Genetic diversity and differentiation of nine populations of Ginkgo biloba L. (Ginkgoaceae)from China were evaluated using RAPD. Of 47 clear and repeatable RAPD bands, 46 were polymorphic (overall polymorphism = 97.9%). A ranged from 1.57 to 1.83 with a mean of 1.75. Mean He was 0.3159 (0.2429-0.3603). The Shannon index ranged from 0.3432 to 0.5119 with a mean of 0.4489. The GST was 0.1609 and AMOVA analysis indicated 89% of the variation within populations. UPGMA clustered the 9 populations into two groups: one containing only population JF and the other including 8 populations. Genetic diversity and differentiation of Chinese populations were higher than those of Korean and North American populations, which are ultimately descended from China, as reported previously.

To understand the evolutionary history of Lymantriinae and test the present higher‐level classification, we performed the first broad‐scale molecular phylogenetic analysis of the subfamily, based on 154 exemplars representing all recognized tribes and drawn from all major biogeographical regions. We used two mitochondrial genes (cytochrome c oxidase subunit I and 16S ribosomal RNA) and six nuclear genes (elongation factor‐1α, carbamoylphosphate synthase domain protein, ribosomal protein S5, cytosolic malate dehydrogenase, glyceraldehyde‐3‐phosphate dehydrogenase and wingless). Data matrices (in total 5424 bp) were analysed by parsimony and model‐based evolutionary methods (maximum likelihood and Bayesian inference). Based on the results of the analyses, we present a new phylogenetic classification for Lymantriinae composed of seven well‐supported tribes, two of which are proposed here as new: Arctornithini, Leucomini, Lymantriini, Orgyiini, Nygmiini, Daplasini trib. nov. and Locharnini trib. nov. We discuss the internal structure of each of these tribes and address some of the more complex problems with the genus‐level classification, particularly within Orgyiini and Nygmiini.

At the forest landscape/region level, based on annual Forest Inventory and Analysis plot data from 1999 to 2010, oak decline and mortality trends for major oak species (groups) were examined in the Ozark Highlands of Arkansas and Missouri. Oak decline has elevated cumulative mortality of red oak species to between 11 and 15 percent in terms of relative density and basal area of standing dead oak trees, respectively. These values are three to five times higher than for white oak group and non-oak species. Oak decline and associated escalating mortality have occurred primarily in red oak species while the white oak group has maintained a relatively stable mortality rate that is comparable to non-oak species. Cross-correlation analyses indicate that mortality in the red OPEN ACCESSForests 2012, 3 615 oak group was significantly correlated with the growing season Palmer drought severity index (PDSI) and usually lagged two to three years following single drought events. Moreover, based on the past 17 years PDSI data, it appears that the cumulative impacts of drought may last up to 10 years. The Ozark Highlands experienced a severe drought extending from 1998 to 2000 and another milder drought from 2005 to 2006. These drought events triggered the escalation of mortality starting around year 2000. Spatially, high red oak mortality sites (hot spots with proportional basal area mortality >0.12) initially occurred in the central Ozarks and spread gradually over most of the Ozark Highlands as regional droughts continued. In contrast, sites with elevated white oak and non-oak mortality occurred sporadically, mainly in the southern portion (Arkansas) of the Ozark Highlands. During the most recent inventory period (2006)(2007)(2008)(2009)(2010), over 60%, 7% and 5% of red oak, white oak and non-oak groups, respectively, had relative mortality rates of >12%.

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Comprehensive sampling is crucial to DNA barcoding, but it is rarely performed because materials are usually unavailable. In practice, only a few rather than all species of a genus are required to be identified. Thus identification of a given species using a limited sample is of great importance in current application of DNA barcodes. Here, we selected 70 individuals representing 48 species from each major lineage of Solanum, one of the most species-rich genera of seed plants, to explore whether DNA barcodes can provide reliable specific-species discrimination in the context of incomplete sampling. Chloroplast genes ndhF and trnS-trnG and the nuclear gene waxy, the commonly used markers in Solanum phylogeny, were selected as the supplementary barcodes. The tree-building and modified barcode gap methods were employed to assess species resolution. The results showed that four Solanum species of quarantine concern could be successfully identified through the two-step barcoding sampling strategy. In addition, discrepancies between nuclear and cpDNA barcodes in some samples demonstrated the ability to discriminate hybrid species, and highlights the necessity of using barcode regions with different modes of inheritance. We conclude that efficient phylogenetic markers are good candidates as the supplementary barcodes in a given taxonomic group. Critically, we hypothesized that a specific-species could be identified from a phylogenetic framework using incomplete sampling–through this, DNA barcoding will greatly benefit the current fields of its application.