宁夏盐池荒漠草原步甲物种多样性

采用巴氏罐诱法于2009年3月到10月对盐池四墩子3种不同类型荒漠草原的步甲物种组成、数量分布进行了系统调查,共获得步甲标本1318号,分属于9属15种,其中直角通缘步甲Pterostichus gebleri、蒙古伪葬步甲Pseudotaphoxnus mongolicus、径婪步甲Harpalus salinus和短翅伪葬步甲Pseudotaphoxnus brevipennis为优势种,个体数量分别占个体总数的33.08%、19.73%、15.94%和8.04%。多样性分析表明适度干扰荒漠草地的Shannon-Wiener多样性、丰富度和均匀度均高于低干扰和强干扰荒漠草地。群落相似性分析显示猪毛蒿和甘草混交带与围栏放牧带及柠条带有较高的相似性,蒙古冰草带和苜蓿与柠条混种带相似性较高。从时间动态上看,步甲群落的个体数量在8月份达到最高。4种优势种季节性变化分别是直角通缘步甲盛发期为8月,径婪步甲发生的高峰期为8、9月,短翅伪葬步甲在5月和8月,蒙古伪葬步甲7-10月个体数量均多;不同物种在不同类型荒漠草地出现的高峰期是不一致的。典范对应分析(CCA)分析表明土壤含水量是影响步甲分布的最重要环境因子,植物生物量和植被密度次之;土壤含水量与步甲的Shannon-Wiener多样性、均匀度显著负相关,与优势度呈显著正相关。     

不同土地利用方式对河北坝上步甲物种多样性的影响

为了探讨土地利用方式对步甲物种多样性的影响及其与环境因子的关系, 于2009年5-10月利用巴氏罐法, 对河北坝上塞北管理区内的灌草丛、马铃薯地、苜蓿地、围封草地、中度放牧草地和重度放牧草地6种生境的步甲进行了系统调查。结果表明: （1）共捕获步甲标本10 804号, 计10属18种, 其中强足通缘步甲Pterostichus fortipes、侧步甲Carabus latreillei和双斑猛步甲Cymindis binotata占优势, 个体数分别占总数的67.5%, 7.53%和7.06%。（2）苜蓿地中的步甲密度、物种丰富度、Margalef丰富度指数、Shannon-Wiener多样性指数和均匀度指数均较高, 其他样地较低。（3）聚类分析结果显示, 不同生境的步甲群落相似性与受干扰强度和土地利用方式一致。（4）步甲主要在6-9月活动, 高峰期为7-8月。各物种在不同土地利用方式生境内的季节变化趋势与不同生境植被生长季节相关, 步甲个体数量随着植物生物量的增加而增加。强足通缘步甲Pterostichus fortipes高峰期大多出现在植物生长旺盛的7月, 仅围封草地内的高峰出现在8月; 双斑猛步甲Cymindis binotata的高峰期出现在8-9月。（5）典范对应分析表明, 土壤含水量、土壤温度、植物盖度、植物生物量及植株高度是影响步甲群落组成的重要环境因子。结论认为, 不同土地利用方式对环境的干扰影响了步甲赖以生存的生境, 进而影响了其物种的组成和数量分布格局。     

Effects of stream restorations on riparian mesohabitats,vegetation and carabid beetles

We investigated the effects of hydromorphological restoration measures (mainly the removal of bank fixations) on riparian mesohabitats, vegetation and carabid beetles by comparing 24 restored to nearby non-restored floodplain sections in Germany. Mesohabitats were recorded along ten equally-spaced transects, plant communities and riparian plant and carabid beetle species along three transects per section. Based on 18 indices including habitat and species diversity, taxonomic diversity and functional indices we compared the frequency and magnitude of changes following restoration, both for the overall dataset and for each site individually. Riparian habitat diversity doubled in restored sections compared to non-restored sections. The numbers of vegetation units and plant and carabid beetle species richness also doubled in restored sections, whereas changes in Shannon diversity were most pronounced for mesohabitats and riparian plants. Taxonomic diversity of carabid beetles decreased in restored sections reflecting post restoration dominance of riparian Bembidion species. Stress-tolerant pioneers of plant and especially carabid species benefit strongly from the re-establishment of open sand and gravel bars, while hygrophilous species, which also include non-riparian species, did not respond to restoration. We conclude that restoring river hydromorphology has almost generally positive effects on riparian habitats and riparian biodiversity. Riparian biota are thus well-suited indicators for the effects of hydromorphological restoration.     

Carabid beetle assemblage under diversified agroecosystems

Corn (Zea mays L.) and soybean (Glycine max Merrill) were planted in monoculture and strip-intercropping plots (18.3×15.5 m each) under conventional tillage and no-tillage to create differences in habitat structure. The effects of these agronomic practices on carabid beetle species composition were measured by pitfall-trap collections during three years. Although neither the number of individuals or number of species were significantly affected by treatments, analyses of variance indicated that four of the six dominant species (75.7% of the total number of carabids captured in three years) responded to tillage treatments.Harpalus pensylvanicus DeGeer andCyclotrachelus sodalis (LeConte) were more abundant in no-tillage plots, whereasPterostichus chalcites Say andScarites substriatus Haldeman were more common in conventional tillage plots.Pterostichus chalcites was also significantly more abundant in soybean plots than in intercropping or corn plots.H. pensylvanicus, a primarily herbivorous carabid, was the most common species collected. However,P. chalcites, a predaceous carabid, was the dominant species in soybean/conventional tillage plots. The results suggest that characteristics of individual species should be carefully considered for studies of communities such as carabid beetles, which have few strongly dominant species and a wide range of resource utilization.     

山西庞泉沟自然保护区步甲物种组成及多样性格局

利用巴氏罐诱法,对山西庞泉沟国家自然保护区的不同功能区——核心区（绿色长廊）、缓冲区（八道沟）、远离农田实验区（神尾沟）及靠近农田实验区（八水沟）——林地地表甲虫步甲物种多样性进行了调查和比较,目的在于探明该保护区有代表性林地步甲物种的组成及受不同程度人为干扰下的多样性格局。结果表明：（1）本研究共捕获步甲物种42种,38种是该保护区的新记录种类,其中粗皱步甲Carabus crassesculptus和沟步甲C. canaliculatus 为优势种,与尖角通缘步甲Pterostichus eschscholtzii,强足通缘步甲P. fortipes,罕丽步甲C. manifestus和长叶步甲C. vladimirskyi一起构成研究地的常见种。（2）不同功能区物种组成和数量分布各不相同,多样性各项指标均是靠近农田的实验区最高,核心区最低。（3）各功能区具有特有的指示性种类,其中黄条春步甲Notiophilus reitteri为核心区指示种; 凹唇春步甲N. impressifrons 为缓冲区指示种; 粒步甲C．granulatus,刻翅步甲C．sculptipennis 和中华通缘步甲P．chinensis为实验区指示种。（4）群落相似性分析表明缓冲区与核心区及远离农田实验区之间具有较高的相似性,靠近农田实验区与其他3个地点相似性较低。结果提示适度干扰可提高物种丰富度,但降低人为干扰（如旅游和交通压力）有利于步甲多样性的保护。     

Relevance of using a vegetation-based method to conserve urban carabid diversity

Urban habitats harbour considerable biological diversity. Ecologists have developed methods to select which habitats should be conserved. The Ecological value, a method based on vegetation, has been created for the urban habitats of Montreal (Quebec, Canada). The main objective of our study was to determine if this method was relevant to assess carabid diversity of Mount Royal Park. This index is calculated using five criteria: uniqueness, representativeness, degree of succession, richness and rarity of the flora, each of which can influence communities of insects. Ground beetles (Coleoptera: Carabidae) were selected because of their success as biological indicators. Despite sampling difficulties, our results demonstrate clearly that the Ecological value method does not represent the high carabid richness of urban open habitats (tall grasses) and their specialised native carabid species. Within forests we found nonetheless that the ecological value index has a significant positive relationship with native carabid abundance. Moreover, maturity and structure of urban forests were positively correlated with carabid abundance and richness. Some urban vegetation characteristics have been shown to influence entomological diversity, but the relevance of using a global floral index to encompass the carabid community seems limited.     

Estimated density of four carabid beetle species in Mongolian oak and Korean red pine forest ecosystems on Baekdudaegan mountain range (Mt. Oade and Mt. Guryong) of South Korea

The estimation of animal population size is a primary field of interest for wildlife biologists, and such numerical estimation of wild animals is a very important factor in establishing national policy towards nature. Therefore, we performed this study to estimate the population density of carabid beetles preying on soil biota at the Mongolian oak (Quercus mongolica) forests and Korean red pine (Pinus densiflora) forests of two mountains, Mt. Odae and Mt. Guryong. We used the trapping web method with pitfall traps to collect the beetles. We calculated the estimated density of a total of four carabid beetle species in two specific regions and converted them to an estimated beetle population size within a certain area by using the study area. From our estimates, one beetle species, Leptocarabus seishinensis seishinensis L., displayed statistically significant results. Although there was no appreciable difference in the makeup of different carabid beetle species between the two forest communities, the population size of the beetle species was larger in Mongolian oak forests than in Korean red pine forests. The spatial distribution of carabid beetles by forest type did not show any preference for particular spots. Our results showed that carabid beetles did not have specific home ranges and that they were not density dependent. We expect to use the raw data to recognize the response of soil organisms to changes in the habitat environment and to track the patterns of change more accurately over long passages of time.     

Species turnover of monkey beetles (Scarabaeidae: Hopliini) along environmental and disturbance gradients in the Namaqualand region of the succulent Karoo, South Africa

Species turnover of monkey beetle (Scarabaeidae: Hopliini) assemblages along disturbance and environmental gradients was examined at three sites within the arid, winter rainfall Namaqualand region of the succulent Karoo, South Africa. At each site two study plots with comparable vegetation and soils but contrasting management (grazing) histories were chosen, the disturbed sites having fewer perennial shrubs and generally more annuals and bare ground. Beetles collected using coloured pan-traps showed a consistently higher abundance in disturbed sites. Lepithrix, Denticnema and Heterochelus had higher numbers in disturbed plots, while Peritrichia numbers were lower in disturbed areas. Measures of species richness and diversity were consistently higher in the undisturbed sites. Distinctive assemblages of monkey beetles and plants occurred at each site. A high compositional turnover ( diversity) was recorded for both monkey beetles and plants along a rainfall gradient; between-site diversity values ranged from 0.7 to 0.8 (out of a maximum of 1.0). Species turnover of beetles was higher between the disturbed sites along the environmental gradient than the corresponding undisturbed sites. The high monkey beetle species turnover is probably linked to the high plant species turnover, a distinctive feature of succulent Karoo landscapes. Monkey beetles are useful indicators of overgrazing disturbance in Namaqualand, as their pollinator guilds are apparently disrupted by overgrazing. A shift away from perennial and bulb pollinator guilds towards those favouring weedy annuals was observed in disturbed areas. The consequences to ecosystem processes due to the effects of disturbance on monkey beetle communities and the role of monkey beetles as indicators of disturbance is discussed, as well as the implications of disturbance on monkey beetle pollination guilds.     

Importance of closed landfills as green space in urbanized areas: ecological assessment using carabid beetles

In a closed landfill, we investigated the diversity and ecological characters of carabid beetles to understand the ecological importance of closed landfills that have the potential as a multi-functional habitat for improving biodiversity in urbanized areas. In addition, we studied the influence of environmental factors (vegetation structure, soil) on distribution and diversity of carabid beetles. A total of 92,495 individuals representing 15 carabid species were collected from the closed landfill. Although the species richness of carabid beetles recorded in the closed landfill was not higher than the other green spaces in the city, the closed landfill could sufficiently provides a stable habitat as a semi-natural area for carabid beetles. Soil pH, Na, and tall grass plant cover influenced carabid assemblage in the closed landfill. However, other environmental variables (e.g., K⁺, Na⁺, Mg²⁺, bare land cover, weedy cover, and tree cover) were not correlated with carabid species composition. It is implied that in the closed landfill, which is a highly modified engineered environment, other abiotic environmental (e.g., drainage, soil texture, leachate, and landscape context, etc.) and biotic factors (e.g., intra- and interspecific competition) may have affected carabid assemblage. Although artificial drainages are essential facilities for landfill management, they are a critical factor that affects the species inhabiting the landfill. However, carabid beetles seemed to randomly fall into the artificial drainage. For successful management of closed landfills, it is very important that minimize the intervention and that develop the ecological sensitively management method.     

Inferring species interactions from ecological survey data: A mechanistic approach to predict quantitative food webs of seed feeding by carabid beetles

1. Ecological networks are valuable for ecosystem analysis but their use is often limited by a lack of data because many types of ecological interaction, for example, predation, are short‐lived and difficult to observe or detect. While there are different methods for inferring the presence of interactions, they have rarely been used to predict the interaction strengths that are required to construct weighted, or quantitative, ecological networks.
2. Here, we develop a trait‐based approach suitable for inferring weighted networks, that is, with varying interaction strengths. We developed the method for seed‐feeding carabid ground beetles (Coleoptera: Carabidae) although the principles can be applied to other species and types of interaction.
3. Using existing literature data from experimental seed‐feeding trials, we predicted a per‐individual interaction cost index based on carabid and seed size. This was scaled up to the population level to create inferred weighted networks using the abundance of carabids and seeds from empirical samples and energetic intake rates of carabids from the literature. From these weighted networks, we also derived a novel measure of expected predation pressure per seed type per network.
4. This method was applied to existing ecological survey data from 255 arable fields with carabid data from pitfall traps and plant seeds from seed rain traps. Analysis of these inferred networks led to testable hypotheses about how network structure and predation pressure varied among fields.
5. Inferred networks are valuable because (a) they provide null models for the structuring of food webs to test against empirical species interaction data, for example, DNA analysis of carabid gut regurgitates and (b) they allow weighted networks to be constructed whenever we can estimate interactions between species and have ecological census data available. This permits ecological network analysis even at times and in places when interactions were not directly assessed.

     

Regional hotspots of butterfly diversity in a protected area: Are they indicators of unique assemblages and areas with more species of conservation concern?

The implementation of biodiversity studies to set conservation priorities assumes that the different criteria used in prioritisation are correlated. Based on butterfly data, we examined whether high total diversity (species density and richness), unique species assemblages, and high numbers of different categories of Species of European Conservation Concern (SPEC) were co-located in the same habitats in the Picos de Europa National Park, Spain. Species density (number of species per sample) declined with elevation and was significantly higher in Genista shrublands on southern slopes (Southern Genista shrubland). We found unique species assemblages for Southern Genista shrublands, heathlands, mown meadows and subalpine meadows, whereas Genista shrubland on northern slopes (Northern Genista shrubland) and pastures were occupied by more habitat generalist species. We also found an effect of elevation on species composition. Species with global distributions concentrated in Europe (SPECs 4b) tended to be associated with Southern Genista shrubland, whereas species with global distributions restricted to Europe (SPECs 4a) were associated with higher elevations. Thus, we suggest a higher conservation value for butterfly assemblages located both on Southern Genista shrublands and at high elevations as they contain unique assemblages with a higher number of SPECs. By comparing our data with a previous study on carabid beetles, we found a low coincidence between butterflies and beetles for habitats with high species diversity and unique assemblages. Our study suggests that preserving areas in the landscape supporting higher butterfly diversity only partially preserves those species of greater conservation concern, and that butterflies cannot be used as a reliable indicator of other priority taxa for conservation, such as carabid beetles.     

Land-use diversity index: a new means of detecting diversity at landscape level

Preservation of ecological diversity is a guiding principle of landscape management and planning. Although diversity is often quantified with measurable indices, common approaches used to measure diversity, for example the Shannon–Weaver index, are not adequate for many landscape studies, because they are affected by scale and sampling efforts. A robust index for measurement of landscape diversity should be able to quantify distinctive components of a landscape mosaic. This paper provides a new diversity index for landscape studies that improves the measurement of diversity at landscape level. The key features of the method are inclusion of an implication of physical moment and quantification of diversity by placing greater weight on the structure and composition of a patch. We have named the new index the land-use diversity index, or LUDI, and have concluded that the LUDI is the preferred measure of diversity at landscape level.     

The effects of vegetation types and microhabitats on carabid beetle community composition in cool temperate Japan

The effects of vegetation types and environmental factors on carabid beetle (Coleoptera: Carabidae) communities were studied. Carabid beetles were collected using pitfall traps (total 2844 trapping days) and seven microenvironmental factors were measured in four vegetation types: grassland, natural evergreen coniferous forest (Pinus densiflora), deciduous broad-leaved natural forest (Quercus crispula, Betula platyphylla, Alnus japonica, or Fagus crenata), and deciduous coniferous plantation (Larix kaempferi) in cool temperate Japan. These four vegetation types provided a novel comparison between natural forests and plantations because the vast majority of related studies have investigated only deciduous broad-leaved natural forests and evergreen coniferous plantations. PERMANOVA indicated that vegetation types affected carabid community composition. Ordination plots showed that community composition differed greatly between grassland and forest vegetation types, but that community composition in the plantation forest overlapped with that of natural forest types. Characteristics differentiating the grassland included a high proportion of winged species and a low mean carabid body weight. Among the examined environmental factors, litter depth, soil water content, and depth of the soil A-horizon had large effects on carabid communities. These results suggest that the effect of afforestation on carabid communities in cool temperate Japan might be insignificant compared with the effects of cover types (deciduous vs. evergreen) and microenvironmental factors.     

Stump‐harvesting for bioenergy probably has transient impacts on abundance,richness and community structure of beetle assemblages

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小兴安岭森林地表鞘翅目成虫对不同干扰梯度的响应

为探讨小兴安岭凉水自然保护区森林生态系统中地表鞘翅目成虫群落对不同人为干扰梯度的响应,于2015年7月、8月和10月分别对轻度干扰[原始阔叶红松林(KY)和谷地云冷杉林(YL)]、中度干扰[阔叶红松择伐林(ZF)和次生白桦林(BH)]及重度干扰[落叶松人工林(RL)和红松人工林(RHS)]的6个林型进行取样调查。结果表明:(1)整个采样周期共捕获地表鞘翅目成虫879只,隶属9科44物种;其中轻度干扰生境共捕获6科29种251只(KY捕获5科21种150只,YL捕获4科20种101只),中度干扰生境捕获6科27种276只(ZF捕获3科20种144只,BH捕获6科23种132只),重度干扰生境捕获6科29种352只(RL捕获4科22种232只,RHS捕获5科17种120只)。(2)7月和8月步甲科和葬甲科占据数量优势,10月步甲科和葬甲科成虫数量明显减少而隐翅虫科数量占优势;不同林型及不同干扰梯度地表鞘翅目成虫物种总数和总个体数于7、8、10月均表现为下降趋势,且群落多样性也呈不同程度下降。(3)林型和月份对地表鞘翅目成虫群落结构具有显著影响,干扰梯度对群落结构无显著影响;6个林型之间地表鞘翅目成虫个体数量具有显著差异,但在物种组成上无显著差异;不同干扰梯度间地表鞘翅目成虫个体数、物种数无显著差异,且随干扰梯度变化没有明显的梯度性规律;相似性系数和聚类分析表明,属于同一干扰梯度的两个林型没有表现出高度的相似性。本研究表明干扰梯度不是决定各林型间地表鞘翅目成虫群落多样性存在差异的主要原因,凉水森林生态系统地表鞘翅目成虫对不同干扰梯度的响应不符合中度干扰假说,林型和时间则是影响地表鞘翅目成虫群落组成的显著因素,本实验为地表生物多样性保护和森林生态系统管理提供数据支撑。     

Carabid beetles (Coleoptera: Carabidae) in coniferous plantations in Hokkaido,Japan: effects of tree species and environmental factors

The distribution, species composition and abundance of carabid beetles in monospecific plantations of three different coniferous tree species (Japanese spruce, Sakhalin fir and larch) were investigated by baited pitfall traps in Hokkaido, Japan. In total, 16 150 carabid beetles consisting of 31 species in 13 genera were collected in 2011 and 2012. The most predominant species was Pterostichus thunbergii Morawitz, followed by Synuchus melantho (Bates) and Carabus opaculus (Putzeys). Average numbers of beetles per trap were significantly reduced in larch. Large‐sized Carabus species (C. arboreus arboreus Lewis and C. opaculus) were collected in large numbers in Japanese spruce. There was no significant difference in diversity and equitability among the three kinds of plantation. The ordination of redundancy analysis showed that medium‐sized forest generalists, Pterosticus subovatus (Motschulsky) and P. thunbergii, were highly associated with Japanese spruce and Sakhalin fir, and the forest specialist Synuchus nitidus (Motschulsky) was with Sakhalin fir. In contrast, in larch there was no such associated forest species, and some species of Carabus, Pterostichus and Synuchus were considerably reduced in number, suggesting that larch has unfavorable effects on some forest species. The most important environmental variables influencing carabid assemblages were soil moisture and foliage layer cover. Practices in forest management to minimize the effects of plantations on carabid assemblages are discussed.     

Effects of Bt maize-fed prey on the generalist predator <Emphasis Type="Italic">Poecilus cupreus</Emphasis> L. (Coleoptera: Carabidae)

We investigated the effects of transgenic maize (Zea mays) expressing Bacillus thuringienses toxin (Bt maize) on larval and adult Poecilus cupreus carabid beetles in laboratory studies. In no-choice trials, neonate P. cupreus larvae were fed exclusively with Spodoptera littoralis caterpillars, which had been raised on Bt maize. S. littoralis raised on conventional maize or high quality Calliphora sp. pupae were fed to the beetle larvae in two control treatments. Bt-maize-fed caterpillar prey increased mortality to 100 within 40days. The experiment was repeated with 10-day-old beetle larvae. Bt treatment resulted in fewer pupae than in both controls, and in a higher mortality than in the Calliphora control. S. littoralis was suitable as exclusive prey in no-choice tests, at least for 40days, although prey quality seemed to be low compared to Calliphora pupae. The observed effects are most likely indirect effects due to further reduced nutritional prey quality. However, direct effects cannot be excluded. In the second part of the study, exposure of P. cupreus to Bt intoxicated prey was examined in paired-choice tests. Adult beetles were offered a choice between different prey conditions (frozen and thawed, freshly killed or living), prey types (S. littoralis caterpillars, Calliphorasp. pupae, cereal aphids) and prey treatments (raised on Bt or conventional maize). Living prey was preferred to frozen and dead prey. Caterpillars were only preferred to fly pupae and aphids when living. Prey treatment seemed to be least important for prey selection. The tests showed that P. cupreus ingested caterpillars readily and there was no evidence of them avoiding Bt containing prey, which means exposure in the field could occur. The presented protocols are a first step towards ecological risk assessment for carabid beetles.     

Impact of Red Deer Cervus elaphus Grazing on Bilberry Vaccinium myrtillus and Composition of Ground Beetle (Coleoptera, Carabidae) Assemblage

We studied the role of red deer Cervus elaphus L. as ecosystem modifier in boreal forest (Tingvoll municipality, 62°52′ N, 8°20′ E, Norway), during early summer of 2001. The effect of grazing by red deer on ground beetles (Carabidae) abundance and diversity was investigated across a gradient of grazing pressures. We trapped ground beetles by pit-fall traps from three homogeneous winter grazing areas (ungrazed, medium grazed, heavily grazed). Bilberry Vaccinium myrtillus (the main winter food for red deer) was sampled and its dry weight was measured for the three locations. Gradient analyses showed that grazing by red deer affects carabid species composition. Grazing significantly affected the amount of bilberry, which correlated with species variation. According to our predictions, we found a higher abundance of carabids in the heavily grazed location, but the species richness and the diversity indices were similar for the three areas. This study shows that overall species composition is altered along a gradient as consequence of red deer winter grazing and that red deer act as ecosystem engineer, by reducing the bilberry heather which dominates the field layer in early summer.     

Diversity and abundance of the coleopteran fauna from organic and conventional management systems in southern England

1 Studies of the epigeal coleopteran fauna on five pairs of organic and conventional farms were carried out between May and July 1994 in southern England using pitfall trapping. A total of 27 749 individuals and 140 species were identified. Overall, abundance of Coleoptera was greatest on organically managed farms. 2 Ground beetles (Coleoptera: Carabidae) and staphylinid beetles (Col. Staphylinidae) formed 79.7% and 16.7%, respectively, of the total catch. Pterostichus melanarius was the dominant carabid among the 45 species captured and significantly higher numbers were found in organic farms. Tachinus signatus was the most common of 44 staphylinid species, and was significantly more abundant on conventional farms. 3 For carabids, the log‐series α diversity index was higher on conventional farms but was not statistically different from that calculated for organic farms. The α index was identical for staphylinid species from organic and conventional farms. Diversity was significantly higher from conventional farms when data were combined for all of the recorded coleopteran species. 4 From this study, it appears that the main effect of farming practice is to influence the overall abundance and dominance of particular species, and the lower diversity of organic farms is a consequence of the large increase in dominance of a single species, namely P. melanarius.     

Disturbance regimes in a wetland remnant: implications for trait-displacements and shifts in the assemblage structure of carabid beetles (Coleoptera: Carabidae)

Studies on disturbance regimes involving carabid beetles have mainly focused on forest habitats. We therefore decided to analyze the effects of disturbance on carabid communities in a wetland remnant (Lake Chiusi, central Italy). Results highlighted the presence of a disturbance gradient affecting the species richness and trait-displacement of carabid communities. Carabids were sampled with pitfall traps from March to October 2008 at nine randomly selected sample stations; a set of landscape attributes were also collected. Principal Component Analysis (PCA) and generalized linear mixed models (GLMMs) were used to link the distribution of carabid life-history traits and species richness with the most informative combination of landscape attributes. The first PCA axis (PC1) showed significant correlation with “distance to the lake shoreline” and “perimeter-area ratio”, highlighting the presence of a disturbance-axis. The second and third axes accounted only for a trivial portion of the total variance. GLMMs revealed a progressive decrease in the number of hygrophilous species from the core of the wetland to its outer areas. Similar trends were observed for species richness and for predator species with good dispersal ability and larval period in summer. Our results highlight the importance of taking into account community-wide functional implications in landscape ecology studies.