1,721,037 research outputs found
Systematics of the Phyllognathopodidae (Copepoda, Harpacticoida): re-examination of Phyllognathopus viguieri (Maupas, 1892) and Parbatocamptus jochenmartensi Dumont and Maas, 1988, proposal of a new genus for Phyllognathopus bassoti Rouch, 1972, and description of a new species of Phyllognathopus
No full textThe family Phyllognathopodidae (Crustacea, Copepoda, Harpacticoida) is heavily affected by the floating
taxonomic status of the type-genus Phyllognathopus. A revision of the different character states displayed
by members of the family is presented, and new phylogenetically informative characters are described,
enlarging the analysis to the remaining genera of the family, Parbatocamptus and Allophyllognathopus.
Phyllognathopus viguieri (Maupas, 1892) and Parbatocamptus jochenmartensi Dumont and Maas, 1988
are redescribed in detail, and Phyllognathopus inexspectatus sp. n. is described from ground water in Italy.
The new genus Neophyllognathopus is established to accommodate Phyllognathopus bassoti Rouch, 1972,
originally collected from Long Island (Papua - New Guinea), and subsequently recorded also from the
Bantayan Island (Philippines), and from the Indian subcontinent. The new genus is presently monotypic
and is easily defined by the unique construction and morphology of leg 5 in both male and female, of
male leg 6, and by the peculiar ornamentation of male third and fourth urosomites. Biogeographical and
ecological considerations are presented for members of the family
PATTERNS OF COPEPOD DIVERSITY (COPEPODA: CYCLOPOIDA, HARPACTICOIDA) IN SPRINGS OF CENTRAL ITALY: IMPLICATIONS FOR CONSERVATION ISSUES
No full textThis paper examines the biodiversity patterns of natural springs across three large hydrogeological
units of the central Apennines (central Italy). The biological dataset obtained was
analysed by selecting the free-living Copepoda, the most species-rich group among the meiofaunal
components of the springs in the study area. The analyses performed focused on distribution
patterns and the prevailing factors that may determine such distributions at the scale of
the spring site as well as at the wider, hydrogeological scale of the entire region. The taxonomic
distinctness of the communities found was also evaluated, in order to integrate the mere species
counts with additional information on the relatedness of the taxa in copepod assemblages, with
the aim of obtaining a more exhaustive assessment of the aspects of the biodiversity found.
Copepod diversity in the various springs did not result in an evenly distributed pattern among
spring sites and the larger hydrogeological units. Low-altitude karstic springs were the most
diverse in terms of species richness, and showed the highest values of taxonomic distinctness
measured for the whole area. Conversely, high-altitude springs from geological formations of
both sandstone and limestone were species-poor, and with relatively similar copepod assemblages.
The observed differences in composition of the communities among springs and hydrogeological
units are discus
Caratterizzazione tipologica, biologica ed ambientale e modellistica statistica di sistemi sorgivi del Gran Sasso (Abruzzo).
No full textInfluenza dei fattori storici ed ecologici sulla biodiversità animale: la copepodofauna (Crustacea: Copepoda) delle sorgenti di Presciano (Fiume Tirino, L’Aquila, Abruzzo).
No full textJumping into the grids: mapping biodiversity hotspots in groundwater habitat types across Europe
Full text linkBiodiversity hotspots are routinely identified by grid-based analyses, despite grids encompassing different habitats, thus hindering the potential to assess which habitat type accounts for the conservation priority assigned to a grid. In this study, we aimed at identifying the main hotspots for the conservation of the European stygobitic Crustacea Copepoda Harpacticoida at the groundwater habitat scale. A multi-metric approach was used, based on six biodiversity indicators: species richness, endemicity, evolutionary origin, phylogenetic rarity, taxonomic distinctness, habitat specificity. The Hot Spot Analysis, based on the statistics Getis-Ord Gi*, was used to compare the local to the global average values of each indicator to identify hotspots of conservation. The operational units used to perform the analyses were the groundwater habitat types, in order to gather all the possible patterns of spatial occupancy in terms of habitat variability. Eight biodiversity hotspots of stygobitic Crustacea Harpacticoida were highlighted: 1) the Pyrenees (Spain and France), 2) the Jura Massif (France), 3) the Alpine arc (France, Switzerland and Italy) embracing southward the River Po alluvial plain and the Slovenian External Dinarides, 4) the Central Apennines (Italy), 5) the Carpathian and Balkan mountains in Romania and at the boundary between western Bulgaria and north-west Macedonia, 6) the Dinaric Alps (from Croatia to Albania), 7) the Sardinia Island, 8) an area in central-northern Europe embracing Denmark, the Netherlands and Germany. The hotspots showed a clear spatial distribution in southern Europe where they were distributed predominantly south to the 45th parallel, in line to what reiteratively observed in previous studies. Many hotspots embraced more than one habitat type. The adoption of discrete groundwater habitat types as working spatial units rather than grids provided a higher resolution of where the stygobitic harpacticoid species effectively live, with the possibility of intervening more precisely to preserve them and their habitats
The impact of nitrate on the groundwater assemblages of European unconsolidated aquifers is likely less severe than expected
No full textIn this study, we analyzed the structure of the stygobiotic copepod assemblages of an unconsolidated European aquifer (VO), in southern Italy, that has been subject to persistent nitrate contamination for over 15 years. To this end, we monitored 25 bores where groundwater was contaminated only by nitrate, and no other chemical pollutants were reported as being above detection limits from 2009 to 2014. We monitored these bores three times, namely in autumn 2014 and in spring and autumn 2015. We expected that the chronic exposure to high nitrate concentrations had a significant and evident impact on the stygobiotic copepod assemblages. Unexpectedly, the assemblages were highly diversified. The stygobiotic species richness (SSR) accounted 17 species, a value that exceeded the European mean value (SSR = 12 species). However, the species density was only 0.6 species/km2, lower than the European mean value (= 1.6 species/km2). Moreover, the juvenile copepods were numerically less abundant than the adults and the biomass-abundance model showed signs of alteration of the structure of the copepod assemblages. This study highlighted that (i) nitrates, even at high concentrations, probably have a less severe impact on groundwater assemblages of unconsolidated aquifers than expected and (ii) the analysis of population traits and biomasses can detect signs of alteration of these assemblages that would, otherwise, not be visible from the analysis of the sole species richness and abundances
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Spatial distribution of stygobitic crustacean harpacticoids at the boundaries of groundwater habitat types in Europe
No full textThe distribution patterns of stygobitic crustacean harpacticoids at the boundaries of three different groundwater habitat types in Europe were analysed through a GIS proximity analysis and fitted to exponential models. The results showed that the highest frequency of occurrences was recorded in aquifers in consolidated rocks, followed by the aquifers in unconsolidated sediments and, finally, by the practically non-aquiferous rocks. The majority of the stygobitic harpacticoid species were not able to disperse across the boundaries between two adjacent habitats, with 66% of the species occurring in a single habitat type. The species were not evenly distributed, and 35–69% of them occurred from 2 to 6 km to the boundaries, depending on the adjacent habitat types. The distribution patterns were shaped by features extrinsic to the species, such as the hydrogeological properties of the aquifers, and by species’ intrinsic characteristics such as the preference for a given habitat type and dispersal abilities. Most boundaries between adjacent habitat types resulted to be “breaches”, that is transmissive borders for stygobitic harpacticoids, while others were “impermeable walls”, that is absorptive borders. Our results suggest that conservation measures of groundwater harpacticoids should consider how species are distributed within the different groundwater habitat types and at their boundaries to ensure the preservation of species metapopulations within habitat patches and beyond them
Linking hydrogeology and ecology in karst landscapes: The response of epigean and obligate groundwater copepods (crustacea: Copepoda)
No full textGroundwater invertebrate communities in karst landscapes are known to vary in response to multiple environmental factors. This study aims to explore the invertebrate assemblages’ composition of an Apennine karst system in Italy mainly described by the Rio Gamberale surface stream and the Stiffe Cave. The stream sinks into the carbonate rock and predominantly feeds the saturated karst into the cave. For a minor portion, groundwater flows from the epikarst and the perched aquifer within it. The spatial distribution of the species belonging to the selected target group of the Crustacea Copepoda between the surface stream and the groundwater habitats inside the cave highlighted a different response of surface-water species and obligate groundwater dwellers to the hydrogeological traits of the karst unit. Our results suggest that fast endorheic infiltration routes promoted the drift of epigean species from the surface to groundwater via the sinking stream while most of the obligate groundwater dwellers come from the perched aquifer in the epikarst from diffuse infiltration pathways
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