Angiosperm phylogeny inferred from 18S rDNA, vbcL, and atpB sequences

A phylogenetic analysis of a combined data set for 560 angiosperms and seven outgroups based on three genes, 18S rDNA (1855 bp), rbcL (1428 bp), and atpB (1450 bp) representing a total of 4733 bp is presented. Parsimony analysis was expedited by use of a new computer program, the RATCHET. Parsimony jackknifing was performed to assess the support of clades. The combination of three data sets for numerous species has resulted in the most highly resolved and strongly supported topology yet obtained for angiosperms. In contrast to previous analyses based on single genes, much of the spine of the tree and most of the larger clades receive jackknife support 250%. Some of the noneudicots form a grade followed by a strongly supported eudicot clade. The early‐branching angiosperms are Amborellaceae, Nymphaeaceae, and a clade of Austrobaileyaceae, Illiciaceae, and Schi‐sandraceae. The remaining noneudicots, except Ceratophyllaceae, form a weakly supported core eumagnoliid clade comprising six well‐supported subclades: Chloranthaceae, monocots, WinteraceaeICanellaceae, Piperales, Laurales, and Magnoliales. Ceratophyllaceae are sister to the eudicots. Within the well‐supported eudicot clade, the early‐diverging eudicots (e.g. Proteales, Ranunculales, Trochodendraceae, Sabiaceae) form a grade, followed by the core eudicots, the monophyly of which is also strongly supported. The core eudicots comprise six well‐supported subclades: (1) Berberidopsidaceae/Aextoxicaceae; (2) Myrothamnaceae/ Gunneraceae; (3) Saxifragales, which are the sister to Vitaceae (including Leea) plus a strongly supported eurosid clade; (4) Santalales; (5) Caryophyllales, to which Dilleniaceae are sister; and (6) an asterid clade. The relationships among these six subclades of core eudicots do not receive strong support. This large data set has also helped place a number of enigmatic angiosperm families, including Podostemaceae, Aphloiaceae, and Ixerbaceae. This analysis further illustrates the tractability of large data sets and supports a recent, phylogenetically based, ordinal‐level reclassification of the angiosperms based largely, but not exclusively, on molecular (DNA sequence) data.     

Polyphyly of Limoniastrum (Plumbaginaceae): evidence from DNA sequences of plastid rbcL, trnL intron and trnL-F intergene spacer

Phylogenetic relationships of Limoniastrum and other genera of subfamily Staticoideae (Plumb-aginaceae) were studied using parsimony analysis of the plastid gene rbc L, the intron of trn L and the intergene spacer of trnL-trn F. Our analysis showed that Limoniastrum was polyphyletic. Limoniastrum ifniense , in both rbc L and combined data analyses, is sister to Armeria and Psylliostachys , whereas in the trn L-F (intron and spacer combined) analysis it is sister to a clade composed of Acantholimon, Dictyolimon and the remaining species of Limoniastrum . In all analyses, the five remaining species of Limoniastrum (excluding Limoniatrum ifniense ) formed a clade with two groups of species: L. monopetalum+L. guyonianum and those sometimes considered as the segregate genus Bubania ( L.feei, L. weygandiorum and L. rechingeri ). Levels of sequence divergence among these three groups of Limoniatrum were greater than for other well supported genera in the family and, in combination with morphological differences and paucity of synapomorphies, led us to conclude that separate generic status for each of the three clades is warranted.     

Elevated CO2 and conifer roots: effects on growth, life span and turnover

Elevated CO₂ increases root growth and fine (diam. 2 mm) root growth across a range of species and experimental conditions. However, there is no clear evidence that elevated CO₂ changes the proportion of C allocated to root biomass, measured as either the root:shoot ratio or the fine root:needle ratio. Elevated CO₂ tends to increase mycorrhizal infection, colonization and the amount of extramatrical hyphae, supporting their key role in aiding the plant to more intensively exploit soil resources, providing a route for increased C sequestration. Only two studies have determined the effects of elevated CO₂ on conifer fine-root life span, and there is no clear trend. Elevated CO₂ increases the absolute fine-root turnover rates; however, the standing crop root biomass is also greater, and the effect of elevated CO₂ on relative turnover rates (turnover:biomass) ranges from an increase to a decrease. At the ecosystem level these changes could lead to increased C storage in roots. Increased fine-root production coupled with increased absolute turnover rates could also lead to increases in soil organic C as greater amounts of fine roots die and decompose. Although CO₂ can stimulate fine-root growth, it is not known if this stimulation persists over time. Modeling studies suggest that a doubling of the atmospheric CO₂ concentration initially increases biomass, but this stimulation declines with the response to elevated CO₂ because increases in assimilation are not matched by increases in nutrient supply.     

Lithinine moths on ferns: a phylogenetic study of insect-plant interactions

We examine host association patterns in pteridophagous moths of the tribe Lithinini (Lepidoptera: Geometridae). This represents the first study where the host associations of oligophagous, pteridophagous Lepidoptera are analysed in a phylogenetic context. We compare the observed phylogenetic patterns of lithinine moths and their hosts with the contrasting coevolutionary scenarios proposed by Mitter et ai , and discuss the support for various hypotheses relative to Thompson's concept of coevolution as 'escape with radiation', and the chemical facilitation model of Jermy. The patterns observed support a scenario where host shifting subsequent to a single colonization event has resulted in lack of strict concordance (i.e. parallel cladogenesis) between moth and fern phylogenies.     

Exploring Migration Data Using Interval-Censored Time-to-Event Models

Abstract: Ecologists and wildlife biologists rely on periodic observation of radiocollared animals to study habitat use, survival, movement, and migration, resulting in response times (e.g., mortality and migration) known only to occur within an interval of time. We illustrate methods for analyzing interval-censored data using data on the timing of fall migration (from spring-summer-fall to winter ranges) for white-tailed deer (Odocoileus virginianus) in northern Minnesota, USA, during years 1991–1992 to 2005–2006. We compare both nonparametric and parametric methods for estimating the cumulative distribution function of migration times, and we suggest a parametric (cure rate) model that accounts for conditional (facultative) migrators as a potential alternative to traditional parametric models. Lastly, we illustrate methods for exploring the effect of environmental covariates on migration timing. Models with time-dependent covariates (snow depth, temp) were sensitive to the treatment of the data (as interval-censored or known event times), suggesting the need to account for interval-censoring when modeling the effect of these covariates.     

Morphological variation in British Folsomia quadrioculata Tullberg (Collembola: Isotomidae): a multivariate study

Abstract. Morphological variation among freshly caught specimens resembling Folsomia quadrioculata Tullberg was examined using principal components analysis and canonical variates analysis. Two distinct groups were identified corresponding with F. quadrioculata and F.manolachei Bagnall. Previous workers have questioned the specific status of F.manolachei and regarded these two species as inseparable using morphometric characters. A study of specimens previously identified as F. quadrioculata suggested that many were mis-identified and that F.manolachei is more abundant in the British Isles than is usually thought. Variation in some characters traditionally used to identify Folsomia species was examined and a method for distinguishing adult and juvenile F.quadrioculata from F.manolachei is provided. The synonomy of F.nana Gisin with F.manolachei is supported. The separation of F.diplothalma Axelson from F. quadrioculata is discussed, concluding that no characters are known which can reliably separate British specimens of these species.