Ri-plasmid mediated transformation and regeneration of Ulmus procera (English Elm)

Infection of Ulmus procera (English elm) cloneSR4 internodal stem explants with Agrobacteriumtumefaciens C58 c1 pRiA4b resulted in callusdevelopment and extensive hairy root production. Shoots which regenerated from hairy roots, followingan extended culture period, were dwarf in stature,with reduced apical dominance and wrinkled leaves whencompared with wild type U. procera SR4. Shootswere rooted successfully and plants with extensiveroot systems have been transferred to soil. Thetransgenic status of regenerants was confirmed by PCRanalysis and DNA sequencing of pRiA4b TL- and TR- DNArolA (329 bp) and agropine synthase (490 bp)primed amplimers, which were 100% homologous to theexpected sequences. No vir D1 primed PCRproducts were obtained, indicating that the Agrobacterium was successfully removed. Thepotential of Ri plasmid mediated transformation forinducing altered elm xylem structure, restrictedspread of the Dutch elm disease fungus and inphytoremediation is discussed.     

Did southern Western Ghats of peninsular India serve as refugia for its endemic biota during the Cretaceous volcanism?

The Western Ghats (WG) of south India, a global biodiversity hotspot, has experienced complex geological history being part of Gondwana landmass and encountered extensive volcanic activity at the end of Cretaceous epoch. It also has a climatically and topographically heterogeneous landscape. Thus, the WG offer a unique setting to explore the influence of ecological and geological processes on the current diversity and distribution of its biota. To this end, three explicit biogeographical scenarios were hypothesized to evaluate the distribution and diversification of wet evergreen species of the WG – (1) southern WG was a refuge for the wet evergreen species during the Cretaceous volcanism, (2) phylogenetic breaks in the species phylogeny would correspond to geographic breaks (i.e., the Palghat gap) in the WG, and (3) species from each of the biogeographic subdivisions within the WG would form distinct clades. These hypotheses were tested on the centipede genus Digitipes from the WG which is known to be an ancient, endemic, and monophyletic group. The Digitipes molecular phylogeny was subjected to divergence date estimation using Bayesian approach, and ancestral areas were reconstructed using parsimony approach for each node in the phylogeny. Ancestral‐area reconstruction suggested 13 independent dispersal events to explain the current distribution of the Digitipes species in the WG. Among these 13 dispersals, two dispersal events were at higher level in the Digitipes phylogeny and were from the southern WG to the central and northern WG independently in the Early Paleocene, after the Cretaceous Volcanism. The remaining 11 dispersal events explained the species’ range expansions of which nine dispersals were from the southern WG to other biogeographic subdivisions in the Eocene‐Miocene in the post‐volcanic periods where species‐level diversifications occurred. Taken together, these results suggest that southern WG might have served as a refuge for Digitipes species during Cretaceous volcanism.     

Tree species compositional change and conservation implications in the white‐water flooded forests of the Brazilian Amazon

Aim The aim of this study was to use compositional changes in tree species along the Amazon River floodplain in Brazil to identify and characterize biogeographic regions that would serve as broad surrogates for conservation planning. Location The main course of the Amazon River in Brazil, covering a river distance of approximately 2800 km. Methods Two sampling methods were employed at specific sites: standardized transects and/or individual‐based samples. Seventy‐three samples were collected from 26 sites at approximately 100‐km intervals along the floodplain. Biogeographic regions were identified by non‐metric multidimensional scaling (NMDS) ordination and by a hierarchical cluster analysis. The relative influence of environmental components (flood depths, annual rainfall, and length of the dry season) on tree species composition and one spatial component (longitude) were analysed by multiple regressions against a one‐dimensional NMDS ordination axis. Results Based on tree species composition, three main biogeographic regions were identified: a western region between Tabatinga and the Negro River confluence; a central region from the Negro River confluence to the Xingu confluence; and an estuarine region from the Xingu confluence to Santana. The regions identified were consistent using different data sets and analytical techniques. Mixed environmental and spatial effects explained most of the variation, but the spatial effect alone had a greater influence on species composition than environmental effects alone. Main conclusions The regions delimited in the analyses differed from those based on geomorphology or World Wildlife Fund (WWF) ecoregions. These results reinforce the need for surrogates to be tested against biological data before they are used to shape approaches to conservation planning. Although a protected area coverage of 25% gives the impression of extensive conservation management on the floodplain, less than 1% of the Amazon’s floodplain in Brazil is strictly protected. The significant compositional differences between regions and the strong spatial variation along the Amazon indicate that strict protection areas should be distributed much more evenly within and between regions.     

A century of tree line changes in sub‐Arctic Sweden shows local and regional variability and only a minor influence of 20th century climate warming

Aim Models project that climate warming will cause the tree line to move to higher elevations in alpine areas and more northerly latitudes in Arctic environments. We aimed to document changes or stability of the tree line in a sub‐Arctic model area at different temporal and spatial scales, and particularly to clarify the ambiguity that currently exists about tree line dynamics and their causes. Location The study was conducted in the Torneträsk area in northern Sweden where climate warmed by 2.5 °C between 1913 and 2006. Mountain birch (Betula pubescens ssp. czerepanovii) sets the alpine tree line. Methods We used repeat photography, dendrochronological analysis, field observations along elevational transects and historical documents to study tree line dynamics. Results Since 1912, only four out of eight tree line sites had advanced: on average the tree line had shifted 24 m upslope (+0.2 m year^?1 assuming linear shifts). Maximum tree line advance was +145 m (+1.5 m year^?1 in elevation and +2.7 m year^?1 in actual distance), whereas maximum retreat was 120 m downslope. Counter‐intuitively, tree line advance was most pronounced during the cooler late 1960s and 1970s. Tree establishment and tree line advance were significantly correlated with periods of low reindeer (Rangifer tarandus) population numbers. A decreased anthropozoogenic impact since the early 20th century was found to be the main factor shaping the current tree line ecotone and its dynamics. In addition, episodic disturbances by moth outbreaks and geomorphological processes resulted in descent and long‐term stability of the tree line position, respectively. Main conclusions In contrast to what is generally stated in the literature, this study shows that in a period of climate warming, disturbance may not only determine when tree line advance will occur but if tree line advance will occur at all. In the case of non‐climatic climax tree lines, such as those in our study area, both climate‐driven model projections of future tree line positions and the use of the tree line position for bioclimatic monitoring should be used with caution.     

A set of 35 consensus primer pairs amplifying genes and introns of plant mitochondrial DNA

Being generally uniparentally inherited, the plant mitochondrial genome is a source of original markers potentially useful for studies of phylogeny and population genetics. We designed 24 new pairs of plant mitochondrial DNA primers that allow amplification of either introns, intergenic regions or genes. They have been defined for consensus over angiosperms and were tested along with 11 previously described mitochondrial primer pairs on 28 plant species representing 19 families of higher plants. The total set allows amplification of 40 kb (～11%) of the mtDNA genome of Arabidopsis thaliana. The amplification rate ranged between 76% and 100% depending on the species.     

Initial responses of rove and ground beetles (Coleoptera,Staphylinidae, Carabidae) to removal of logging residues following clearcut harvesting in the boreal forest of Quebec,Canada

Increased interest in biomass harvesting for bioenergetic applications has raised questions regarding the potential ecological consequences on forest biodiversity. Here we evaluate the initial changes in the abundance, species richness and community composition of rove (Staphylinidae) and ground beetles (Carabidae), immediately following 1) stem-only harvesting (SOH), in which logging debris (i.e., tree tops and branches) are retained on site, and 2) whole-tree harvesting (WTH), in which stems, tops and branches are removed in mature balsam fir stands in Quebec, Canada. Beetles were collected throughout the summer of 2011, one year following harvesting, using pitfall traps. Overall catch rates were greater in uncut forest (Control) than either stem-only or whole-tree harvested sites. Catch rates in WTH were greater than SOH sites. Uncut stands were characterized primarily by five species: Atheta capsularis, Atheta klagesi, Atheta strigosula, Tachinus fumipennis/frigidus complex (Staphylinidae) and to a lesser extent to Pterostichus punctatissimus (Carabidae). Increased catch rates in WTH sites, where post-harvest biomass was less, were attributable to increased catches of rove beetles Pseudopsis subulata, Quedius labradorensis and to a lesser extent Gabrius brevipennis. We were able to characterize differences in beetle assemblages between harvested and non-harvested plots as well as differences between whole tree (WTH) and stem only (SOH) harvested sites where logging residues had been removed or left following harvest. However, the overall assemblage response was largely a recapitulation of the responses of several abundant species.