Beetle Abundance Research Articles

Logging operations creating snags, logs, and stumps under open and closed canopies promote stand-scale beetle diversity

Conservation tools to enrich habitat diversity in the widely distributed homogeneous production forests include stumps as logging residues but also the intentional creation of logs or snags, as well as varying canopy conditions. While an open canopy has been shown to foster forest biodiversity, the impact of different deadwood types at stand scale is less clear, which is crucial since this is the most relevant scale for silvicultural decisions. In this study, we experimentally manipulated canopy conditions (open vs. closed) and created deadwood (stumps, logs, snags) in different combinations in five mature European beech (Fagus sylvatica L.) forests to test the potential of active manipulations to increase the diversity of beetles, one of the most diverse insect orders in temperate forests. We estimated abundance, species number and species richness (controlled for abundance) of saproxylic (i.e., deadwood-dependent) and non-saproxylic beetles using flight-interception traps and analyzed species assemblages within the first 3 years of the experiment. Using generalized linear mixed effect models we found a 33.7 % and 43.4 % higher abundance as well as a 26.1 % and 23.5 % higher species number under open canopies for saproxylic and non-saproxylic beetles respectively, accompanied by a higher species richness of both groups. Stands with deadwood had a 38.6 % and 32.7 % higher species number followed by higher species richness of saproxylic and non-saproxylic beetles compared to stands without manipulation but manipulations did not affect beetle abundances. We identified sampling year, followed by canopy condition and deadwood type (in addition to an overall higher impact of spatial distance between stands and sites) by applying multiple regression analyses as most important to explain species assemblages of both beetle groups. Saproxylic abundance and species number in stump treatments were initially high but decreased over 3 years, while treatments containing snags and logs resulted in an increase in both abundance and species number over time. These temporal trends were mediated by canopy cover. Our findings provide three major insights for biodiversity-orientated management in mature beech forests: First, opening the canopy increases the stand-scale abundance, species number, and species richness of saproxylic and non-saproxylic beetles. Second, while stumps are attractive for saproxylics shortly after the logging operation, snags and logs provide longer-lasting deadwood resources, thus underlining longer sustainability of snag and log enrichment for forest biodiversity. Third, deadwood enrichment at the stand scale promotes not only deadwood-dependent but also other beetle species.

Influence of tillage and fertilizers on the fauna of sodpodzolic gleyic soil and the yield of field crops

The results of the study of the mouldboard, surface-mouldboard and surface soil treatment systems, as well as straw-based fertilizer systems used both separately and in combination with full mineral fertilizer are presented. Data for 2019-2021 on soil fauna, yield of perennial grasses of the 1st and 2nd years of use and spring wheat are given. The studies were conducted on sod-podzolic gleyic middle-loamy soils (experimental field of the Yaroslavl State Agricultural Academy). During the period under study, the highest abundance of beneficial soil fauna (earthworms (Lumbricina), ladybugs (Coccinellidae) and carabid beetles (Carabidae) was observed during surface-mouldboard treatment which indicates that this system has favorable feeding conditions for these organisms. The number of nematodes (Nematoda) in this variant decreased with significant changes recorded in different soil layers depending on the year, which may be associated with stronger plant growth and an increase in their ability to resist helminths. It was found that the greatest impact on the beneficial fauna had a combined application of straw and total mineral fertilizer: an increase in the beneficial soil fauna and a decrease in the population of nematodes were observed, which can be explained by the reduction of bacterio- and mycotrophs. In all the years of research the surface-mouldboard treatment provided the yield of field crops at the level of the mouldboard tillage or slightly lower. Application of straw together with full norm of mineral fertilizers caused the highest values of the above-mentioned indicator.

Effect of climatic factors on the diversity and abundance of Scolytinae and Platypodinae (Coleoptera: Curculionidae) in a pine-oak forest of north-eastern Puebla, Mexico.

Objective: The aim of this work was to evaluate the diversity and abundance of bark beetles and ambrosial beetles and their relationship with temperature and relative humidity.
 Design/methodology/approach: The study was carried out in a pine-oak forest of the northeastern Sierra of the state of Puebla, where a monitoring system was established using Lindgren traps baited with frontalin, brevicomine, alpha-pinene and beta-pinene.
 Results: The presence of 23 species of bark beetles and ambrosial beetles was recorded. Gnathotrichus sulcatus (LeConte) and Pseudips mexicanus (Hopkins) were the most abundant species and their presence was significantly associated with places having high relative humidity.
 Limitations on study/implications: The results obtained are limited to the studied ecosystem. 
 Findings/conclusions: It was concluded that the abundance of the species observed was closely related with climatic factors.

Random year intercepts in mixed models help to assess uncertainties in insect population trends

Abstract An increasing number of studies is investigating insect population trends based on time series data. However, the available data is often subject to temporal pseudoreplication. Inter‐annual variability of environmental conditions and strong fluctuations in insect abundances can impede reliable trend estimation. Temporal random effect structures in regression models have been proposed as solution for this issue, but remain controversial. We investigated trends in ground beetle abundance across 24 years using generalised linear mixed models. We fitted four models: A base model, a model featuring a random year intercept, a model featuring basic weather parameters, and a model featuring both random year intercept and weather parameters. We then performed a simple sensitivity analysis to assess the robustness of the four models with respect to influential years, also testing for possible spurious baseline and snapshot effects. The model structure had a significant impact on the overall magnitude of the estimated trends. However, we found almost no difference among the models in how the removal of single years (sensitivity analysis) relatively affected trend coefficients. The two models with a random year intercept yielded significantly larger confidence intervals and their p‐values were more sensitive during sensitivity analysis. Significant differences of the model with random year intercept and weather parameters to all other models suggest that the random year effects and specific weather effects are rather additive than interchangeable. We conclude that random year intercepts help to produce more reliable and cautious uncertainty measures for insect population trends. Moreover, they might help to identify influential years in sensitivity analyses more easily. We recommend random year intercepts in addition to any variables representing temporally variable environmental conditions, such as weather variables.

Effects of plantation intensity on longhorn and carabid beetles in conifer plantations mixed with broadleaved trees in northern Japan

ABSTRACT Reconciling timber production with biodiversity conservation is essential. Increasing the mixture of broadleaved (BL) trees into conifer plantations increases the abundance of species that prefer natural BL forests but can reduce conifer yields. Therefore, modeling of the relationships of the abundances of various taxa with conifer and BL trees is necessary for effective biodiversity conservation. Longhorn and carabid beetles are useful ecological indicators; however, their responses to the amount (e.g. basal area and coverage) of conifer and BL trees within stands remain unknown. We surveyed the abundances of longhorn and carabid beetles in plantations of Todo fir Abies sachalinensis and Sakhalin spruce Picea glehnii mixed with various amounts of BL trees and in natural BL forests. We analyzed the response of each taxon to the basal area of conifer trees (CBA) within stands. Unexpectedly, for longhorn beetles, no effect of CBA was detected for species using BL trees as larval host plants and the effect was positive for generalist species. For carabid beetles, the total abundance of forest-dependent species decreased almost linearly with increasing CBA. The species-level mean response was decreasing abundance with increasing CBA, which occurred more rapidly in the lower range of CBA. These results suggest large negative impacts of conifer trees, even in small amounts, for many carabid species. To reconcile timber production with carabid beetle conservation, it is essential to maintain remnant natural BL forests and revert unsuccessful conifer plantations containing abundant BL trees into BL forests.

Spatiotemporal Distributions of Scolytinae Beetles in the Subtropical Forests of Southern China

Scolytinae beetles serve as important regulators of ecosystem integrity. However, some of these species have been identified as important pests. The Guangdong region of China exhibits unique geographic characteristics, but is also subject to substantial anthropogenic disturbances, making it an important region for ecological research. This study was designed to assess the biodiversity and abundance of these Scolytinae beetles in subtropical areas, to define indicators associated with environmental disturbances, and to thereby provide additional valuable information that can support the conservation of the ecosystem and the monitoring and controling of pest species. For these analyses, a two-season survey of Scolytinae communities was performed across three habitats to examine the patterns of variation within these communities. These analyses revealed that environmental disturbances were associated with a drop in Scolytinae beetle population diversity, with Hypothenemus sp.2, Xyleborinus andrewesi, and Xyleborinus artestriatus offering particular value as indicators associated with severe environmental disruptions. Plant diversity and composition also impacted Scolytinae beetle communities through a range of complex mechanisms. Scolytinae beetle diversity was also found to be higher during the rainy season relative to the dry season, with beetle abundance being responsive to average temperatures, but unrelated to average relative humidity levels.

Dung Beetle Community Composition in the Presence and Absence of Mesopredators in a Longleaf Pine Forest

Dung beetles provide essential ecosystem services and serve as biodiversity indicators. Despite their importance, no studies have assessed their role in Pinus palustris (Longleaf Pine) forests. We assessed dung beetle diversity and abundance in a pristine Longleaf Pine forest in southwest Georgia, USA, by collecting beetles with pitfall traps in sites that excluded mammalian mesopredators as well as unfenced control sites. We collected 22 dung beetle taxa in total over a 24-month period and found higher beetle abundance and species richness in exclosure sites, though they showed no preference for dung source (i.e., Odocoileus virginianus [White-tailed Deer], Lynx rufus [Bobcat], Canis latrans [Coyote]). Melanocanthon bispinatus was the most abundant species (49.6% of total beetles). Results provide insight into the interactions of dung beetles and predators in Longleaf Pine ecosystems.

Substantial niche overlap in carrion beetle habitat and vegetation use

Abstract The habitat affinities of carrion beetles (Coleoptera: Silphidae), a speciose group with wide cooccurrence, are only coarsely described for well‐studied species, particularly in the western United States. We aim to identify if the 15 species of montane carrion beetle in Colorado differ substantially in their use of habitats and across more uniquely defined, fine‐scale vegetation characteristics. Habitat and vegetation data as well as carrion beetle abundance were collected along four elevational transects in the Front Range and San Juan Mountains from 2010 to 2012 across 32 sites. Multiple habitat types were sampled, including forest, meadow, riparian, rocky outcrops and tundra. The fine‐scale vegetation characteristics included percent coverage of ground vegetation (grass, forb, shrub, cacti, bare ground), understory vegetation biomass and height, canopy cover and tree species, number and size. Canonical correspondence analysis models examined whether vegetation characteristics strongly segregated species using abundances and presence‐absences. Habitat and vegetation models explained a maximum of 18.93% of the variation in species' abundances and 2.48% in species' presence–absences. Only one likely habitat specialist was identified by the models (Heterosilpha ramosa) and the remaining species had substantial overlap in habitat and vegetation use. The arid, low productivity and generally open understory habitats in Colorado mountains likely play a large role in the substantial vegetation overlap. Other mechanisms of partitioning likely exist in this system to reduce niche overlap, which could include differences in activity time and seasonality, physiological traits, other life history strategies and body size.

Does habitat type in no‐tillage agroecosystems influence ground‐dwelling macroarthropod community structure? A case study in KwaZulu‐Natal, South Africa

AbstractLoss of biodiversity in agroecosystems has negative implications for crop production and the functioning of the ecosystem. As such, agroecologists advocate minimum tillage practices in order to conserve biological diversity. To establish the influence of agricultural practices on biodiversity, we compared the species richness, abundance and composition of beetles, ants, spiders and small groups of ground dwelling arthropods in a veld and three agroecosystems (maize, sugarcane and multispecies pasture) under minimum tillage. Sampling was by pitfall trapping during the summer rainfall season in December 2019. Although ants were the most abundant (47%), followed by beetles (31%); beetles were the most speciose making up 40% of the morphospecies followed by spiders (31%). The veld had significantly greater relative proportion of species richness of spiders (54%) than the three agroecosystems, while significantly low relative proportion of species richness of ants was in the pasture (6%) compared to the veld (63%). Species richness and abundance of beetles were similar across habitat types. The four habitats supported different assemblages of ants, beetles and spiders. The differences in species composition among the habitats support the notion that agricultural practices with minimum soil disturbance enhance conservation of biological diversity, particularly, specialist species.

Eco-friendly management of the flea beetle, <i>Podagrica</i> species (Coleoptera: Chrysomelidae) on okra (<i>Abelmoschus esculentus</i> (L.) Moench) with <i>Artemisia annua</i> L. seed extract

<p>Okra, grown and consumed in every ecological zone, is amongst the most sort after fruit vegetable crops in Nigeria. The crop is often infested by diverse field insect pests, especially the flea beetle <em>Podagrica</em> species, which impinges on its growth and productivity. The application of synthetic pesticides has been the generic insect pest control measure due to its touted effectiveness. These synthetics, however, has safety concerns which include; hazard to human health, amplification of toxins in the food chain, pest resurgence, domestic animals and human poisoning, environmental pollution, insect resistance, natural enemies destruction; springs, wells, rivers, and underground water contamination. Stakeholders are advocating an alternative management approach that is sustainable with less negative social and environmental impact. This study, therefore, compared the insecticidal efficacy of <em>Artemisia annua</em> (source of the antimalarial artemisinin) seed extract in comparison with Cypermethrin 10 EC, a synthetic insecticide, in controlling <em>Podagrica</em> species, the major field insect pests of okra. The trial was set out in a 7 x 4 factorial arrangement integrated into a randomized complete block design and replicated thrice. Cypermethrin 10 E.C was tested at 0.25 ml, 0.50 ml, and 0.70 ml/100 ml of water, while <em>Artemisia annua</em> extract was applied at 1.00 ml, 2.00 ml, and 3.00 ml/100 ml of water respectively. The control for both treatments was designated 0.0 ml. Data on leaf damage and flea beetle abundance were carried out from 4-10 weeks after planting (WAP) whilst the pods’ weight was measured at maturity. The result shows that i) the concentrations of Artemisia extract and Cypermethrin sprayed provided comparable protection to okra against the flea beetle; ii) the yield of okra (pod weight) does not vary between <em>Artemisia annua</em> extract and Cypermethrin treated plots; and iii) flea beetle infestations vary with okra developmental stages.</p>

Two-Dimensional Projection of Distribution and Abundance of Common Species of Spiders and Beetles in South Korea Caused by Climate Change

The selection of explanatory variables is very important in a species distribution model for predicting changes in the distribution of organisms caused by climate change. In this study, a two-dimensional prediction of the abundance and distribution of beetles and spiders using temperature and precipitation was compared with the results of previous studies that employed a one-dimensional prediction using temperature. This study used the data from previous surveys for 366 forest sites in South Korea between 2006 and 2009 using pitfall traps. Species distribution models were created for 51 species with a high occurrence (collected from more than 10% of the total sites). A generalized additive model (GAM) was used for the distribution models. The future abundance and distribution based on climate scenarios RCP 4.5 and 8.5 were predicted by selecting 35 species from 51 common species for which climatic factors (temperature and precipitation) had a significant effect on abundance and distribution. In a two-dimensional prediction using temperature and precipitation, the range of change was larger compared with a one-dimensional prediction using temperature, and precipitation had a significant effect on decreasing species.

Does a Rural-Urban Gradient Affect Beetle Assemblages in an Arid Ecosystem?

Urbanization affects all elements of the pre-urban environment, including soils, hydrology, vegetation, and microclimate. Recently, Saudi Arabia has experienced rapid urbanization and growth. Thus, the country’s biodiversity has been threatened. In the Riyadh region, beetle assemblages were assessed along a rural-suburban-urban gradient. A total of 2791 individuals from 94 species belonging to seven families were collected at 15 sites along three different gradients of urbanization in Wadi Hanifa, which runs for a length of 120 km from northwest to southeast. Tenebrionidae dominated abundance (60.1%) and richness (38%). Beetle abundance, evenness, and diversity were not different among habitats; however, species richness was higher in rural habitats. Detrended correspondence “DCA” and canonical correspondence “CCA” analyses showed distinct differences among sites along gradients. Urbanization intensity, soil variables, and land cover were significantly correlated with CCA axis 1, while elevation and flora were significantly correlated with CCA axis 2. The most critical operating environmental variables in Wadi Hanifa were buildings, elevation, soil organic carbon, litter cover, and litter depth, as well as plant species such as Launaea capitata, Lycium shawii, Alhagi graecorum, and Heliotropium currasavicum. Ten species in our study were associated with urban habitats, six with suburban habitats, and seven with rural habitats. Consequently, expanding urban areas may negatively affect the richness and composition of beetles and may result in the loss of some native species.

Response of ants, beetles and spiders to disturbance varies among taxa in a South African savannah biome

Savannahs are structurally complex ecosystems consisting of a diverse community of plants and animals such as arthropods. Arthropods are essential in many ecosystem processes that help maintain life on Earth. The anthropogenic conversion of natural landscapes into croplands, residential and industrial areas has a negative impact on surface-active arthropods that have limited dispersal abilities and narrow habitat preferences. This study investigated the effect of disturbance on assemblages of ants, beetles and spiders in the savannah vegetation in Mpumalanga province, South Africa. We compared species richness, abundance and composition of these three taxa between the pristine savannah and the savannah that is exposed to a variety of anthropogenic activities (disturbed savannah). Arthropods were collected using pitfall traps in 15 sites in pristine savannah and 15 sites in disturbed savannah. We found that disturbance affects species richness and abundance of these taxa differently. Disturbance did not affect species richness of spiders and abundance of beetles, while greater species richness of ants and beetles, as well as abundance of ants and spiders was in disturbed than in pristine savannah. Furthermore, the species compositions of all taxa were different between disturbed and pristine savannah. The disturbed savannah had twice more unique indicator species than the pristine savannah. Differences in assemblages of arthropods between pristine and disturbed habitats suggest that it may be important to consider habitats in and outside protected areas in the conservation of arthropods, particularly in areas with greater percentage of natural and semi-natural landscapes occurring outside protected areas.

No detrimental effects of soil disturbance resulting from grassland restoration operations on aboveground‐dwelling invertebrate communities

Active grassland restoration requires soil disturbance by harrowing or plowing prior to seeding to create favorable conditions for plant germination. Yet, it is still unknown if these soil interventions are detrimental to the local ground‐dwelling invertebrate fauna. We evaluated how ground beetle (Carabidae) and spider (Araneae) communities, two important grassland bioindicators, respond to three common grassland restoration methods, differing in soil disturbance intensity and seed application method. The study was carried out in 47 extensively managed mesic meadows using a before‐after‐control‐intervention design. It was applied at the field scale and replicated 12 times across selected Swiss lowland sites. We did not detect any significant differences in abundance and species richness of ground beetles and spiders between restored and control meadows 1 year after restoration. At the community level we observed a slight shift towards a preference for wetter habitat (for both invertebrate groups), and restored meadows harbored a smaller weighted mean body size of spiders than control meadows. The latter was mainly driven by a higher abundance of some small pioneer species typically found in frequently disturbed habitats, notably in arable fields. Our results suggest that 1 year after restoration action, the ground‐beetle and spider communities recovered almost entirely to their predisturbance state, indicating that, with respect to above ground‐dwelling invertebrates, harrowing or plowing can be applied when restoring plant species‐poor grasslands.

Variation in Dung Removal Rates by Dung Beetles (Coleoptera: Scarabaeoidea) in a Temperate, Dry Steppe Ecosystem

During their feeding process, dung beetles perform a series of ecosystem functions that provide valuable ecosystem services, such as soil fertilization, improvement of soil properties, plant growth enhancement, and biological pest control. However, in the grasslands of the Central Asian dry steppe, the effects of dung beetles on dung removal remain almost unstudied. Here, we examined dung removal by different dung beetle species (Colobterus erraticus (Linnaeus, 1758), Onthophagus bivertex Heyden, 1887, Onthophagus gibbulus (Pallas, 1781), Gymnopleurus mopsus (Pallas, 1781), Cheironitis eumenes Motschulsky, 1859, and Geotrupes koltzei Reitter, 1892), and compared the impacts with control treatments (without beetles) under natural pasture conditions and in the laboratory. We examined the influence of different variables on dung removal rates, such as dung type and dung beetle traits (nesting strategies, abundance, body size, and biomass). We found higher dung removal rates during the initial 48 h in field and laboratory conditions. Among nesting strategies, tunnellers demonstrated significantly higher dung removal rates than dweller and roller species. The highest amount of dung removal was estimated for C. eumenes (6.5 g/day by seven individuals). We found no significant relationship between dung removal rates and dung beetle body size or biomass, but we observed a strong negative correlation between dung beetle abundance and dung removal rates. Our findings highlight the importance of dung type and age, nesting strategies and abundances of dung beetles, and experimental conditions, which are the main factors driving the process of dung removal.

Apparent niche differences between native and exotic lady beetles

Generalist predators can enhance biological control by filling unique niches and complementing other natural enemies, or disrupt it by preying upon other predators and parasitoids, complicating their net value for biological control. We searched for evidence of complementarity and/or interference between native (primarily Eriopis chilensis and E. eschscholtzi) and exotic (primarily Hippodamia variegata and Harmonia axyridis) lady beetles attacking aphids in alfalfa (Medicago sativa) fields near Santiago, Chile. Across 60 fields and three growing seasons, exotic lady beetle adults and larvae reached peak abundance relatively earlier in the growing season than the natives. Furthermore, exotic lady beetle peaks aligned more closely with aphid peak abundance than did native lady beetle peaks. Abundances of native lady beetle adults and larvae were weakly positively correlated with those of exotics, and peak aphid densities were generally lowest in fields where native and non-native lady beetle adults were similarly abundant. Therefore, we did not see evidence of strong interference between exotics and natives. Natural-agricultural habitat edges reduced native, but not exotic, larval lady beetle lag behind aphid peaks and was associated with greater lady beetle and lower aphid densities. Moreover, farms embedded in landscapes with greater natural habitat cover supported more exotic, but not native, lady beetles, and increased the lag between larval lady beetles and aphids for natives but not exotics. These findings support the idea that farms embedded within mosaics of natural and agricultural habitats may provide greater interaction potential between native lady beetles and aphid pests on farms as they move across the landscape, leading to greater top-down control. In contrast, exotic lady beetle lags were unaffected by landscape composition or configuration, but their greater densities in farms surrounded by more natural habitats might reflect a 'concentration effect' whereby exotic lady beetle abundance becomes concentrated in the agricultural habitats that they prefer. Our findings suggest that some lady beetles introduced for biocontrol may be better adapted to intensively managed habitats than natives, possibly leading to spatiotemporal complementarity between native and exotic lady beetles.

Diversity of beetle species and functional traits along gradients of deadwood suggests weak environmental filtering

BackgroundGradients in local environmental characteristics may favour the abundance of species with particular traits, while other species decline, or favour species with different traits at the same time, without an increase in average species abundances. Therefore, we asked: do variations in species and traits differ along gradients of deadwood variables? Do species abundance and trait occurrence change with species richness within or between functional groups? Thus, we analysed the beetle assemblages of five forest sites located in Italy, along the Apennines mountains. MethodsFrom 2012 to 2018 we sampled beetles and five deadwood types in 193 plots to characterise the deadwood gradient: standing dead trees, snags, dead downed trees, coarse woody debris, and stumps. We modelled beetle species relative abundances and trophic traits occurrences against the deadwood variables using joint species distribution models. ResultsOut of 462 species, only 77 showed significant responses to at least one deadwood type, with a weak mean response across species. Trophic groups showed mostly negative responses to deadwood variables. Species abundance increased with species richness among sites only for phytophagous and saproxylophagous. Trait occurrence did not increase with species richness among sites, except for phytophagous and saproxylophagous. However, trait occurrence changed significantly with species richness of several trophic groups within some sites. We found that increases in species richness do not result in decreases in species abundance of a given trophic group, but rather null or positive relationships were found suggesting low interspecific competition. ConclusionsOur findings suggest that in Mediterranean mountain forests there is still room for increasing the level of naturalness, at least for what concerns deadwood management. On one side, our findings suggest that competition for deadwood substrates is still low, on the other side they indicate that increasing deadwood volume and types to improve overall beetle richness may increase also beetle abundances.

A baseline account of scarabaeid beetles of area within and around historic Ahmednagar city (Maharashtra) India

The present study provides a preliminary account of Scarabaeid (Coleoptera: Scarabaeoidea) beetles of some areas in and around Ahmednagar city, Maharashtra, India. A total of 27 scarabaeoid taxa representing 22 genera and 4 families were recorded. Family Scarabaeidae is the most diverse of all 4 families recorded. The Scarabaeidae is represented by 24 taxa under 5 subfamilies (Scarabaeinae, Cetoniinae, Dynastinae, Melolonthinae, and Rutelinae). The important scarabaeoid families such as Geotrupidae, Hybosoridae, Trogidae are also represented from study area. The scarabaeid beetles were recorded for the first time from the study area, including 5 different localities in and around Ahmednagar city. The genus Onthophagus was the most dominant comprising 05 species. The result obtained serves as baseline information on the diversity and abundance of Scarab beetles of Ahmednagar. It will be helpful for future research on the beetle fauna of the study area.

Comparative analysis of the beetle fauna (Coleoptera: Carabidae) of small steppe plots in the forest-steppe zone

The fauna and abundance of Carabidae inhabiting small steppe plots in the forest-steppe zone of European Russia were analysed. In total, 14 such plots (biotopes) were studied, they were grouped by vegetation type into two groups: meadow steppe (5 plots) and calcareous steppe (9 plots). A total of 104 species of beetles from 6 subfamilies were collected. In meadow steppe, 91 species of beetle species were found, in calcareous steppe, 64 species were collected. Species richness was significantly higher in some meadow steppe plots (14-67 species) than in calcareous steppe plots (4-27 species). Numerical abundance of beetles was also higher in meadow steppe. Nine indicator species for calcareous steppe and no indicator species for calcareous steppe were identified. The structure of beetle dominance was analysed for individual biotopes. Beetle populations are analysed by life forms and life cycle types. NMDS scaling results are presented, demonstrating significant diversity of species composition and structure both in meadow steppe and calcareous steppe.

Is the effectiveness of policy-driven mitigation measures on carabid populations driven by landscape and farmland heterogeneity? Applying a modelling approach in the Dutch agroecosystems.

The growing challenges of protecting biodiversity in agro-ecosystems and maintaining high agricultural productivity has become an important issue within the European Union, shaping both European and national agro-policies. The presented study is part of a broader evaluation of the interim targets of the 2013 Dutch policy plan on sustainable use of pesticides, carried out in 2019 by the PBL (Planbureau voor de Leefomgeving) Netherlands Environmental Assessment Agency. We aimed to assess the effectiveness of selected mitigation measures suggested in the policy plan on non-target terrestrial arthropods using a common carabid beetle Bembidion lampros as a model species. We combined dynamic landscape models with detailed agent-based population modelling to simulate impacts of reduction of toxicity of insecticides, reduction of spray drift to the off-crop area, and increase in area of field margins on the beetle population dynamics in ten agricultural landscapes representing different farming systems. Our simulations showed that a shift towards low-risk products should be the priority if the goal is to increase beetle range. To promote local beetle abundance this needs be coupled with increasing amount of field margins in a landscape. Overall, the observed treatment and landscape effects were highly context-specific and therefore we suggest that care is used when defining and interpretting metrics based on population effects of policy measures. This caveat notwithstanding, the use of simulation to assess complex interactions between landscape, ecology and behaviour of species, and policy measures can be a powerful tool supporting innovative policy management. This should include the development of landscape-context specific targets and/or mitigation measures.