Complexity of biogeographic pattern in the endangered crayfish Austropotamobius italicus in northern Italy: molecular insights of conservation concern.

The protection of freshwater biodiversity has become a priority task for conservation practices, as freshwater ecosystems host high levels of cryptic diversity, while also record similarly high rates of extinction. The Italian white-clawed crayfish Austropotamobius italicus is an endemic freshwater crustacean, threatened by several anthropogenic impacts such as habitat fragmentation, pol- lution, invasion of exotics, and climate change. Previous phylogenetic studies conducted in Italy pointed out a complex phylogeographic framework for the species, with four different subspecies currently recognized. Conserva- tion efforts, particularly when involving restocking and reintroduction, require a detailed knowledge of their pop- ulation genetics. In this study we describe the genetic structure of A. italicus populations in northern Italy (Lombardy Alpine foothills and northern Apennines) by using the informative mitochondrial marker cytochrome c oxidase subunit I, in order to assess their current evolu- tionary diversity and past phylogeographic history from a conservation perspective. Our results contribute to the mapping of the contact area among A. i. carsicus and A. i. carinthiacus in the Orobie Larian Prealps. Moreinterestingly, we highlight the existence of two deeply differentiated evolutionary lineages within A. i. carsicus, showing alternative phylogeographic patterns and past demographic trends. We propose to consider these two clades as distinct molecular operational taxonomic units for the conservation of this endangered crayfish

Taxonomic distinctness in the diet of two sympatric marine turtle species

Marine turtles are considered keystone consumers in tropical coastal ecosystems and their decline through overexploitation has been implicated in the deterioration of reefs and seagrass pastures in the Caribbean. In the present study, we analysed stomach contents of green (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) harvested in the legal turtle fishery of the Turks and Caicos Islands (Caribbean) during 2008–2010. Small juveniles to adult-sized turtles were sampled. Together with data from habitat surveys, we assessed diet composition and the taxonomic distinctness (and other species diversity measures) in the diets of these sympatric marine turtle species. The diet of green turtles (n = 92) consisted of a total of 47 taxa: including three species of seagrass (present in 99% of individuals), 29 species of algae and eight sponge species. Hawksbill turtles (n = 45) consumed 73 taxa and were largely spongivorous (16 species; sponges present in 100% of individuals) but also foraged on 50 species of algae (present in 73% of individuals) and three species of seagrass. Plastics were found in trace amounts in 4% of green turtle and 9% of hawksbill turtle stomach samples. We expected to find changes in diet that might reflect ontogenetic shifts from small (oceanic-pelagic) turtles to larger (coastal-benthic) turtles. Dietary composition (abundance and biomass), however, did not change significantly with turtle size, although average taxonomic distinctness was lower in larger green turtles. There was little overlap in prey between the two turtle species, suggesting niche separation. Taxonomic distinctness routines indicated that green turtles had the most selective diet, whereas hawksbill turtles were less selective than expected when compared with the relative frequency and biomass of diet items. We discuss these findings in relation to the likely important trophic roles that these sympatric turtle species play in reef and seagrass habitats.This work was funded by Simon & Anne Notley, MCS, and Natural Environment Research Council (CASE PhD studentship to TS with MCS as CASE partners, Ref: NE/F01385X/1)

Orientation and symmetries of Alexandrov spaces with applications in positive curvature

We develop two new tools for use in Alexandrov geometry: a theory of ramified orientable double covers and a particularly useful version of the Slice Theorem for actions of compact Lie groups. These tools are applied to the classification of compact, positively curved Alexandrov spaces with maximal symmetry rank.Comment: 34 pages. Simplified proofs throughout and a new proof of the Slice Theorem, correcting omissions in the previous versio