Revision of the New Caledonian endemic genus Gracilipsodes (Trichoptera: Leptoceridae: Grumichellini)

The taxonomy and systematics of the New Caledonian endemic caddisfly genus Gracilipsodes Sykora, 1967 (Trichoptera: Leptoceridae: Grumichellini) are reviewed. Seven new species represented by males are described and illustrated: Gracilipsodes aoupiniensis sp. nov. , Gracilipsodes aureus sp. nov. , Gracilipsodes aurorus sp. nov. , Gracilipsodes grandis sp. nov. , Gracilipsodes koghiensis sp. nov. , Gracilipsodes lanceolatus sp. nov. , and Gracilipsodes robustus sp. nov. Molecular phylogenetic analyses are applied to discern the relationships among the species of the genus and their closest relatives, based on sequence characters from the nuclear gene translation elongation factor-1α (EF-1α) and the three mitochondrial genes cytochrome oxidase I (COI), COII, and ribosomal large subunit (16S). The data are analyzed using parsimony and Bayesian inference, revealing a monophyletic Gracilipsodes with the eastern Australian monotypic genus Triplexa as its closest relative. Gracilipsodes is in turn divided into two major lineages.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 153 , 425–452.     

Effects of soil frost on nitrogen net mineralization, soil solution chemistry and seepage losses in a temperate forest soil

Freezing and thawing may alter element turnover and solute fluxes in soils by changing physical and biological soil properties. We simulated soil frost in replicated snow removal plots in a mountainous Norway spruce stand in the Fichtelgebirge area, Germany, and investigated N net mineralization, solute concentrations and fluxes of dissolved organic carbon (DOC) and of mineral ions (NH₄⁺, NO₃⁻, Na⁺, K⁺, Ca²⁺, Mg²⁺). At the snow removal plots the minimum soil temperature was −5 °C at 5 cm depth, while the control plots were covered by snow and experienced no soil frost. The soil frost lasted for about 3 months and penetrated the soil to about 15 cm depth. In the 3 months after thawing, the in situ N net mineralization in the forest floor and upper mineral soil was not affected by soil frost. In late summer, NO₃⁻ concentrations increased in forest floor percolates and soil solutions at 20 cm soil depth in the snow removal plots relative to the control. The increase lasted for about 2–4 months at a time of low seepage water fluxes. Soil frost did not affect DOC concentrations and radiocarbon signatures of DOC. No specific frost effect was observed for K⁺, Ca²⁺ and Mg²⁺ in soil solutions, however, the Na⁺ concentrations in the upper mineral soil increased. In the 12 months following snowmelt, the solute fluxes of N, DOC, and mineral ions were not influenced by the previous soil frost at any depth. Our experiment did not support the hypothesis that moderate soil frost triggers solute losses of N, DOC, and mineral ions from temperate forest soils.     

Genic microsatellite markers derived from EST sequences of switchgrass (Panicum virgatum L.)

Switchgrass is a large, North American, perennial grass that is being evaluated as a potential energy crop. There is a need to assess genetic diversity in stored accessions and in remaining native stands to assist breeding and conservation efforts. Marker development will also be necessary for genetic linkage mapping. Toward this end, 32 switchgrass genic di‐, tri‐ and tetranucleotide repeat microsatellites were identified from expressed sequence tags (ESTs). These microsatellites were used to screen individuals from two different named cultivars. The markers displayed a high level of polymorphism consistent with the tetraploid, allogamous behaviour of the cultivars tested.