Small-scale spatial variation of pasture molluscan faunas within a relic watermeadow system at Wylye, Wiltshire, U.K.

Aim To acquire general quantitative data on the molluscan faunas of floodplain pastures, assessing the influence of (minor) topographic variation on molluscan distribution. Additionally, to examine the potential for analogous comparison with fossil data Location The study was located within a relic watermeadow system currently used as floodplain pasture near Wylye, Wiltshire, U.K. Methods Mollusca were extracted from forty turf samples collected from relic carriers (cf. ridges) and relic drains (cf. furrows). Molluscan faunal differences between carriers and drains were assessed using TWINSPAN and diversity indices. Results The dry relic carriers, characterized by a short grassy sward, showed a low-diversity Trichia-Vallonia-Cochlicopa-Nesovitrea fauna. The damper relic drains, characterized by longer vegetation comprising both rushes and grasses, additionally contained other molluscan species indicative of wetter and/or more sheltered conditions and had significantly more diverse faunas Main conclusions Intra-site variability of molluscan faunas can be demonstrated with relatively minor changes in topography, hydrology and/or vegetation structure. In addition, the study clearly aids in the analogous interpretation of Holocene subfossil assemblages from the same region.     

Paleoecology of some molluscan assemblages from the badenian (Miocene) marine sandy facies of Poland

Three molluscan assemblages from the Badenian (Miocene) marine sandy facies of Poland are described in terms of their taxonomic composition, diversity, and trophic structure. The structural variation between the molluscan assemblages seems to be largely controlled by a gradient in water energy which in turn results in gradients in substrate mobility and organic content of bottom sediments. Together with a subordinate factor of local sedimentation rate, these gradients control the distribution of lucinoid mucus tube feeders vs. deep burrowing siphonate suspension feeders, of browsers, and of deposit feeders vs. suspension feeders. Some structural features of the molluscan assemblages are regarded as related to biotic factors. The graphs of cumulative species frequencies vs. the logarithm of cumulative individual frequencies are used as a measure of community organization. These graphs indicate distinct differences in ecological maturity between the molluscan assemblages. On this basis, two different stages of ecological succession in an offshore sandy bottom environment are recognized. The evidence from the comparison of the Miocene molluscan assemblages with their recent counterparts may support the view that the evolutionary stability of species populations of a given community, and long-term stability of the community structure are independent. High environmental variability and stress seem to be correlated with evolutionary stability of species populations rather than with long-term permanence of community structure.     

Diurnal butterflies (Lepidoptera, Rhopalocera) of the Solovetskie Islands (Northwestern Russia, the White Sea)

The species composition and diversity of Lepidoptera Rhopalocera were studied on the Solovetskie Islands during five years (2001–2005). Twenty-nine species of five families were recorded. The most abundant species are Leptidea sinapis, Boloria aquilonaris, Heodes virgaureae, Plebejus argus, Arcia eumedon, and Cyaniris semiargus. The fauna of these islands is poorer than local faunas of the continental northern taiga, forest-tundra, and southern tundra of Europe. The species diversity of insular assemblages of diurnal lepidopterans is lower in comparison with analogous continental assemblages. They are characterized by the mixed species composition, when species with different ecological preference occur within the same habitat.     

Spatial variation in species diversity and composition of flea assemblages in small mammalian hosts: geographical distance or faunal similarity?

Aim Spatial variation in the diversity of fleas parasitic on small mammals was examined to answer three questions. (1) Is the diversity of flea assemblages repeatable among populations of the same host species? (2) Does similarity in the composition of flea assemblages among populations of the same host species decay with geographical distance, with decreasing similarity in the composition of local host faunas, or with both? (3) Does the diversity of flea assemblages correlate with climatic variables? Location The study used previously published data on 69 species of small mammals and their fleas from 24 different regions of the Holarctic. Methods The diversity of flea assemblages was measured as both species richness and the average taxonomic distinctness of their component species. Similarity between flea assemblages was measured using both the Jaccard and Morisita–Horn indices, whereas similarity in the composition of host faunas between regions (host ‘faunal’ distance) was quantified using the Jaccard index. Where appropriate, a correction was made for the potentially confounding influence of phylogeny using the independent contrasts method. Results Flea species richness varied less within than among host species, and is thus a repeatable host species character; the same was not true of the taxonomic distinctness of flea assemblages. In almost all host species found in at least five regions, similarity in flea assemblages decreased with increases in either or both geographical and faunal distance. In most host species, the diversity of flea assemblages correlated with one or more climatic variable, in particular mean winter temperature. Main conclusions Spatial variation in flea diversity among populations of the same mammal species is constrained by the fact that it appears to be a species character, but is also driven by local climatic conditions. The results highlight how ecological processes interact with co‐evolutionary history to determine local parasite biodiversity.     

The shapes of phylogenetic trees of clades, faunas, and local assemblages: exploring spatial pattern in differential diversification

Life on Earth is characterized by strong diversity skewness: related lineages typically show pronounced variation in diversification success, and clades contain hyperdiverse and depauperate subclades. Previous studies have documented diversity skewness only for entire (global) clades. We demonstrate methods for measurement and significance testing of diversity skewness of local assemblages and regional biotas; we illustrate this with an analysis of geographic structure in diversity skewness of primate assemblages. For primates, continental faunas differ in diversity skewness from expectations based on the global phylogeny: South American faunas have significantly low skewness and African faunas have significantly high skewness. However, no local assemblage has diversity skewness different from that expected based on sampling the continental fauna. We also document a latitudinal gradient in diversity skewness for the African assemblages and test for (but do not find) associations of skewness with longitude, local species richness, and net primary productivity. Our data suggest that continental-scale biogeographic events rather than local-scale processes have shaped diversity skewness in modern primate faunas.     

Increasing habitat connectivity in agricultural landscapes as a weed management strategy reconciling ecology and agronomy

While studies have explored how habitat amount drives weed assemblages in agroecosystems, knowledge remains limited of the effects of habitat connectivity. The response-effect trait framework provides insights into the mechanisms underpinning the relationship between landscape structure and the taxonomic diversity and abundance of weed assemblages. This study evaluated how habitat connectivity and habitat amount affect weed diversity and abundance in winter cereal fields, and whether these effects are driven by the functional composition of weed assemblages. We sampled weeds in 27 winter cereal fields. We measured habitat connectivity and habitat amount provided by wooded, grassland and cropland elements. We selected five traits related to the dispersal, establishment, and competitive abilities of weed species likely to respond to landscape structure: seed number per plant, type of reproduction, seed dry mass, plant vegetative height and seed germination rate. The functional composition of weed assemblages was assessed using community weighted mean trait values. Weed diversity and abundance were used as proxies of weed management. The taxonomic approach did not reveal any effect of landscape structure on weed diversity and abundance. Only the grassland elements that contributed to habitat connectivity, and to a lesser extent to habitat amount, drove the functional composition of weed assemblages. High habitat amount favoured species with many seeds, while high habitat connectivity favoured species with fewer seeds, a higher ability to reproduce vegetatively and higher seed germination rates. In turn, higher seed germination rates increased weed evenness and reduced weed abundance. Some of these relationships were influenced by the presence of rare species. Overall, high connectivity provided by grassland elements increases weed evenness and reduces weed abundance by shaping weed functional composition. Our study suggests that land-use planning policies that enhance the connectivity provided by grassland elements could be considered as a weed management strategy reconciling ecology and agronomy.     

A palaeoecological model for the interpretation of wild plant species

The interpretation of subfossil records of wild plant species with respect to both environmental conditions and past vegetation is complicated by the following: (1) production and dispersal of plant remains including diaspores, (2) the formation of the soil flora, (3) taphonomic processes and differential preservation that act on subfossil assemblages and (4) methods applied to produce subfossil records. Whereas the similarity between recent plant communities and seed banks is often weak, the relationship between past vegetation and subfossil assemblages is still more complicated. It is therefore unlikely that macrofossil assemblages derived from soil samples can be considered as pure samples representing particular palaeobiocoenoses. The assumption that plant communities, in the past, may have been in some way aberrant with respect to composition and that the ecological ranges of species varied during the Quaternary has to be rejected, if not based on well considered assumptions or evidence from pure samples. Only if a sufficient number of suitable studies is available, which enable evaluation between all kinds of plant communities and their respective seed floras, can progress be made with regard to the reconstruction of past vegetation and environmental conditions. As long as these data are not available, the ecological interpretation of particular subfossil assemblages isolated from soil samples has to be carefully evaluated within their particular context.     

Contrasting patterns of elevational zonation for birds and mammals in the Andes of southeastern Peru

Abstract. To determine the generality of avian diversity patterns, we investigated patterns of elevational zonation shown by birds and mammals along the eastern slope of the Andes Mountains in southeastern Peru. The strong environmental gradient sampled, entirely within Peru's Manu National Park and Biosphere Reserve, supports highly diverse faunas. Elevational distributions of 901 bird species, 129 bat species, and twenty-eight species of native mice exhibit contrasting patterns in species richness, species composition, and species turnover. Birds and bats showed smooth declines of species richness with elevation, whereas the richness of mouse assemblages was unrelated to elevation. For all three groups, the greatest differences were between lowland and highland faunas, although cutoff points for this contrast varied among groups (≈ 500 m for birds, 750 m for bats, and 1000 m for mice). Differences in composition also separated bird and bat faunas on either side of c. 1400 m (the boundary between montance forest and cloud forest); for mice, this faunal transition may take place nearer to 2000 m. Bird and bat faunas lacked the more discrete zonations suggested for mouse assemblages, as indicated by elevational range profiles and nested subset analyses. Distinct highland assemblages are apparent in two-dimensional histograms of range limits of birds and mice, but not for bats. Highland bat species occupy broader elevational ranges than lowland bat species, but for both birds and mice, species at intermediate elevations had the broadest amplitudes. Finally, clumping of range maxima and minima along the gradient identified zones of pronounced species turnover in each group, but these were generally not strongly associated with the locations of ecotones. Differences in zonation of these groups appear to reflect their different biological attributes and phylogenetic histories. Such differences obviously complicate discussions of ‘general’ diversity patterns, and limit the usefulness of birds to forecast or predict diversity patterns in other more poorly known groups—other groups may show elevated diversity and endemism in areas where avian diversity patterns appear unremarkable. The pronounced contrasts between bats and mice, and the generally intermediate character of avian patterns, suggest that future analyses might profitably partition birds into finer, more homogeneous groups of historically and/or ecologically similar species. Group differences in zonation may ultimately prove explicable with information on both species-abundance patterns and resource distributions.     

Demersal fish assemblages and spatial diversity patterns in the Arctic-Atlantic transition zone in the Barents Sea

Direct and indirect effects of global warming are expected to be pronounced and fast in the Arctic, impacting terrestrial, freshwater and marine ecosystems. The Barents Sea is a high latitude shelf Sea and a boundary area between arctic and boreal faunas. These faunas are likely to respond differently to changes in climate. In addition, the Barents Sea is highly impacted by fisheries and other human activities. This strong human presence places great demands on scientific investigation and advisory capacity. In order to identify basic community structures against which future climate related or other human induced changes could be evaluated, we analyzed species composition and diversity of demersal fish in the Barents Sea. We found six main assemblages that were separated along depth and temperature gradients. There are indications that climate driven changes have already taken place, since boreal species were found in large parts of the Barents Sea shelf, including also the northern Arctic area. When modelling diversity as a function of depth and temperature, we found that two of the assemblages in the eastern Barents Sea showed lower diversity than expected from their depth and temperature. This is probably caused by low habitat complexity and the distance to the pool of boreal species in the western Barents Sea. In contrast coastal assemblages in south western Barents Sea and along Novaya Zemlya archipelago in the Eastern Barents Sea can be described as diversity "hotspots"; the South-western area had high density of species, abundance and biomass, and here some species have their northern distribution limit, whereas the Novaya Zemlya area has unique fauna of Arctic, coastal demersal fish. (see Information S1 for abstract in Russian).     

Contribution to the fauna of mollusk-eating marsh flies (Diptera,Sciomyzidae) of Yakutia

A total of 38 species belonging to 14 genera and 2 tribes of the family Sciomyzidae were recorded from Yakutia. Among these species, 23, 6, and 8 species were recorded from Yakutia, eastern Siberia, and Siberia, respectively, for the first time. The fauna of Central Yakutia, comprising 33 species, is examined best of all. The range diversity of investigated sciomyzids is classified into 13 types. Species with Holarctic and trans-Eurasian ranges constitute the largest groups comprising 12 species each. Colobaea punctata, Ilione albiseta, Pherbellia brunnipes, and Sepedon sphegea are very abundant. The species composition of the Yakut fauna noticeably differs from neighboring faunas of the Russian Far East, Mongolia, and Alaska, but the generic composition of these faunas is more similar. The Yakut fauna of the Sciomyzidae is intermediate between the fauna of Mongolia and the faunas of the Russian Far East and Alaska. The fraction of marsh flies in dipteran assemblages of meadow cenoses is usually small, but their abundance in some years grows significantly. The population density of marsh flies in the valleys of large rivers is higher in comparison with that found in isolated alas hollows in the plakors (= euclimatopes). Analysis of the trophic associations of the larvae of the Yakut sciomyzids has revealed 5 out of the 7 groups known in the family.     

Quantitative studies of modern wet-ground molluscan faunas from Bossington, Hampshire

There have been few quantitative studies of modern Mollusca in Britain, especially from wet-ground areas. This is particularly true of the English chalklands, which is surprising given the focus of sub-fossil molluscan research in that area. Those studies that are available highlight the difficulty of separating molluscan faunas from structurally complex habitats such as fen and carr. Quantitative molluscan data from a variety of wet-ground habitats situated within the chalklands of southern England were analysed using an indirect ordination technique, Principal Components Analysis. This demonstrated that the separation of faunas from structurally complex wet-ground habitats is possible. The numerical separation does not rely on indicator species, but is a function of variation of the predominant species. It is suggested that further studies of this type might aid the interpretation of sub-fossil Mollusca from wet-ground contexts.     

Does urbanization decrease diversity in ground beetle (Carabidae) assemblages?

Aim We wanted to test whether urbanization has similar effects on biodiversity in different locations, comparing the responses of ground beetle (Coleoptera, Carabidae) assemblages with an urbanization gradient. We also wanted to see if urbanization had a homogenizing effect on ground beetle assemblages. Locations Nine forested temperate locations in Europe, Canada and Japan. Methods Published results of the Globenet Project were used. At all locations, three stages were identified: (1) a forested (rural) area, (2) a suburban area where the original forest was fragmented and isolated, and (3) remnants of the original forest in urban parks. These habitats formed an urbanization series. Study arrangements (number and operation of traps) and methods (pitfall trapping) were identical, conforming to the Globenet protocol. Assemblage composition and diversity patterns were evaluated. Diversity relationships were analysed by the Rényi diversity ordering method considering all ground beetles and – separately – the forest specialist species. Taxonomic homogenization was examined by multivariate methods using assemblage similarities. Results Overall biodiversity (compared by species richness and diversity ordering) showed inconsistent trends by either urbanization intensity or by geographic position. However, when only forest species were compared, diversity was higher in the original rural (forested) areas than in urban forest fragments. Within‐country similarities of carabid assemblages were always higher than within‐urbanization stage similarities. Main conclusions Urbanization does not appear to cause a decrease in ground beetle diversity per se. Forest species decline as urbanization intensifies but this trend is masked by an influx of non‐forest species. The rural faunas were more similar to the urban ones within the same location than similar urbanization stages were to each other, indicating that urbanization did not homogenize the taxonomic composition of ground beetle faunas across the studied locations.     

Disentangling the role of management,vegetation structure,and plant quality for Orthoptera in lowland meadows

Seminatural grasslands provide habitats for various species and are important for biodiversity conservation. The understanding of the diverse responses of species and traits to different grassland managenient methods is therefore urgently needed. We disentangled the role of grassland management (fertilization and irrigation), vegetation structure (biomass, sward height) and plant quality (protein and fiber content) for Orthoptera communities in lowland hay meadows in Germany. We found vegetation structure to be the most important environmental category in explaining community structure of Orthoptera (species richness, total individuals, fiinctional diversity and species composition). Intensively used meadows (fertilized, irrigated, high plant biomass) were characterized by assemblages with few species, low functional diversity, and low conservation value. Thereby, the relatively moderate fertilizer inputs in our study system of up to -75 kg N/ha/year reduced functional diversity of Orthoptera, while this negative effect of fertilization was not detectable when solely considering taxonomic aspects. We found strong support for a prominent role of plant quality in shaping Orthoptera communities and especially the trait composition. Our findings demonstrate the usefulness of considering both taxonomic and functional comp on ents (functio nal diversity) in biodiversity research and we suggest a stronger involvement of plant quality measures in Orthoptera studies.     

Morphological diversity among fishes in a Great Plains river drainage

Longitudinal succession of stream fish faunas is commonly related to increasing stream size and stability. However, effects of succession on assemblage morphology are seldom quantified. We used an ecomorphological approach to determine differences in faunal structure among distinct stream types of the Cheyenne River drainage in South Dakota, USA. During May–October 2004 we collected fishes monthly from five streams. We examined 28 morphological traits of the dominant fish species and compared morphological structure among faunas using univariate analysis of variance (ANOVA) tests and multivariate ordination and distance calculation techniques. Species richness and composition varied between smaller creeks and larger rivers. Morphological diversity increased with richness, but richer assemblages were also more tightly packed in morphospace, partly because of increased cyprinid richness. Some morphological differences were predicted by variation in mean discharge and discharge flashiness (flow stability). Fishes of more stable or larger river stations characteristically had smaller heads and mouths and longer intestines. Larger mean standard length was also associated with less flashy flow regimes and higher mean discharge. All assemblages were hyperdispersed in morphological space, consistent with the harsh zoogeographical history of the region and suggesting the presence of open niches. Increasing species and morphological diversity despite increasing discharge flashiness suggests higher niche diversity in Great Plains rivers compared to adjacent creeks. Handling editor: J. A. Cambray     

Effects of urbanization on ground beetle assemblages (Coleoptera, Carabidae) of grassland habitats in western Canada

We pitfall-trapped carabid beetles across an urban-rural gradient in central Alberta, Canada to assess the relative contributions of landscape structure and habitat quality in explaining variation in composition of assemblages. The gradient ranged from the "urban" zone in the city of Edmonton, through a "suburban" zone just outside the city, into a "rural" zone 25–60 km east of the city. We trapped beetles at three replicated sites for each of two habitats (unmanaged grasslands and highly managed graveyards) in each of the three zones. Most of the 24 species (3162 individuals) captured were commonly associated with open habitats. Pterostichus melanarius , an introduced species, made up 80% of the total catch. Carabid assemblages of grasslands and graveyards were distinct, with lower species richness and lower catch rates of native, introduced and brachypterous carabids in graveyards. Graveyard assemblages also had proportionally fewer brachypterous carabid individuals (32 vs 52%) and species (20 vs 36%), suggesting that populations recruit locally from elsewhere after disturbances. Native carabids were least abundant in the urban areas. Brachypterous carabids were similarly abundant across the gradient, but more occurred in the urban zone than elsewhere (32 vs 5–10%). Samples from graveyards were characterized by lower beta diversity (variation among samples) than those from grasslands, but beta diversity was more-or-less equally variable across the gradient within habitats. The amount of unmanaged grassland habitat and the degree of urbanization significantly influence carabid assemblages, and therefore are relevant to management and conservation of urban grassland areas.     

Community Associations of Chalk Grassland Leafhoppers (Hemiptera: Auchenorrhyncha): Conclusions for Habitat Conservation

Due to their confinement to specific hostplants or restricted habitat types, Auchenorrhyncha have the potential to make suitable biological indicators to measure the quality of chalk grassland under different management practices for nature conservation. The Auchenorrhyncha data from a study designed to identify the factors influencing the invertebrate diversity of chalk grasslands in southern England was used to evaluate the potential use of this group of insects as biological indicators. Between 1998 and 2002 altogether 81 chalk grassland sites were sampled. Vegetation structure and composition were recorded, and Auchenorrhyncha were sampled at each site on three occasions in each of two seasons using a ‘Vortis’ suction sampler. Auchenorrhyncha assemblages were then linked to the different grassland plant communities occurring on chalk soils according to the British National Vegetation Classification (NVC). Altogether 96 Auchenorrhyncha species were recorded during the study. Using data on the frequency and dominance of species, as is commonly done for plant communities, it was possible to identify the preferential and differential species of distinct Auchenorrhyncha assemblages. Significant differences between the Auchenorrhyncha assemblages associated with the various chalk grassland plant communities of the NVC were observed down to a level of sub-communities. We conclude that data on Auchenorrhyncha assemblages can provide valuable information for the setting of conservation management priorities, where data on floristic composition alone may not be sufficient, providing additional information on aspects of vegetation structure and condition.     

Ordovician eunicid polychaetes of Estonia and surrounding areas: review of their distribution and diversification

Scolecodonts, the jaws of polychaete worms, are common and diverse palynomorphs in the Ordovician rocks of Estonia and surrounding areas. Some 120 apparatus-based species representing about 40 genera have been recorded thus far. Relatively long stratigraphical ranges of the majority of species reflect a low rate of evolution of jawed polychaetes. However, some individual species, as well as structural changes in the assemblages, appear to be useful for stratigraphical purposes. Environmental events like those in the middle Caradoc and late Ashgill had some impact on polychaete faunas, but less than on several other groups. In order to study the spatial distribution of eunicids, faunas of particular intervals of the Ordovician were investigated. Quantitative analysis revealed that polychaete assemblages with a very consistent qualitative and quantitative composition were widespread over long distances within the belts of similar facies conditions in the Baltoscandian Palaeobasin. On the other hand, it appears that species of Ordovician jawed polychaetes were strongly influenced by particular facies, and accordingly well differentiated along the palaeobasin gradient. The decrease in diversity and abundance towards the deeper-water part of the palaeobasin indicates that the majority of Ordovician eunicids preferred relatively shallow-water conditions. The increase in differentiation of environments is accompanied by an increase in differentiation of polychaete assemblages.     

Influence of setting,sieve size,and sediment depth on multivariate and univariate assemblage attributes of coral reef-associated mollusc death assemblages from the Gulf of Aqaba

Measures of diversity and ecology of marine invertebrate assemblages depend on a variety of factors including environmental conditions and methodological decisions. In this study, the influence of such factors on multi- and univariate assemblage parameters of molluscan death assemblages from the Gulf of Aqaba (Red Sea, Jordan) was evaluated. Sediment samples were collected at two coral reef types, a patch reef at 13 m of water depth characterized by fine-grained sediments and a Millepora-fringing reef with coarse-grained sediments at 5 m of water depth. The upper and lower 10 cm of the sediment column were separately removed and sieved with mesh sizes of 1 and 2 mm. A large dataset of 6400 bivalve and gastropod shells was compiled to evaluate how setting, sediment depth, and sieve size influenced taxonomic composition and species richness, species-abundance patterns and the Shannon–Wiener index, the number of drilled shells per species and drilling frequency (DF) of the assemblage. Setting had the strongest impact on all aspects, followed by sieve size, but sediment depth was insignificant, probably due to complete homogenization of the sediments by reworking and bioturbation. Multivariate assemblage parameters distinguished much better between categories (setting, sieve size) than univariate measures. Sieve size-related disagreements recognized between the two higher taxa are mostly due to the underlying difference in body-size distribution of bivalve and gastropod assemblages. We conclude that species richness and other ecological characteristics of molluscan death assemblages in coral reef-associated sediments will most strongly reflect habitat complexity of the sites chosen, are significantly influenced by methodological decisions (i.e., sieve size), will only poorly preserve temporal patterns, and the results will differ between bivalves and gastropods.     

Weichselian chironomid and cladoceran assemblages from maar lakes

Sediments from maar lakes in the periglacial area were analysed to obtain information about the limnetic fauna of Pleniglacial lakes. On the basis of abundance and species composition of the subfossil chironomid and cladoceran assemblages, three major zones were biostratigraphically separated: the Upper Pleniglacial, the Middle Pleniglacial, and the Eem Interglacial.