Integrated analyses of litho- and biofacies in a Pliocene cyclothemic, alluvial to shallow marine succession (Tuscany, Italy)

Lithofacies analysis of the upper part of the Pliocene succession of the Valdelsa basin (central Italy) unravelled a number of depositional environments, ranging from alluvial plain to coastal, to marine. Strata are arranged in a hierarchy of elementary and composite unconformity-bounded units. A palaeoecological study of macro- (molluscs) and microfossils (pollen, dinocysts, foraminifera) allowed to finely reconstruct sub-environments within fine-grained terrestrial, coastal and marine deposits and thence to track the spatial and temporal change of physical conditions. The stacking pattern of sedimentary units highlights the lateral switching of onshore-offshore gradients and documents relative sea-level changes. These units are interpreted in a sequence stratigraphic framework. Elementary depositional sequences are arranged to form six composite depositional sequences, in turn encased within two major synthems. This hierarchy of unconformity-bounded sedimentary units suggests that sea-level variation has occurred at different time-frequencies. Glacio-eustasy and active tectonism are discussed as the main forcing factors regulating the different scales of sedimentary cyclicity.     

Diversity,geographic variation and conservationof the serpentine flora of Tuscany (Italy)

The specialised flora of serpentine outcrops in Tuscany (Italy) is analysed in terms of species richness and geographic variation, in order to identify main centres of diversity and provide a basis for conservation programmes. Five edaphic groups are distinguished, among which obligate endemics, serpentine-preferential taxa, facultative basiphilous and facultative calcifuge serpentinophytes. Relatively low diversity (87 taxa) and high taxonomic distinctiveness (28.7% of endemics plus preferentials) underscore the insular condition of the ophiolitic outcrops. Hemicryptophytes and chamaephytes are the dominat life-forms, in line with the mainly continental character revealed by the phytogeographical analysis. Presence/absence of the taxa in 10 serpentine island systems was assessed using literature and original field data. Number of species and surface of the areas are significantly correlated. Cluster analysis identifies five groups of areas, while ordination indicates the species which are more effective in determining the floristic differences among the areas. Cecina valley, Monte Ferrato, Murlo hills and upper Tiber valley are the main centres of endemism and taxonomic diversity. However, the positive relationship between floristic and geographic distances and the remarkable proportion of species with frequency < 50% highlights a considerable among-area variation. To ‘catch’ such variation, a network of distant protected sites appears more effective than to search for single areas with high diversity. At least one site in each of the five clusters should be included in a ‘Important Plant Area’ network which would ensure the conservation of such a peculiar component of the Italian vascular flora.     

Relationships between foraminiferal assemblages and depositional sequences in Jahrum Formation,Ardal area (Zagros Basin,SW Iran)

The Jahrum Formation was deposited in the foreland basin in southwest Iran (Zagros Basin). The Zagros mountain belt of Iran, a part of the Alpine–Himalayan system, extends from the NW Iranian border through to SW Iran, up to the strait of Hormuz. The various facies of the Jahrum Formation were deposited in four main genetically related depositional environments, including: tidal flat, lagoon, shoal and open marine. These are represented by 14 microfacies. The Jahrum Formation represents sedimentation on a carbonate ramp. Tidal flat facies are represented by fenestral fabric, stromatolitic boundstone and thin-bedded planes. Carbonate deposition in a shallow marine lagoon was characterised by wacke–packstone, dominated by various taxa of imperforate foraminifer. The shoals are made up of medium- to coarse-grained skeletal and peloidal grainstone. This facies was deposited predominantly in an active high energy wave and current regime, and grades basinward into middle ramps facies are represented by wackestones–packstones with a diverse assemblage of echinoderm and large benthic foraminifers with perforate wall. Outer ramp facies consist of alternating marl and limestones rich in pelagic foraminifera. There is no evidence for resedimentation processes in this facies belt. The sequence stratigraphy study has led to recognition of three third-order depositional sequences.     

Onset of temperate carbonate sedimentation during transgression in a low-energy siliciclastic embayment (Pliocene of the Val d’Orcia Basin,Tuscany, Italy)

A Mid-Pliocene sequence in the sedimentary fill of the Val d’Orcia Basin (Tuscany, Italy) records coeval accumulation of temperate carbonate and siliciclastic deposits in close proximity. This study investigates the role played by local parameters in influencing the spatially discontinuous onset of carbonate sedimentation. Carbonate facies developed during transgression of an irregular coastline and were restricted to the more enclosed portion of an embayment. Coralline red algae were the main carbonate producers and are preserved in the skeletal association as isolated branches, rhodoliths, and incipient bindstone. When comparing the sedimentological attributes of the siliciclastic- and carbonate-dominated deposits, no significant differences are observed. They both appear to have accumulated in shallow-marine areas, subjected to general low-energy conditions punctuated by sporadic higher-energy events. Nevertheless, coastal morphology and bedrock composition at the basin margin created local heterogeneities that were sufficient to induce restricted spatial distribution of the carbonate-producing factory.     

Survival patterns of macrobenthic marine assemblages during the end-Permian mass extinction in the western Tethys (Dolomites, Italy)

The ecological competition between brachiopods and bivalves is analysed by means of a quantitative palaeoecologic method applied on four assemblages located within a short stratigraphic interval, approximately 2 m thick, in the lower Tesero Member of the Werfen Formation (in the Southern Alps). The assemblages originate from the Tesero, Bulla and Sass de Putia sections. The analysed stratigraphic interval, uppermost Changhsingian in age, is located between the early and heaviest phase of the end-Permian mass extinction, which occurred across the Bellerophon/Werfen formational boundary (Event Boundary), and the Permian/Triassic boundary (Chronological Boundary), when nearly all the Permian stenotopic holdovers disappeared.These assemblages are characterised by small sized skeletons (“Lilliput effect”), which represent an adaptive survival strategy in stressed and harsh habitats resulting from the climatic and palaeoceanographic changes connected with the mass extinction. The Tesero assemblages are dominated by rhynchonelliform brachiopod Orbicoelia (bed CNT10) or Streptorhynchus (bed CNT11A), which were mostly attached at the top of shallow microbialitic mounds. These assemblages are again dominated by Permian stenotopic taxa and show a Palaeozoic structure. The Tesero habitat, which again permitted the survival of brachiopods, represented one of the last refuges in the western Tethys. On the contrary, the Bulla (BU9-10) and Sass de Putia (wPK13A) assemblages are bivalve-dominated, and thus show an ecologic structure typical of Early Triassic post-extinction marine benthic communities or Palaeozoic stressed marine communities. The bivalve-dominated assemblages proliferated in prevailing muddy siliciclastic substrates, with brief episodes of microbial algal growth. The most important environmental limiting factors and leading causes of end-Permian mass extinction are discussed in terms of palaeoautecologic and palaeosynecologic analysis.The different taxonomic composition and ecologic structure of the assemblages is related to palaeogeography, including water depth and connections with the open sea. The brachiopod-dominated assemblage, exclusive of the Tesero section, proliferated in microbial carbonate habitats in near-shore environments. The bivalve-dominated assemblages, which were more widespread than the brachiopod assemblages in the Dolomites and also occurred in other western Tethys localities, occur in more open and deeper marine environments. In the western Tethys margins, the local distribution of mixed faunas suggests that the extinction of Permian stenotopic taxa was caused by the onset of poisonous water on the shelves originating from deep marine environments.This extinction pattern appears to be a regional phenomenon and does not seem be applicable on a global scale. The extinction events were controlled by a complex network of interactive factors and the survival of faunal elements was probably stochastic.     

基于SOM的野生秤锤树群落的空间分布和环境解释

本文采用自组织特征映射网络(self-organizing map, SOM)对南京老山野生秤锤树(Sinojackia xylocarpa)群落进行数量分类和排序, 分析了其与环境因子之间的关系。结果表明: (1) SOM将秤锤树野生群落的100个样方划分为5个群丛类型, 分类结果在空间上反映了秤锤树野生群落的演替变化趋势, 各群丛的群落结构和物种组成存在差异且群丛界限明显, 可较好地进行排序与分类的环境解释。(2)通过环境因子梯度的可视化方法, 确定了海拔、坡位和土壤厚度是影响该地区秤锤树生长和分布的主要因子, 同时也揭示了以不同优势种为代表的各群丛和环境因子的关系。(3) SOM可以摆脱许多定量技术的限制性假设, 使得神经网络对于群落生态特征及探索群落和环境相互关系具有良好展现力; SOM群落生态数据具有更高的映射能力, 进行群落分类以及较少程度的排序的潜力, 将有利于不同群落类型的分类和管理, 对于濒危植物保护具有重要意义。     

Archaeal communities in High Arctic wetlands at Spitsbergen, Norway (78 degrees N) as characterized by 16S rRNA gene fingerprinting

Emissions of the greenhouse gas methane from Arctic wetlands have been studied extensively, though little is known about the ecology and community structure of methanogenic archaea that catalyze the methane production. As part of a project addressing microbial transformations of methane in Arctic wetlands, we studied archaeal communities in two wetlands (Solvatnet and Stuphallet) at Spitsbergen, Norway (78 degrees N) during two summer seasons. Directly extracted peat community DNA and enrichment cultures of methanogenic archaea were analyzed by nested PCR combined with denaturing gradient gel electrophoresis and subsequent sequencing of 16S rRNA gene fragments. Sequences affiliated with Methanomicrobiales, Methanobacteriaceae, Methanosaeta and Group I.3b of the uncultured crenarchaeota were detected at both sites. Sequences affiliated with Methanosarcina were recovered only from the site Solvatnet, while sequences affiliated with the euryarchaeotal clusters Rice Cluster II and Sediment 1 were detected only at the site Stuphallet. The phylogenetic affiliation of the recovered sequences suggested a potential of both hydrogenotrophic and acetoclastic methanogenesis at both sites. At Solvatnet, there were clear temporal trends in the archaeal community structure over the Arctic summer season. The archaeal community composition was significantly affected by factors influencing the activity of the overall bacterial community, as measured by in situ emissions of CO2. Methane emissions at both sites were influenced more by peat temperatures and thaw depth than by the archaeal community structure. Enrichment cultures for methanogenic archaea determined that most of the methanogens detected directly in peat could grow in culture at 10 degrees C. Culture based biases were indicated in later enrichment steps by the abundant growth of a Methanosarcina strain that was not detected directly in peat samples.     

Fruits and seeds of Ruppia (Potamogetonaceae) from the Pliocene of Yushe Basin, Shanxi, northern China and their ecological implications

Numerous fruits and seeds of Ruppia are reported from the Upper Pliocene (2.3–3.5 Myr ago) Zhangcun Formation in Yushe Basin, Shanxi, northern China. They are the first fossil Ruppia from China and demonstrate the importance of fruit and seed fossils in recording genera not represented by fossil leaves. These Ruppia are characterized by possessing a small oval endocarp, smooth endocarp surface, distinct elliptical external depressions, distinct apical mucro, slightly curved seed shape and conspicuous globose hilum. A new species, R. yushensis Zhao, Collinson and Li, is described from these endocarp and seed features. Comparison with the two European Miocene species, R. palaeomaritima Negru and R. maritime-miocenica Szafer, indicates the existence at that time of three different geographical and stratigraphical species. R. yushensis constitutes the first Pliocene record of Ruppia and extends the range of fossils of this genus from Europe to eastern Asia. R. yushensis is the only aquatic plant in the uppermost middle part of the Zhangcun Formation. This monotypic occurrence indicates a brackish, clear, tranquil and shallow lake in this region in the Late Pliocene. The smooth endocarp surface further suggests a warm temperate or temperate palaeoclimate.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 317–329.     

Quantifying the response of structural complexity and community composition to environmental change in marine communities

Habitat structural complexity is a key factor shaping marine communities. However, accurate methods for quantifying structural complexity underwater are currently lacking. Loss of structural complexity is linked to ecosystem declines in biodiversity and resilience. We developed new methods using underwater stereo‐imagery spanning 4 years (2010–2013) to reconstruct 3D models of coral reef areas and quantified both structural complexity at two spatial resolutions (2.5 and 25 cm) and benthic community composition to characterize changes after an unprecedented thermal anomaly on the west coast of Australia in 2011. Structural complexity increased at both resolutions in quadrats (4 m²) that bleached, but not those that did not bleach. Changes in complexity were driven by species‐specific responses to warming, highlighting the importance of identifying small‐scale dynamics to disentangle ecological responses to disturbance. We demonstrate an effective, repeatable method for quantifying the relationship among community composition, structural complexity and ocean warming, improving predictions of the response of marine ecosystems to environmental change.     

Carbon isotopic record of terrestrial ecosystems spanning the Late Miocene extinction of Oreopithecus bambolii, Baccinello Basin (Tuscany, Italy)

Oreopithecus bambolii is a Late Miocene hominoid with an extensive fossil record in the Baccinello Basin (Tuscany, Italy), and was the only western European hominoid to survive a major extinction event ca. 9.6 Ma (millions of years ago). Oreopithecus lived in the insular Tusco-Sardinian paleobioprovince, where it evolved many unique anatomical specializations that make it important for understanding the mechanisms and history of Late Miocene hominoid evolution. The eventual extinction of Oreopithecus and its associated fauna ca. 6.5 Ma has generally been attributed to interaction with species that arrived from continental Europe following tectonic collision of the Tusco-Sardinian province with mainland Italy, but palynological, paleontological, and sedimentological records indicate an environmental shift toward more variable climate across the extinction event.To explore the possibility of environmental change as a contributing factor in the extinction of Oreopithecus, we developed a stable carbon and oxygen isotope record from organic matter in paleosols from the Baccinello Basin. These data show very low temporal and spatial variability (indicating plant ecosystem stability through time and space) and provide no evidence for ecologically significant changes in floral composition spanning the extinction event, suggesting that environmental change was not an underlying cause for the extinction of Oreopithecus and its associated fauna. The carbon isotope values fall entirely within the range of isotopic variability for modern plants following the C₃ photosynthetic pathway (trees, shrubs, cool-season grasses), indicating that C₄ vegetation (warm-season grasses) was not an important component of biomass. When corrected for temporal variation in the carbon isotopic composition of atmospheric carbon dioxide, the paleosol carbon isotope values are consistent with predicted values based on modern plants and the Baccinello palynoflora, supporting the reliability of paleosol isotopic records as paleoecological proxies.     

Necropsy and coprology in wild boar (Sus scrofa) in Livorno Mountain Park (Tuscany, Central Italy)

The present research analyses the reliability of coprological tests, both quantitative and qualitative, as indicators of the parasite burden of hosts, using data from wild boars (Sus scrofa) living in Livorno Mountain Park (Tuscany, Central Italy). In the case of intestinal strongyles, which turned out to be the dominant helminths of wild boars, the qualitative coprological test appears as a bad predictor of the real parasite situation of the herds, due to the high number of false negative results (34 animals out of 68). On the other hand, the positive predictive value of the test is high (90%). The quantitative test is significantly correlated with the individual parasite burden of wild boars.     

Prevalence of Leptospira and Brucella antibodies in wild boars (Sus scrofa) in Tuscany, Italy

Five hundred sixty-two blood samples were collected from wild boars (Sus scrofa) shot in six districts of Tuscany, central Italy, between 1997 and 2000. Sera were examined for antibodies specific for Leptospira interrogans by microagglutination test and Brucella spp. by the Rose Bengal test and indirect enzyme-linked immunosorbent assay. Thirty-four (6.0%) samples tested positive for anti-Leptospira antibodies, 29 (5.1%) sera were positive for anti-L. interrogans serovar bratislava antibodies (titres ranging from 1:100-1:400), and 5 (0.9%) sera were positive for anti-L. interrogans serovar icterohaemorrhagiae antibodies (titres 1:100). All the examined sera were negative for anti-Brucella antibodies.     

Butterfly,spider, and plant communities in different land-use types in Sardinia,Italy

Butterfly, spider, and plant species richness and diversity were investigated in five different land-use types in Sardinia. In 16 one-hectare plots we measured a set of 15 environmental variables to detect the most important factors determining patterns of variation in species richness, particularly endemicity. The studied land-use types encompassed homogeneous and heterogeneous shrublands, shrublands with tree-overstorey, Quercus forest and agricultural land. A total of 30 butterfly species, among which 10 endemics, and 50 spider (morpho)species, were recorded. Butterfly and spider community composition differed according to land-use type. The main environmental factors determining diversity patterns in butterflies were the presence of flowers and trees. Spiders reacted mainly to habitat heterogeneity and land-use type. Traditional land-use did not have adverse effects on the diversity of butterflies, spiders, or plants. The number of endemic butterfly species per treatment increased with total species richness and altitude. Butterfly and spider richness did not co-vary across the five land-use types. Butterflies were, however, positively associated with plant species richness and elevation, whereas spiders were not. Conclusively, butterflies did not appear to be good indicators for spider diversity and species richness at the studied sites.     

甬江干流浮游动物群落结构季节动态与水环境的关系

对采自2011年3月-2012年2月间甬江干流13个断面的水样, 按照国家标准测试了9项理化指标, 并应用浮游动物定性和定量方法, 研究了浮游物群落结构特点和季节变化. 研究共记录浮游动物95种, 其中轮虫24属72种、枝角类5属10种、桡足类11属13种和4种其他门类无脊椎动物幼虫; 优势种主要来自于轮虫动物的臂尾轮虫属(Brachionus)和龟甲轮虫属(Keratella), 前者占了浮游动物总丰度的22.1%, 后者占总丰度的20.2%. 浮游动物的丰度值在各断面均呈明显的季节变化, 从断面1至断面6, 最大峰值出现在春季, 从断面7至断面13, 最大峰值多出现在夏季; 全干流最大峰值出现在断面5 (3160 ind./L). 浮游动物群落生物多样性指数呈上游段低, 中、下游河段高的现象; 应用中度干扰假说(Intermediate disturbance hypothesis)对此结果给予了解释. Two-way ANOSIM相似性分析和Bray-Curtis相似性等级聚类分析显示: 不同断面上不同季节的浮游动物群落间均存在显著差异, 分别为R=0.264、P=0.1%和R=0.234、P=0.1%, 且季节性差异大于断面间差异. 在季节性差异中以春季和夏季间的差异性最大. 主成分分析(PCA)表明: 对不同断面浮游动物群落起作用的理化因子依次为CODCr、TN、DO和BOD5; 对不同季节浮游动物群落起作用的理化因子依次为pH、TN/TP、盐度和水温.       

Lack of stasis in late Cenozoic marine faunas and communities, central California

Pliocene strata in the Kettleman Hills of west-central California were deposited in the broad San Joaquin embayment as a cyclic succession of parasequences during approximately three million years. Depositional environments within each cycle ranged from relatively open marine to brackish and non-marine. Although the strata were deposited in similar, recurrent environments, the fauna changed gradually rather than during brief intervals separating periods of stasis. Although environmental gradients and community structure in the Pliocene San Joaquin Embayment and in the present-day San Francisco Bay are similar, species compositions of the faunas and of parallel communities at the two sites are markedly different. In addition, times of origination and extinction of species in the Pliocene strata of the Kettleman Hills and in San Francisco Bay do not document coordinated stasis within the Late Cenozoic. In contrast, Silurian and Devonian faunas and communities of the Appalachian Basin persisted with little change in ecological-evolutionary units that lasted for up to eight million years. Relatively brief intervals of great biotic change separate these intervals of stasis. One intriguing explanation of this pattern of coordinated stasis within an ecologic-evolutionary unit is ecological locking, in which interaction between species within the community is sufficiently strong that only major changes in the environment are able to change community and faunal composition. Probably the late Cenozoic fauna underwent rapid evolution as a result of rapidly changing environmental conditions within a complex and changing shallow, inshore marine paleogeography. In contrast, coordinated stasis in the lower Paleozoic probably resulted from negligible evolution during long periods of stable to gradually changing environments in an outer shelf setting, punctuated by brief episodes of abrupt environmental change and large-scale turnover. The independent assortment of species in late Cenozoic parallel communities indicates that ecological locking did not exist.     

Depositional sequences in the Kimmeridgian of the Vocontian Basin (France) controlled by carbonate export from shallow-water platforms

Detailed sedimentological analyses and sequential and cyclostratigraphic interpretations in the Kimmeridgian of the Swiss Jura and the Vocontian Basin lead to a high-resolution correlation from the platform to the basin where the biostratigraphy is well established. Several orders of depositional sequences are defined. Their duration is estimated from the time frame given in the sequence-chronostratigraphic chart of Hardenbol et al. (1998). It is suggested that an elementary sequence formed in tune with the 20 ky precession cycle. Small-scale and medium-scale sequences correspond to the 100 and 400 ky eccentricity cycles, respectively. The platform-to-basin correlation shows that the composition of the hemipelagic and pelagic deposits depends to a large part on cyclical variations of carbonate production in shallow-marine environments and subsequent export to the basin. The distribution of thick versus thin marl-limestone alternations and carbonate-dominated versus marl-dominated intervals observed in the basinal sections is explained by the superposition of high- and low-frequency sea-level changes that controlled the carbonate productivity on the platform and the export potential of carbonate mud to the basin.     

Vegetation change and pollen recruitment in a lowland lake catchment: Groby Pool,Leics (England)

This investigation adopts an historical approach to pollen recruitment in a lowland English lake. The history of woodland and land-use has been reconstructed for the past 200 years from documentary sources and from the lake sediment pollen record. Comparison of these data sets are used to establish the effective pollen catchment of the lake and to investigate how well these support predictive models of pollen input to lakes.