Annual phytoplankton cycle in a meromictic anoxic basin of a Rhode Island (USA) estuarine river

Hydrobiologia - Estuarine Pettaquamscutt River is a unique habitat 10 km in length with physical and biogeochemical characteristics analogous to a miniature fjord. Its meromictic upper...     

Non-linear dielectric spectroscopy of microbiological suspensions

Background  

Non-linear dielectric spectroscopy (NLDS) of microorganism was characterized by the generation of harmonics in the polarization current when a microorganism suspension was exposed to a sinusoidal electric field. The biological nonlinear response initially described was not well verified by other authors and the results were susceptible to ambiguous interpretation. In this paper NLDS was performed to yeast suspension in tripolar and tetrapolar configuration with a recently developed analyzer.     

Does divergence from normal patterns of integration increase as chromosomal fusions increase in number? A test on a house mouse hybrid zone

Chromosomal evolution is widely considered an important driver of speciation because it can promote the establishment of reproductive barriers. Karyotypic reorganization is also expected to affect the mean phenotype, as well as its development and patterns of phenotypic integration, through processes such as variation in genetic linkage between quantitative trait loci or between regulatory regions and their targets. Here we explore the relationship between chromosomal evolution and phenotypic integration by analyzing a well-known house mouse parapatric contact zone between a highly derived Robertsonian (Rb) race (2n = 22) and populations with standard karyotype (2n = 40). Populations with hybrid karyotypes are scattered throughout the hybrid zone connecting the two parental races. Using mandible shape data and geometric morphometrics, we test the hypothesis that patterns of integration progressively diverge from the “normal” integration pattern observed in the standard race as they accumulate Rb fusions. We find that the main pattern of integration observed between the posterior and anterior part of the mandible can be largely attributed to allometry. We find no support for a gradual increase in divergence from normal patterns of integration as fusions accumulate. Surprisingly, however, we find that the derived Rb race (2n = 22) has a distinct allometric trajectory compared with the standard race. Our results suggest that either individual fusions disproportionately affect patterns of integration or that there are mechanisms which “purge” extreme variants in hybrids (e.g. reduced fitness of hybrid shape).     

Congruence between cytochrome oxidase I (COI) and morphological data in Anuraphis spp. (Hemiptera,Aphididae) with a comparison between the utility of the 5’ barcode and 3’ COI regions

The discrimination of species in the genus Anuraphis is particularly difficult due to the overlap of morphological characters. In this study, we used the 5’ (barcode) and 3’ regions of cytochrome oxidase I (COI) to test their utility in the identification of species in this genus as well as closely related species. Both regions were useful to discriminate all the species tested. However the non-barcode 3’ region resulted in higher resolution and support for species relationships when the data were analyzed using both Maximum Likelihood and MrBayes. We propose the development of an integrated database that encompasses morphological, molecular, life-cycle, host plant and bibliographic information to facilitate and increase the accuracy of aphid identification.     

Using unmanned aerial vehicles for vegetation mapping and identification of botanical species in wetlands

High-resolution aerial photographs have important applications in vegetation mapping, especially in environments, such as wetlands, which are not easily accessible by ground operators. Unmanned aerial vehicles (UAVs), equipped with cameras capable of taking photographs of <?1 cm pixel resolution, are promising not only for the vegetation mapping but also for the identification of plant species. This paper illustrated the results of three different flight heights (5 m?=?3.5126 mm/pixel; 10 m?=?7.0252 mm/pixel; 25 m?=?17.5630 mm/pixel), using 12MP images and their magnification, on the identification of vegetation and botanical species in a rewetted peatland populated mainly by Phragmites australis and Myriophyllum aquaticum within the Massaciuccoli Lake basin (Northern Tuscany, Italy). Among the obtained images, we selected the best flight height for the vegetation mapping and the botanical identification of the plant species using both visual and automated image analyses. Images taken from flights at 25 m of height proved to be useful for a sufficiently detailed mapping, while those from 10 m of height were more suitable for the detection of plant microcommunities. However, the most accurate identification of the species (at the taxonomic level of genus/species) was possible only with the images taken from 5 m of height.

     

Alien flora in Calabria (Southern Italy): an updated checklist

Biological Invasions - An updated checklist of the Calabrian alien vascular flora is presented. By way of field, bibliographic, and herbarium research, we recorded 382 alien taxa (representing...     

Integrative taxonomy and conservation of cryptic beetles in the Mediterranean region (Hydrophilidae)

Arribas, P., Andújar, C., Sánchez‐Fernández, D., Abellán, P. & Millán, A. (2012). Integrative taxonomy and conservation of cryptic beetles in the Mediterranean region (Hydrophilidae). —Zoologica Scripta, 00, 000–000. Because biodiversity inventory forms the basis for the effective conservation of species and habitats, there is an imperative need to discover and describe new species. A significant part of presently unknown biodiversity is constituted by cryptic species complexes, where traditional taxonomy usually fails due to a lack of clear taxonomic characters in the external structures of specimens. Integrative taxonomy offers a powerful tool to shed light on this part of encrypted biodiversity, combining multiple operational criteria in an evolutionary context in order to delineate species boundaries. The present study used an integrative approach to explore the species boundaries in a water beetle complex (Enochrus falcarius species complex) inhabiting saline streams, a rare and threatened habitat across the Mediterranean region. First, hypotheses about the candidate species on the basis of phylogenetic analyses and biogeographical information were proposed. Second, lineage divergence was evaluated between candidate species using (i) molecular cluster delimitation, (ii) morphometry (both linear body morphometrics and pronotum outlines) and (iii) ecological niche similarity estimates. We found divergence between candidate species on the basis of molecular, biogeographical and niche information, and consequently, four species were delimited within the E. falcarius complex (i.e. Enochrus jesusarribasi sp. n., Enochrus blazquezae sp. n., Enochrus risii sp. n. and Enochrus falcarius), despite the fact that they showed high morphological similarity. Enochrus falcarius, as previously considered, had not been proposed to be of conservational concern, because until now, it had been regarded as a single broadly distributed species in the Mediterranean region. However, the four entities here delimited within this species complex displayed characteristics that categorised them as vulnerable taxa. Hence, these results show how applying integrative taxonomy approaches and rapid vulnerability assessments to lineages from threatened habitats with the potential to comprise cryptic diversity could become a fundamental tool for biodiversity conservation, driving the discovery of cryptic species and consequently the modification of previous, inadequately evaluated vulnerability categorisations.