Carabid Species Composition Research Articles

Raised bog biodiversity loss: A case‐study of ground beetles (Coleoptera, Carabidae) as indicators of ecosystem degradation after peat mining

AbstractPeatlands are unique ecosystems inhabited by highly specialized biota. Due to extraction and drainage, these valuable ecosystems decline or represent only fragmented habitat patches. The aim of this study was to compare the carabid species composition, diversity, and life history traits between bog habitat types: 20 and 40 year post‐extraction sites and undisturbed one. We tried to determine whether populations of rare carabid bog specialists would persist in the post‐extraction habitats. The study was conducted in the raised bog, where 30 sampling transects with a total of 90 pitfall traps were established. 1616 individuals belonging to 30 carabid species were collected. The results revealed the significance differences in carabid species composition between studied habitat types and increasing the abundance and species richness in post‐extraction sites. According to spontaneous succession in post‐mining sites, the shift in life history traits of carabids towards forest assemblages was observed. We observed decline of the most valuable bog species in post‐mining sites. Agonum ericeti, Pterostichus rhaeticus and Bembidion humerale were present on the reference bog, with large covers of Sphagnum and shrubs, but sporadically at the 20 year post‐extraction site (except for A. ericeti), or not at all at the 40 year post‐extraction site overgrown by trees. Therefore measures should be undertaken in post‐extraction areas to enable the restoration of such specific conditions and a properly functioning raised bog ecosystem. This mainly requires restoration of a suitable hydrological regime, which is the key factor for the preservation of groups of bog specialist plants and animals.

Cross-taxon relationships in Mediterranean urban ecosystem: A case study from the city of Trieste

Urbanization directly and indirectly impacts biodiversity to the extent that it is considered one of the main causes of biotic homogenization and extinction. However, urban green areas can act as reservoir of biodiversity, and knowledge regarding species distribution in such contexts is crucial to define appropriate conservation and management strategies. Since inventories of species are generally time-consuming and costly, a commonly used approach consists in the use of surrogate species. However, studies investigating the effectiveness of surrogate species in urban environments still seem to be under-represented. In this research, we investigated the biodiversity of ants, plants, and carabid beetles in six different green areas within the urban area of the city of Trieste. The role of vascular plants as a potential surrogate for the diversity of ants and carabid beetles has been tested, investigating the influence of the environmental variables (dead wood, litter, anthropic disturbance, bare soil, bedrocks and rocks) on these relationships. Patterns of species richness and complementarity were compared among the sampled sites and their correlations were tested with Mantel tests and Co-Correspondence Analysis (Co-CA). Results pointed out that even disturbed and isolated sites within the urbanised matrix can sustain a high diversity of species of ants, carabids and plants, while in the semi-natural sites intermediate diversity levels were found. Plants were found to correlate directly with the diversity of ants; on the contrary, carabid species composition resulted only indirectly influenced by vascular plants, confirming the key role of abiotic variables in determining carabid diversity. Co-CA showed a clear distinction between forested and semi-natural environments and more open and disturbed environments. Furthermore, the Co-CA highlighted that the considered environmental variables (particularly dead wood, anthropic disturbance, rocks and litter) can significantly influence the distribution of analyzed taxa. Our results highlight the important role of urban green areas within the urban matrix as source of biodiversity and, furthermore, once more, support the role of vascular plants as meaningful surrogate for the diversity of ants and carabids.

Species composition of Ground beetles (Coleoptera: Carabidae) on spring wheat in the Right-Bank Forest-Steppe of Ukraine

Goal. To clarify the species composition of carabids in spring wheat agrocenosis, to determine the dominant species, to compare the number of ground beetles on application of mineral fertilizers and organic nutrients.
 Methods. Field method — accounting of insects on the sowing of spring wheat in accordance with generally accepted methods. Laboratory method — determination of the species composition of ground beetles. The study was conducted in 2017—2019 on the basis of National Research Center «Institute of Agriculture of NAAS of Ukraine», department of plant protection against pests and diseases (Chabany, Kyiv-Sviatoshynskyi district, Kyiv region).
 Results. The species composition of carabid beetles on the sowings of spring wheat under modern conditions has been specified. 41 species of ground beetles from 15 genera were found. On application of mineral fertilizers, the dominant species were Bembidion properans Stephens, 1828, Harpalus affinis Schrank, 1781, Harpalus rufipes De Geer, 1774, Poecilus cupreus Linnaeus, 1758, Harpalus distinguendus Duftschmid, 1812. H. affinis Schr., H. rufipes Deg., H. distinguendus Duft., P. cupreus L., Calathus fuscipes Goeze, 1777, Harpalus smaragdinus Duftschmid, 1812 were dominant species on application of organic nutrients. In both variants, Broscus cephalotes Linnaeus, 1758, Poecilus punctulatus Schaller, 1783, Poecilus versicolor Sturm, 1824, Microlestes minutulus Goeze, 1777 were subdominant species. The ratio of trophic groups of carabid beetles in the agrocenosis of spring wheat has been established. The seasonal dynamics of the number of ground beetles has been reflected.
 Conclusions. In the first variant (mineral fretilizers) 40 species of carabids were registered, in the second (organic nutrients) — 35. Among all identified species (according to trophic specialization) the number of phytophages and zoophages was similar — 21 and 19, but in the experimental variants their ratio differed. The average number of ground beetles during 2017—2019 was: variant 1 — 30.8 specimens per trap, variant 2 — 28.1 specimens per trap.

Seasonal Occurrence of Adult Carabid Beetles (Coleoptera: Carabidae) in West-Central Illinois

Abstract The Carabidae is a diverse family of beetles with many species of interest in conservation and biological control. Carabid beetle adult seasonal activity patterns were studied in a west-central Illinois forest/reconstructed tallgrass prairie matrix over a 2-yr period using pitfall traps. We found a threefold or greater difference in carabid abundance between years. Despite lower abundance, a second year of sampling yielded seven previously undetected species. Abundance and species richness were greatest in May–July and lower in August–October. Relative abundance and species richness were consistent among months between years. Shannon diversity and effective number of species were lowest in June and July. Cyclotrachelus sodalis (LeConte) and Chlaenius platyderus Chaudoir were the two most abundant species, comprising 54.3% of total captures. These species were most abundant in July and June, respectively. Most species showed greatest abundance in spring or early summer, and declined thereafter. Collections of several species were suggestive of bimodal seasonal patterns. Carabid species composition differed significantly among months, but not between years. Our results document seasonal variation in carabid abundance and species composition, and show that sampling throughout the growing season, and multiple sampling years, provide substantial benefits for assessments of carabid diversity in this region.

Islands in cities: Urbanization and fragmentation drive taxonomic and functional variation in ground arthropods

The conversion of natural lands in urban areas is exponentially increasing worldwide, causing a major decline in biodiversity. Environmental alterations caused by urbanization, such as land conversion and isolation of natural patches, favour tolerant and generalist species, causing both species loss and replacement. In addition, selective pressure is exerted on particular functional traits, driving a functional homogenization or turnover of biotic communities. We sampled ground arthropods within the municipality of Turin (NW-Italy), wherein an isolated and a connected control subplot were repeatedly sampled at 15 stations distributed along a gradient of increasing urbanization. Such a nested sampling design allowed us to investigate the taxonomic and the functional responses of carabids and spiders to both the urbanization level and patch isolation. First, we highlighted the dominant role played by species homogenization (nestedness) in explaining both taxonomic and functional variation in both groups of arthropods. Secondly, we showed that urbanization causes simultaneously functional homogenization and replacement in both carabid and spider assemblages, whereas patch isolation influences carabid species composition and homogenizes and shifts spider taxonomic and functional composition. Lastly, by relating community-weighted means of body length, dispersal capacity and trophic strategy to the urbanization and isolation gradients, we demonstrated that urbanization alters the trophic structure of both taxonomic groups and increases the average dispersal capacity of spiders. On the other hand, patch isolation affected the functional composition of spiders only, reducing the body size and increasing dispersal capacity and the proportion of web-builder species. Our results demonstrate that both urbanization and patch isolation alter species composition by causing functional and taxonomic homogenization. In addition, they exert a strong filtering effect on community functional traits, increasing the proportion of phytophagous species in carabids, and increasing dispersal capacity and web-builders occurrence in spiders, while reducing spider body size.

Differential effects of American pokeweed (Phytolacca americana) invasion on ground-dwelling forest arthropods in southwest Germany

Non-native plants can have strong effects on the structure and functioning of ecosystems. Recently, the American pokeweed (Phytolacca americana), indigenous to east United States, has expanded its range in many regions all over the world. The species combines several traits that facilitate its invasiveness and its impact on ecosystems in its introduced range. The aim of this study was to analyse the effects of P. americana on multiple ground-dwelling arthropods by conducting a field survey in three forest sites in southwest Germany. Key findings were that P. americana invasion resulted in an altered arthropod community structure compared to native reference sites. Furthermore, the carabid species composition was influenced by the invasion, however this effect was dependent on the forest site. Contrasting effects of P. americana invasion on individual numbers of single ground-dwelling arthropod taxa were observed including positive (3 taxa), negative (1 taxa) and neutral effects (8 taxa). For 2 taxa (Carabidae and Formicidae) the effect of P. americana invasion was dependent on forest site. Reasons for the effects on the local fauna might be altered environmental conditions (reduced herbaceous plant cover) and biotic interactions. The study shows that P. americana induces shifts in the native faunal assemblages. Since responses depend on taxonomic groups and regions, the study highlights the importance for considering multiple taxonomic groups in evaluating the ecological impacts of invasive plants and that the evaluation of impacts must consider the regional context.

Ground beetles (Coleoptera: Carabidae) diversity from pastures in Southern Bulgaria

This study aimed at clarifying the species composition and ecological structure of carabids, associated with active pastures. Field work was carried out in 2017 and 2018. Pitfall traps (5 in each site) were set in 10 sampling sites in Thracean Lowland and Sarnena Sredna Gora Mts. Captured beetles belonged to 90 species and 33 genera, representing 12% of the species and 26% of the ground beetle genera occurring in Bulgaria. The most diverse was genus Harpalus (22 species), followed by the genera Amara (7 species), Microlestes (6 species), Ophonus (6 species) and Parophonus (5 species). Twenty species were new for the region of the Thracean Lowland: Amara fulvipes (Audinet-Serville, 1821), Anisodactylus binotatus (Fabricius, 1787), A. intermedius Dejean, 1829, Apotomus clypeonitens Müller, 1943, Calathus cinctus Motschulsky, 1850, Carterus gilvipes (Piochard de la Brûlerie, 1873), Gynandromorphus etruscus (Quensel en Schönherr, 1806), Harpalus fuscicornis Ménétriés, 1832, H. subcylindricus Dejean, 1829, Microlestes apterus Holdhaus, 1904, M. corticalis (L. Dufour, 1820), M. fulvibasis (Reitter, 1901), M. maurus (Sturm, 1827), M. minutulus (Goeze, 1777), Notiophilus laticollis Chaudoir, 1850, Pangus scaritides (Sturm, 1818), Parophonus laeviceps (Ménétriés, 1832), P. planicollis (Dejean, 1829), Polystichus connexus (Geoffroy in Fourcroy, 1785) and Pterostichus strenuus (Panzer, 1796). Twenty species were new for the whole Sredna Gora Mts.: Acinopus picipes (Olivier, 1795), A. megacephalus (P. Rossi, 1794), Amara anthobia A. Villa et G. B. Villa, 1833, Ditomus calydonius (P. Rossi, 1790), Harpalus albanicus Reitter, 1900, H. angulatus Putzeys, 1878, H. attenuatus Stephens, 1828, H. dimidiatus (P. Rossi, 1790), H. flavicornis Dejean, 1829, H. pumilus Sturm, 1818, H. pygmaeus Dejean, 1829, H. subcylindricus Dejean, 1829, H. tardus (Panzer, 1796), H. signaticornis (Duftschmid, 1812), Lebia scapularis (Geoffroy, 1785), Microlestes fissuralis (Reitter, 1901), M. fulvibasis (Reitter, 1901), M. maurus (Sturm, 1827), M. minutulus (Goeze, 1777) and Ophonus sabulicola (Panzer, 1796). Fourty-one species were new for the region of the Sarnena Sredna Gora. Genus Apotomus, Gynandromorphus, Pangus and Polystichus were new geographic records for Thracean Lowland. Genera Acinopus and Ditomus were new for the Sredna Gora Mts. Fourteen life form categories were established (9 zoophagous and 5 mixophytophagous). The analysis of the life forms showed a slight predominance of the mixophytophages (53 species; 59%) over the zoophages (37 species; 41%). Microlestes minutulus was a constant species occurring in all sampling sites.

The influence of landscape alterations on changes in ground beetle (Carabidae) and spider (Araneae) functional groups between 1995 and 2013 in an urban fringe of China

Urbanization is one of the main causes of land use change, especially from 1990 to now in China, but knowledge of its effect on different functional groups of carabids and spiders in the adjacent rural areas over time remains limited. We assessed whether landscape alterations (1993 versus 2013) drove changes in carabid and spider functional groups (1995 versus 2013) in an agricultural landscape located on the fringe of a rapidly growing city in China. Although built-up land increased from 6.3% to 32% across the whole landscape, the overall species richness of carabids and spiders did not decline. In contrast to the reduction in species richness of large carabids, the species richness of small carabids increased. Species richness of both large and small spiders increased. The species composition of carabids and spiders significantly changed between 1995 and 2013. Species compositions of large, predatory carabids and large or ground-hunting spiders were more sensitive to the changes in built-up land than those of small, omnivorous carabids and small or web-building spiders. The amount of grassland (abandoned land covered by wild grass) also increased as farmers began to work in the city. The increased grassland significantly contributed to the increased species richness of predatory and macropterous carabids. However, increased landscape diversity did not affect species richness of either carabids or spiders. High landscape diversity was related to reduction in field size, resulting in a decrease in the mean body size of carabids. This indicates that evaluating the effect of landscape change on carabid and spider diversity should be based on their functional traits. Different taxa, even different functional groups, have different responses to landscape change. The increase in built-up land did not immediately reduce species richness at the urban fringe. Increasing wild grasslands and combining smaller fields may benefit farmland biodiversity in this region.

Epiedaphic Ground Beetle (Carabidae) Diversity in Ecosystems Transformed by Plantations of Eucalyptus pellita in the Orinoco Region of Colombia.

Patterns of land use are changing dramatically in the Orinoco region of Colombia, including extensive commercial forestation of Pinus caribaea, Acacia mangium, and Eucalyptus pellita that are replacing savannas, with unknown consequences for biodiversity. We studied the effects of E. pellita plantations on the diversity of epiedaphic carabid beetles (Carabidae) sampled with pitfall traps at El Vita (Vichada) and Villanueva (Casanare). Furthermore, we assessed stand structure data (basal area, and canopy cover), and soil physical and chemical properties to explain differences in ground beetle composition using redundancy analysis (RDA). We compared diversity and species turnover using Hill numbers and Bray-Curtis dissimilarity, respectively. Low differences in richness were observed between savannas and plantations (at El Vita) and between pastures and plantations (at Villanueva). In general, carabid richness was significantly (not overlap in 95% confidence intervals) higher during the rainy season, and in young plantations than in other habitats. Variation in carabid species composition was mainly explained by a gradient of volumetric humidity, number of trees, basal area at El Vita and pH, nitrogen content of the soil, number of trees, soil clay content, and area of exposed ground at Villanueva. Thirteen carabid (which eight are commons in natural forests) species were identified as indicators of 3- and 14-year-old E. pellita plantations and pastures. Results suggest a strong response of ground beetles (Carabidae) to changes in land use, seasonality, and plantation age. Further research is needed to better understand how landscape heterogeneity, and distance to contiguous of natural habitats, influences biodiversity.

Progressively excluding mammals of different body size affects community and trait structure of ground beetles

Mammalian grazing induces changes in vegetation properties in grasslands, which can affect a wide variety of other animals including many arthropods. However, the impacts may depend on the type and body size of these mammals. Furthermore, how mammals influence functional trait syndromes of arthropod communities is not well known.We progressively excluded large (e.g. red deer, chamois), medium (e.g. alpine marmot, mountain hare), and small (e.g. mice) mammals using size‐selective fences in two vegetation types (short‐ and tall‐grass vegetation) of subalpine grasslands. We then assessed how these exclusions affected the community composition and functional traits of ground beetles (Coleoptera, Carabidae), and which vegetation characteristic mediated the observed effects.Total carabid biomass, the activity densities of carabids with specific traits (i.e. small eyes, short wings), the richness of small‐eyed species and the richness of herbivorous species were significantly higher when certain mammals were excluded compared to when all mammals had access, regardless of vegetation type. Excluding large and medium mammals increased the activity density of herbivorous carabid species, but only in short‐grass vegetation. Similarly, excluding large mammals (ungulates) altered carabid species composition in the short‐, but not in the tall‐grass vegetation. All these responses were related to aboveground plant biomass, but not to plant Shannon diversity or vegetation structural heterogeneity.Our results indicate that changes in aboveground plant biomass are key drivers of mammalian grazers’ influence on carabids, suggesting that bottom–up forces are important in subalpine grassland systems. The exclusion of ungulates provoked the strongest carabid response. Our results, however, also highlight the ecological significance of smaller herbivorous mammals. Our study furthermore shows that mammalian grazing not only altered carabid community composition, but also caused community‐wide functional trait shifts, which could potentially have a wider impact on species interactions and ecosystem functioning.

Monitoring the Impact of Hedgerows and Grass Strips on the Performance of Multiple Ecosystem Service Indicators

The importance of semi-natural vegetation elements in the agricultural landscape is increasingly recognized because they have the potential to enhance multiple ecosystem service delivery and biodiversity. However, there is great variability in the observed effects within and between studies. Also, little is known about the simultaneous delivery of multiple ecosystem services and biodiversity because most studies focus on monitoring one service at a time and in conditions specifically suited to observe this one service. In this study, the results are presented of 1 year of monitoring of a set of parcel-level and simplistic ecosystem service and biodiversity indicators on parcels with grass strips or hedgerows. In the grass strips, an increase in soil organic carbon stock, a decrease in soil mineral nitrogen content, a different carabid species composition and a higher spider activity density were found, compared to the adjacent arable parcel. These results indicate a contribution of grass strips to climate regulation, the regulation of water quality, an increase of beta diversity and potential for pest control. Next to hedgerows, crop yield was reduced and winter wheat thousand kernel weight, soil organic carbon stock and spider activity density were increased. These indicators show an effect of the hedgerow on food production, climate regulation and potential for pest control. The study concludes that both grass strips and hedgerows have the potential to increase multiple ecosystem service delivery, but that an increase of every service is not assured and that multifunctionality is affected by management choices. Also, an improved experimental setup in order to enhance ecosystem service monitoring is suggested.

Different response patterns of epigaeic spiders and carabid beetles to varying environmental conditions in fields and semi-natural habitats of an intensively cultivated agricultural landscape

Agricultural intensification has resulted in major losses of biodiversity due to landscape homogenization and an increasing use of agrochemicals. It has often been assumed that associated changes in environmental conditions are impacting composition and diversity of two main ground-dwelling generalist predator taxa, carabid beetles and epigaeic spiders, in similar ways. Here, we test how variations in environmental conditions at local scales (plant diversity and total soil nitrogen, Ntot) and landscape-scale (mean patch size) affect species composition, richness and abundance of ground beetles and epigaeic spiders in semi-natural and cultivated habitats of an agricultural landscape. We specifically test the hypotheses that both taxa are more diverse in semi-natural than cultivated habitats, but that due to their weaker dispersal ability, ground beetles are more strongly linked to local factors than spiders. Our results indicate that in our study area, carabid diversity shows no significant difference between semi-natural habitats and cropland, while spider abundance is significantly enhanced in semi-natural habitats. Ntot significantly affected carabid species richness and abundance, but had a limited influence on spider abundances. The species composition of both carabids and spiders was influenced by plant diversity, while Ntot played a significant role in determining spider assemblages but not carabid composition. There was no significant effect of the mean patch size in the surroundings landscape on either spider or carabid species. Nonetheless, in landscapes with small patch sizes, spider abundance decreased with increasing Ntot, while in landscapes with large sized patches, this relationship was reversed. The differences in responses of these taxa to local and landscape-scale environmental factors suggests that scale- and taxon-specific targets need to be established to improve the efficiency of measures aimed at enhancing ecosystem services provisions by these key pest control agents.

Time-lagged response of carabid species richness and composition to past management practices and landscape context of semi-natural field margins

Field margins are key features for the maintenance of biodiversity and associated ecosystem services in agricultural landscapes. Little is known about the effects of management practices of old semi-natural field margins, and their historical dimension regarding past management practices and landscape context is rarely considered. In this paper, the relative influence of recent and past management practices and landscape context (during the last five years) were assessed on the local biodiversity (species richness and composition) of carabid assemblages of field margins in agricultural landscapes of northwestern France. The results showed that recent patterns of carabid species richness and composition were best explained by management practices and landscape context measured four or five years ago. It suggests the existence of a time lag in the response of carabid assemblages to past environmental conditions of field margins. The relative contribution of past management practices and past landscape context varied depending on the spatial scale at which landscape context was taken into account. Carabid species richness was higher in grazed or sprayed field margins probably due to increased heterogeneity in habitat conditions. Field margins surrounded by grasslands and crops harbored species associated with open habitats whilst forest species dominated field margins surrounded by woodland. Landscape effect was higher at fine spatial scale, within 50 m around field margins. The present study highlights the importance of considering time-lagged responses of biodiversity when managing environment. It also suggests that old semi-natural field margins should not be considered as undisturbed habitats but more as management units being part of farming activities in agricultural landscapes, as for arable fields.

Relative effects of landscape composition and configuration on multi-habitat gamma diversity in agricultural landscapes

Landscape composition and configuration are considered important factors influencing biodiversity in agricultural landscapes. Evaluating the relative importance of each component is complicated because they are often correlated. Overcoming this problem could lead to a better understanding of the mechanisms that drive biodiversity and help to determine effective actions. Usually, landscape-biodiversity relationships are studied at the local scale for a single habitat type (alpha diversity). However, for a better understanding of ecological processes at the landscape scale, it is also important to look at the overall diversity at the landscape level, including all habitat types. The present study was conducted to determine the relative effects of landscape composition and configuration on multi-habitat gamma diversity of carabid beetles and vascular plants in an agricultural region of western France. Twenty 1km2 landscapes were sampled for plants and carabids. Data from 10 sampling sites representing crop fields, grasslands and woody covers in each landscape were pooled to obtain the total multi-habitat gamma diversity. Results showed that both landscape composition and configuration influenced carabid communities, while only landscape composition affected plant communities. Carabid species richness increased with increasing length of edge between crops and grasslands. Plant richness was negatively and positively affected by the percentage of crops and grasslands respectively. Carabid species composition was more dissimilar between landscapes with increasing difference in percentage of woody covers and crops, and length of grassy-crop edge. Plant species composition was more dissimilar between landscapes with a greater difference in percentage of crops. These results suggest grassy-crop adjacencies may enhance processes of resource complementation between habitats for carabids, while habitat availability and quality are the main factors for plants. This approach provided new insights for sustaining overall biodiversity in agricultural landscapes: e.g. encourage adjacencies between grasslands and crop fields and continue to subsidise grasslands for plant diversity.

Environmental factors acting at multiple scales determine assemblages of insects and plants in agricultural mountain landscapes of northern China

Mountainous regions harbor high levels of biodiversity, while often experiencing substantial pressure from agricultural production. Our current understanding of factors driving changes in the highly diverse species assemblages of these regions is generally limited. We used variance partitioning based on redundancy analysis to establish the effects of environmental variables on the species composition of vascular plants and three insect taxa (Geometridae, Arctiinae and Carabidae). These environmental determinants are linked to three distinct spatial levels: the regional level – the four study regions positioned at ∼400m altitudinal intervals, the landscape level – the landscape structure in the vicinity of each study plot, and the plot level — the environmental conditions at individual sampling locations. Our results showed that variations in the species composition of vascular plants and carabids were more closely linked to plot-level characteristics than to regional-level factors, while the opposite trend was observed for the two moth taxa. When effects explicitly linked to the four study regions were controlled, plant and carabid assemblages showed strong links to the percentage of semi-natural habitat at the landscape level, while geometrid and arctiinid assemblages were affected primarily by the overall plant species richness and plant coverage at the plot level. Overall, the variations in the species composition of different taxa can be explained by varying sets of environmental variables acting at different spatial scales, and the relative role of these variables is highly taxon-specific. Regional-scale approaches are crucial for biodiversity conservation in mountainous agricultural landscapes, as exemplified by the responses in the two moths taxa, while a high proportion of semi-natural habitats in the agricultural landscape is not only linked to a diverse vegetation, but also to species-rich carabid assemblages.

Effects of a Major Tree Invader on Urban Woodland Arthropods.

Biological invasions are a major threat to biodiversity; however, the degree of impact can vary depending on the ecosystem and taxa. Here, we test whether a top invader at a global scale, the tree Robinia pseudoacacia (black locust or false acacia), which is known to profoundly change site conditions, significantly affects urban animal diversity. As a first multi-taxon study of this kind, we analyzed the effects of Robinia dominance on 18 arthropod taxa by pairwise comparisons of woodlands in Berlin, Germany, that were dominated by R. pseudoacacia or the native pioneer tree Betula pendula. As a negative effect, abundances of five arthropod taxa decreased (Chilopoda, Formicidae, Diptera, Heteroptera, Hymenoptera); 13 others were not affected. Woodland type affected species composition of carabids and functional groups in spiders, but surprisingly did not decrease alpha and beta diversity of carabid and spider assemblages or the number of endangered species. Tree invasion thus did not induce biotic homogenization at the habitat scale. We detected no positive effects of alien dominance. Our results illustrate that invasions by a major tree invader can induce species turnover in ground-dwelling arthropods, but do not necessarily reduce arthropod species abundances or diversity and might thus contribute to the conservation of epigeal invertebrates in urban settings. Considering the context of invasion impacts thus helps to set priorities in managing biological invasions and can illustrate the potential of novel ecosystems to maintain urban biodiversity.

Response of carabid beetles to wetland creation in an intensive agricultural landscape

In order to reduce the farming intensity and increase habitat heterogeneity, wetlands are often created in agricultural landscapes. This is because wetlands in agricultural landscapes can decrease sediment deposition, i.e., phosphorus and nitrogen, released as a result of cultivation and fertilization. Additionally, the creation of wetlands can improve heterogeneity within an agricultural landscape. We investigated the response of carabid beetles to restoration and creation of wetlands in a paddy field-dominated agricultural landscape in South Korea. Degraded wetlands, paddy fields, and dry fields (previous habitats) were converted to wetlands, including an abandoned paddy field that existed as a spontaneously restored wetland. Carabid beetle diversity significantly increased with wetland restoration and abandonment of farming practices, while the wetland creation did not have a significant effect. Carabid species composition, from nestedness and co-occurrence indices, did not show significant segregation patterns. Carabid assemblages in the previous habitats and current wetlands were similar to the previous habitats and current wetlands. Only flying carabid beetles showed a significant response to both wetland restoration and creation. Species capable of flight can migrate from surrounding habitats or closely connected habitat areas. Carabid abundance was only elevated with reduction of disturbance by wetland restoration and abandonment, although re-colonized carabid beetles were the dominant species in paddy fields and their landscape. The reduction of farming intensity creates the heterogeneity within restored wetlands and abandoned paddy fields, significantly improving carabid diversity. Our results suggest that in order to achieve the ecological benefits from restoration and creation of wetlands in paddy field-dominated landscapes, the farming intensity should be reduced. The complex configuration of agricultural landscapes can improve carabid diversity therein.

Vegetation cover and grasslands in the vicinity accelerate development of carabid beetle assemblages on restored landfill sites

There is an increasing evidence that rare and scarce carabid species of conservation importance are frequent in brownfield sites such as restored landfills. However, this potential has largely been unexplored. The present study was undertaken to examine carabid species composition, richness and abundance in relation to habitat quality and landscape structure on landfill sites in comparison with paired reference sites of existing wildlife value. Sampling was conducted by collecting carabids in ten pitfall traps set along two 100 m transects on each of nine restored landfill sites and their paired reference sites in the East Midlands region of the UK. A total of 1014 individuals representing 37 carabid species were found during April–September of 2007 and 2008. On the surveyed landfill sites, generalist species were common, while no nationally rare or scarce species were found. Neither species richness nor diversity of carabid species was found to be different from that of the reference sites. Seeding durin...

Reconsidering the role of ‘semi‐natural habitat’ in agricultural landscape biodiversity: a case study

AbstractSemi‐natural habitats are considered as the main source of biodiversity in agricultural landscapes. Most landscape ecology research has focused on the amount (relative surface) and spatial organisation of these habitats. However, these two components of landscape heterogeneity, composition and configuration, are often correlated. Also, landscape structure effects on biodiversity were mostly observed locally, while there is a great need for studying landscape‐scale gamma diversity. We conducted a mensurative experiment to determine the independent effects of semi‐natural habitat amount and configuration on gamma diversity of carabid beetles and vascular plants. The influence of landscape heterogeneity components were tested on species richness, evenness and composition. Local diversity (species richness and composition) was compared across the various cover types to determine their relative contributions. Only carabid species evenness and composition were influenced by semi‐natural habitat amount. Carabid and plant species richness and plant species composition remained unaffected by semi‐natural habitats. Local diversity analysis showed that three types of habitats can be distinguished in agricultural landscapes: grasslands (temporary and permanent ones), woody habitats (woodlands and hedgerows) and row crops. These results beg for a re‐evaluation of the semi‐natural covers. Temporary and permanent grasslands are often similar, probably because of comparable farming management. Permanent grasslands and woody habitats are often combined as semi‐natural covers, although they support very different communities. The lack of effect of semi‐natural habitat amount and configuration on gamma diversity results from a more complex organisation of biodiversity in landscapes and supports the move from semi‐natural vs. farmland to habitat mosaic landscape representations.

Carabid beetles as indicators for shrub encroachment in dry grasslands

Semi-natural grasslands are key habitats for biodiversity conservation in Central Europe. Shrub encroachment is one of the most threatening drivers of grassland degradation and affects soil properties, microclimate, and vegetation with possible impacts on higher trophic levels. We aimed to analyse the impact of shrub encroachment with broom (Cytisus scoparius) on carabid beetle diversity, species composition, and functional traits. In a field study on dry grasslands on the island of Hiddensee (Germany) we studied 15 sites along a gradient of increasing broom encroachment and classified them into three dry grassland types with low, medium, and high shrub cover. Our results provide evidence that shrub encroachment initially has positive effects on species richness and activity densities of dry grassland carabids. Carabid species composition differed among differently shrub-covered dry grassland types, and sites with low and high shrub cover were each characterised by unique carabid assemblages. The species composition of sites with a medium shrub biomass had a transitional character and contained species which are typical for open dry grassland, but also shared species with sites with a high shrub cover. Among functional trait parameters investigated, especially the body size of carabid beetles was related to environmental parameters associated with shrub encroachment. Body size was positively correlated to shrub biomass and soil humidity, but negatively to temperature. Eurytopy values of carabids were related to high litter cover, i.e. habitat generalist (eurytopic) species mainly occurred in densely shrub-encroached sites. In order to preserve unique carabid assemblages of open dry grasslands with stenotopic and smaller species, it is most important to prevent a shrub encroachment higher than about 60% cover. For management we suggest extensive grazing (by cattle, sheep or horses) to prevent shrub encroachment on dry grasslands. In areas with high shrub cover additionally the use of goats or mechanical removal of shrubs might be necessary.