Main Taxa Research Articles

Meiobenthic communities structure at different spatial scales on sandy beaches from a ria environment: The role of abiotic factors

This work aimed to study meiobenthic communities at different spatial scales in a Galician estuary–ria (NW Spain), elucidating the role of abiotic factors on their structure. Rias are transitional environments with brackish habitats on their inner part and fully marine environments in the outer area, and Galician estuarine–rias are very productive habitats due to upwelling events. Results showed that meiobenthic communities from estuarine–ria beaches, even in the range of other temperate beaches not in rias, reported high number of taxa and density values probably due to the highest primary production associated with estuarine–ria environment. Meiobenthic community variability increased as the scale widens, showing significant differences among almost all the studied beaches. Selected environmental variables were, in general, useful for explaining the variability of the main taxa. Meiobenthic community structures for beaches with different exposure and distances from the inner part of the estuary–ria were significantly different. However, the environmental variables studied were not able to fully explain the significant variability of whole meiobenthic assemblages. This fact pointed to the possible importance of biological factors structuring meiobenthic communities on beaches within rias.

Phylogeny and character evolution in the jelly fungi (Tremellomycetes, Basidiomycota, Fungi)

The Tremellomycetes (Agaricomycotina, Basidiomycota, Fungi) are a nutritionally heterogeneous group comprising saprotrophs, animal parasites, and fungicolous species (fungal-inhabiting, including lichen-inhabiting). The relationships of many species, particularly those with a lichenicolous habit, have never been investigated by molecular methods. We present a phylogeny of the Tremellomycetes based on three nuclear DNA ribosomal markers (nSSU, 5.8S and nLSU), representing all main taxonomic groups and life forms, including lichenicolous taxa. The Cystofilobasidiales, Filobasidiales, Holtermanniales, and Tremellales (including the Trichosporonales) are recovered as monophyletic, but this is not the case for the Tremellomycetes. We suggest, however, that the Cystofilobasidiales tentatively continue to be included in the Tremellomycetes. As currently circumscribed, the Filobasidiaceae, Sirobasidiaceae, Syzygosporaceae and Tremellaceae are non-monophyletic. Cuniculitremaceae, Sirobasidiaceae and Tetragoniomycetaceae are nested within Tremellaceae. The lichenicolous species currently included within the Tremellomycetes belong in this group, distributed across the Filobasidiales and Tremellales. Lichen-inhabiting taxa do not form a monophyletic group; they are distributed in several clades and sometimes intermixed with taxa of other nutritional habits. Character state reconstruction indicates that two morphological traits claimed to characterize groups in the Tremellomycetes (the basidium habit and basidium septation) are highly homoplastic. Comparative phylogenetic methods suggest that the transitions between single and catenulate basidia in the Tremellales are consistent with a punctuational model of evolution whereas basidium septation is likely to have evolved under a graduational model in the clade comprising the Holtermanniales, Filobasidiales, and Tremellales.

Participation of soil invertebrates in the organic matter decomposition in forest ecosystems of Central Siberia

The biomass of large invertebrates was studied in the soils of forest ecosystems in the forest-tundra and southern taiga of Central Siberia. Its formation is shown to be controlled by the integrated effect of the soil and climatic conditions. The distribution of the zoomass according to the main taxonomic groups testifies to the higher functional significance of the large saprophagous invertebrates in the ecosystems of the southern taiga compared to those of the forest-tundra. The quantitative contribution of the invertebrates-destroyers to the organic matter decomposition was assessed on the basis of field experiments; it was shown to be determined by the quality of the material decomposed irrespective of the conditions and time of its exposition. Every year, soil saprophages decompose 0.5–2.0% of the total phytodetritus reserves in the forest-tundra and 3–14% in the southern taiga amounting to 12–54% of its losses upon decomposition.

Atlas do zooplâncton dominante no baixo estuário do Rio Itajaí-açu, Santa Catarina, Brasil - Copepoda e Cladocera

The Itajai-acu river basin is the most extensive basin in the State of Santa Catarina, covering an area of 15,500 Km2, and it houses an important industrial park of the South of Brazil. The estuarine region receives sediments and pollutants from the entire basin, with an area characterized by high demographic density and intense industrial and fishing activity, making this a critical area for the study of biological indicators. The objective of this study was to present a checklist of the zooplankton species in the estuary of the Itajai-acu river, identifying the groups of species occurring in the different hydrological domains of the estuary and the morphological description of the dominant species, as the basis for future studies of the group in the region. The zooplankton community was investigated in 131 samples obtained between 2005 and 2007, at 7 collection points in the lower estuary of the Itajai-acu river. The zooplankton consisted of 14 main taxonomic groups and 100 identified taxa. Three associations of species were identified: (a) the limnic community, dominated by the Cladocerans Bosmina longirostris, Camptocercus dadayi, Ceriodaphnia quadrangula, Ilyocryptus spinifer and Moina minuta and by the Copepods Eucyclops serrulatus, (b) the marine community comprised of the Copepods Acartia lilljeborgi, Centropages velificatus, Oithona ovalis, O. plumifera, Paracalanus quasimodo and Temora turbinate, and the Cladocerans Penilia avirostris and Pseudoevadne tergestina, and (c) the mixohaline group, comprised of Copepods, Pseudodiaptomus acutus and Pseudodiaptomus richardi.

DYRK family of protein kinases: evolutionary relationships, biochemical properties, and functional roles

Dual-specificity tyrosine-regulated kinases (DYRKs) comprise a family of protein kinases within the CMGC group of the eukaryotic kinome. Members of the DYRK family are found in 4 (animalia, plantae, fungi, and protista) of the 5 main taxa or kingdoms, and all DYRK proteins studied to date share common structural, biochemical, and functional properties with their ancestors in yeast. Recent work on DYRK proteins indicates that they participate in several signaling pathways critical for developmental processes and cell homeostasis. In this review, we focus on the DYRK family of proteins from an evolutionary, biochemical, and functional point of view and discuss the most recent, relevant, and controversial contributions to the study of these kinases.

External sense receptors in microdrile oligochaetes (Annelida, Clitellata) as revealed by scanning electron microscopy: Typology and patterns of distribution in the main taxonomic groups

This work summarizes the observations on 30 species of microdriles belonging to the families Naididae (Rhyacodrilinae, Pristininae, Naidinae, Phallodrilinae, and Tubificinae), Phreodrilidae, Lumbriculidae, and Enchytraeidae using scanning electron microscopy. The lumbricid Eiseniella tetraedra, a megadrile species common in typical microdrile habitats, was used for comparison. Microdriles display external ciliate sense structures along the entire body; even at the clitellum and in budding and regeneration zones. According to the shape of the cilia, these sense structures can be divided into receptors of blunt cilia, receptors of sharp cilia, and composed receptors. Sense receptors can be morphologically unconspicuous or clearly defined on sensory buds or papillae. All microdriles studied have receptors of blunt cilia. Enchytraeids have characteristic receptors of short cilia. Pristina (Pristininae), Chaetogaster, Ophidonais, and Stylaria (Naidinae) have receptors of long blunt cilia. Composed receptors were found only in some microdriles and E. tetraedra. Receptors of sharp cilia have been found in most microdriles. Enchytraeids might be the only exception, but sharp cilia are probably present in the amphibiotic Cognettia sphagnetorum. Sensory cells with long sharp cilia might play a rheoreceptor role, and their presence in E. tetraedra and C. sphagnetorum would imply the reappearing of an ancient character that was probably lost with the transit from aquatic to terrestrial habitats. Some lumbriculids have ciliated fields. Anatomically, these structures appear as intermediate between the typical isolate sensory structures of microdriles and the sensillae of the hirudineans. The general pattern in microdriles is that uniciliate receptors and multiciliate receptors are separated, which supports the presumed aquatic origin of the clitellates.

Effect of vegetation data collection strategies on estimates of relevant source area of pollen (RSAP) and relative pollen productivity estimates (relative PPE) for non-arboreal taxa

Thirteen surface moss samples were collected for pollen analysis from an area of heathland in western Norway. Vegetation composition at different distances around the sampling locations was measured using three different survey methods; rooted frequency within a sub-divided 1 m × 1 m quadrat, visual estimates of cover within a 1 m × 1 m quadrat and a modified form of the ‘circle-walking method’. Extended R-value analysis was used to explore the pollen–vegetation relationships for five main taxa, Calluna vulgaris, Vaccinium-type, Cyperaceae, Poaceae and Potentilla-type. The estimates of relevant source area of pollen obtained were similar regardless of the vegetation survey method. Values obtained were always under 4 m. However, estimates of relative pollen productivity and the background pollen component (proportion of pollen coming from vegetation growing beyond the relevant source area of pollen) differ markedly depending on the method of vegetation survey chosen. This has important implications for the quantitative reconstruction of past vegetation cover.

Effects of ocean acidification on invertebrate settlement at volcanic CO2 vents

We present the first study of the effects of ocean acidification on settlement of benthic invertebrates and microfauna. Artificial collectors were placed for 1 month along pH gradients at CO2 vents off Ischia (Tyrrhenian Sea, Italy). Seventy-nine taxa were identified from six main taxonomic groups (foraminiferans, nematodes, polychaetes, molluscs, crustaceans and chaetognaths). Calcareous foraminiferans, serpulid polychaetes, gastropods and bivalves showed highly significant reductions in recruitment to the collectors as pCO2 rose from normal (336–341 ppm, pH 8.09–8.15) to high levels (886–5,148 ppm) causing acidified conditions near the vents (pH 7.08–7.79). Only the syllid polychaete Syllis prolifera had higher abundances at the most acidified station, although a wide range of polychaetes and small crustaceans was able to settle and survive under these conditions. A few taxa (Amphiglena mediterranea, Leptochelia dubia, Caprella acanthifera) were particularly abundant at stations acidified by intermediate amounts of CO2 (pH 7.41–7.99). These results show that increased levels of CO2 can profoundly affect the settlement of a wide range of benthic organisms.

Introductory notes to factsheets. Chapter 14

Among the 1590 terrestrial arthropod species alien to Europe identified in this book, 78 were selected to produce specific factsheets in order to provide more information on their biology, distribution and impact. We included two more species which are alien in Europe, the horse-chestnut leaf miner (Cameraria ohridella) and the African cotton leafworm (Spodoptera littoralis) because of their importance. These 80 species are perhaps not the most important alien invaders, but they are rather representatives of the main taxonomic groups of alien terrestrial arthropods. They were selected so as to represent different pathways of introduction and diverse impacts on ecosystems, economic activities and human and animal health. These species include two myriapods, one spider, one mite, 18 coleopterans, seven dipterans, 23 hemipterans, 10 hymenopterans, one termite, 14 lepidopterans, and three thrips. Each factsheet includes information on the following aspects: Description and biological cycle: A brief description of adults and immature stages is given, whenever possible illustrated by a photograph, to help the reader identify the species. Further information details the general characteristics of the biological cycle in the invaded area, especially the species' potential to reproduce and the hosts it has colonized. Native habitat: The factsheet includes the habitat type where the species is found in its native range. In order to make habitat types comparable among taxa, we adopted the classification of the European Nature Information System (EUNIS) database (http://eunis.eea.europa.eu). The habitat type codes are detailed in Appendix II. When information was available, we included specific habitat requirements which may help understand the potential of the species to establish and spread in Europe. Habitat occupied in invaded range: The different habitats colonized by the alien species are described as for native habitats. Native range: The native distribution of the species is described. For some species, there is very precise information available, but for others, only brief details of a region or even continent can be given. Introduced range: The date of the first record in Europe and the location of this record is given, as well as details of the process of dispersion in the continent when available. A distribution map is supplied for all species. For most of them, presence/ absence data have been obtained only at country level, but for a few species, more detailed maps are given to show the distribution at regional scale. However, the missing occurrence of species from some countries does not always mean that these countries are not colonized, but may rather result from a lack of data for the country concerned. The map also indicates eradication records where relevant. Pathways: We included information on the routes of introduction to Europe, and the potential of the species to disperse within the continent once it has established. Impact and management: This section details the importance of the species' impacts in the colonized habitats. Both ecological and economical impacts are detailed when known. Practical advice where known is given regarding mechanical, chemical and biological control methods. Selected references: Three of the most relevant references to the history of the species' introduction and spread in Europe are given.

Meiofauna communities in exposed sandy beaches on the Galician coast (NW Spain), six months after the <i>Prestige</i> oil spill: the role of polycyclic aromatic hydrocarbons (PAHs)

The effect of polycyclic aromatic hydrocarbons (PAHs) on Galician sandy beach ecosystems, six months after the Prestige oil spill, was evaluated using the meiobenthos at a higher taxon level as an indicator. Meiobenthos community structure, environmental variables and sediment PAH content from six affected exposed beaches were studied and compared with three reference sites. They were also compared with data from polluted beaches obtained during the first days of the spill. Significant amounts of PAHs were found in affected beach sediments and both univariate and multivariate analyses showed differences between affected and reference beaches. Correlation analyses between PAH content and the meiobenthos community structure showed that 1,2-dimethylnaphthalene (C2-NAPH) and 1-methylphenanthrene (C-PHEN) affected both the community structure and the abundance of the main taxa. These two PAHs seem to be responsible for the low meiofauna density values, which suggests that there is a relationship between the oil spill and the differences between affected and reference localities.

Composition of epiphytic leaf community of Posidonia oceanica as a tool for environmental biomonitoring

The demand for sensitive biological tools to assess the environmental quality of coastal waters at broad spatial scales is increasing. Many of the tools used are based on the taxonomic composition of biotic assemblages. They usually require a valuable taxonomic expertise while are unique reflecting the overall ecosystem integrity. Here, we evaluate the potential indicator value of several features of the epiphytic community (overall assemblage composition, species richness, and proportion of the main taxonomic groups) growing on the seagrass Posidonia oceanica leaves. We do so by empirically examining their changes along a disturbance gradient where multiple human activities have interactive and cumulative impacts, sampling at different spatial scales and at two different depths (5 and 15 m). Our results show that the specific composition of the epiphytic assemblages (i.e. species composition) closely reflects, in the deep meadows, the combined effects of different anthropogenic stressors along the gradient, showing an integrative and non-specific response. Similarly, an increase in the proportion of hydrozoans, and a decrease in the proportion of rhodophytes and chlorophytes are observed in deep meadows along the gradient. In shallow meadows, grazing and biotic features of the seagrass seem the main forcing factors determining species composition, and therefore masking the response of epiphytes to the deterioration gradient. After address the effect of natural sources of variability (water depth, within- and between-meadow heterogeneity), changes in epiphyte assemblages and in the proportion of hydrozoans, rhodophytes and chlorophytes in relatively deep meadows seem promising monitoring tools for detecting coastal environmental deterioration.

Potential biological indicators of heavy metal stress in mangrove ecosystems

The effects of heavy metals Cu, Pb, and Zn on a number of biological structural components of Avicennia dominated mangrove ecosystems is reviews and their potential as biological indicators of metal stress discussed. Three main taxa groups were chosen for examination, representing key structural components of Avicennia systems at different trophic levels. As the primary producer, Avicennia marina (Forsk.) Vierh, the grey mangrove, was studied most intensely. Heloecious cordiformis (Milne Edwards, 1852), the semaphore crab, was chosen as a higher level consumer. A suite of benthic organisms were also studied, representing a range of trophic associations at the community level. Potential biological indicators of metal stress were investigated in each group, at various organisational levels. A combination of laboratory and field based experiments have shown that most biological indicators investigated have merit in terms of reflecting exposure and effect of heavy metal stress in Avicennia systems. Avciennia marina was found to be highly tolerant to Cu, Pb and Zn. Both field and laboratory studies revealed the three metals were accumulated in root tissue in proportion to sediment metal loadings, and Cu and Zn showed some limited mobility to leaf tissue. Zn was the only metal in leaf tissue. Zn was the correlated with sediment loadings. All metals in root tissue and Zn in leaves were appropriate for accumulative indication. In both field and laboratory studies, increases in peroxidase activity and decreases in photopigments (most notably the chlorophyll a/b ratio) were found with increasing Cu and Zn. Significant relationships with peroxide ase activity only, were found for Pb. Both peroxidise activity and photopigment may be employed as sensitive early warning biomarkers of metal stress in A. Marina. For H. Cordiformis, Cu and Zn were regulated in the hepatopancreas. Lead was accumulated in the hepatopancreas in proportion to sediment Pb levels, and Pb was the main metal loadings tended to support lower numbers of crabs, greater proportions of females with purple chelae (rather than orange) and less females in the population, and thus may be employed as population level indicators of metal stress. Monitoring of macrobenthic community assemblage diversity and abundance along with natural variables and low-level anthropogenic contaminnts including Cu, Pb, Zn, revealed no significant pollutant related patterns. Natural physiochemical sediment differences were found to be the main determinants in species assemblage patterns among sites. An integrated approach of both field and laboratory based testing, with a range of species measured at various organisational hierarchies, is most instructive in the assessment of metal impacts on mangrove ecosystems.

The Neogene cercopithecids (Mammalia, Primates) of Greece

Th e presence of the cercopithecids in the Neogene of Greece is known since the beginning of the 19th century. Th e excavations of the last 20 years increase their number in Greece. Th e main taxon of the cercopithecids is Mesopithecus Wagner, 1839 found originally in the middle Turolian (MN 12) locality of Pikermi, near Athens. Th e Pikermi Mesopithecus sample is rich and belongs to a medium-sized form, M. pentelicus Wagner, 1839. Besides the well-known M. pentelicus, two other species were recognized. Th e new species M. delsoni Bonis, Bouvrain, Geraads & Koufos, 1990, a large-sized form found in the early Turolian (MN 11) locality Ravin des Zouaves-5 of Axios Valley (Macedonia, Greece) has several diff erences from the type species. In the middle Turolian (MN 12) localities of Vathylakkos (Axios Valley) and Perivolaki (Th essaly) a large to medium-sized Mesopithecus form with “delsoni” and “pentelicus” characters was found and is referred to as M. delsoni/pentelicus. A small-sized form named M. cf. monspessulanus was recognized by a mandibular fragment in the late Turolian (MN 13) locality Dytiko-2 of Axios Valley and indicates the early appearance of the taxon at the end of Miocene. Th e rest of the material found in the late Turolian localities of Dytiko has some diff erences from the typical M. pentelicus. Moreover, Mesopithecus was traced in several late Miocene localities, indicating its wide distribution in Greece. Two other cercopithecids were also found in the Pliocene of Greece. Dolichopithecus ruscinensis Deperet, 1889 was recognized in the locality of Megalon Emvolon and in Ptolemais Basin (Macedonia, Greece); both are dated to late Ruscinian (MN 15). Th e second Pliocene cercopithecid is Paradolichopithecus arvernensis (Deperet, 1929), found in the locality of Vatera (Lesvos Island) and dated to late Pliocene. Th e stratigraphic distribution and the palaeoenvironment of these cercopithecids are also discussed.

Acridid (Orthoptera: Acrididae) abundance in Western European Grasslands: sampling methodology and temporal fluctuations

AbstractThe estimation of Acridid (Orthoptera: Acrididae) density is the goal of a wide variety of conservation studies to monitor the impacts of grassland management or habitat change. The first aim of this paper was to study the influence of surveyors, time of the day and size/form of the box quadrat method on density values of Acridids in grassland habitats in Western France. The main taxa were Calliptamus italicus (L.) and Gomphocerinae sub‐family. Surveyor and day‐time (early morning vs. mid‐day) were not significantly influencing the density values of Acridids produced using a 1 m2 box quadrat. A smaller box quadrat of 0.5 m2, square or rectangular, produced underestimates of Acridid density, such as square 1 m2 box quadrat should be preferred. Population densities change through time. Thus, data‐based inferences about density are tied to the time periods during which data are collected. This was the main focus of this paper to provide a description of Acridid density fluctuations from egg hatching to adult’s death in grasslands with differing vegetation structures and grasshopper densities. Acridid densities were monitored weekly in 23 grassland plots over three seasons from 2004 to 2006. Weibull formulation was used to model density fluctuations for the two main taxa in each field with the Julian date as time. Phenological parameters of density were quite similar for the two taxa in the three years. This could be explained by similar meteorological conditions in the three years. However, these parameters exhibited a great variability between fields in the same year. Divergences between the fields could be attributable to different field ecological characters and to different grasshopper associations in the case of Gomphocerinae sub‐family. This study provided data which may be useful in determining the optimum survey dates.

Composição e variabilidade espaço-temporal da meiofauna de uma praia arenosa na região amazônica (Ajuruteua, Pará)

Este trabalho avalia a variabilidade espaço-temporal da meiofauna do médiolitoral na praia de Ajuruteua, Estado do Pará. As coletas foram realizadas a cada dois meses, entre abril de 2003 a fevereiro de 2004 durante as marés de sizígia, em diferentes zonas da praia. As amostras foram retiradas com um amostrador cilíndrico de 3,14 cm² e fixadas em formalina salina a 5%. Em laboratório, as amostras foram passadas em malha de 0,063 mm de abertura e os organismos retidos identificados em nível de grandes grupos taxonômicos, contados e fixados em álcool etílico a 70%. A meiofauna esteve representada por oito grupos: Turbellaria, Nematoda, Tardigrada, Polychaeta, Oligochaeta, Acari, adultos de Copepoda Harpacticoida e juvenis de Copepoda Harpacticoida. Nematoda foi o grupo dominante, representando 74% do total de indivíduos, seguido de Copepoda (19%). Pôde-se observar clara zonação horizontal da fauna, que se distribuiu em três faixas paralelas à linha de praia, com características significativamente distintas quanto à abundância, riqueza e densidade dos principais grupos taxonômicos. No médiolitoral médio foram observados valores significativamente mais elevados de riqueza e abundância, enquanto os valores mais baixos foram registrados no médiolitoral superior e inferior. A comunidade de meiofauna, ainda que não tenha variado significativamente entre períodos climáticos, foi mais rica e abundante nos meses secos. Os principais fatores responsáveis pelas variações espaço-temporais da meiofauna foram a ação das ondas e das marés e as variações na salinidade da água.

Zooplankton fluctuations in Jurumirim Reservoir (São Paulo, Brazil): a three-year study

During three consecutive years, monthly samples of zooplankton were taken in the lacustrine (dam) zone of Jurumirim (São Paulo, Brazil). The seasonal effect on basic limnological features (thermal regime, oxygen distribution, phytoplankton biomass, etc.) was also examined. The influence of the seasonality on the fluctuation of the zooplankton composition and abundance was not clearly detected (low degree of recurrent patterns). Rotifers (32 taxa) were the most abundant organisms during almost the entire study period with some seasonal alternations in the maximum abundance peaks of the main taxa (Conochilus unicornis, Keratella americana, K. cochlearis and Hexarthra spp.), except for Polyarthra (mainly P. vulgaris). Only occasionally copepods were numerically dominant. Higher copepod abundance was positively associated to periods of increase in the water retention time. Among the Copepoda (10 taxa) the calanoids (mainly Notodiaptomus iheringi) were more abundant, especially in warmer periods. Conversely, cyclopoids had higher abundance in autumn and winter. The species Thermocyclops minutus and T. decipiens co-occurred, but the first attained higher abundance. Some evidence of co-existence strategies between both species are considered. Cladocera (17 taxa) was never numerically dominant and the main taxa (Bosmina spp., Ceriodaphnia spp. and Diaphanosoma spp.) occurred almost the whole study period and did not present a seasonal pattern of fluctuation. Diaphanosoma (mainly D. birgei) attained the highest abundance among cladocerans. Most organisms were always found at the surface, but they also occupy the whole water column, even in periods of stratified conditions and low oxygen concentration in the bottom layers. Among the main zooplanktonic taxa, only Hexarthra avoids deep layers. An exceptionally high concentration of Copepoda nauplii on the surface was influenced by low transparency, high concentration of phytoplankton at this layer and low oxygen concentration at the bottom. In periods of higher retention timevariability there was a more heterogeneous distribution of the zooplankton in the water column. The increase in the retention time seems also to favor the copepod development. Finally, some inter-decade changes are considered on the basis of zooplankton assemblage structure observations.

Biogeographical patterns derived from remote sensing variables: the amphibians and reptiles of the Iberian Peninsula

Abstract The biogeographic patterns in species density of herptiles were analysed in the Iberian Peninsula. Geoclimatic regions were identified using a PCA. Individual habitat suitability (HS) models for 23 amphibians and 35 reptiles at 10 × 10 km scale were calculated with ENFA, using 12 environmental factors established with Remote Sensing (RS) techniques. The species presence proportion in each geoclimatic region was calculated through a cross-tabulation between each potential occurrence model and the geoclimatic regions. Species chorotypes were determined through Hierarchical Cluster Analysis using Jaccard's index as association measure and by the analysis of marginality and tolerance factors from individual HS models. Predicted species density maps were calculated for each geoclimatic region. Probable under-sampled areas were estimated through differences between the predicted species density maps and observed (Gap analysis). The selected PCA components divided the Iberian Peninsula in two major geoclimatic regions largely corresponding to the Atlantic and Mediterranean climates. The Jaccard's index clustered herptiles in two main taxonomic groups, with distribution similar to the Atlantic and Mediterranean geoclimatic regions (7 amphibian + 13 reptile species in three Atlantic subgroups and 16 amphibian + 22 reptile species in four Mediterranean subgroups). Marginality and tolerance factor scores identified species groups of herptile specialists and generalists. The highest observed and predicted species density areas were broadly located in identical regions. Predicted gaps are located in north-western, north-east and central Iberia. RS is a useful tool for biogeographical studies, as it provides consistent environmental data from large areas with high accuracy.

Faunal responses to oxygen gradients on the Pakistan margin: A comparison of foraminiferans, macrofauna and megafauna

The Pakistan Margin is characterised by a strong mid-water oxygen minimum zone (OMZ) that intercepts the seabed at bathyal depths (150–1300 m). We investigated whether faunal abundance and diversity trends were similar among protists (foraminiferans and gromiids), metazoan macrofauna and megafauna along a transect (140–1850 m water depth) across the OMZ during the 2003 intermonsoon (March–May) and late/post-monsoon (August–October) seasons. All groups exhibited some drop in abundance in the OMZ core (250–500 m water depth; O2: 0.10–0.13 mL L?1=4.46–5.80 ?M) but to differing degrees. Densities of foraminiferans >63 ?m were slightly depressed at 300 m, peaked at 738 m, and were much lower at deeper stations. Foraminiferans >300 ?m were the overwhelmingly dominant macrofaunal organisms in the OMZ core. Macrofaunal metazoans reached maximum densities at 140 m depth, with additional peaks at 850, 940 and 1850 m where foraminiferans were less abundant. The polychaete Linopherus sp. was responsible for a macrofaunal biomass peak at 950 m. Apart from large swimming animals (fish and natant decapods), metazoan megafauna were absent between 300 and 900 m (O2 0.2 mL L?1=8.92 ?M). The progressively deeper abundance peaks for foraminiferans (>63 ?m), Linopherus sp. and ophiuroids probably represent lower OMZ boundary edge effects and suggest a link between body size and tolerance of hypoxia. Macro- and megafaunal organisms collected between 800 and 1100 m were dominated by a succession of different taxa, indicating that the lower part of the OMZ is also a region of rapid faunal change. Species diversity was depressed in all groups in the OMZ core, but this was much more pronounced for macrofauna and megafauna than for foraminiferans. Oxygen levels strongly influenced the taxonomic composition of all faunal groups. Calcareous foraminiferans dominated the seasonally and permanently hypoxic sites (136–300 m); agglutinated foraminiferans were relatively more abundant at deeper stations where oxygen concentrations were >0.13 mL L?1(=5.80 ?M). Polychaetes were the main macrofaunal taxon within the OMZ; calcareous macrofauna and megafauna (molluscs and echinoderms) were rare or absent where oxygen levels were lowest. The rarity of larger animals between 300 and 700 m on the Pakistan Margin, compared with the abundant macrofauna in the OMZ core off Oman, is the most notable contrast between the two sides of the Arabian Sea. This difference probably reflects the slightly higher oxygen levels and better food quality on the western side.

First data on the expansion of Larix gmelinii (Rupr.) Rupr. into arctic regions of Beringia during the early Holocene

The international program on paleoclimates of El’gygytgyn Lake contemplates the study of different genetic types of sediments established in its basin. The lake, which provided one of the longest continuous climatic records of the Arctic Region, was formed about 4 Ma ago when a meteorite fell in the northern Chukchi Peninsula in the region of 67 ° 30 � N, 172 ° 05 � E [1]. The region belongs to a mountainous variant of a typical tundra subzone [2]. Slopes of the Anadyr Tableland surrounding the lake are occupied by the undershrub‐ lichen tundra. Dwarf birch and willow are encountered on protected areas in valleys of the Enmyvaam River flowing out of the lake and its tributaries (the Anadyr River system). Present-day climatic parameters for El’gygytgyn Lake are as follows: the average temperature is +8.3 ° C for July and ‐28.4 ° C for January; average precipitation is 47.4 mm in July and 21.5 mm in January. A series of radiocarbon ages (figure) accompanies the palynological and paleocarpological analyses of loose deposits exposed in the scarp of the 4-m terrace of the Ol’ga Creek running into the Enmyvaam River on the left at a distance of 1 km from the lake (67 ° 26 � 45 � N, 172 ° 13 � 14 � E). The first age (9125 ± 30 years ago, MAG-994) in this series was established for a large trunk of alder ( Duschekia fruticosa ) found in peat at the depth of 163 cm (figure). This age and two other ages for fragments of shrub branches: 9250 ± 90 years ago (MAG-1477), at the depth of 172 cm, and 8120 ± 25 years ago (MAG-1478), at the depth of 150 cm, allow for correlating the peat formation time with the Boreal interval of the Holocene. The age 7770 ± 50 years ago (MAG-1480) established for plant remains from the depth of 109 cm indicates that peat with sand lenses (figure, Bed 5) formed during the period corresponding to the Atlantic interval of the Holocene. The spore-and-pollen diagram of deposits on the terrace comprises three pollen zones (figure). Subdivision of zones is determined by variations in the content of main pollen taxons and each spore taxon calculated in percent out of the total pollen. It is significant that in contrast to spectra of sediments from El’gygytgyn Lake represented by pollen brought by wind from the Anadyr Tableland [1], peat spectra reflect local plant communities. Pollen zone 1 is distinguished as a zone of birch (figure). It is similar to birch pollen zones in climatic records of Beringia lakes and reflects a response of the vegetation cover to climate warming in the period transitional from the Pleistocene to the Holocene [3]. Spore-and-pollen spectra of the zone underline a wide distribution of such shrubby birch species as Betula middendorffii, B. exilis, and B. fruticosa that replaced herb communities of the Last Glaciation [3].

Basin scale distribution of zooplankton in the Ligurian Sea (north-western Mediterranean) in late autumn

Mesozooplankton biomass and abundance were evaluated in epipelagic waters at 59 stations covering the Italian sector of the Ligurian Sea (north-western Mediterranean) in December 1990. This region is characterised by a cyclonic circulation which encloses a central divergence zone and is associated with a main thermohaline front offshore the western Ligurian coast. At the end of autumn, mesozooplankton biomass (range: 0.80–4.24 mg DW m−3) and the abundance (range: 83.8–932 ind. m−3) were lower in the divergence zone. On the contrary, in the Ligurian frontal zone at the periphery of the divergence and on the eastern continental shelf the greatest values of biomass and abundance were recorded. Copepods and appendicularians dominated the mesozooplankton community, the main taxa being the copepods Clausocalanus spp. (46% of total zooplankton) and Oithona spp. (15%) and the appendicularian Fritillaria spp. (12%). Three hydrological sub-regions, i.e. the divergence, the eastern continental shelf and the periphery of the divergence, were characterised by different zooplankton communities and characteristic species. Environmental differences between the three zones were mainly related to changes in bottom topography, sea surface temperatures and quantity of particulate organic matter. Vertical mesozooplankton abundance and taxa distribution from the surface to 1,900 m depth were also examined in one station. The results showed that the bulk of the community was concentrated in the upper 200 m, small copepods being dominant particularly in the upper 50 m. The copepod community was more diversified in sub-superficial waters, with a maximum observed in the 200–400 m layer. The distributions of main zooplankton taxa described in epipelagic waters in the eastern Ligurian Sea in autumn were compared with their distribution at surface in the north-western Mediterranean obtained by sampling performed with the Continuous Plankton Recorder in 1997–1999. The analysis of the zooplankton community in CPR samples confirms the dominance of small copepods (Paracalanus spp., Clausocalanus spp., Oithona spp.) and appendicularians in the north-western Mediterranean in late autumn-winter and shows that their distribution is mainly related to the main mesoscale hydrographic features characterising this basin.