Carabid Abundance Research Articles

The impact of forest ski-pistes on diversity of ground-dwelling arthropods and small mammals in the Alps

Forest clearing for winter sport activities is the major force driving loss and fragmentation of the alpine forests. The establishment of ski-pistes involves impacts on every ecosystem component. To assess the extent of this threat we studied ground-dwelling arthropods (namely ground beetles and spiders) and small mammals (shrews and voles) at two ski resorts in north-western Italian Alps by pitfall trapping. Diversity parameters (mean abundance, species richness and Shannon index) of spiders and macropterous carabids increased from forest interior to open habitats (i.e., ski-piste or pasture), whereas parameters of brachypterous carabids significantly decreased from forest interior to open habitats. Diversity parameters of macropterous ground beetles were higher on pastures than on ski-pistes. Small mammals were virtually absent from ski-pistes. Observed frequencies in the three adjacent habitats were significantly different from expected ones for the bank vole Myodes glareolus and the pygmy shrew Sorex minutus. Generalized linear models showed that abundance, species richness and diversity of spiders and macropterous carabids of ski-pistes were best modelled by combination of factors, including grass cover and width of the ski-piste. Indicator Species Analysis showed that species that significantly preferred ski-pistes were less than those preferring pastures, and species which were exclusive of ski-pistes were very few. To retain arthropod ground-dwelling fauna of open habitats environmentally friendly ways of constructing pistes should be developed. After tree clearing, only the roughest ground surfaces should be levelled, in order to preserve as much natural vegetation as possible. Where necessary, ski-pistes should be restored through the recovery of local vegetation.

Insect pests and their natural enemies on spring oilseed rape in Estonia : impact of cropping systems

To investigate the impact of different cropping systems, the pests, their hymenopteran parasitoids and predatory ground beetles present in two spring rape crops in Estonia, in 2003, were compared. One crop was grown under a standard (STN) cropping system and the other under a minimised (MIN) system. The STN system plants had more flowers than those in the MIN system, and these attracted significantly more Meligethes aeneus, the only abundant and real pest in Estonia. Meligethes aeneus had two population peaks: the first during opening of the first flowers and the second, the new generation, during ripening of the pods. The number of new generation M. aeneus was almost four times greater in the STN than in the MIN crop. More carabids were caught in the MIN than in STN crop. The maximum abundance of carabids occurred two weeks before that of the new generation of M. aeneus, at the time when M. aeneus larvae were dropping to the soil for pupation and hence were vulnerable to predation by carabids.

Management effects on carabid beetles and spiders in Central Hungarian grasslands and cereal fields

Modern agriculture is one of the main anthropogenic threats to biodiversity. To explore the effects of agricultural intensification we investigated carabids and spiders in two studies; in 2003 in grasslands and two years later in cereal fields in the same region. Both aimed to study the effect of management on arthropod diversity and composition at local and landscape scales. In 2003, we used a paired design for grasslands (extensively vs. intensively grazed). In 2005, a gradient design was applied with a total of seven land-use intensity categories. In both studies, sampling was carried out using funnel traps with the same sampling effort. Linear mixed models showed that high grazing intensity in grasslands had a positive effect on carabid species richness and abundance, but no effect on spiders. Landscape diversity had a positive effect only on carabid abundance. In the case of cereal fields, the management intensity (nitrogen fertiliser kg/ha) had a negative effect on spider richness and no effect on carabids. After variance partitioning, both local and landscape characteristics seem to be important for both cereal and grassland arthropod communities. Based on our results, we think that current and future agri-environmental schemes should be concentrated on cropland extensification. Low intensity croplands could act as a buffer zone around the semi-natural grasslands, at least in this biogeographic region.

Forest management effects on carabid beetle communities in coniferous and broadleaved forests: implications for conservation

Abstract. Carabid beetles (Carabidae, Coleoptera) were sampled by pitfall trapping to determine the effects of plantation forest management on beetle abundance, diversity and community composition. Five habitats were chosen for study to represent the different environments created by the clear‐fell and re‐plant forestry cycle: clear‐fell, new‐plant, mixed (conifer and broadleaved) and mature stage conifer plantation. The results from these sites were compared with semi‐natural deciduous woodland. Beetles were trapped for 6 weeks during June and July 2005. At each site, a range of environmental parameters were measured; soil pH, soil organic matter content, soil water content, percentage canopy cover, amount of dead wood, leaf‐litter depth, tree species present, tree diameter at breast height and percentage cover of ground vegetation. These were used to interpret differences in carabid abundance, diversity and community assemblage. Beetle abundance was highest in the deciduous habitat, but species diversity was not significantly different between any of the sites, except the clear‐fell habitat which was less diverse. Carabid community assemblages of forest specialist, forest generalist and open‐habitat species were investigated. Only the broadleaved deciduous woodland contained large populations of forest specialist species. These results suggest inclusion of purely broadleaved stands in the forest landscape is necessary to maximise diversity at the landscape scale and enhance the overall conservation potential of managed forest land. Within habitats the amount of dead wood, number of tree species present, percentage canopy cover and leaf‐litter depth were significant determinants of carabid abundance and diversity.

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.

Effects of habitat loss and fragmentation on the abundance and species richness of aphidophagous beetles and aphids in experimental alfalfa landscapes

In agro-ecosystems, habitat loss and fragmentation may alter the assemblage of aphidophagous insects, such as foliar-foraging (coccinellids) and ground-foraging predators (carabids), potentially affecting intraguild interactions. We evaluated how habitat loss (0, 55 and 84%), fragmentation (1, 4 and 16 fragments) and their combination affected the abundance and species richness of coccinellids and carabids, and aphid abundance, both in the short-term (summer: December to February) and over a longer time span (autumn: March to May), when different demographic mechanisms may participate. We created four types of 30 × 30 m patches (landscapes) in which alfalfa was grown: Control (1F - 0%, 30 × 30 m patch of alfalfa with no fragmentation or habitat loss), 4F - 55% (4 alfalfa fragments, with 55% total habitat loss), 4F - 84% (4 alfalfa fragments, with 84% total habitat loss), and 16F - 84% (16 alfalfa fragments, with 84% total habitat loss). Each landscape type was replicated five times. Insects were sampled by sweep-netting and pitfall traps, from December (summer) to May (autumn). Total abundance and species richness of carabids, in the short-term, was highest in the 16F - 84% landscapes. Total abundance of adult coccinellids was similar among landscapes, but at the species level Hyperaspis sphaeridioides, in the short-term, and Adalia bipunctata, in the long-term, had their highest densities in fragments within landscapes with high habitat loss (84%), independently of habitat fragmentation. Species richness in the long-term was higher in the landscapes with 84% habitat loss. Among aphids, in the long term Aphis craccivora was less abundant in landscapes with high habitat loss and fragmentation (16-84%), while Therioaphis trifolii showed the opposite trend. These results suggest that habitat loss and fragmentation may increase the density and diversity of aphidophagous insects, while their effects on aphids are more variable.

Agricultural policy-induced landscape changes: effects on carabid abundance and their biocontrol potential

One of the most important services provided by biodiversity is thought to be the biological control of pests in agricultural landscapes, including aphids on cereals. The food webs potentially contributing to biological control of aphids primarily consist of polyphagous predators, parasitoids and pathogens. The problems of aphid pests have increased greatly since the 1970-ies, possibly as an effect of agricultural intensification, which is thought to have reduced diversity and abundance of these predators and parasites and consequently their biocontrol potential. The main objective of this study was to test this by measuring this potential for bio- logical control of aphids, and relate it to agricultural intensification and predator abundance. We selected 30 farms distributed along agricultural intensification gradients, based on the amount of fertilizers applied per hectare. Estimates of ground-living predator den- sity were obtained using pitfall trapping over a one-week period. Traps were placed inside the cereal fields, 10 m from the margin, in 2 replicates per field. Predation risk due to ground-living predators (biocontrol potential) was estimated by monitoring removal of aphids glued to labels. This was done in the same fields, in the immediate vicinity of the traps, over a period of 2 days. The propor- tion of aphids eaten per unit time was the response variable. We present the correlations between intensity of agricultural exploita- tion, predator abundance and biocontrol potential. The outcomes are not straightforward in that intensification begets a reduction in predator density and biocontrol potential. We discuss the potential confounding issues that might have affected our results.

Ground-dwelling predators can affect within-field pest insect emergence in winter oilseed rape fields

We investigated, (i) whether the emergence from pupation of two coleopteran pest insect groups in oilseed rape (OSR, Brassica napus L.)—pollen beetles (Meligethes spp. F., Nitidulidae) and stem weevils (Ceutorhynchus pallidactylus Marsh and C. napi Gyll., Curculionidae)—is affected by the exclusion of ground-dwelling predatory arthropods, and (ii) the role for pest control of the widely abundant carabid beetles Anchomenus dorsalis Pontop. and Poecilus cupreus L. Densities of ground-dwelling arthropods were manipulated using enclosures; emerging pest adults were assessed using emergence traps. Where arthropods had been excluded, between two (June sampling) and tenfold (August sampling) more stem weevils emerged than where predators had free access. The addition of 25 adult A. dorsalis m−2 to formerly predator-free enclosures showed similar stem weevil emergence than plots where predators had free access; the addition of 25 adult P. cupreus m−2 did not reduce stem weevil emergence. In August, both A. dorsalis and P. cupreus additions marginally significantly reduced pollen beetle emergence.

Climbing behaviour and aphid predation byAgonum muelleri(Coleoptera: Carabidae)

AbstractField-collectedAgonum muelleri(Herbst) adults were videotaped to assess their ability to climb soybean (Glycine max(L.) Merr. (Fabaceae)) plants. All individuals climbed up and down soybean plants multiple times.Agonum muellerispent from 12.5 ± 3.4% to 54.1 ± 11.3% of their time on soybean plants. CagedA. muelleriadults on plants infested with soybean aphids,Aphis glycines Matsumura (Hemiptera: Aphididae), reduced the number of apterous adults. The presence of predators had an indirect effect on the density of nymphal aphids by reducing the numbers of adult aphids.Agonum muelleri, an abundant carabid in soybean fields, readily climbs soybean plants to feed on soybean aphids.

Distribution of carabid beetles among 40-year-old regenerating plantations and 100-year-old naturally regenerated forests in Southwestern China

Effects of reforestation by native tree species on species assemblages of carabid beetles were studied between 40-year-old regenerating plantations and 100-year naturally regenerated forests in Southwestern China. Two old naturally regenerated forest types (ca.100 years old) were chosen: hemlock-spruce forests ( Tsuga chinensis and Picea brachytyla) and birch forests ( Betula albo-sinensis). Three young regenerating forest types (ca. 40 years old), including spruce plantations ( P. brachytyla), larch plantations ( Larix kaempferi and Larix mastersian), and natural broad-leaved forests, were established after the logging of the old naturally regenerated forests. Using pitfall traps, we compared the distribution of carabid beetles in the five forest types. Three replicated plots for each forest type were chosen, and each plot was investigated with four trap sites twice each month during the growing season (May to October) in 2004. Our results showed that species richness and abundance were significantly higher in the young regenerating forests than in the old naturally regenerated forests. Analysis of complementarity in carabid species lists across the forest ages and types showed that the old naturally regenerated birch forests had the lowest similarity with the young regenerating larch plantations, and the highest similarity was shown between the two young regenerating plantations. Although PCoA ordination grouped the carabid assemblages according to forest type and forest age, the overall similarity among all forest types was high. Moreover, quantitative character species analysis did not detect significant species associated with forest types and ages. Based on the specificity and fidelity, most carabid species were abundant in all habitats, and only a few species were restricted in one or two forest types. Multiple linear regression between the species richness, abundance and Shannon diversity of carabids and of five environmental variables showed that the cover of canopy and herbaceous layer, and the depth of leaf litter had significant effects in determining richness, abundance and diversity of carabid beetles. Thus, the young regenerating forests at the mature stage could provide an appropriate habitat for most forest species of carabids survived in adjacent old naturally regenerated forests and might replace the role in part of the old-growth forests in sustaining the diversity of carabid assemblages. But some species are still restricted in old naturally regenerated forests, so in order to protect the diversity of carabid assemblages, it is necessary to sustain the intact old naturally regenerated forests when reforesting with some native tree species following natural succession.

Ground Beetle (Coleoptera: Carabidae) Assemblages in Apple Orchards Receiving Pheromone-based or Conventional Tortricid Management Programs

Pitfall trapping was used to assess the effect of a low-spray mating disruption program targeted against the codling moth and leafrollers on carabid communities (potential predators of codling moth, Cydia pomonella [L.], leafrollers [Lepidoptera: Tortricidae] and apple maggot, Rhagoletis pomonella [Walsh]) in the orchard ground cover. Abundance and species richness of carabids were generally higher in mating disruption blocks relative to conventionally-managed blocks. Over 2 yrs, 3,173 carabids representing 62 species in 27 genera were collected. The most common carabids (more than 5% of the total carabid population) were Harpalus pensylvanicus (DeGeer) (38.2%), Harpalus erythropus Dejean (11.4%), Poecilus lucublandus (Say) (10.1%), Dicaelus elongatus Bonelli (6.2%) and Harpalus longicollis LeConte (5.9%).

Distribution of Carabid Beetles (Coleoptera: Carabidae) Across a Forest-Grassland Ecotone in Southwestern China

This paper studied the occurrence of carabid beetles (Coleoptera: Carabidae) in the forest edge, the adjacent forest interior, and the surrounding grassland in southwestern China. Beetles were collected with pitfall traps along five replicated transects. Forest species rarely penetrated into the grassland from the forest interior, and the grassland specialists were not found in the forest interior. The forest edge hosted additional species from the adjacent grassland that increased its overall species richness. Nearly all forest species (23 of 24 species) and grassland species (13 of 15 species) can be found in the forest edge. Carabids of the forest edge were more similar to those of the forest interior than to those of the grassland by ordination and cluster analysis. Based on the specificity and fidelity, carabids can be distinguished into five species groups: habitat generalists, grassland-associated species, forest generalists, forest specialists, and edge-associated species. Multiple linear regression analysis showed that canopy cover and/or shrub cover were the most important factors in determining the richness, abundance, and diversity of carabids. The forest edge may serve as a transition zone for dispersal and re-colonization of carabid beetles from adjacent habitats and therefore is important for natural conservation.

Carabids of differently aged reforested pinewoods and a natural pine forest in a historically modified landscape

Abstract We studied the responses of carabid beetles to Pinus sylvestris ageing in four plantations aged 2–3, 10–12, 40–45 and 80 years, and one mature natural pine forest – in NW Spain. In 2003, a total of 16,866 carabid individuals (50 species) were collected using pitfall traps. Overall carabid abundance and species richness differed significantly among the five age classes with the highest values occurring in the youngest age class. The carabid assemblages of the initial stages of the ageing sequence differed considerably from the later stages that were relatively similar to each other – a consequence of differences in species dominance at specific age classes. Yet, the carabid assemblage of the 80-year-old stage did not approach that of the natural pine forest, but, unexpectedly, the 40–45-year-old age class did. Canopy cover and soil pH were the main environmental variables that affected the carabid distribution. We also detected species-level responses to the ageing process, with open habitat species more abundantly collected at the youngest stages and forest specialists at the older stages. We conclude that carabid beetles responded predictably to the pine plantation ageing process, and that although pine forests in NW Spain do not seem to provide habitat for unique species, they act as secondary habitats for forest specialist species.

Differences in responses of herpetobionts and geobionts to impact from the Kosogorsky Metallurgical Plant (Tula region, Russia)

The influence of the Kosogorsky Metallurgical Plant (KMP; Tula region, Russia) on the abundance and biodiversity of carabid beetles and soil macrofauna and on the trophic activity of soil biota was studied. Metal concentrations in the impact plot were many times higher than those in the control plot located on the same transect. As the transect approached KMP, both the abundance of soil invertebrates (geobionts) and trophic activity of the soil biota remained unchanged, whereas the abundance and diversity of carabids (herpetobionts) decreased drastically. It is suggested that the impact of the KMP on herpetobionts is accounted for by modification of the structure of ecosystems and that herpetobiontic and geobiontic groups of the macrofauna respond differently to this impact because of differences in the ecological mechanisms of population response.

The role of moose Alces alces L. in boreal forest – the effect on ground beetles (Coleoptera, Carabidae) abundance and diversity

The indirect effect of moose Alces alces browsing on ground beetle's abundance and diversity was investigated by pitfall trapping in a mixed coniferous forest in Vestfold County (59°19′ N, 9°50′ E, Norway), during the summer of 2002. Three areas with different browsing pressures, ranging from non- to medium- and heavily browsed were chosen and dry weight of bilberry Vaccinium myrtillus and humidity at ground level were measured in the three locations. As predicted, the gradient analyses showed that browsing by moose influenced the composition of carabid fauna, and that browsing intensity and humidity covaried with the most important gradient in carabid species composition found across the three locations. Species that live in light stands with rather dry soil, were more often captured in the browsed areas, whereas shade tolerant and hygrophilous species were more abundant in the non-browsed area. The carabid abundance increased significantly with increasing browsing pressure. According to our predictions, the diversity at trap level (α-diversity) was higher in the highly browsed area. Conversely, species turnover (β-diversity) decreased with browsing intensity. On the other hand, the rarefaction analysis showed that the regional species richness (γ-diversity) was considerably higher in the medium browsed area than in the heavily browsed one, which is consistent with the intermediate disturbance hypothesis. This study indicates that moose, by reducing the bilberry that constitutes the field layer in summer, affect carabid species composition and might be capable to reshape the whole ecosystem in our study area by a cascade effect.

Effects of post-fire salvage logging on boreal mixed-wood ground beetle assemblages (Coleoptera, Carabidae)

The frequency and intensity of salvage logging has recently increased in burned forests of the Canadian boreal so that post-fire areas make up a significant annual share of all harvested forest land in some years. However, little is known about how this practice affects re-establishment of animal and plant communities that already have been strongly altered by the fire. We pitfall-trapped carabid beetles (Coleoptera, Carabidae) for two consecutive years following a large-scale boreal wildfire (276,000 ha) in burned mixed-wood forests of 12 landscape units (2.5 km × 2.5 km each). These units included four salvage treatments, each replicated three times: control (no salvaging), low (ca. 20–30% of merchantable mixed-wood removed), moderate (40–50%) and high salvage intensity (60–70%). We established 16 sampling sites in each unit: on the control landscapes, all 16 sites were in un-logged stands; in low-salvage units, 4 out of 16 sites were in salvaged areas; in moderate- and high-salvage units, 8 and 12 out of 16 sites, respectively, were in salvaged areas. Salvage logging positively affected carabid species richness. However, there was an overall salvage-caused decrease in the abundance of many common forest-dwelling carabids, and an increase in the abundance of disturbance or open-habitat specialists. Interestingly, the effects of salvage logging on the total catch and several abundant forest species (e.g., Calosoma frigidum, Harpalus laevipes, Pterostichus punctatissimus, P. adstrictus and Platynus decentis) appeared to be more important at the landscape level (the four landscape treatments) than at the level of sampling sites (site logged versus not). We suggest that this observation resulted from ambiguous site-level responses to salvage that collectively contributed to the (mostly negative) significant responses at the landscape level. Effects of fire severity (estimates based on tree survival) on carabids were species-specific; however, the impact of this measure was most often significant at the site, and not at the landscape, level. A Multivariate Regression Tree revealed that fire severity and the overall (pre-fire) amount of mixed-wood forest on the landscape were significant determinants of assemblage structure, with the local effects of fire severity being strongest.

Effect of Microhabitat Complexity on the Local Distribution of Arthropods in Clear-Cuts

Structural complexity may affect activity and abundance of ground-dwelling arthropods. In this field experiment, the short-term effect on abundance of ground-active carabid beetles (Coleoptera: Carabidae) and lycosid spiders (Araneae: Lycosidae) from slash (logging residue) on the ground was studied. Arthropods were collected by pitfall trapping in three clear-cuts in southwest Sweden. The distribution of slash on the ground was manipulated, and two types of microhabitats were created adjacent to traps, i.e., either slash was cleared (bare ground traps) or slash was aggregated in heaps (slash-covered traps). Overall, carabids were significantly less abundant on the bare ground compared with the slash covered ground. For lycosids, no difference in abundance between the two microhabitat types was found. In reference plots, where no manipulation of microhabitat complexity was carried out, an overall positive relationship between structural complexity (slash height) and abundance of carabids was found. For lycosids, however, no correlations in reference plots were found. Bare ground microhabitats are mimicking structural complexity in clear-cuts after commercial slash harvest for biofuel. Large-scale removal of structural elements in clear-cuts might have short-term local effects, such as altered composition of arthropod communities.

Multiscale and surface pattern analysis of the effect of landscape pattern on carabid beetles distribution

It has been often shown that spatial distribution of species can be related to the main characteristics of their habitat. Usually, such relationships refer to point pattern analysis and try to determine whether the distribution of species is conditioned by their surroundings or not. They often seek correlations at a given place, date and scale and neglect the information potentially extracted from detailed surface pattern analyses that would require extended data. This study investigated the impact of landscape pattern and landscape context (of habitats) on carabid beetles assemblages in each place and on a continuous range of scales of a landscape. For this purpose, we develop a tool able to visualize and quantify the spatial variations of indices commonly used in point pattern analyses, such as contagion (heterogeneity) of a landscape and abundance (counts) of species. Using moving windows, we plotted contagion maps of two Brittany sites (France) and cross-correlation maps between the latter and carabid beetles spatial distributions, in order to study their local relationships. Associated landscape and insect index scaling profiles helped to interpret the correlations found. A rather good agreement with landscape ecology predictions over both sites has been found: significant relationships between land cover contagion and total carabid abundance on one hand, between agricultural intensification (mainly maize fields) and carabid body size on the other hand, have been observed. Nevertheless, detailed surface pattern analyses over a wide range of scales show quite high deviations from empirical results with no correlation, or even negative correlation, in some places between otherwise correlated indices.

Variability of Carabidae in time and space in open areas

The temporal and spatial variability of carabid fauna was studied on a colliery spoil heap area in Germany and on an area of post-agricultural soil in Poland using pitfall traps. Applying Mean Individual Biomass (MIB) of carabids as an indicator of environmental quality, all plots were assessed as being young stages of succession. Species richness and total carabid abundance fluctuated remarkably among different plots and study years. Total numbers of individuals fluctuated significantly in time, whereas species richness remained strikingly constant. The Jaccard’s index ofspecies similarity was low for the level of individual sampling plots but high for the total catches when comparing different years. Individual species showed asynchronicity of fluctuations in numbers of individuals at the level of individual plots. Based on these results we suggest that the observed patterns can be explained by the ‘spreading of risk’ hypothesis.

Salvage Logging, Edge Effects, and Carabid Beetles: Connections to Conservation and Sustainable Forest Management

We used pitfall traps to study the effects of fire and salvage logging on distribution of carabid beetles over a forest disturbance gradient ranging from salvaged (naturally burned and subsequently harvested) to unsalvaged (naturally burned and left standing). Significantly more carabids were caught in the salvaged forest and the overall catch decreased steadily through the edge and into the unsalvaged forest. We also noted a strong negative correlation between carabid abundance and percent vegetation cover. Beetle diversity as measured through rarefaction was significantly greater at the edge relative to both the unsalvaged and salvaged forest. This stand level study suggests that the amount of edge habitat created by salvage logging has significant implications for recovery of epigaeic beetle assemblages in burned forests by inflating the abundance of “open habitat” species in the initial communities. Carabid beetle responses to salvage logging can differ from responses to harvesting in unburned boreal forest suggesting that management of postfire forests requires special consideration.