inbreeding of the unrestricted nucleus strategy (NUCU) increased slightly quicker than that of the restricted nucleus strategy , but with respect to all other parameters NUCU behaved almost identically to NUCR. Hence, only NUCU will be shown and discussed further in this study.The inbreeding coefficient  (Genetic gains in breeding populations were more complex than the inbreeding coefficient accumulation . In the D) . For theD). From D lower at generation 20 than at the outset. This behavior is consistent with so-called slow purging, which can be performed without the systematic mating of related individuals. Only scenarios with complete dominance are shown here because the partial dominance scenario results were similar in all respects, excepting only the scale of the ID capacity. Additive scenarios, as expected, never exhibited any ID.From a breeding context, successful purging of the genetic load should encompass the decrease of unfavorable allele frequencies, as well as the ID capacity itself . Thus the expected probability of unfavorable fixation at the outset was (1-p)2 = 0.25. For major loci, fixation in SELFL at generation 20 was somewhat lower (39–40%), likely due to their greater individual contribution to the additive genetic variance, making them easier targets for selection. The minor loci counterparts, however, showed a comparatively greater degree of fixation as their small effects were overshadowed by that of the major loci, and their fate was thus mainly dominated by drift . Therefore, an additional SELFL strategy was designed where the selection was intensified four times in comparison with the normal SELFL strategy. Unfavorable allele fixation for such a strategy was nonetheless very similar to the normal SELFL strategy with respect to the unfavorable allele fixation 44%, .In summary, selfing strategies appeared to substantially reduce their capacity to show ID, but this happened partly at the expense of fixing high percentages of unfavorable variants. At the opposite extreme, SBPW kept high levels of potentially harming alleles hidden at the heterozygote state, with little unfavorable fixation. NUCU and SBPM appeared as the best compromises among tested strategies due to their slow but continuous purging of both ID capacity and unfavorable alleles, and by avoiding the fixation of unfavorable alleles.Figure S1). Selfing strategies showed the fastest decline while the within-family selection strategy declined the least. The theoretical expectation of genetic variance distributed between lines (2Fσ02) and within lines ((1-F)σ02) was observed in this study where, at generation 1, the within-line selection strategy of SELFL could access only 50% of the additive genetic variance available to the nonselfing strategies, whereas the selfing within a single population strategy could access an additive genetic variance 50% larger than that of the nonselfing strategies as a consequence of the selfing itself. The SELFP peak in σA2 at generation 1 most probably also contributed to the higher genetic gains observed for SELFP . The selfing strategy performed in a single population (SELFP) was completely unable to keep inbreeding low in the PP, as the best individuals were chosen without restrictions from one single population in which inbreeding increased very quickly . However, the inferiority of SUBL was very slight under intermediate allele frequencies  and single breeding population strategy with mass selection (SBPM) accumulated the highest long-term genetic gains and, given the replicate variation, they also performed equally well. SUBL and SBPW were consistently inferior in comparison to the NUC and SBPM strategies, both in the short and long-term perspective despite their lower PP inbreeding coefficients .The genotypic variation in the PP is an important measure of the uniformity of the deployed genotype mix. In the completely additive scenario, the genotypic variance decreased by time for all strategies and the decline was fastest for the selfing strategies . HoweverScientific and theoretical examination of breeding strategies for tree species is more relevant than for other crops due to the impracticality of performing multiple generation experiments on long-lived tree species. Furthermore, most tree breeding programs are still at a comparatively early stage among domesticated species. Therefore, designing optimal breeding methods is essential for ensuring short- and long-term genetic gain. Traditionally, the design of breeding strategies was regarded as half science and half art (i) inbreeding should be actively avoided and the genetic load could be slowly purged by gradual increase of favorable allele frequencies as a result of selection; and ii) fast purging could be performed using deliberate inbreeding as a tool in combination with directed selection.How to deal with inbreeding effectively is a central issue in the decision of which strategy is best for long-term tree breeding. Inbreeding and diversity can be managed implicitly through design of the breeding scheme, or explicitly when selection and mating decisions are to be taken. This paper deals with the former type of management being the first important step when designing a breeding strategy. Explicit management can be added later on to the design for further efficiency. In order to efficiently manage advanced breeding programs, several strategies were proposed or adopted from animal and crop breeding. Among these strategies, two general approaches are noteworthy: Pinus radiata (Pinus pinaster after selfing (P. radiata (Picea abies (D)/σA) are comparable to the corresponding parameters used in our simulations  fairly close to the initial ID capacity of the complete dominance with intermediate allele frequencies scenario (7.1) used in this study. At the other end, the milder ID observed for P. radiata and Pinus banksiana (1.7–3.2) were more similar to those of the partial dominance with U-shaped allele frequencies (2.0) or the major loci complete dominance (2.9) scenarios. In conclusion, the genomic scenarios designed and simulated in this study exhibited an initial capacity to show ID that compared well with the ID observed in a collection of forest tree species.Inbreeding depression has been observed in forest trees for number of sound seeds, seedling performance, adult growth, and fecundity. The ID for survival of seedlings and adults was often observed to be considerable (43–93%)  and the  radiata  to high ulations . From a ulations , speciesFigure S1). The reasons for the successful performance of NUC could be the combination of intensive selection and continuous supplies of genetic diversity from the main to the nucleus tier. Also, NUC appeared to purge both detrimental alleles and ID capacity at a slightly higher rate than SBPM , unfavorable alleles were still not effectively purged  performed relatively worse than strategies devoid of such structures (SBPM and SELFP) or permitted a certain gene flow across compartments . It appears that the existence of isolated breeding compartments limits the choices when optimizing selection and mating decisions. Strategies devoid of compartment structures appear better suited for the implementation of optimal procedures that explicitly control inbreeding. For instance, selection in SBPM, NUC, or even SELFP could be enhanced by applying optimum contribution selection and minimum coancestry mating designs, which could optimize the balance between accumulated inbreeding and genetic gains  for the favorable alleles could make the situation for selfing more favorable than in our scenarios, as unfavorable fixation is then less likely. Hence, the selection of a superior base population could increase the probability of generating high quality inbred lines .In summary, fixation of unfavorable alleles due to drift and inefficient selection was found to be the main issue for selfing and cross-breeding strategies in tree breeding. For noninbreeding strategies, the ability to prevent fixation of unfavorable alleles and to decrease the effects of ID by slow purging were both found to be important factors for safeguarding short- and long-term genetic gains. In general, strategies devoid of structured restrictions to selection, such as nucleus breeding and breeding within a single population with mass selection, were found to be superior to subline and single breeding population with within-family selection strategies. The inbreeding and cross-breeding strategies of this study could be effective in the first few generations provided that selection was conducted from one single progeny population of high value. Several proposals exist in order to improve inbreeding and cross-breeding, like reducing the fixation of recessive alleles, control of relatedness and selection of superior hybrids. However, among the breeding strategies studied here, nucleus breeding and single breeding population are likely the best long-term choices.


Sphagnum warnstorfii is an important ecosystem engineer in fen peatlands, the causes of its rather wide niche along the pH/calcium gradient are poorly understood. Here, we studied the genetic variability of its global populations, with a detailed focus on the wide pH/calcium gradient in Central Europe. Principal coordinates analysis of 12 polymorphic microsatellite loci revealed a significant gradient coinciding with water pH, but independent of geography; even samples from the same fens were clearly separated along this gradient. However, most of the genetic variations remained unexplained, possibly because of the introgression from phylogenetically allied species. This explanation is supported by the small heterogeneous cluster of samples that appeared when populations morphologically transitional to S. subnites, S. rubellum, or S. russowii were included into the analysis. Alternatively, this unexplained variation might be attributed to a legacy of glacial refugia with recently dissolved ecological and biogeographic consequences. Isolation by distance appeared at the smallest scale only (up to 43 km). Negative spatial correlations occurred more frequently, mainly at long distances (up to 950 km), implying a genetic similarity among samples which are very distant geographically. Our results confirm the high dispersal ability of peatmosses, but simultaneously suggested that their ability to cope with a high pH/calcium level is at least partially determined genetically, perhaps via specific physiological mechanisms or a hummock-forming ability.Bryophytes dominate some ecosystems despite their extraordinary sensitivity to habitat quality. Nevertheless, some species behave differently across various regions. The existence of local adaptations is questioned by a high dispersal ability, which is thought to redistribute genetic variability among populations. Although  Sphagnum subnitens distributed from the Pacific coast of the continental United States (Oregon) to the western end of the Aleutian Islands appear to comprise a single genotype, some other studies on peatmoss genetics found at least a small signal of the effect of the local environment on genetic structure  and other bryophytes, interspecific differences in the tolerance to superfluous calcium in tissues are a major explanation of this strong compositional gradient . It is because the calcium uptake is increasing with increasing pH; a high calcium concentration does not matter under a low pH, and vice versa. In addition, in our study areas, the same geochemical process determines high pH and a high calcium level via the enrichment of the groundwater by calcium hydrogencarbonate. Sphagnum warnstorfii . We collected two original and rigorously sampled datasets, including plant material and water chemistry, covering uniformly the pH/calcium gradient in the Hercynian mountains (Czech Republic) and in the Inner West Carpathians (Slovakia). In addition, we analyzed samples from refugial fens from Bulgaria (Hájková and Hájek The aim of our study was to describe the genetic structure of the The major questions this research addresses are as follows: (1) Are there differences in the levels of genetic variability between and within the regions that were studied in greatest detail ? (2) Are plants from other regions  genetically divergent from those from central southeastern Europe? (3) Is there a relationship between the genetic and physical distance separating the plants, that is, is there evidence of isolation by distance, reflecting dispersal limitations? (4) Is there a relationship between ecological distance, especially habitat pH/calcium levels, and genetic divergences that may reflect ecotypic differentiation?+ ions was subtracted), and water chemistry . Multiple samples from some populations  were included to assess the genetic variations at more local scales. This dataset has the code CZ-SK throughout this paper.We collected an original dataset in the Hercynian (Czech Republic) and West Carpathian mountains (Slovakia), using a formal sampling protocol and stratified selection of sites Fig., equallyFor some analyses, we enlarged this dataset by more geographically distant samples. For the Balkans (Bulgaria), we utilized data for pH and conductivity from a previous ecological study , in the Duke University Herbarium (DUKE), or private herbariums of authors. The locations for the vouchers are indicated in Appendix S1. A total of 335 samples of http://biology.duke.edu/bryology/protocols.html. The microsatellite genotyping protocols were described by Ricca et al.  for electrophoresis on an ABI 3730 sequencer. Size determinations and genotype assignments were made using a GeneMarker, version 2.4.0 .DNA extraction was accomplished according to the protocol of Doyle and Doyle , modifiea et al. . The pria et al. . InitialFifteen samples with six or more missing loci were omitted. The final dataset included 320 samples from around the Northern Hemisphere  and geographic distances among individuals, Mantel tests based on Pearson's correlations were calculated using GENALEX. Spatial autocorrelations for assessing the relationships between the geographic and genetic distances between populations were also accomplished with GENALEX. The distance classes were created using the “even sample sizes” method, so that each class had an equal number of comparisons. The average values for each distance class were computed, and standard the errors for the multilocus estimates of the kinship coefficients per distance class were estimated using a jackknife procedure over the loci. The significance of all the coefficients was tested using 1000 random permutations within distance classes. Because we have exact coordinates only for samples from the Czech Republic, Slovakia, Bulgaria, and a few samples from North America, we divided the analysis of those samples into two parts. First, the autocorrelation analyses were run on the data from the dataset CZ-SK-BG; additional analyses were carried out with samples from North America only.K = 2 through K = 9, with 10 replicate runs of 1 million generations  at each value of K. The optimum number of clusters (K) was assessed using the Δ-K method  and CZ-SK . The PCoA coordinates for the first three axes were calculated in GENALEX, using the same way as in the previous analyses, and transferred in R (version 2.15.3). For modeling and testing the relationship between ordination scores and environmental factors, we used the function S. warnstorfii). Locus 1 was almost monomorphic, loci 17, 18, 19, 20, 22, 29, and 30 had 5–9 alleles, and loci 9, 10, and 14 were highly variable with 15–23 alleles (see Appendix for details). 135 unique multilocus genotypes were identified in the final dataset of 320 gametophytes. The analysis performed on the CZ-SK-BG dataset showed 71 unique multilocus genotypes of 269 gametophytes . A high level of the genetic differentiation was at the locality level (among fens) (39%), and the majority of the intraspecific genetic variability occurred within fens (57%). All the components of variations were significant (P < 0.01). Several samples had distinct genetic profiles ; however, the removal of these samples did not erase the significant genetic structure (results not shown).AMOVAs Table indicateK = 2 . Sixty-five percent of all the samples seemed to be genetically pure (<1% of admixture) for one or the other genetic cluster. The majority of the samples showed <10% of genetic admixture in these two clusters, seven samples showed 10–30% of genetic admixture, and four samples showed a high level of admixture. The genetic structure (clusters) did not clearly correspond to geographic regions  or to measured environmental characteristics . The exact nature of the admixture in these individuals would require a more detailed analysis beyond the scope of this paper.The Bayesian analysis of the complete dataset (with 135 unique genotypes) using STRUCTURE produced consistent results for K = 2), but all the individuals were admixtures between 30% and 70% for the first cluster. In this case, we should assume that the value of K is inappropriate and there is essentially no clustering in the dataset. This is very similar to the PCoA results and AMOVA results, which showed only 4% variability among the countries. We should conclude that the remaining samples make up only one wide population, with a very limited geographic structure.The STRUCTURE analysis without the 20 “outlier” genotypes resolved by the first analysis identified two main genetic clusters . When we split the data into blocks of geographic distances among individual samples, we should test the correlation between geographic and genetic distance within each block  due to the presence of clones within fens in the dataset CZ-SK-BG. These results corroborate the interpretation that cushions are largely clonal, as indicated by the AMOVA. At farther geographic distances , the correlation was significantly negative. At those distances, there was no isolation by distance – the samples which were very far apart geographically could be very similar genetically .R2 = 0.1869, P < 0.05; Fig.R2 = 0.1002, P < 0.05; Fig.When we omitted samples from the “outlier” cluster from the PCoA, the first three axes of the genetic PCoA of the CZ-SK dataset (51 samples) correspond to 14.5%, 11.8%, and 9.0% of the total genetic variance, respectively. The only significant explanatory variable in the summary test of 20 environmental parameters was water pH  of these samples (E. Mikulášková in prep.). These samples were removed from further analyses, but back-hybridization may take place forming a cline of genetic variations not corresponding well with morphology. Interspecific hybridization has been already documented in the subgenus Acutifolia by Cronberg  among the samples from different continents. Low levels or even a lack of genetic differentiation between plants on different continents occur in other bryophytes, including the Sphagnum species  level, mainly among separated cushions within fens. Closely similar genotypes were shared both among countries within Europe and between Europe and North America.In our study, the genetic differentiation in Sphagnum capillifolium, in the high Bulgarian mountains. The unique genotypes have been distributed across all the regions as well. We explain these observed patterns by the high levels of gene flow across the Northern Hemisphere.The similar genotypes are found both in the most densely sampled regions  and all around the Northern Hemisphere. Contrary to this, Natcheva and Cronberg  found a S. warnstorfii readily spreads over long distances, in agreement with the results from some other bryophytes that have been studied (see, e.g., Ramaiya et al. Sphagnum. Individual populations may establish from multiple sources distributed regionally. As a consequence, genetic diversity within a fen is a subset of the genetic diversity within the region.The spatial autocorrelation analyses show no general trends in correlation between genetic and geographic distances. A significant correlation was found only at small spatial scales, that is, for individual gametophytes within populations, or between geographically proximate populations. Significantly negative autocorrelations at large geographic scales support our conclusion that S. warnstorfii, the establishment of individual populations appears to arise from multiple sources. The genetic diversity within a fen is a subset of the genetic diversity within the region. Individual cushions within a fen are mainly of clonal origin.As evidenced by the genetic structure of There is no correlation between genetic and geographic distances among samples at a coarse spatial scale.S. warnstorfii, there is much more variation, which is difficult to explain. Its major part is possibly accounted for by a cline of genetic variation shaped by hybridization and back-hybridization with other species, especially S. subnitens, S. rubellum, and S. capillifolium. This unexplained variation can, however, also mirror a fine-scale spatial autocorrelation or a legacy of past genetic differentiation.Although water pH explains a significant part of the genetic variation within Our data support an idea that well-dispersing organisms such as spore-producing plants form one metapopulation operating at a large-scale, rather than the existence of particular regional metapopulations. This pattern, however, does not exclude the existence of local adaptations, because pH as a strong environmental determinant of peatmoss occurrence could filter particular genotypes from a species pool and hence could support isolation by environment.S. warnstorfii, but cannot explain differences in the pH niche between particular regions, as we initially expected.Our results generally confirm the high dispersal ability of peatmosses, but simultaneously suggest that their ability to cope with a high pH/calcium level is at least partially determined genetically. Genetics may explain a rather wide niche of


The success of a breeding program depends on the existence of genetic variability . TherefoThus, we used agronomic traits and microsatellite markers to evaluate the genetic diversity of 35 soybean genotypes to determine their potential as parents for breeding programs. Phenotypic analysis was carried out in the field at Fazenda Capim Branco and molecular analysis was conducted at the Laboratório de Genética do Instituto de Genética e Bioquímica (Genetics Laboratory at the Institute of Genetics and Biochemistry) at the Universidade Federal de Uberlândia . We evaluated 35 soybean genotypes using seven agronomic traits and nine microsatellites markers. These genotypes were then grouped by UPGMA and Tocher cluster analyses and the relative importance of the agronomic traits was obtained. Molecular analysis was used to calculate polymorphic data for each microsatellite marker. Genetic variability was found for all agronomic traits except for first pod height. UPGMA was used to form ten groups phenotypic analysis and eleven groups for molecular analysis. Additionally, the Tocher method was used to form twelve groups for both of these analyses.-1. Agronomic traits and microsatellite markers are effective tools for the study of genetic diversity in soybeans. Thus, we concluded that using agronomic traits and molecular microsatellite markers together makes it possible to detect potential parents for the soybean breeding program at UFU. Hybrids of the G11, G12, G16, G22, G26 and G33 genotypes promise segregating populations with superior genetic variability.The nine microsatellite markers amplified 26 alleles, ranging from 2 to 4 and averaging 2.88 per marker. Polymorphic data varied between 0.29 and 0.66 and averaged 0.44. Seven potential parents G11, G12, G16, G21, G22, G26 and G33) were identified from the UPGMA and Tocher clusters. These genotypes had average grain yields greater than 5000 kg ha


Vandiemenella, viatica species group) are an excellent model for studying the role of chromosomal rearrangement in speciation because they show extensive chromosomal variation, parapatric distribution patterns, and narrow hybrid zones at their boundaries. This species group stimulated development of one of the classic chromosomal speciation models, the stasipatric speciation model proposed by White in 1968. Our population genetic and phylogeographic analyses revealed extensive non-monophyly of chromosomal races along with historical and on-going gene introgression between them. These findings suggest that geographical isolation leading to the fixation of chromosomal variants in different geographic regions, followed by secondary contact, resulted in the present day parapatric distributions of chromosomal races. The significance of chromosomal rearrangements in the diversification of the viatica species group can be explored by comparing patterns of genetic differentiation between rearranged and co-linear parts of the genome.Chromosomal rearrangements can alter the rate and patterns of gene flow within or between species through a reduction in the fitness of chromosomal hybrids or by reducing recombination rates in rearranged areas of the genome. This concept, together with the observation that many species have structural variation in chromosomes, has led to the theory that the rearrangements may play a direct role in promoting speciation. Australian morabine grasshoppers (genus  VariatiDrosophila  and an anonymous nuclear marker Mvia11) and one mitochondrial cytochrome c oxidase subunit I (COI) sequence marker . Th. Thviatillozymes  and an iterflies .Mvia11 locus, and 65% in EF-1α locus), and the remaining half of the total genetic variation is explained by between populations within chromosomal taxa  and within populations . Phylogenetic analyses using these three nuclear markers show moderate differentiation among the chromosomal taxa; however, extensive non-monophyly is prevalent with numerous shared alleles among the taxa. Including taxa represented by single alleles, only five taxa formed monophyletic or nearly monophyletic groups for EF-1α, and one taxon formed a monophyletic group for Mvia11. The weak correspondence between molecular markers and chromosomal variants is further supported by allozyme clustering analyses implemented by STRUCTURE and BAPS. These Bayesian clustering analyses resolved 13 genetic clusters within the species group; only four chromosomal taxa formed exclusive genetic clusters, while the other seven taxa share clusters with another taxon  and viatica17 races [Vandiemenella chromosomal taxa generally represent genetically distinct units in the nuclear genome, a substantial portion of the total genetic variation was not explained by the chromosomal variation.When all the 12 chromosomal taxa distributed on mainland Australia, Tasmania, and Kangaroo Island were analyzed, the association between genetic and chromosomal variation was not as clear as that found in the Kangaroo Island populations. The Analyses of Molecular Variance (AMOVA) revealed that chromosomal variants explain about half of the total genetic variation in the three nuclear markers  showed ariation .3.Vandiemenella viatica species group have been contentious. White [Vandiemenella was ‘essentially’ contiguous through the entire process of chromosomal diversification, and that allopatric processes played little or no role in the diversification within the group. This supposition further emphasizes that narrow hybrid zones between taxa have been maintained since the emergence of daughter chromosome types . In contrast, Key [viatica species group. Specifically, it is important to test i) whether allopatric fragmentation has played a role in the diversification of the viatica species group, and ii) whether the origins of parapatric distributions of chromosomal races of the viatica species group were primary or secondary.Geographical modes of speciation/diversification within the s. White ,28 hypotast, Key  and Hewiast, Key  argued tast, Key –44. Therviatica species group [viatica19, which has the widest distribution among the Vandiemenella taxa, is composed of multiple, genetically divergent populations , mismatnd Rozas , and populations ,54 detecequences . Given tequences ,55. Duriequences , which ao Island ).viatica17 on Kangaroo Island [w = 310 m and dispersal parameter σ = 48.7 m/generation1/2 for 10 autosomal markers . In contrast to the nuclear markers, the mitochondrial COI marker showed a significantly wider cline (911 m) with center offset toward the P24(XY) side (409 m). Although there are several mechanisms that could result in the discordance between the mitochondrial and nuclear clines, such as asymmetrical hybridization, differences in fitness, differences in female mate preference and male aggression, hybrid zone movement toward the viatica17 side after secondary contact would be the most likely given the overall asymmetry of the clines in the nuclear markers. The results further suggest that reduction of nuclear gene flow may be associated with the chromosomal variation, or underlying genetic variation linked with chromosomal variation, whereas mtDNA gene flow appeared to be independent of this variation.A secondary origin of the parapatric distribution is supported by the narrowness of the hybrid zones relative to the dispersal rate of grasshoppers and patterns of gene introgression across a hybrid zone between P24(XY) and o Island . Hybrid  markers . If the 4.viatica species group of Australian morabine grasshoppers provided an important study system in the development of early chromosomal speciation theory in the 1960s, but its mode of speciation/diversification has been the subject of considerable debate. A series of population genetic and phylogeographic studies [viatica17 contact zone suggest that it formed by secondary contact and that barriers to gene flow in the nuclear genome are generally associated with the chromosomal variation. Although not statistically significant, the chromosomal variants (involving the X-chromosome and one of the autosomes) showed a narrower cline than any of the clines for nuclear markers, suggesting that selection is strongest for the chromosomal rearrangements.The  studies –31 reveaTaken together, our phylogeographic, population genetic and hybrid zone analyses, suggest that different parts of the genome, in addition to the chromosomal variation, are under selective constraints. However, there are a number of limitations. First, we have no knowledge of where any of the markers map in the genome. It is possible that some are located on rearranged chromosomes, or act in combination with markers on the chromosomal rearrangements. Second, there was insufficient power in the analyses to provide statistical support for the chromosomal variants being under stronger selection than the other nuclear makers.In order to discriminate between reproductive barriers caused only by genetic factors or in combination with chromosomal differences, further analyses are required to investigate differential gene flow using a large number of genetic markers within and outside the rearranged chromosome regions. Such analyses are particularly relevant for assessing the potential role of the suppressed- recombination models, where chromosomal rearrangements may facilitate diversification after secondary contact by reducing recombination and so maintaining linkage disequilibria between genes in a large block of the genome ,9. Such viatica species group is that various types and numbers of chromosomal rearrangements are involved, there are divergent populations that lack chromosomal differences, and a number of hybrid zones composed of different combinations of chromosomal races are available for study. It is expected that different pairs of chromosomal races, different levels of genetic divergence through different degrees of isolation in allopatry, and different ages of contact zones , may show different levels of genetic admixture between pairs of chromosomal races and, hence, have different sizes/numbers of genomic islands. We believe that the new molecular data in addition to the extensive chromosomal variation make the viatica species group an ideal model system for further exploring the potential role of chromosomes in speciation.One of the exciting features of the


Ursus maritimus) from across their circumpolar range was published in PLOS ONE, which used microsatellites and mitochondrial haplotypes to apparently show altered population structure and a dramatic change in directional gene flow towards the Canadian Archipelago—an area believed to be a future refugium for polar bears as their southernmost habitats decline under climate change. Although this study represents a major international collaborative effort and promised to be a baseline for future genetics work, methodological shortcomings and errors of interpretation undermine some of the study’s main conclusions. Here, we present a reanalysis of this data in which we address some of these issues, including: (1) highly unbalanced sample sizes and large amounts of systematically missing data; (2) incorrect calculation of FST and of significance levels; (3) misleading estimates of recent gene flow resulting from non-convergence of the program BayesAss. In contrast to the original findings, in our reanalysis we find six genetic clusters of polar bears worldwide: the Hudson Bay Complex, the Western and Eastern Canadian Arctic Archipelago, the Western and Eastern Polar Basin, and—importantly—we reconfirm the presence of a unique and possibly endangered cluster of bears in Norwegian Bay near Canada’s expected last sea-ice refugium. Although polar bears’ abundance, distribution, and population structure will certainly be negatively affected by ongoing—and increasingly rapid—loss of Arctic sea ice, these genetic data provide no evidence of strong directional gene flow in response to recent climate change.Recently, an extensive study of 2,748 polar bears ( Ursus maritimus) are Holarctic marine mammals that are dependent on sea ice as a platform for mating, reproduction, and locomotion. The southern boundary of their distribution is limited by the extent of the sea ice, which forms the habitat for their primary prey, pagophilic seals such as ringed seals (Pusa hispida) and bearded seals (Erignathus barbatus). Though long-distance swimming  , as was Structure analysis  were not given in Peacock et al., 2015 [et al., 2012 [Structure 2.3.4 [K-values was generated in CLUMPAK’s “Best K” feature using the Evanno method [Structure with output from BAPS 6.0 using its non-spatial admixture mode  that we detected within the Canadian Arctic Archipelago and the Polar Basin, we ran Structure on the full set of samples collected within each of these MUs using LOCPRIOR = 1 to improve the power to detect weak differentiation [The settings used for l., 2012 : 20 indere 2.3.4 , 59. Runre 2.3.4 ), and suo method  and the o method . As has o method , we compit = 10; , 65). Toit = 10; , using nntiation .Structure results for K = 6 showed an east–west cline in Q-values across the Polar Basin, and because there was a large sampling discontinuity in the middle of this cline , we suspected that one of these two clusters may have been spuriously generated by IBD. To test for IBD across this region, we performed a Mantel test between genetic distances [SPAGeDi) for all individuals that were highly assigned  to either the Eastern or Western Basin clusters (N = 62). To determine if IBD alone might be responsible for observed east–west genetic clustering in the Basin, we performed a partial Mantel test of association between a matrix of genetic distances and a model matrix denoting whether each pair of individuals belonged to the same genetic cluster (= 0) or not (= 1), while conditioning on geographical distances (cf. [vegan 2.2–1 [Isolation by distance (IBD) can confound clustering analyses . Becauseistances  and geogces (cf. ). Both tan 2.2–1 , using 1BayesAss 3.0.3 [et al., 1999 [K = 4 Structure results . We omitted Norwegian Bay from both of these runs because its small sample size might result in non-converged estimates [BayesAss, we used assignment tests in GenoDive to remove any significant  immigrants from Norwegian Bay found in other MUs. Because our dataset of ~30 samples per MU does not accurately reflect differences in MU population size that would affect gene-flow estimates when MUs were merged into regions, we generated balanced subsets using the sampling regimes shown in Table D of et al., 2015 [BayesAss runs, we followed the recommendations of Faubet et al., 2007 [Nit = 21,000,000, Nburn-in = 2,000,000, sampling interval = 2,000), and we used the Bayesian deviance , indicating that microsatellites were unlikely to underestimate population differentiation because of high mutation rates or marker diversity. Three MUs had inadequate sampling  to accurately determine mitochondrial haplotype frequencies: namely, M’Clintock Channel, Norwegian Bay, and Viscount Melville Sound. Therefore, we excluded these MUs in pairwise population comparisons and AMOVAs of mtDNA.No locus deviated significantly from Hardy–Weinberg equilibrium. Two pairs of loci were in significant LD ; however, both had s method , and neis method . Even ifs method . TherefoK = 2–7 are shown in K = 2: the Polar Basin, K = 3: the Canadian Arctic Archipelago, K = 4: Norwegian Bay, K = 5: west–east differentiation in the Polar Basin, K = 6: west–east differentiation in the Canadian Arctic Archipelago, K = 7: apparent noise. Although the Evanno ΔK method selected K = 2 , the Eastern Archipelago, the Western Archipelago, Norwegian Bay, the Eastern Polar Basin, and the Western Polar Basin. Because these results were geographically defensible and corresponded roughly with previously discovered genetic structure in the Archipelago  and acroFig B in . GenoDivr = 0.2354, P < 0.0001), though genetic clustering remained marginally significant after accounting for IBD . Therefore, we decided to retain both the Eastern and the Western Basin clusters, though we note that traversable distances between individuals in this region will be underestimated by SPAGeDi if it calculates distances over the poor-quality Arctic Basin MU. Results are mapped in There is significant IBD across the Polar Basin . Tests of pairwise population differentiation revealed many significant differences between major genetic clusters, but few significant differences within clusters. In total, 121/136 (≈89%) of population pairs were significantly differentiated after a Holm correction based on nuclear FST, genic, or genotypic differentiation . Importantly, all tests of genetic differentiation show that Norwegian Bay is significantly differentiated from all other MUs  were at stationarity after burn-in, according to Heidelberger-and-Welch diagnostics. Estimates were surprisingly robust to large amounts of systematically missing data, as results for 14 loci and 21 loci were nearly identical in terms of means and confidence intervals  was maximized through eninsula , 82; theeninsula , 83; andeninsula , 85 and eninsula .et al., 2015 [et al., 2015 [Structure analyses [et al., 2015 [et al., 2015 [et al., 2015 [ΘSC values or purportedly explain negative percentages of variance. We were unable to reproduce these unusual AMOVA results using Arlequin on the full dataset , and—tol., 2015 . The stal., 2015 . This sul., 2015 , and we analyses –27. In aet al., 2015 [FST values and the inclusion of populations with inadequate mtDNA sampling , which may suggest male-biased dispersal within—but not among—genetic clusters  calculated using Migrate [BayesAss analysis was not described in the manuscript, and their results show known signs of non-convergence [et al., 2015 [BayesAss typically works best when sample sizes are much larger than this [Polar bears rely on sea ice as a platform for locomotion , hunting Migrate . They fovergence , 22. A cl., 2015  publishehan this , and we BayesAss results detected exactly the opposite pattern of Peacock et al., 2015 [BayesAss results showed ~30-fold directional gene flow from the Western Archipelago into the Eastern Archipelago, though this pattern only held true in 8/20 runs; the remaining 12/20 runs suggested ~30-fold directional gene flow from the Eastern Archipelago into the Western Archipelago. Estimates of these immigration rates were close to the upper bound of 1/3 and—taken together—this suggests that all estimates of gene flow within the Archipelago and the Polar Basin in both this paper and in Peacock et al., 2015 [, probably because of low genetic differentiation (FST ≈ 0.01) between these regions [et al., 2015 [BayesAss run . We encourage both reviewers and readers to further explore this invaluable dataset.The three–four major genetic clusters selected in Peacock l., 2015 . We hopeS1 File(DOCX)Click here for additional data file.


Invasive alien species represent a growing threat for natural systems, economy and human health. Active surveillance and responses that readily suppress newly established colonies are effective actions to mitigate the noxious consequences of biological invasions. However, when an exotic species establishes a viable population in a new area, predicting its potential spread is the most effective way to implement adequate control actions. Emerging invasive species, despite monitoring efforts, are poorly known in terms of behaviour and capacity to adapt to the new invaded range. Therefore, tools that provide information on their spread by maximising the available data, are critical.Aedes koreicus, in Northeast Italy: 1) an automatic statistical approach based on information theory, 2) a statistical approach integrated with prior knowledge, and 3) a GIS physiology-based approach. Each approach possessed benefits and limitations, and the required ecological information increases on a scale from 1 to 3. We validated the model outputs using the only other known invaded area in Europe. Finally, we applied a road network analysis to the suitability surface with the highest prediction power to highlight those areas with the highest likelihood of invasion.We apply three different approaches to model the potential distribution of an emerging invasive mosquito, Aedes koreicus represent only a small fraction of the potentially suitable area. Furthermore, the modelled niche included areas as high as 1500 m a.s.l., only partially overlapping with Aedes albopictus distribution.The GIS physiological-based model had the highest prediction power. It showed that localities currently occupied by Aedes albopictus may limit it. According to our analysis, some of the major cities in the study area may have already been invaded. Further monitoring is needed to confirm this finding. The developed models and maps represent valuable tools to inform policies aimed at eradicating or mitigating Aedes koreicus invasion in Northeast Italy and Central Europe.The simulated spread indicated that all of the suitable portion of the study area is at risk of invasion in a relatively short period of time if no control policies are implemented. Stochastic events may further boost the invasion process, whereas competition with The online version of this article (doi:10.1186/s13071-016-1340-9) contains supplementary material, which is available to authorized users. An increasing number of species is rapidly spreading outside of their original distributional range and invading new territories, gaining the name of invasive species. The factors underpinning invasion processes are numerous and include socio-economical determinants linked to the intensified speed and density of transcontinental commercial and tourist fluxes , 2. AmonAedes species. These are highly invasive container-breeding mosquitoes, with a native geographical distribution barycentre located in tropical and subtropical regions )nce 2008 . By contAe. koreicus. In support of this hypothesis we noted that the trap with the highest Ae. koreicus abundance was located at an altitude of 451 m. Another interesting outcome is that PHY predicted as suitable areas between 600 and 1500 m. This altitudinal range represents a still empty niche for invasive Aedes, as 600 m is the altitudinal limit for Ae. albopictus distribution [Ae. koreicus should be particularly monitored as, here, the invasion would not be constrained by biotic interactions with species with similar evolutionary traits.The percentage of the study area predicted as suitable varied from 3 to 30 %, encompassing different topographic and environmental conditions. To better characterize the predicted suitable area, we cross-tabulated it with a digital elevation model. PHY and logBAY indicated most of the low-altitude areas as highly suitable, while MaxEnt showed a peak in suitability distributed around moderate altitude (400 m). This outcome may be due to the buffer size (5 km) chosen around the presence points to derive background data, which may over-represent hilly areas, influencing the MaxEnt output. However, all three models showed a peak in suitability around 400–500 m, which may indicate optimal ecological conditions for ribution  in NorthAe. koreicus may further spread in Northeast Italy. The spread analysis was achieved considering the observed dispersal rate since introduction, the preferred dispersal pathways, study area connectivity and habitat suitability. Aedes species have a short flight range, with a flying dispersal capability of 200–300 m radius per week around the hatching location [Dracaena sp.) in the form of drought resistant eggs [Ae. koreicus spread over the next years.The accuracy assessment indicates PHY as the model with the highest prediction power, being in moderate-to-high agreement with observed data in the study area and predicting high suitability in a positive location with a different environmental setting. Therefore, PHY model was chosen as reference to investigate how location , 101. Hoant eggs . The locant eggs , 103. Asant eggs . FurtherAe. koreicus distribution range since it integrates a validated suitability surface as well as the most likely dispersal pathways at local scale. A partial validation of the adopted spread analysis comes from a similar study on Ae. albopictus by [Ae. albopictus is currently surfing a dispersal wave in Southern France, with occasional “jumps” that did not result in new colonization fronts. However, it should be remembered that the proposed approach may underestimate the dispersal rate. This is due to the choice to consider the centroids as indication of the invaded area shift as well as the deterministic nature of our approach which does not integrate stochastic events such as occasional introductions in spatially distant but ecologically close locations. Stochasticity in species distribution change underlies unpredictable events that sometimes strongly boost species dispersal and colonization of new areas. Besides, in the southern part of the study area, biotic interactions and out-competition by Ae. albopictus, not considered in this study, may slow down Ae. koreicus spread [Ae. koreicus might be negatively affected by the presence of Ae. albopictus .The simulated spread is a reliable approximation of the future expansion of ictus by . The auts spread , modifyiDrosophila suzukii  and Xylella fastidiosa  as crop pests and Ae. albopictus as a vector of tropical pathogens; [Ae. koreicus in the study area. Multiple control and mitigation strategies are available to eradicate, mitigate or control invasive species [Ae. koreicus, the most effective control strategy is through inspections followed by destruction of removable breeding sites  and treatment with larvicidae of fixed sites . This strategy is time consuming and might be improved in terms of cost-effectiveness by targeting the most productive breeding sites. However, there is often a limited understanding of the biology of emerging invasive species and, consequently, of the hazard they represent [Ae. koreicus invasion in Northeast Italy. Despite the rising concern about biological invasions after recent economic and human health issues due to invasive species , a species . At the epresent . Delays epresent , 110. iSepresent . We sugg


Nucifraga caryocatactes) is a widespread resident corvid found throughout the Palearctic from Central Europe to Japan. Characterized by periodic bouts of irruptive dispersal in search of Pinus seed crops, this species has potential for high levels of gene flow across its range. Previous analysis of 11 individuals did not find significant range-wide population genetic structure. We investigated population structure using 924 base pairs of mitochondrial DNA control region sequence data from 62 individuals from 12 populations distributed throughout the nutcracker’s range. We complemented this analysis by incorporating additional genetic data from previously published sequences. High levels of genetic diversity and limited population genetic structure were detected suggesting that potential barriers to dispersal do not restrict gene flow in nutcrackers.The Eurasian or spotted nutcracker ( Pica pica; Corvus frugilegus; Ficedula parva; Microtus oeconomus; Emberiza schoeniclus; Otis tarda; Lutra lutra; Dendrocopos major; Actitis hypoleucos; Pica pica; In Eurasia, phylogeographic studies of many widespread vertebrate species have revealed a variety of geographical patterns of population structure influenced by current and historical landscapes, with little overall consensus among species. Using mitochondrial DNA, east–west splits have been documented for a variety of vertebrates including bats , and sevNucifraga caryocatactes, Linnaeus, 1758) is a corvid with a widespread Palearctic distribution. Although generally classified as a resident species of continental coniferous forests, nutcrackers are known to irruptively disperse to take advantage of mast conifer seed crops  collected throughout the Eurasian nutcracker’s range (n = 11) were obtained from GenBank ) and H1030 JCR 18 . DNA sequencing was performed on an ABI 3730xl DNA Analyzer at McGill University and Génome Québec Innovation Centre.DNA from muscle samples stored in ethanol or lysis buffer was extracted using a modified Chelex extraction protocol . A 924 boma jays ). DNA wanH), haplotype diversity (dH), and nucleotide diversity (π) for museum samples using DnaSP v5.10 . We aligned 11 additional GenBank sequences  sequences for 62 individuals from 12 populations  0.967 and nucleotide diversity (π) was 0.00537.For the 62 individuals we sequenced, we found 45 unique haplotypes and high levels of genetic diversity in most populations . We founn = 2) exhibited high haplotype diversity and relatively high nucleotide diversity. No geographic clustering was observed in statistical parsimony networks, even when integrating samples from the western part of the range. Despite potential barriers to dispersal for this species, such as isolation on an island ) or peninsula ), most populations of N. caryocatactes do not appear to be geographically differentiated from each other, likely due to gene flow during irruptive dispersal in search of mast pine seed crops. Overall, our work supports that done by N. caryocatactes sister species, N. columbiana . This may be due to the portion of control region sequenced and the larger sample sizes used in this study. The sequences obtained from our samples are predominantly composed of domains I and II of the mtDNA control region , an important source of food for nutcrackers, is thought to have survived in refugia near the Alps  sample codes, geographic location, voucher number from Burke Museum of Natural History and Culture – University of Washington, and GenBank accession numbers.Eurasian nutcracker (Click here for additional data file.


Homonota uruguayensis from Southern Brazil and Uruguay to assess the tempo and mode of population divergence, using both morphological measurements and molecular markers. Our results indicate that, in spite of its narrow geographic distribution, populations of H. uruguayensis show high levels of genetic structure. We found four major well-supported mtDNA clades with strong geographic associations. Estimates of their divergence times fell between 3.16 and 1.82 million years before the present. Populations from the central portion of the species distribution, on the border between Uruguay and Brazil, have high genetic diversity and may have undergone a population expansion approximately 250,000 years before the present. The high degree of genetic structure is reflected in the analyses of morphological characters, and most individuals could be correctly assigned to their parental population based on morphology alone. Finally, we discuss the biogeographic and conservation implications of these findings.The Pampas is a biologically rich South American biome, but is poorly represented in phylogeographic studies. While the Pleistocene glacial cycles may have affected the evolutionary history of species distributed in forested biomes, little is known about their effects on the habitats that remained stable through glacial cycles. The South American Pampas have been covered by grasslands during both glacial and interglacial periods and therefore represent an interesting system to test whether the genetic structure in such environments is less pronounced. In this study, we sampled Pampean populations of  In spite of its rich biological diversity, South America is one of the least studied continents in terms of its phylogeography . Phyloge2 in Central-Eastern Argentina, Uruguay, and Southern Brazil . B. B2 in Cn Brazil , 11]). ). 2 in Cn Brazil . Importaxpansion . On the 00 years , 15], a, a2 in Cl mammal .Homonota uruguayensis  is a small lizard  belonging to the Phyllodactylidae family of Neotropical geckos  tha thaHomonH. uruguayensis populations exhibit stable population size throughout the Pleistocene and a relatively homogeneous genetic structure shaped by isolation by distance. In the second scenario, however, phylogeographic structure among populations may be greater, with the main intraspecific clades being associated with major rivers in the landscape. H. uruguayensis is an interesting model system to test these hypotheses as the strong ecological requirements of this species may limit dispersal among populations and lead to population differences in the absence of physical barriers or climatic oscillations. In this study, we take a phylogeographic approach to better understand the evolutionary history of H. uruguayensis, using molecular markers and morphological measures. More specifically, we aim to answer the following questions: How strong is the genetic structure in this species and what is the temporal depth of the mtDNA genealogy? Is there evidence of changes to this species’ population size during the Pleistocene? Is morphological variation within this species concordant with the levels of population structure suggested by genetic data?The Pampas have been dominated by grasslands during both glacial and interglacial periods , and theH. uruguayensis from 12 localities . Euthanasia of all specimens was performed by injecting 2mg of 10% ketamine hydrochloride close to the animal’s heart (http://www.asih.org/sites/default/files/documents/resources/guidelinesherpsresearch2004.pdf). The abovementioned permits include the method of euthanasia employed in this study. Specimens collected in Brazil were deposited in the Herpetology Laboratory’s scientific collection at the Federal University of Rio Grande do Sul. Specimens collected in Uruguay were deposited in the scientific reptile collection of the Faculty of Sciences, at the National Museum of Natural History in Montevideo. Currently, H. uruguayensis is not designated as an endangered species in any list.Collection of et al. . W. WSSC st v.1.1.1 . Phyloge v.1.1.1  on the wsoftware  with nucstrategy . We assed et al. , who ana& Greene , which re family . Diverge species . A recenur study .ST, which is analogous to Wright’s F-statistics but takes into account the genetic distance among haplotypes . T. THomonoHomonota , which aHomonota ). AnotheHomonota . These pressions , 69]. I. IHomonoon event .Ctenomys, a subterranean mammal . T. T70]. Tn mammal , 72], a, aCtenomxillaris .Bothrops vipers , an, anH. uru Moritz , which iS1 FigH. uruguayensis haplotypes. This topology was strongly rejected based on the Bayes Factor in favour of a topology where haplotypes from CTI are sister to all others (see text for details).Note the low bootstrap support values , and the alternative topology showing haplotypes from ART1 as sister to all other (DOC)Click here for additional data file.S1 Table(DOC)Click here for additional data file.S2 TableVoucher numbers in scientific collections can be obtained from the respective Genbank files.(DOC)Click here for additional data file.


Geographic variation in trees has been investigated since the mid‐18th century. Similar patterns of clinal variation have been observed along latitudinal and elevational gradients in common garden experiments for many temperate and boreal species. These studies convinced forest managers that a ‘local is best’ seed source policy was usually safest for reforestation. In recent decades, experimental design, phenotyping methods, climatic data and statistical analyses have improved greatly and refined but not radically changed knowledge of clines. The maintenance of local adaptation despite high gene flow suggests selection for local adaptation to climate is strong. Concerns over maladaptation resulting from climate change have motivated many new genecological and population genomics studies; however, few jurisdictions have implemented assisted gene flow (AGF), the translocation of pre‐adapted individuals to facilitate adaptation of planted forests to climate change. Here, we provide evidence that temperate tree species show clines along climatic gradients sufficiently similar for average patterns or climate models to guide AGF in the absence of species‐specific knowledge. Composite provenancing of multiple seed sources can be used to increase diversity and buffer against future climate uncertainty. New knowledge will continue to refine and improve AGF as climates warm further. Long‐lived, largely undomesticated and slow to reach reproductive maturity, forest trees have never been ideal genetic subjects. As a result, genetic knowledge of trees has lagged behind that of agricultural crops and model organisms. However, one area in which knowledge of genetic variation within forest trees has led many other life forms for over two centuries is genecology, the study of relationships between natural populations and their native environments. The economic importance of trees for wood and fibre combined with their ecological importance as foundation species motivated scientists to characterize geographic variation as a prerequisite for deciding what to plant where. The synchronization of growth and dormancy timing of trees with their local climate was recognized early on to be a prerequisite for successful reforestation and led to a general practice of using locally collected seed for reforestation. A rapidly warming global climate is now disrupting adaptation of local populations, and the long, historically appropriate conservative tradition of ‘local is best’ has been slow to evolve to address this new challenge.The future health and productivity of tree populations will depend on the match between genotypes and new environments. Contemporary scientists are addressing these questions using traditional common garden approaches, as well as new phenotyping and genomic methods, to assess capacity for adaptation to new climates and inform ‘assisted gene flow’ (AGF), the managed translocation of individuals within the current species range to facilitate rapid adaptation to climate change  in 1979.I knew I wanted to be an evolutionary biologist from an early age. When I was 5 years old, my family spent a month camping at the Burgess Shale, while my father worked as part of an international team of geologists to quarry for branch origins in the tree of life in one of the world's most important fossil beds. At the age of 12, my father encouraged me to read Darwin's “The almost complete male domination of forestry in the 1970s did not dissuade me, thanks to my parents’ influence. My mother had a degree in agriculture and had worked in various research labs prior to starting a family, and through my father I met many scientists, mostly men but a few women. At sixteen, when looking for a part‐time job that would accommodate ski racing, I observed that only guys seemed to work as ski technicians. On hearing this, my father said he never wanted to hear me say I couldn't do something because I was female. I applied at three ski shops, and was offered three jobs.At UBC, there were no female professors in the Faculty of Forestry while I was an undergraduate. However, my cohort had had a higher proportion of female students than ever before, and the environment was supportive. A summer job in 1981 working on silvicultural research trials near Prince George, BC, landed me by chance next to Jon Dietrichson, a Norwegian forest geneticist, on a field trip bus. This encounter started my career in forest genetics; he hired me the next year as a Trainee in Tree Breeding at the Norwegian Forest Research Institute. I recommend that students and postdocs talk to people they don't know at conference coffee breaks, receptions and field trips, as these encounters might open doors unexpectedly.Pinus contorta ssp. bolanderi in the Mendocino pygmy forest. An internship at the historic Institute of Forest Genetics with postdoctoral fellows Claire Kinlaw and David Neale in the early days of DNA sequencing helped me decide I did not want to become a molecular biologist, but instead wanted to stick with population, quantitative and ecological genetics. It is more than a little ironic that genomic methods now play a large role in my research.In 1984, I started graduate studies with W.J. (Bill) Libby at the University of California, Berkeley. Bill mentored many people, both women and men, in forest genetics. He was a prolific source of new ideas and something of a futurist in predicting technologies, and he taught me to think broadly. I had many other mentors in Berkeley, including Connie Millar, who completed her PhD with Bill Libby a few years ahead of me in conifer population and conservation genetics, and is now a well known expert on trees and climate change. Tom Ledig and Tom Conkle were generous with their advice and with their laboratory facilities at the USDA Forest Service Southwest Research Station. They hosted a weekly forest genetics coffee with W.B. (Bill) Critchfield, who inspired me to study the origins of My first post‐doctoral academic position was at Oregon State University, as first a Research Associate then as Research Assistant Professor with the Pacific Northwest Tree Improvement Research Cooperative, working with Director and Professor W. T. Adams (1990–1996). I gained experience in tree breeding and quantitative genetics, and developed a better understanding of seasonal growth and dormancy cycles through repeatedly phenotyping field common gardens. I also developed more fluency in operational forestry, which later helped me establish collaborations, successfully obtain applied funding, and identify genetic questions that addressed applied problems. Close collaborators included Katy Kavanagh, Barbara Bond, Barbara Lauchenbrach, and Les Fuchigami, all of whom taught me phenotyping techniques for drought and cold hardiness. I also learned how not to do some things: how not to be relegated to the role of a research assistant while an assistant professor; and how not to get bogged down by administration and service at the expense of publishing. My daughter was an infant when I started this position, and balancing work and motherhood was challenging. It gets much easier to publish and parent simultaneously with time. My daughter is now a PhD student herself, and I learn a great deal from her.alma mater in 1996. Given my research record at the time, my department took a chance on me. In the 18 years since then I have been very fortunate to have hardworking, intelligent and kind graduate students, postdocs, research associates and research assistants; supportive colleagues; productive and thoughtful collaborators; and good research funding. We started the Centre for Forest Conservation Genetics in 2001, and I owe much to our talented Associate Director Tongli Wang and lab and project manager Pia Smets. Half the professors in my Department are now women, and our undergraduate students in Forest Resources Management, Forest Sciences, and Natural Resources Conservation are close to gender balanced. Judith Myers  has been a key mentor for me and many other women scientists at the University of British Columbia. The large‐scale AdapTree genomics project has allowed me to collaborate in an emerging area of science with a group of outstanding evolutionary biologists, and they have taught me a great deal. My partner Jack Woods is very supportive of my career, which has been an enormous help. While subconscious gender bias in science and academia remains common, I increasingly see both male and female colleagues working cooperatively against it. One important lesson I've learned over my career is what really matters for wellbeing and productivity is maintaining a positive and supportive atmosphere in my research group, and choosing collaborators carefully. Finally, at this career stage, great pleasure comes from seeing young scientists I have worked with progress in their careers in the directions they desire.In academia, we get little say in where a tenure‐track offer might come from, so it felt like winning a lottery when I was offered the job of my dreams, an NSERC Industry Chair at my 1This paper has been written for a special issue featuring women in evolutionary biology; and these personal reflections are in response to a request by the editors.Achillea millefolium and other species. Olof Langlet  from Central Europe, Russia, Scotland and the Baltic region on his estate in the 1740s and 1750s, but the results were never published  temperate and boreal tree species vary geographically in a manner corresponding to their provenance climate of origin, (ii) trees need to be planted in common gardens to observe this variation, (iii) most variation is continuous along environmental gradients rather than discrete or ecotypic, (iv) variation is more often physiological (e.g. in growth rate or phenology) than morphological and involves tradeoffs between growth rate and cold tolerance in many cases, and (v) seed for reforestation should in most cases be procured locally to ensure adequate growth and hardiness. More recent studies improved on experimental design, multiple sites or environments, phenotyping methods, and sources of climate data for provenance trials, and produced a more nuanced understanding of the genetic influence of provenance, the environmental effects of experimental environments and their interactions. New population genomic analyses are generating a better understanding of the genetic architecture of climate‐related traits and confirming geographic patterns of local adaptation.QST, the proportion of total genetic variation due to among‐population variation , on average  for selectively neutral genetic markers  allowed for the detection of standing variation in the form of adaptive alleles present at low frequency, and the genotyping of older trees allowed assessment of adaptive alleles present in reproductively mature populations. Most of these SNPs showed clinal variation in frequencies across the species range, but were polymorphic in most populations  and in the interior spruce complex  . However, in this synthesis we focus on phenotypic variation in common garden experiments for characterizing patterns of local adaptation as few comprehensive population genomic studies are available at this time.Population genomic approaches that analyse large numbers of loci have the potential to provide genetic information on the environmental drivers and spatial scale of local adaptation within a much shorter timeframe than provenance trials. Sampling designs and analytical methods for detecting outlier loci under divergent selection through genotype–environment associations are maturing . Wang et al. , and timing of fall phenological events associated with growth cessation . We identified clines along gradients in mean annual temperature (MAT), selected as a broad proxy for overall climate, and mean summer precipitation (MSP), intended to reflect growing season drought stress. Due to few studies on trees species from very dry climates, and less consistent adaptive clines identified along the gradient in MSP, we focus primarily on results for MAT and caution that our results may not be applicable to species and regions where climates are becoming much drier and drought‐related mortality is a major concern  for articles on provenance trials and common gardens individually for each tree species native to British Columbia . We retained data sets in which multiple populations were grown in a common environment, including greenhouse environments and field sites within and beyond the species’ native range. All data sets for ‘spring events’ recorded the timing of bud flush, whereas we pooled timing of bud set, growth cessation and leaf abscission into a single category of ‘fall events’ because of an insufficient number of studies assessing bud set. All three fall events are steps towards the initiation of dormancy prior to development of cold hardiness, and the timing of these events reflects local adaptation to maximize the length of the growing season while avoiding fall frost injury  the common environment must have been free of major pest or pathogen outbreaks, severe frost or drought damage, and other biotic or abiotic stressors. These stressors could differentially impact certain genotypes and thus mask genetic differences in growth potential among populations. (ii) Provenance geographic coordinates must have spanned at least five degrees of latitude or 50% of the species distribution to ensure clines reflect broad‐scale species‐level patterns. Small, geographically isolated populations and populations from a different subspecies or variety compared to the rest of the other populations were also excluded. (iii) To avoid pseudoreplication, if height data were available for the same set of populations tested at multiple sites or measured at different ages, only the most recent data from the site with the greatest mean height were included. Because height was assessed at locations with relatively high site productivity, clines represent height growth potential under good growing conditions. If multiple observations of spring or fall events were available, only those from the year with the greatest variance in timing of these events were included. (iv) Studies must have met minimum sample size criteria. These criteria recognize the practical limitations to experiments in total sample size and tradeoffs between the number of individuals per population and the number of populations for estimating clines. While experiments with many individuals per population (bulk samples) or more families per population estimate means precisely, experiments with many populations provide better estimates of clines. Thus, we accepted studies that had (i) at least 50 populations with as few as three individuals each, (ii) at least nine populations of at least three open‐pollinated families each with at least three individuals per family, or (iii) at least nine populations with 25 individuals each, regardless of family structure. Populations and open‐pollinated families not meeting these criteria were excluded, if population size and family structure were known (Tables S1–S3). Timing of spring and fall events must have been measured in units of calendar days, not using a quantitative scale on a single day.ClimateWNA , with 100% assigned to the expected height growth potential at the midpoint of provenance MAT. Regression slopes for timing of spring and fall events were retained in days per degree Celsius increase in provenance MAT (d·°C−1), but a value of zero was assigned to the expected date of spring and fall events at the midpoint of the provenance MAT values. Similar analyses were conducted for population MSP (Tables S1–S3). Although variation in phenotypic traits along climatic gradients may be nonlinear and better modelled by a quadratic function, visual inspection confirmed that most relationships were approximately linear , and linear models were applied to all species to facilitate interspecific comparisons.Provenance MAT was estimated for each population using Cornus nuttallii and Populus trichocarpa) that were not included in the initial data set  were available for height growth potential, 11 data sets (eight species) for spring events and six data sets (five species) for fall events Fig. . In addiP < 0.05) in 14 of 23 data sets . Mean R2 was 0.43 . The relationship between height growth potential and provenance MAT was positive in all statistically significant cases. It is remarkable that with such a simple analysis and such a broad proxy for overall climate, adaptive clines of similar magnitude and consistent direction were detected in so many species. There is undoubtedly much nuance to patterns of adaptation not captured by our results. For example, genotype‐by‐environment interaction, including the impacts of damage due to cold or drought, may create adaptive clines that are nonlinear, or vary in magnitude or even direction depending on the harshness of the test site   and Que Huebert ). These d Aitken  report hsensu stricto in plants in only 45% of pairwise population comparisons and superior performance of local genotypes in 71% of test sites. They also found that species with large population sizes, true for most widespread tree species, are more likely to be locally adapted. While our criteria are less stringent for detecting local adaptation, they are more risk averse in terms of forest management and conservation, as it is safer to assume that populations differ when they do not than to assume that they are not locally adapted when they are.Local adaptation appears to be extremely common in widespread tree species and more common than in plants in general, although we have not used stringent reciprocal transplant criteria to define local adaptation. Leimu and Fischer  found ev−1, with a mean R2 of 0.46 . In three species, spring events occurred earliest in populations from colder provenances, while in one species, the opposite trend was observed. In contrast, regressions of timing of fall events versus provenance MAT were statistically significant and consistent in direction in all six data sets (five species), with fall events occurring earliest in populations from colder provenances (Table S3). Population mean date of fall events increased by an average of 6.3 d·°C−1 , with a mean R2 of 0.63 (range: 0.25 to 0.90). Alberto et al. . The signs of slopes varied and were mostly shallow, ranging from −5.1 to 4.6 d·°Co et al.  also conFagus sylvatica compared to Fraxinus excelsior and Quercus petraea  is decreasing, but in some cold locations with common subfreezing temperatures, chilling is increasing with warming . This pattern likely reflects greater interest of foresters in faster‐growing populations from milder environments, and greater sampling accessibility of these populations, and these are also areas where forest harvest and reforestation is most likely to occur. (iii) Test sites for common gardens were also warmer and wetter than average . This may also reflect our deliberate avoidance of data sets for experiments with major damage due to biotic or abiotic stresses that could differentially inhibit growth potential among populations.The climatic scope of the 23 data sets we reanalysed for height growth potential covers a large proportion of each species’ realized niche in temperature Fig. B and preDespite these biases, the breadth of knowledge revealed from provenance trials in western North American tree species is large, and our analysis includes only a subset of these trials. Our results are consistent with studies including other species and regions . Moderate drought stress can reduce growth, while severe drought stress can result in tree mortality through hydraulic failure or carbon starvation  climate models alone, (ii) climate models combined with patterns of local adaptation identifying climatic drivers of differentiation for sympatric species, or (iii) climate models combined with species‐specific provenance trial data. Gray and Hamann  used cliAt any given location, the horizontal movement required to track a given climate spatially depends on both the local rate of climate change and the topographic heterogeneity, as climate changes more rapidly with increasing elevation than with increasing latitude or longitude. Loarie et al.  developeReverse velocities (future‐to‐present) can be used to evaluate planting sites that will benefit most from AGF, for example in terms of health, productivity and carbon sequestration. In general, valley bottom sites and large, relatively flat areas will likely benefit the most from AGF as they have the highest velocities and are farthest from pre‐adapted populations.ex situ conservation, and for AGF moving individuals to a location where they are more likely to persist as climates warm. Generally, mountaintops have the highest forward velocities as populations in these areas cannot migrate uphill farther and would have to travel large horizontal distances to find suitable future climates.Forward velocities (present‐to‐future) indicate the distance and direction that populations would need to move in order to track climate. Higher forward velocities indicate populations that are the farthest from suitable future habitat. These populations should be high priority for both Local topographical variation can affect levels of genetic variation within populations due to gene flow across heterogeneous landscapes. Yeaman and Jarvis  found loPicea sitchensis based on single nucleotide polymorphisms , genetic diversity for selectively neutral genetic markers diminishes somewhat across species ranges from central to peripheral populations, on average  if those lineages and their hybrids have not been well studied, and if populations are expected to naturally regenerate in the future  and vs. mean summer precipitation (MSP).Table S2. Regressions of population mean timing of spring events vs. provenance mean annual temperature (MAT) and vs. mean summer precipitation (MSP).Table S3. Regressions of population mean timing of fall events vs. provenance mean annual temperature (MAT) and vs. mean summer precipitation (MSP).Figure S1. Adaptive clines in height growth potential along a precipitation gradient are relatively uncommon and inconsistent.Figure S2. Height growth potential vs. provenance mean annual temperature from provenance trials in western North American tree species .Figure S3. Height growth potential vs. provenance mean annual temperature from provenance trials in western North American tree species .Figure S4. Height growth potential vs. provenance mean summer precipitation from provenance trials in western North American tree species .Figure S5. Height growth potential vs. provenance mean summer precipitation from provenance trials in western North American tree species .Figure S6. Date of spring events (see text) vs. provenance mean annual temperature from provenance trials in western North American tree species.Figure S7. Date of spring events (see text) vs. provenance mean summer precipitation from provenance trials in western North American tree species.Figure S8. Date of fall events (see text) vs. provenance mean annual temperature from provenance trials in western North American tree species. Each box represents an independent provenance trial, and each point represents a single population.Figure S9. Date of fall events (see text) vs. provenance mean summer precipitation from provenance trials in western North American tree species.Click here for additional data file.