Heavy metals in carabids (Coleoptera, Carabidae)

Carabid beetles (Coleoptera, Carabidae) are one of the most studied soil groups in relation to heavy metal (HM) accumulation and use for bioindication of environmental pollution. Accumulation of Zn and Cu in carabid beetles was species-, sex- and trophic group-specific. No differences were found in HM contents between omnivorous and carnivorous species. The use of carabid beetles as indicators of HM accumulation appears to be rather limited.     

温带落叶阔叶林地表鞘翅目成虫小尺度空间格局动态分析

土壤动物空间格局是格局—过程以及生物多样性维持机制研究的重要基础,目前小尺度空间土壤动物空间格局动态特征仍不清楚。基于地统计空间分析方法,以鞘翅目成虫为研究对象,研究帽儿山温带落叶阔叶林小尺度空间(5m)地表鞘翅目成虫群落及类群的空间格局动态特征。结果表明:4次调查共捕获鞘翅目成虫11科、29类、1021只个体,调查月份鞘翅目成虫群落具有较强的时空变异性;Moran'sⅠ系数表明鞘翅目成虫群落和类群具有复杂的正的空间自相关性,其空间异质性可用球状、指数、高斯和线性模型进行拟合。这种空间异质性具有一定的时间变化特征,且这种空间分异是由随机性因素单一调控或结构性因素和随机性因素共同调控的结果;类群之间在多种尺度上表现为复杂的以负相关居多的空间关联性,这种空间关联性的形成主要是结构性因素或随机性因素单一调控的结果。本实验表明地表鞘翅目成虫群落在小尺度空间具有明显的空间异质性特征,这种空间异质性时间变异性较明显。     

Effects of reduced pesticide dosages on carabids (Coleoptera: Carabidae) in winter wheat

Abstract

• 1 The effects of reduced insecticide and herbicide dosages on total dry mass of carabids and their generic components were examined using fenced pitfall traps in winter wheat fields on three farms in Southern Zealand, Denmark.
• 2 The estimated total dry mass of carabids increased by 25% when the pesticides were reduced to one fourth of the normal application rates.
• 3 At reduced dosages, the activity of the genus Pterostichus was increased by 62%. The activities of Loricera and Demetrias were increased by 67% and 56%, respectively, although significant interaction terms indicated that the dosage effect was not uniform for these genera on all farms. Calathus tended to be more numerous with reduced pesticide applications. By contrast, catches of Bembidion, Synuchus and Trechus decreased by up to 45% at reduced dosages.
• 4 A higher weed cover due to reduced herbicide applications probably benefited most species, except those having habitat associations with sparse vegetation such as the field‐inhabiting Bembidion and Synuchus.
• 5 The higher activity of larger carabids may lead to enhanced predation on smaller carabids and hence different carabid assemblages.

     

The importance of scale and spatial variables for the fungivorous beetle Bolitophagus reticulatus (Coleoptera, Tenebrionidae) in a fragmented forest landscape

Effects of isolation, habitat size and several microhabitat variables on presence/absence of the monophagous Bolitophagus reticulatus (L.) (Coleoptera. Tenebrionidae) were investigated in 58 forest fragments in an agricultural landscape (15 km²) in south-eastern Norway, All potential habitats of the beetle, dead Fomes fomentarius (L,) Kiekx basidiocarps (n = 587), were collected from trees (n = l85) within the study area. The basidiocarps were dissected and the number of B, reticulatus specimens (larvae, pupae and adults) counted. The material was analysed at four distinguishable spatial scales; basidiocarp-. tree-, tree-group- and forest island level. Different patterns of beetle presence emerged at the different scales, increasing habitat size and decreasing degree of isolation increased the probability of B, reticulatus presence at three (basidiocarp-, tree- and forest island level) and one (tree level) scales, respectively, whilst no such trends were found at the fourth level (tree-group level). Increasing insolation and thereby higher ambient temperatures, indicated by several microhabitat variables, improved the probability of beetle presence amongst the trees. The number of beetle specimens correlated positively with an increase in the habitat size at the tree level.     

Littoral macroinvertebrate communities: spatial scale and ecological relationships

SUMMARY 1. Spatial correlations between ecological patterns and processes are thought to be scale-dependent, yet surprisingly few studies have evaluated the correspondence between different levels of spatial scale and ecosystem structure and function.
2. We evaluated the strength of relationships between the benthic macroinvertebrate communities of stony littoral habitats and levels of ecological scale and geographical position, using partial constrained ordination. Our hypothesis was that correlation strength would be inversely related to ecological scale, i.e. habitat > ecosystem > riparian > catchment > ecoregion.
3. The effect of habitat was greater than that of other levels of spatial scale: 23% of the variance in taxonomic composition and 11% of that in functional composition was explained by habitat variables alone. However, greater spatial scales were also important. For example, the combined influence of riparian, catchment and ecoregion classification accounted for 24% (taxonomic) and 11% (functional) of the explained variance.
4. Relationships between organisms and scale variables were, however, non-linear and a substantial amount of the functional variance was hidden in joint effects. These findings were not unexpected, and presumably indicate a close interdependence between local and regional-scale variables.     

A comparative study of the immigration of carabids (Coleoptera,Carabidae) into a new polder

Summary The immigration of carabids into the Lauwerszeepolder (constructed in 1969) was studied in 4 areas. These areas have different types of soil and consequently different vegetations. The carabid fauna was sampled by means of striptraps and window traps. In this way a total number of 116000 specimens was caught.A comparison of the catches shows great differences between the fauna in different study areas in successive years. The data are compared with those of another Dutch polder (IJsselmeer polder). It is shown that about 50% of all species caught are able to fly. Moreover it is demonstrated that relatively more specimens of sparse populations than of dense populations fly.The data, especially those on ovarian development, show that flight occurs mostly in early adult life. Moreover, flight muscle autolysis at the onset of ovarian development is a common feature among carabids. Females fly more readily than males. Whereas the flight of most species covers only short distances, some species fly across the borders of their habitats. The data suggest five categories in carabids with respect to flight.Brachypterous carabids were very rarely found in the polder. It is suggested that changes in the numbers of macropterous specimens in carabid populations outside the polder proper are not due to dispersal.The role of migration in the stabilization of carabid populations is estimated to be very small.     

Transpiration from forest dwelling and woodland Mygalomorphae (Araneae)

Rates of water loss in dry air at room temperature (21±2°C) have been measured from seven species of forest-dwelling mygalomorph spiders. They range from 0.260% body wt h^?1 in the tube-dwelling trapdoor spiderDyarcyops sp. (from the humid coastal regions of eastern Australia) to 0.030% wt h^?1 inBrachypelma smithi (from drier environments in Mexico). There is a tendency for rates of transpiration to be related to the humidities of the spiders' normal environments and micro-habitats.     

Conceptual problems and scale limitations of defining ecological communities: a critique of the CI concept (Community of Individuals)

Recently, Looijen & van Andel (1999) proposed a new definition of an ecological community by using two criteria: (1) restricting membership by taxonomic relatedness, and (2) defining boundaries by the intersection of the area of population range boundaries. I analyze the implications of their definition and explore the limitations of the approach. Overall, I show this definition to be highly scale-limited, to not encompass many ecological concepts developed for the community level, and to have hidden assumptions that are not met in natural systems. An alternative model of the ecological community is proposed as a contrast, a model based on the community of an individual, in which individuals and interactions are used to develop the larger entity of an ecological community. This alternative model illustrates that the principal problems Looijen & van Andel (1999) discussed about previous community concepts with respect to application to vegetation classification are not ‘problems’ but are characteristics of ecological communities. Any definition of an ecological community must be able to incorporate these characteristics as well as current ecological concepts used at the community level.     

A faunistic review of carabids (Coleoptera,Carabidae) of the Barguzin Mt. Range (Northern Baikal Area)

The list of carabids from the Barguzin Mt. Range includes 132 species belonging to 29 genera of 17 tribes. Five new species endemic or subendemic to the Barguzin Mt. Range have been discovered. The carabid fauna of the Northern Baikal Area has a high percentage of species with wide distribution in the Palaearctic. The bulk of the fauna consists of species with Circumholarctic, Transpalaearctic, Euro-Siberian, Siberian, and Asian-American ranges. Sayano-Baikalian, Southern Siberian, Baikalian, and Transbaikalian species with local distribution are less numerous than the Mongolian, Kazakhstan, Amur, and Okhotian species. Lake Baikal and mountain ranges framing it form a meridional barrier for the distribution of some species.     

The effect of femel- and small scale clear-cutting on ground dwelling spider communities in a Norway spruce forest in Southern Germany

The early effects of femel-cutting (removing 20% of the trees) and small scale clear-cutting on ground-living spiders in a Norway spruce (Picea abies (L.) Karst.) forest in Southern Germany were investigated. The study was carried out as BACIP (before and after, control-impact, many paired samplings) study: Spiders were sampled during the pre-treatment year, the year of cutting, and the year after cutting. In total 7101 individuals were sampled, of which 4530 individuals were identified, 4468 were adult and 2633 individuals were juvenile. We identified 107 species, but a single species, Coelotes terrestris, dominated the control (spruce stand) comprising up to 49% of the total identified individuals. Clear-cutting changed the species composition in the traps, while the first step in femel-cutting preserved it. The number of individuals of the families Linyphiidae, Amaurobiidae, Agelenidae and Clubionidae decreased drastically within the 2 years after the clear-cutting, while the Lycosidae became numerically dominant in the clear-cut stands. The number of individuals with the following characterisation decreased significantly after clear-cutting: Small (<3.0 mm) and large spiders (>10.5 mm), web builders, ‘forest habitat species’, species favouring hygrophilic to medium moisture conditions, and preferences to live below ground or in and on the moss layer. On the other hand, middle-sized spiders, free hunters, ‘open habitat species’, spiders favouring dry conditions or that are euryoecious, preferring patterns covered by grasses or uncovered patches, increased in number. Clear-cut habitats with dense spruce regeneration showed a delayed and less pronounced response. With femel-cutting, species composition of ground-living spider communities may be preserved during the first step of regeneration of mature forest stands.     

中国北方桃李间作对步甲群落组成和营养级结构的影响

【目的】由于桃树和李树在生态环境要求上很相似, 在生产实际中, 在中国很多地方存在桃李间作或邻作的现象。本研究将通过试验明确桃李间作对步甲营养级结构的影响以便更全面地评价桃李间作是否有利于害虫防治。【方法】2006和2007年的4 -10月, 在山西省临汾市郊, 通过陷阱法对3块桃李间作果园和3块单一桃园内的步甲进行抽样, 每块果园的面积约0.3 hm²。比较两类桃园内步甲物种丰富度。将6种优势步甲物种, 两两单一成虫个体组合放在玻璃瓶内, 放在桃树下, 统计步甲相互攻击后的伤亡情况, 比较各物种的相互攻击能力, 确定主要步甲所属的营养级。统计分析两类桃园步甲营养级结构的差异。【结果】桃李间作园和单作桃园调查到的步甲物种均为24种, 估测步甲物种数在两类果园的差异也不显著（P≥0.38）。6种优势步甲可以分为4个营养级： 大盗步甲Lesticus magnus （Motschulsky）为高级捕食者, 大锹步甲Scarites acutides Chaudoir为次级捕食者, 双斑青步甲Chlaenius bioculatus Chaudoir和躅步甲Calathus halensis （Schaller）为初级捕食者, 毛婪步甲Harpalus griseus （Panzer）和直隶婪步甲Harpalus tschiliensis Schauberger为植食者。各营养级步甲相对多度均是桃李间作果园大于单一桃园, 独立T检验结果表明, 植食者步甲相对多度差异达极显著水平（P≤0.002）; 而捕食者步甲相对多度, 除2006年初级捕食者步甲相对多度差异显著（P=0.013）外, 在调查的两年中其他捕食者营养级步甲相对多度差异均不显著（P≥0.085）。【结论】结果表明, 桃李间作对步甲群落的物种组成和丰富度没有影响, 但是对果园内各营养级步甲相对多度有影响, 其中, 对植食者营养级步甲相对多度影响显著, 而对捕食者营养级步甲相对多度影响多不显著。     

The influence of forest stand and site characteristics on the composition of exotic dominated ambrosia beetle communities (Coleoptera: Curculionidae: Scolytinae)

Economic and biological consequences are associated with exotic ambrosia beetles and their fungal associates. Despite this, knowledge of ambrosia beetles and their ecological interactions remain poorly understood, especially in the oak-hickory forest region. We examined how forest stand and site characteristics influenced ambrosia beetle habitat use as evaluated by species richness and abundance of ambrosia beetles, both the native component and individual exotic species. We documented the species composition of the ambrosia beetle community, flight activity, and habitat use over a 2-yr period by placing flight traps in regenerating clearcuts and older oak-hickory forest stands differing in topographic aspect. The ambrosia beetle community consisted of 20 species with exotic ambrosia beetle species dominating the community. Similar percentages of exotic ambrosia beetles occurred among the four forest habitats despite differences in stand age and aspect. Stand characteristics, such as stand age and forest structure, influenced ambrosia beetle richness and the abundances of a few exotic ambrosia beetle species and the native ambrosia beetle component. Topographic aspect had little influence on ambrosia beetle abundance or species richness. Older forests typically have more host material than younger forests and our results may be related to the amount of dead wood present. Different forms of forest management may not alter the percent contribution of exotic ambrosia beetles to the ambrosia beetle community.     

Fossil carabids from Baltic amber -II - A new subgenus of Bembidion Latreille 1802 (Coleoptera: Carabidae: Bembidiini)

Bembidion (Archaeophilochthus) christelae a new subgenus and species belonging to the tribe Bembidiini (Coleoptera: Carabidae: Trechinae) preserved in a piece of Baltic amber (Eocene) is described. A comparison with recent fauna is made, and paleobiology of the species is hypothetized.     

The importance of streamside sandbars to ground beetle (Coleoptera, Carabidae) communities in a deciduous forest

We used pitfall traps to sample ground beetles on sandbars along a small woodland stream and in the adjacent floodplain forest (Oglethorpe Co., GA, USA). We captured a total of 1,477 ground beetles representing 41 species. Twenty-two species were exclusive to sandbars, while eight were found only in the forested habitat. Ground beetles were captured in significantly greater numbers from sandbars, especially Brachinus janthinipennis and Omophron americanum. The B. janthinipennis record represents a new state record for the species. This study demonstrates that many unique species can be found in specialized microhabitats and emphasizes the need for biodiversity assessment surveys to include a wide range of these microhabitats within a survey area. In addition, it appears that many generalist forest species might use sandbars seasonally to exploit available resources. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Structure in temperate predaceous diving beetle communities (Coleoptera: Dytiscidae)

Collection records of adult dytiscid beetles (Coleoptera, Dytiscidae) from 312 sites within the province of Alberta, Canada, were analyzed for patterns of similarity in species distribution. Sites compared on the basis of species occurrence (Jaccard coefficient of similarity and group average cluster analysis) separated into 12 principal clusters, interpreted as communities. However, cluster inclusion occurred at very low levels of similarity and 30% of sites were unclustered outliers. Ecological charade us tics of sites that were recognized as varying between dusters were salinity, productivity, stability, water temperature, substrate type, flow and vegetation. An index relating these qualitatively defined variables to species numbers is presented. An analysis of co-occurrence patterns of species was conducted as an alternative approach to definition of multispecies associations. Each possible combination of co-occurrence between pairs of species occurring in more than 5 collections each was tested for significance (p = 0.005) by means of Yates corrected χ² tests. Results of tests were expressed in binary terms, blank – no significance, x - significant. Species were then clustered on the basis of patterns of significant co-occurrences as above. This analysis was used as the basis for ordination of species in a symmetrical matrix with species ordered so as to maximize density of points of significant co-occurrence (x) around the principal diagonal. Areas in the matrix showing high densities of co-occurrence were interpreted as representing communities. The cluster analysis of species produced a better cluster pattern than obtained for sites but while generally similar, the species clustering pattern was less fine. The principal species groups consisted of those of saline water, alpine/subalpine lotic sites, other lotic habitats, and lentic habitats with two subgroups, species in forest areas and grassland species. The ordination, while reflecting this grouping of species, demonstrated that each group graded into others through loss of certain species and acquisition of others and thus showed the continuum nature of these communities. Restricting ordination to congeneric species indicated that these do not usually show identical patterns of co-occurrence but neither are patterns coincident with mutual exclusion. Within genera, considerable overlap in occurrence between species is the norm but species tend to occupy slightly different positions relative to one another along qualitatively defined ecological gradients. Relative position of species in these ordinations shows good correlation with patterns of geographical distribution lending support to the interpretation of ordination patterns reflecting relative ecological segregation. The dytiscid beetle fauna of north temperate regions is especially rich. Also, the large number of significant co-occurrences observed between species shows that species packing in many habitats of this region is dense. It is speculated that this species richness is possible because of the seasonality of habitats at these latitudes which reduces competition and predation from other groups and produces seasonal pulses of high productivity permitting a species rich fauna to develop because of abundant resources. It is likely that factors other than interspecific competition for resources are important in shaping dytiscid communities in habitats with strong nutrient pulses.     

The effect of local anthropogenic habitat heterogeneity on assemblages of carabids (Coleoptera,Caraboidea) endemic to the Alps

We assessed the response of a guild of endemic medium and large-bodied carabid species to the local (fine-grained) habitat heterogeneity induced by man. The study was conducted by means of trapping (without killing and preservative agents) and radio-tracking methods (to collect data on the spatial ecology of the endangered species Carabus olympiae Sella). Habitat differentiation induced by man (a mosaic of beech forests, alpen rose shrubberies and pastures) affected species richness and abundance of the guild, which were significantly higher in forests and/or shrubberies than in pastures. Most species preferred forests and shrubberies, with the only exception of Carabus concolor Fabricius, which preferred open areas. Species distribution was also affected by stone density and cattle grazing intensity. In particular, petrophilous species peaked on the roadside because of the high stone density there (stones amassed during road construction), while species abundances significantly lowered in overgrazed pastures. The compactness of the paths made by C. olympiae individuals (evaluated through a tortuosity index) was significantly higher in beech forests than in alpen rose shrubberies, indicating movements in the latter habitat type were bound by the spatial distribution of shrubs, which imposes a limit on path tortuosity. Our findings suggest that local ground beetle species diversity strongly depends on small-scale anthropogenic variables (namely habitat type, stone density and grazing intensity), and that habitat modifications (namely from forest to shrubbery) may significantly affect species movement patterns. General and local conservation management suggestions are given in conformity with these results.     

The role of spatial scale and intraspecific variation in secondary chemistry in host-plant location by Ceutorhynchus assimilis (Coleoptera: Curculionidae)

To understand the ecological role of secondary plant compounds in host location by phytophagous insects it is important to consider attraction at different scales in natural populations. The cabbage seed weevil, Ceutorhynchus assimilis, which lays eggs in pods of crucifers where the larvae feed on seed, is attracted to purified extracts of specific glucosinolate-derived volatiles. We considered the possibility that C. assimilis adults are attracted to and preferentially attack patches of plants and/or individual plants producing these volatiles. Using discrete natural populations of Brassica oleracea and Brassica nigra, we found that oviposition was highest in populations of B. oleracea producing high amounts of 3-butenylglucosinolate. No links were found between the other glucosinolates, 2-propenylglucosinolate, 2-hydroxy-3-butenylglucosinolate, 1-indolylmethylglucosinolate or 1-methoxy-3-indolylmethylglucosinolate, and oviposition in B. oleracea. B. nigra, which contains only 2-propenylglucosinolate, was not attacked by C. assimilis. Within populations of B. oleracea, neither oviposition nor the number of seeds eaten was related to the glucosinolate profiles of individual plants. We suggest that C. assimilis adults use 3-butenylglucosinolate-derived volatiles to locate host populations, whereas other cues determine oviposition on individual plants. The consequences of these results for natural selection of glucosinolate phenotypes are discussed.     

Vegetative communities as indicators of ground beetle (Coleoptera: Carabidae) diversity

Accurately measuring biodiversity is essential for successful conservation planning. Due to biodiversity’s complexity, specific taxa are often chosen as indicators of patterns of diversity as a whole. Such taxa can include vegetation which can inform conservation decisions by demarcating land units for management strategies. For land units to be useful, they must be accurate spatial representations of the species assemblages present on the landscape. In this study, we determined whether land units classified by vegetative communities predicted the community structure of a diverse group of invertebrates—the ground beetles (Coleoptera: Carabidae). Specifically, that (1) land units of the same classification contained similar carabid species assemblages and that (2) differences in species structure were correlated with variation in land unit characteristics, including canopy and ground cover, vegetation structure, tree density, leaf litter depth, and soil moisture. The study site, the Braidwood Dunes and Savanna Nature Preserve in Will County, Illinois is a mosaic of differing land units. Carabid beetles were sampled continuously with pitfall trapping for 1 year (excluding winter) from September 2011 to November 2011 and from March 2012 to September 2012. Land unit characteristics were measured in July 2012. Nonmetric multidimensional scaling (NMDS) ordinated the land units by their carabid species assemblages into five ecologically meaningful clusters: disturbed, marsh, prairie, restoration, and savanna. The subset of land unit characteristics with the highest rank correlation with the NMDS ordination included soil moisture, leaf litter depth, percentage of canopy cover, and percentage of grass ground cover. Land units classified by vegetative communities effectively represented carabid species assemblages.     

Improving generalized regression analysis for the spatial prediction of forest communities

Aim This study used data from temperate forest communities to assess: (1) five different stepwise selection methods with generalized additive models, (2) the effect of weighting absences to ensure a prevalence of 0.5, (3) the effect of limiting absences beyond the environmental envelope defined by presences, (4) four different methods for incorporating spatial autocorrelation, and (5) the effect of integrating an interaction factor defined by a regression tree on the residuals of an initial environmental model. Location State of Vaud, western Switzerland. Methods Generalized additive models (GAMs) were fitted using the grasp package (generalized regression analysis and spatial predictions, http://www.cscf.ch/grasp ). Results Model selection based on cross‐validation appeared to be the best compromise between model stability and performance (parsimony) among the five methods tested. Weighting absences returned models that perform better than models fitted with the original sample prevalence. This appeared to be mainly due to the impact of very low prevalence values on evaluation statistics. Removing zeroes beyond the range of presences on main environmental gradients changed the set of selected predictors, and potentially their response curve shape. Moreover, removing zeroes slightly improved model performance and stability when compared with the baseline model on the same data set. Incorporating a spatial trend predictor improved model performance and stability significantly. Even better models were obtained when including local spatial autocorrelation. A novel approach to include interactions proved to be an efficient way to account for interactions between all predictors at once. Main conclusions Models and spatial predictions of 18 forest communities were significantly improved by using either: (1) cross‐validation as a model selection method, (2) weighted absences, (3) limited absences, (4) predictors accounting for spatial autocorrelation, or (5) a factor variable accounting for interactions between all predictors. The final choice of model strategy should depend on the nature of the available data and the specific study aims. Statistical evaluation is useful in searching for the best modelling practice. However, one should not neglect to consider the shapes and interpretability of response curves, as well as the resulting spatial predictions in the final assessment.     

Below-ground ectomycorrhizal communities: the effect of small scale spatial and short term temporal variation

Ectomycorrhizal (ECM) associations are an important form of symbiosis for the majority of tree species. In forest ecosystems where nutrients are often limited, ECM associations are vital for seedling establishment and tree survival. ECM communities are often very species rich and frequently follow the log normal distribution??with a few species being abundant and many species being rare. Much of the current knowledge of ECM communities has been revealed through a combination of above-ground sporocarp and below-ground root tip analyses. However, above-ground surveys of ECM communities reveal largely different findings regarding ECM diversity and community structure to below-ground surveys. Therefore below-ground surveys are vital to our understanding of ECM biology, ecology and community dynamics. In this article I review the recent findings regarding how ECM communities vary both spatially and temporally in forests. Spatial variation occurs at the centimetre scale both horizontally and vertically in forests, and can be explained by the separation of the ECM community into distinct niches. Temporal variation occurs over relatively short time scales, with ECM communities showing large changes even on a monthly basis. I then apply the niche concept to ECM fungi, and review a recent theory, ECM functional morphology, and examine how this may be used to explain a significant amount of spatial and temporal variation in forest ECM communities. The functional morphology theory is particularly useful in explaining patterns of ECM community variation across the distinct successional stages of the forest cycle. However, the effect of other abiotic and biological variables on ECM communities should not be ignored. Finally, as ECM communities are non-randomly distributed and vary widely in species richness over time, I lay out a sampling strategy to provide representative samples of the actual ECM community in the study area. Using (i) an extensive sampling methodology, (ii) separation of samples at distances greater than levels of spatial autocorrelation, and (iii) samples collected throughout the year, over a number of years, an ample picture of the ECM community in temperate forests can be collected.