Impact of anthropogenic disturbances on beetle communities of French Mediterranean coastal dunes

In coastal dunes, influenced by anthropogenic activities such as tourism, it is important to determine the relative influence of environmental factors at different spatial scales to evaluate the sensitivity of local communities to disturbances. We analyzed beetle communities of 14 dunes of the French Mediterranean coast: four in the relatively preserved Camargue area, and ten in the Var department, where tourism is intensive. Beetle communities were studied three times in early spring using sand sampling. Species-environment relationships were evaluated at the regional, landscape and local scale using redundancy analysis (RDA) and variability partitioning. About 28 species were identified, of which 15 were sand-specialist species, which accounted for more than 93% of total abundance. The beetle communities of Camargue were significantly different from those of the Var department owing to the pullulation of a Tenebrionid species (Trachyscelis aphodioides Latr.) in the Var, except for one restored dune where the community was very similar to those of Camargue. Our results showed no longitudinal gradient between the two regions. Local factors (dune height, preservation and disturbance index) significantly explained most of the variation in the dominance of T. aphodioides, while some other local factors were important for other psammophilous species. This study also suggests that dune beetle communities are strongly affected on beaches intensively managed for tourism, but beetles are still abundant in much disturbed sites

A late Pleistocene long pollen record from Lake Urmia, NW Iran

A palynological study based on two 100-m long cores from Lake Urmia in northwestern Iran provides a vegetation record spanning 200 ka, the longest pollen record for the continental interior of the Near East. During both penultimate and last glaciations, a steppe of Artemisia and Poaceae dominated the upland vegetation with a high proportion of Chenopodiaceae in both upland and lowland saline ecosystems. While Juniperus and deciduous Quercus trees were extremely rare and restricted to some refugia, Hippophaë rhamnoides constituted an important phanerophyte, particularly during the upper last glacial sediments. A pronounced expansion in Ephedra shrub-steppe occurred at the end of the penultimate late-glacial period but was followed by extreme aridity that favoured an Artemisia steppe. Very high lake levels, registered by both pollen and sedimentary markers, occurred during the middle of the last glaciation and upper part of the penultimate glaciation. The late-glacial to early Holocene transition is represented by a succession of Hippophaë, Ephedra, Betula, Pistacia and finally Juniperus and Quercus. The last interglacial period (Eemian), slightly warmer and moister than the Holocene, was followed by two interstadial phases similar in pattern to those recorded in the marine isotope record and southern European pollen sequences

Modern pollen rain–vegetation relationships along a forest–steppe transect in the Golestan National Park, NE Iran

Pollen rain-vegetation relationships were studied over a forest-steppe transect in Golestan National Park, NE Iran. The surface pollen percentages were compared to the vegetation composition of the respective vegetation types in 18 sampling points using both descriptive and numerical approaches. Hyrcanian lowland forests are characterized by pollen assemblages dominated by Quercus, Carpinus betulus and low frequencies of Zelkova carpinifolia. Both Parrotia persica and Zelkova carpinifolia show a very low pollen representation in modern surface samples, an under-representation that should be taken into account in the interpretation of past vegetation records. Transitional communities between the forest and steppe including Acer monspessulanum subsp. turcomanicum, Crataegus and Paliurus scrubs, Juniperus excelsa woodlands and shrub-steppe patches are more difficult to distinguish in pollen assemblages, however, they are characterized by higher values of the dominant shrub species. The transitional vegetation communities at the immediate vicinity of the forest show also a substantial amount of grass pollen. Many insect-pollinated taxa are strongly under-represented in the pollen rain including most of the rosaceous trees and shrubs, Rhamnus, Paliurus, Acer and Berberis. Artemisia steppes are characterized by very high values of Artemisia pollen and the near absence of tree pollen

Precipitation changes in the Mediterranean basin during the Holocene from terrestrial and marine pollen records: a model–data comparison

Climate evolution of the Mediterranean region during the Holocene exhibits strong spatial and temporal variability. The spatial differentiation and temporal variability, as evident from different climate proxy datasets, has remained notoriously difficult for models to reproduce. In light of this complexity, we examine the previously described evidence for (i) opposing northern and southern precipitation regimes during the Holocene across the Mediterranean basin, and (ii) an east-to-west precipitation gradient or dipole during the early Holocene, from a wet eastern Mediterranean to dry western Mediterranean. Using quantitative climate information from marine and terrestrial pollen archives, we focus on two key time intervals, the early to mid-Holocene (8000 to 6000 cal yrs BP) and the late Holocene (4000 to 2000 yrs BP), in order to test the above mentioned hypotheses on a Mediterranean-wide scale. Palynologically derived climate information is compared with the output of regional-scale climate-model simulations for the same time intervals. Quantitative pollen-based precipitation estimates were generated along a longitudinal gradient from the Alboran (West) to the Aegean Sea (East); they are derived from terrestrial pollen records from Greece, Italy and Malta as well as from pollen records obtained from marine cores. Because seasonality represents a key parameter in Mediterranean climates, special attention was given to the reconstruction of season-specific climate information, notably summer and winter precipitation. The reconstructed climatic trends corroborate a previously described north-south partition of precipitation regimes during the Holocene. During the early Holocene, relatively wet conditions occurred in the south-central and eastern Mediterranean region, while drier conditions prevailed from 45° N northwards. These patterns reversed during the late Holocene, with a wetter northern Mediterranean region and drier conditions in the east and south. More sites from the northern part of the Mediterranean basin are needed to further substantiate these observations. With regard to the existence of a west-east precipitation dipole during the Holocene, our pollen-based climate data show that the strength of this dipole is strongly linked to the seasonal parameter reconstructed: Early Holocene summers show a clear east-to-west gradient, with summer precipitation having been highest in the central and eastern Mediterranean and lowest over the western Mediterranean. In contrast, winter precipitation signals are less spatially coherent. A general drying trend occurred from the early to the late Holocene; particularly in the central and eastern Mediterranean. However, summer precipitation in the east remained above modern values, even during the late Holocene interval. Pollen-inferred precipitation estimates were compared to regional-scale climate modelling simulations based on the HadAM3 GCM coupled to the dynamic HadSM3 and the high-resolution regional HadRM3 models. Climate model outputs and pollen-inferred precipitation estimates show remarkably good overall correspondence, although many simulated patterns are of marginal statistical significance. Nevertheless, models weakly support an east to west division in summer precipitation and there are suggestions that the eastern Mediterranean experienced wetter summer and winter conditions during the early Holocene and wetter summer conditions during the late Holocene. The extent to which summer monsoonal precipitation may have existed in the southern and eastern Mediterranean during the mid-Holocene remains an outstanding question; our model, consistent with other global models, does not suggest an extension of the African monsoon into the Mediterranean. Given the difficulty in modelling future climate change in Southern Europe, more simulations based on high resolution global models and very high resolution regional downscaling, perhaps even including transient simulations, are required to fully understand the patterns of change in winter and summer circulation patterns over the Mediterranean regio

Chapitre 5. Analyses entomologiques (coléoptères)

1. Introduction L’intérêt de l’analyse paléoentomologique en contexte archéologique a été maintes fois souligné, comme le montrent la bibliographie de Buckland et Coope (1991) et le manuel d’Elias (1994). En France ce type de recherche est resté relativement confidentiel, bien qu’une certaine impulsion semble avoir été donnée récemment grâce aux efforts de quelques pionniers, voir par exemple la petite synthèse réalisée par Ponel et Yvinec (1997). L’analyse paléoentomologique d’un site archéo..

VARIATIONS DEPUIS 10000 ANS DE LA REPARTITION ET DE LA PRODUCTIVITE DES FORETS D'ALTITUDE DANS LES ALPES ET LE JURA ET SIMULATION DES CHANGEMENTS FUTURS

Ce travail repose sur les charbons de bois enfouis dans les sols et les autres macrorestes ont été datés par 14C et identifiés botaniquement, et pour un site particulier (lac Cristol), sur les analyses de pollens, d'insectes, de macro-restes végétaux, charbons de bois et tronc d'arbres ont été combinés en une « approche multi-proxy » afin de mieux comprendre les variations de la forêt de montagne en réponse aux changements climatiques globaux et à l'activité anthropique. Les variations de la limite de la forêt sont de plus de 500 m durant l'Holocène. La période la plus chaude semble avoir été 9000-8000 ans cal B.P. (années calendaires avant le présent). Les hauts niveaux lacustres du début et de la fin de l'Holocène sont de natures en fait assez différentes. Au début de l'Holocène ils sont principalement dus à une évapotranspiration plus faible, et à la fin de l'Holocène à des précipitations plus élevées. L'ensemble de ces informations a permis de tester un modèle de végétation (Biome3) par une utilisation en mode inverse et à essayer de prédire l'évolution de la végétation. Un doublement de CO2 permet à la végétation d'évoluer vers des conditions plus tempérées. Une « forêt mixte tempérée », pourra devenir une forêt décidue tempérée grâce à des hivers nettement plus doux et à une meilleure efficacité dans l'utilisation de l'eau en été. Ces sites d'altitude ont connu une telle végétation entre 9000 et 8000 ans cal B.P

The Branding Effect of Contracts

In his case study of the MasterCard IPO and its predecessor piece on the Google IPO, Victor Fleischer claims to find evidence of a branding effect of legal infrastructure. The branding effect is not aimed at reducing the potential for opportunism by a counterparty to a contract, but rather at increasing the attractiveness of a product to present and future users or improving the image of a company in the eyes of regulators, judges, and juries. In this essay commenting on Fleischer\u27s work, I endorse the notion that deal structures have branding effects and position Fleischer\u27s work within a larger stream of scholarship that focuses on the substantive terms of contracts rather than on contract doctrine or dispute resolution in various contractual settings. In addition, I offer a few refinements to Fleischer\u27s notion of branding effect

The Palaeoentomological record of Cavallo island (Lavezzi archipelago, southern Corsica): 7000 years of a complex environmental history

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Different Response Patterns of Beetle Communities to Environmental Factors in Ramsar Wetland, West Algeria

An ecological study was carried out to estimate and measure the importance of environmental factors on the abundance, diversity and regularity of terrestrial beetle communities in the Ramsar wetland (Dayet El Ferd, Algeria). Samples were collected bimonthly for one year, with peripheral reference to the water point along the two transects. A micro-distribution and ecology have been tackled besides the degree of maturity of the wetland are discussed. On the basis of 432 samples and 12341 depicted diverse specimens, 221 species belonging to the Adephaga and Polyphaga equally, have been identified, grouped in 30 families, 71 subfamilies with a net dominance of Carabidae. Bagous argillaceus (Gyllenhall, 1836), Calomera lunulata (Fabricious, 1741) and Morica favieri (Lucas, 1859) were abundant, accounting for 18% of the global fauna; a large number of rare taxa (= present in at least 10 individuals) were found. The diversity and regularity of these communities generate a positive correlation of great importance according to a certain rate of organic matter present in the soil. Maximum diversity is found at the highest levels, while regularity is mainly found at intermediate levels

Coleopteran communities of the salt marsh at the mouth of the Tafna River (Algeria)

A study of Coleopteran communities was conducted between October 2009 and September 2010 in the salt marsh at the mouth of the Tafna River. Bimonthly trappings were carried out in five groups of vegetation and yielded 3833 specimens belonging to 140 species. This richness varies from one group to another (19 to 87 species). The high values are directly related to a shorter period of submersion, a lower salinity but also a greater floristic richness. Diversity indicators show that communities are diversified, regular and well structured with the exception of the samples from the lowest points where the highest salt concentrations are recorded. The highest richness and abundance are recorded mainly between early spring and early summer. Community composition is very different from one group to another ; the similarity index does not exceed 40 %. The spatial micro-distribution of grouping floristic species has been demonstrated through an ascending hierarchical analysisUne étude des peuplements des Coléoptères a été réalisée entre octobre 2009 et septembre 2010 dans le marais salé de l'embouchure de la Tafna. Des piégeages bimensuels effectués dans cinq groupements de végétation ont fourni 3833 spécimens répartis en 140 espèces. Cette richesse spécifique varie d'un groupement à un autre (de 19 à 87 espèces). Les richesses élevées sont en relation directe avec une période de submersion moins longue, un taux de salinité moins élevé mais également une richesse floristique plus importante. Les indicateurs de diversité montrent que les peuplements sont diversifiés, réguliers et bien structurés dans l'ensemble à l'exception du groupement des points les plus bas où les plus fortes concentrations salines sont enregistrées. L'évolution temporelle fait ressortir des richesses et des abondances maximales essentiellement entre le début du printemps et le début de l'été. La composition des peuplements reste très différente d'un groupement à un autre, l'indice de similitude n'excède pas les 40 %. L'analyse biotypologique par classification ascendante hiérarchique des 140 espèces dégage six unités coenotiques définies en fonction de la dominance moyenne et de l'occurrence, mettant ainsi en évidence une microdistribution spatiale des espèces