Quantitative habitat models for the conservation of the endangered European crayfish Austropotamobius pallipes complex (Astacoidea: Astacidae)

Crayfish are the largest mobile freshwater invertebrates and are keystone species in European aquatic ecosystems particularly in small streams and rivers. The white-clawed crayfish Austropotamobius pallipes (a species complex) is currently classified by the IUCN Red List as an endangered species (EN), because its populations have decreased significantly over the last decades in a number of European countries including Italy, due mainly to habitat modifications and the introduction and spread of alien species. Data on the ecological requirements of A. pallipes are needed to quantify the effects of habitat alteration, to simulate restoration scenarios, and to implement effective conservation measures for this species. We describe here a new methodology for modelling the habitat requirements for this endangered crayfish using the mesohabitat scale approach based on data from crayfish living in small streams draining the Italian foothills of the Alps (Lombardy region) and in streams in the mountainous areas of the Gran Sasso and Monti della Laga National Park (Abruzzo region). Data from seven morphologically different streams were used to train and validate the habitat models. The Random Forests algorithm was used to identify the best and most parsimonious habitat model, and to define the lowest number of variables to be surveyed in the future. The best habitat models were applied to each stream and used to classify each mesohabitat into suitability categories. Habitat flow-rating curves were developed to analyze spatio-temporal variation of habitat availability, and habitat time series analysis were used to define detailed management schemes for environmental river management. Flow releases and water temperature regimes were assessed for individual water diversions in order (1) to represent how physical habitat changes through time, and (2) to identify stress conditions for A. pallipes created by the persistent limitation of habitat availability. Results indicated that the kind of substrate in the stream bed (such as the proportion of fine-grained substrates), the water depth (whether shallow or deep), and the available cover (such as the presence of boulders, woody debris, and undercut banks) were all significant factors governing the occurrence of crayfish. The habitat models performed well in both calibration and validation phases (with accuracy ranging from 71% to 79% in training and from 69% to 73% in validation) and can be considered to be a valuable tool to predict the distribution of A. pallipes over a wide range of stream types. An example of how to establish environmental standards for small streams is presented. The proposed habitat model provides a useful tool that can be applied even when other commonly used methodologies are unsuitable. As such, this habitat model can be used to develop regional rules for the conservation of the endangered crayfish A. pallipes complex and for defining more site-specific management criteria

Colour variation in signal crayfish Pacifastacus leniusculus

External colouration in animals depends on the interaction of several different factors including the genetics and epigenetics processes that underlie the colour expression, the mechanisms of colour perception, and the general mechanisms controlling colour evolution and function. Among all, camouflage from predators and conspicuousness are of particular interest since pose animal to choose between opposite adjustment in colouration. The external colouration of crustaceans is mainly due to the accumulation of carotenoids in the exoskeleton and the epidermal layer, and the trade-off between camouflage and communication had lead to a variety of responses, involving signal partitioning, spectral sensibility, changing colouration or signalling behaviour. Here, we used digital images to explore intrapopulation variability of the external colouration of Pacifastacus leniusculus among body regions within an individual and between sexes. We found that i) ventral colouration of claws are more saturated and brilliant than upperparts, ii) males express a more saturated and brightness colouration than females, especially on the lower portion of claws, iii) colour intensity and brightness increases with size differently in different body regions, and iv) brightness is more variable in males than in females. All the above patterns support the hypothesis that colour in this species could be the result of a compromise between camouflage from predators and conspicuousness for communication. The results of this study suggest that carotenoid might have something to do with intraspecific communication and perform more complex functions than that of a simple pigment

[First reporting of the signal crayfish (Decapoda, Astacidae) in the Province of Savona, Italy]

In this short note we report the sudden and numerically significant expansion of signal crayfish (P. leniusculus) from Piedmont towards Liguria. P. leniusculus (Decapode Astacidae) is native to northwestern America, introduced in Italy in 1981 in the province of Bolzano, a few years later it was reported in Brugneto Lake (Genova district) and during the 2009 in the Valla stream (Alessandria district). The peculiarities of this species, originally from "cold water", making it potentially invasive in the Apennine watercourses and also the presence of this allochthonous decapod in the Savona district, would like to suggest the implementation of containment plans, acts at least to limit its spread

Modelling Environmental Niche for the Endangered Crayfish Austropotamobius pallipesComplex in Northern and Central Italy

The potential distribution of endangered species is a necessary step to assess species conservation status and manage reintroduction plans. In the context of a EU project on the endangered Austropotamobius pallipescomplex, we modelled the environmental niche of the species in two large areas of Northern (Lombardy, 43 records) and Central Italy (Abruzzo, Province of Isernia, Gran Sasso e Monti della Laga National Park; 69 records). Ecological niche models (ENMs) were built by using the maximum entropy approach as implemented in the MaxEnt software, which predicts the occurrence of a species using presence-only data. The environmental niche was modelled using six variables: altitude, slope, aspect, human disturbance, mean temperature of warmest quarter and distance from stream. Each study area was modelled independently. Both ENMs obtained high performance scores as measured by the AUC index (Northern Italy: 0.854; Central Italy: 0.817). Slope in Northern Italy and the mean temperature of warmest quarter in Central Italy achieved the greatest predictive power. Our results clearly show that the endangered white-clawed crayfish has a narrow range of habitat selection in the two study areas. Our findings may help researchers to select the best sites for future reintroductions in conservation projects

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

IGLV3-21*01 is an inherited risk factor for CLL through the acquisition of a single-point mutation enabling autonomous BCR signaling

The prognosis of chronic lymphocytic leukemia (CLL) depends on different markers, including cytogenetic aberrations, oncogenic mutations, and mutational status of the immunoglobulin (Ig) heavy-chain variable (IGHV) gene. The number of IGHV mutations distinguishes mutated (M) CLL with a markedly superior prognosis from unmutated (UM) CLL cases. In addition, B cell antigen receptor (BCR) stereotypes as defined by IGHV usage and complementarity-determining regions (CDRs) classify ∼30% of CLL cases into prognostically important subsets. Subset 2 expresses a BCR with the combination of IGHV3-21-derived heavy chains (HCs) with IGLV3-21-derived light chains (LCs), and is associated with an unfavorable prognosis. Importantly, the subset 2 LC carries a single-point mutation, termed R110, at the junction between the variable and constant LC regions. By analyzing 4 independent clinical cohorts through BCR sequencing and by immunophenotyping with antibodies specifically recognizing wild-type IGLV3-21 and R110-mutated IGLV3-21 (IGLV3-21R110), we show that IGLV3-21R110-expressing CLL represents a distinct subset with poor prognosis independent of IGHV mutations. Compared with other alleles, only IGLV3-21*01 facilitates effective homotypic BCR-BCR interaction that results in autonomous, oncogenic BCR signaling after acquiring R110 as a single-point mutation. Presumably, this mutation acts as a standalone driver that transforms IGLV3-21*01-expressing B cells to develop CLL. Thus, we propose to expand the conventional definition of CLL subset 2 to subset 2L by including all IGLV3-21R110-expressing CLL cases regardless of IGHV mutational status. Moreover, the generation of monoclonal antibodies recognizing IGLV3-21 or mutated IGLV3-21R110 facilitates the recognition of B cells carrying this mutation in CLL patients or healthy donors

FUNDAMENTAL AND APPLIED RESEARCH ON FRESHWATER DECAPODS IN ITALY

The study group of freshwater decapods established within the Italian Association of Freshwater Ichthyologists aims at improving knowledge on the biology of both native and alien freshwater crayfish, shrimps, and crabs which currently inhabit Italian lentic and lotic waters, promoting at the same time the establishment of a network of experts that guarantees an adequate spread of correct useful and usable information, not only for management activities by the local and national competent authorities, but even by non-experts. The group deals with taxonomy, systematic, zoogeography, ecology, ethology, physiology, anatomy, genetics, conservation (of natives) and management (of aliens) of freshwater decapods in Italy. Our main aim is to update the status of freshwater decapods within the national territory, useful for monitoring programs on these species and the habitats where they inhabit. It is necessary to study all the aspects of this order because many species represent an ecological (as a keystone species), fauna (some taxa are interesting peninsular endemisms), biogeographical (the Whole order includes peculiar models of dispersion, migration and vicariance) and evolutionary (there are stimulating case studies of adaptive radiation phenomena linked to a specific ecological value) heritage. Also from an applied perspective, freshwater decapods have a peculiar double aspect linked to the conservation of aquatic environments: on the one side some species can be considered as valuable biological indicators, but on the other side many alien species are reported to be invasive and their management is mandatory, according to the new European and Italian legislations, and should be ecologically, economically and culturally examined to evaluate their effects on environment, human activities and health