Mortality of ground beetles (Coleoptera, Carabidae) in discarded containers: Evidence from urban forests

Urban and peri-urban forests are important habitats for maintaining biodiversity in cities. In this paper, we report a method for using hoverflies as biodiversity indicators in urban forest habitats. As a case study, forest habitats in three peri-urban and urban forests were assessed and compared to rural forests in Slovenia. Rožnik (Ljubljana) was chosen as the urban forest site, Mestni log (Ljubljana) and Brdo (Kranj) were chosen as the peri-urban sites, and eight sites were chosen in rural forests in different ecoregions in Slovenia. Forest hoverfly species richness and the species composition of different biological traits were compared between the peri-urban forests, urban forest and rural forest sites. In addition, species richness was assessed for changes in response to weather conditions between years. The number of species with the investigated traits in the urban and peri-urban forests was within the range of the number of species observed in the rural forests. The number of saproxylic species was higher in the urban forest but lower in the peri-urban forests compared to the rural forests. The proportions of species with different feeding modes and different development times were similar between the peri-urban, urban and rural forests. The proportions of species with development times of less than 2 months or more than 1 year and of predatory species were similar in the urban and peri-urban forests but higher in the rural forests. The species composition of the other biological traits differed between the peri-urban, urban and rural forests. Species richness and abundance displayed large differences in phenological patterns between 2012 and 2013; these differences are related to differences in the minimum temperature for these years. The results are discussed in relation to forest management in urban forests, the usefulness of hoverflies as a biodiversity indicator and possible extrapolation to other species groups.

The characterization of ecological communities with functional traits allows to consider simultaneously the ability of a species to survive and reproduce in an environment, its interactions with other species and its effects on the ecosystem. Functional traits have been studied mainly by plant ecologists, but are increasingly common in the study of other taxa including arthropods. Arthropods represent a group for which a functional trait approach could be highly profitable because of their high diversity, abundance, ubiquity and role in many important ecological processes. This review synthesizes two decades of functional trait research on terrestrial arthropods. We show that while the approach has gained popularity, particularly in the last decade, the absence of clearly postulated hypotheses is a recurrent problem limiting generalization. Furthermore, studied traits are often poorly related to studied functions. To address these problems, we propose a step-by-step protocol to postulate clear hypotheses prior to trait selection and emphasize the need for a common set of more generalizable traits in future studies. Extending the functional trait approach to arthropods opens the door to improving our understanding of interspecific interactions and potential links between response and effect traits. We present the concept of trait-matching with several examples of arthropod traits known to be effective predictors of consumer-resource interactions. The development of a successful functional trait approach for terrestrial arthropods will necessitate an understanding of relevant traits, standardized measurement protocols and open access databases to share this information. Such progress will provide ecologists with a new set of tools to answer broad questions in several fields including the study of community assembly, ecological networks and multitrophic functionality.

Background and purpose: The importance of forest ecosystem services, related to provisioning of fresh water and water purification are of increasing importance, especially in urbanized areas. This study investigates key indicators for ecosystem services, related to drinking water protection, provided by urban and peri-urban forests. Materials and methods: Seven different monitoring programs, projects or directives, assessing water quality variables were analysed. We determined which indicators, describing the drinking water protection services in forest ecosystems, can be applied to urban forests. A list of core indicators sensitive to the specifics of the drinking water supply and urban forest ecosystems in Ljubljana were suggested. Results and conclusions: Analysis included over 86 potential indicators related to nutrient regulation, storage capacity and water purification in forest canopies, forest soils, surface streams, lakes and groundwater. Through scientific review and the application of “necessary” and “feasible” criteria to urban forests the number of indicators was reduced to 62. According to the specifics of drinking water supply and urban forest in Ljubljana 52 core indicators have been selected. Due to the influence of urbanization on water bodies, special emphasis should be given to indicators for storage capacity and water purification capacity of urban forest ecosystems for hazardous substances. This might increase the willingness of decision and policy makers to acknowledge the water protection capacity of urban forests.

By using the variance analysis the absence of a correlation between the different gradations of soil humidity and the number of dominant taxons of litter invertebrates, the ground beetles ( Coleoptera, Carabidae ), separate life-forms of the ground beetles and the indices of species diversity is demonstrated. The most sensitive indicator of soil humidity gradations in forest ecosystems is the mixophytophages part in the ground beetles’ complex.

Wooded pastures combine trees and pastures in a land-use system resulting from traditional silvopastoral practices. With their sparse tree cover, wooded pastures represent an ecotone between open area pastures and forests with potentially high species diversity, although this is poorly tested for animal groups especially insects. In this study, we aimed to characterise and compare species communities in terms of species composition and diversity indices, biomass and ecological traits of ground beetles in wooded pastures, forests and non-wooded pastures. Pitfall traps were set up in 29 study sites located in the Swiss Jura mountains. Ground beetle communities in wooded pastures largely encompass those in open pastures and forests, although some species are found only in forests or open areas. Wooded pastures and open pastures have an equivalent species diversity level, which is significantly higher than the one in forests. Ground beetle diversity is positively correlated with the surfaces of Biodiversity Promotion Areas within a 100 m radius. Areas with high tree cover (70–100%) favour brachypterous and hygrophilic species, whereas areas with reduced tree cover (0–20%) favour xerophilic and winged species. Ground beetles’ size and biomass increase with tree cover. Wooded pastures are an important ecotone, ensuring a gradual change of land-use systems between open areas and forests, where a wide range of species from both land-use systems are found. These semi-natural systems are important for the conservation of ground beetles.

Global change has a large and growing influence on forests, particularly in urban and urbanizing areas. Compared to rural forests, urban forests may experience warmer temperatures, higher CO2 levels, and greater nitrogen deposition, with exacerbated differences at urban forest edges. Thus, comparing urban to rural forests may help predict future effects of global change on forests. We focused on the conifer western red-cedar (Thuja plicata) to test three hypotheses: at urban forest edges, relative to rural forests and urban forest centers, trees experience 1) higher temperatures and nitrogen levels, 2) lower seedling recruitment, and 3) greater growth. We additionally tested anecdotal reports that 4) tree seedling recruitment in urban and rural forests is much lower than in "pristine" old-growth forests. To test these hypotheses, we quantified air temperature, soil nitrate, adult T. plicata growth and seedling recruitment in five urban and three rural parks at both forest edges and centers. We also quantified T. plicata recruitment at five old-growth "pristine" sites. Temperatures were highest at urban forest edges, and soil nitrate was highest in urban forests. In urban relative to rural forests, we observed greater T. plicata growth, but no difference in seedling densities. However, seedling densities were lower in urban and rural forests than in old-growth forests. In all, our results suggest urban influences enhance adult T. plicata growth, but not seedling recruitment. Recruitment in urban and rural forests was reduced compared to old-growth forests, implying that fragmentation and logging reduce T. plicata seedling recruitment.

This study used pitfall trapping to examine community composition and diversity of ground beetles in five different habitats (coniferous, deciduous, mixed coniferous, farmland, and settlements) within Anhui Yaoluoping National Nature Reserve from May to September 2014. In total, 1,352 ground beetles were collected, belonging to 16 genera and 44 species. Of these, four dominant species Dolichus halensis, Harpalus pastor, Carabus casaleianus, and Pheropsophus jessoensis were identified, respectively, comprising 370, 177, 131, and 123 individuals. The deciduous forest showed greater diversity (3.78 according to Shannon–Weiner index), equitability (0.80 according to Pielou’s index), and dominance (9.52 according to Simpson’s index) when compared with farmland, but species richness in the deciduous forest (27) was lower than that in farmland (35). One-way analysis of variance showed that ground beetle species composition and abundance among different habitats varied significantly. Cluster analysis and principal coordinate analysis showed that farmland shared low community similarity with other habitat types, and coniferous and mixed coniferous forests shared similar community types. Our results indicate that species composition, abundance, and diversity of ground beetles are affected by different habitat types, with deciduous forest types being critical in maintaining the diversity of rare species. We recommend reducing cultivated farmland area and increasing the area of carefully planned deciduous forest in order to better protect ground beetle diversity in the region.

Species assembly in ground beetle (Coleoptera: Carabidae) communities in local microhabitats was studied in a forest. The following questions were addressed: are there important filters that sort the species in the assemblages? If so, what is the specific nature of these filters? In order to address these questions rarefaction analysis was used to determine whether ground beetle species are distributed non-randomly. Next, the nature of filters was determined by analyzing (1) the community matrix and searching for the consequences of competitive exclusion and (2) species-environmental relations. Rarefaction analysis revealed that the species composition is filtered: species richness was less than expected and there were fewer than expected congeneric species coexisting at high beetle population densities. However, community matrix and body size analyses did not detect significant competition among the beetle species and the matrix was significantly nested. Species-environmental analyses indicated that the ground beetle assembly was strongly linked to ground vegetation. It is concluded that spatial distribution of ground beetles across local communities in this forest habitat is determined more by local environmental conditions than competition, and ground beetles do not interact strongly among themselves so that competitive effects do not play an important role in their distribution except at high beetle population densities.

<p>Forests are important ecosystems for mitigating CO<sub>2</sub>. However, droughts affect the vitality of forests and alter CO<sub>2</sub> uptake. In worst cases, forest ecosystems can even turn from a carbon sink to a source in consequence of water shortage. Forest stands in urban areas are more prone to droughts because of elevated temperatures in comparison to rural land and unfavorable growth conditions such as limited rooting depth and low soil carbon content.</p><p>The drought years 2018 and 2019 in the Ruhr Metropolitan Region (Germany) were characterized by a 0.6 K higher mean annual temperature as normal and only 75 % of the normal annual precipitation. During this period, we investigated the CO<sub>2</sub> balance of urban forest ecosystems, considering annual changes in carbon stocks of tree biomass and litterfall and annual CO<sub>2</sub> effluxes from soil respiration, at eleven monitoring sites across the Ruhr Metropolitan Region by combining measuring and modelling approaches. The chosen sites represent the different urban forest types found here: old-grown semi-natural forests (beech, oak, maple), autochthon non-managed succession forests of birch, poplar or willow on brownfields and allochthone mixed forest stands planted in urban parcs and on heaps (urban greening forests).</p><p>Tree growth, leaf expansion, and CO<sub>2 </sub>efflux decreased at nearly all sites in 2019 in comparison to 2018 in consequence of the ongoing drought. While the semi-natural forests were able to increase CO<sub>2</sub> uptake by 11 % in 2019, the urban greening forests decreased their CO<sub>2</sub> uptake by 62.9 %. The succession forests were CO<sub>2</sub> sources in both years but increased the CO<sub>2 </sub>release in the second year by 85 % in comparison to the first year. Two sites turned from carbon sinks in 2018 to carbon sources in 2019. Correlation analyses showed that the soil hydraulic properties such as depth of the rooting zone, soil carbon content, and plant available water were the main influencing factors describing the decrease in tree growth and leaf development. Overall, the results indicate that, semi-natural forests on mesophilic sites are more resilient against droughts due to unlimited rooting zone, high soil carbon content, which favor the amount and accessibility of plant available water, while urban greening and succession forests are more vulnerable to droughts due to limiting rooting zone, low soil carbon content, and low plant available water. More vulnerable to droughts are also semi-natural forests on more extreme sites, like an examined Stellario-Carpinetum, which turned from a carbon sink in 2018 to a source in 2019. Furthermore, two patterns of seasonal changes in soil respiration were found in reaction to the drought. i) those of elevated soil respiration associated to elevated temperature in 2018 and decrease of soil respiration in 2019 in consequence of thermal denaturation of the microbial community, and one ii) those where, the mineralization activity was shifted to winter when the upper soil layer was rewetted, leading to larger soil respiration during the cold season.</p><p>Urban planners should ensure a deep rooting zone and carbon rich soils by establishing new urban forest stands to tackle drought periods.</p>

Urban and forest trees provide valuable ecosystem services. However, they are increasingly threatened by invasive forest pests and pathogens. Trees in urban areas are often the first potential hosts non-native tree-feeding insects and tree pathogens (“pests”) encounter after introduction in a novel region. If the trees encountered are suitable hosts, these pests can establish and become invasive – eventually also in surrounding forests. Here, we compared tree species and genus composition between urban areas and surrounding forests and examined the implications for host availability for forest pests and potential effects on invasibility. We compiled and standardised 26 urban tree inventories, containing ∼ 500.000 individual trees. We used multivariate analyses to compare urban tree composition with forest tree composition from forests surrounding each municipality (10 km radius), derived from the Swiss National Forest Inventory. With > 1300 different tree species, species richness of urban trees was 17 times higher than species richness in surrounding forests. Linear models and multivariate analyses revealed that host availability for forest quarantine pests is significantly higher in urban areas than in forests, with large differences in host suitability for different quarantine pests between urban and forest tree assemblages. This indicates that differences in species composition in urban and forest trees can result in increased host availability, possibly facilitating the establishment of quarantine forest pests.

Epigeic generalist predators play a crucial role in terrestrial ecosystems, connecting aboveground and belowground food webs. Using stable isotope compositions (δ13C and δ15N values), we assessed the trophic niches of the two main groups of generalist predators (ground beetles (Coleoptera, Carabidae) and spiders (Arachnida: Aranei)), as well as their potential prey (phytophagous and saprophagous insects), plants, and soils in the forest, steppe, and transitional ecosystems located in the forest–steppe of southwestern Siberia. We hypothesized that (1) the trophic niche of carabids is wider than that of spiders, because some ground beetles are omnivorous, and (2) the contribution of invertebrates from the detrital food web (saprophages) to the diet of generalist predators is higher in the “detrital” forest ecosystem than in the steppe, which should be reflected in increased δ13C and δ15N values of the predators in the forest. In total, 16 species of carabid and 17 species of spider were analyzed. The δ15N values of ground beetles suggested a wide range of trophic niches corresponding to two or three trophic levels. Omnivorous carabids of the genera Amara and Harpalus had the minimum δ15N values. The carbon isotope compositions of the ground beetles suggests that most predatory species were predominantly involved in grazing food chains. Spiders had on average increased δ15N values compared to ground beetles, and a relatively narrow range of δ15N values. The isotopic niche occupied by spiders hardly overlapped with the isotopic niche of carabids, which may indicate a significant difference in the range of consumed resources. Thus, our data suggest a significant difference in the trophic niches of the key generalist predators, ground beetles and spiders, which was observed both in the forest and the steppe habitats. Spiders appear to be more closely associated with detrital food webs than ground beetles. Contrary to our expectations, we did not find higher δ13C and δ15N values in ground-dwelling generalist predators in the forest compared to the steppe ecosystem.

Patterns in ground beetle (Coleoptera: Carabidae) assemblages along an urbanisation gradient in Denmark

The habitat-specific effects of highway proximity on ground-dwelling arthropods: Implications for biodiversity conservation

Drivers of global climate change and the increased frequency of extreme climate events may affect urban and periurban forest ecosystems more rapidly than natural forest ecosystems. Multi stressors of urban forest ecosystems include alterations in forest soils and to the diversity and composition of forest ecosystem, as well as higher temperatures during heat waves periods and increasing carbon dioxide content due to high traffic issue. Global conservation targets and management practices of urban forest ecosystems in Romania requires adequate novel monitoring methodology for monitoring the dynamics changing status. Ground-based measurements are valuable tools with limited spatial footprints. Multispectral and multitemporal satellite remote sensing data allow detailed information on forest structure and can deliver ecologically relevant, long-term datasets suitable of vegetation phenology for analyzing changes in periurban and urban forest ecosystem areas, structure and function at temporal and spatial scales relevant to forest dynamics monitoring. The aim of this paper was to evaluate and characterize forest changes for selected test area Cernica –Branesti in Ilfov county located in the Eastern part of Bucharest metropolitan region, Romania, where the climate and anthropogenic stressors endanger natural and economical values of forest environment. Based on time-series Landsat 5 TM, 7 ETM+, 8 OLI/TIRS, MODIS Terra/Aqua and Sentinel 2A satellite data have been investigated urban forest land cover and forest biophysical parameters (LST, NDVI/EVI and LAI) changes over 2000-2016 period of time. Accuracy of image processing results (spectral classification) was confirmed through in-situ spectroradiometrical analysis of reflectance spectra with portable GER 2600 spectroradiometer.

We used pitfall trapping to measure the species richness and relative abundance of ground beetles (Coleoptera: Carabidae) in four forest habitats on Kent Island, a 80-ha island in the Bay of Fundy, New Brunswick, Canada. Sixteen species of ground beetles representing 11 genera were identified in the forested habitats on Kent Island; the relative paucity of ground beetle species may be a result of the island’s harsh climate, dense colonies of breeding seabirds, and isolation from the mainland. Estimates of ground beetle population densities on Kent Island ranged from 50 000 to 250 000/ha. Most ground beetle species were trapped in all habitats and appeared to be habitat generalists. In a series of experiments in which we removed all ground beetles trapped daily over a 3-week period in two experimental plots, ground beetle densities remained as high as in a control plot; other ground beetles quickly moved into the experimental plots to replace beetles that had been removed. The density of ground beetles was highest in intact forest and large forest patches; in contrast, the density of invertebrates other than ground beetles (i.e., possible prey or competitors of ground beetles) was highest in open habitats and isolated forest patches, where ground beetles were less common. Removing ground beetles from experimental plots did not result in an increase in the density of other invertebrates.