Carabid Diversity Research Articles

Carabid diversity in alpine environments: Investigating biogeographic and ecological traits of the communities living in the Dolomites (Italy)

Carabid diversity in alpine environments: Investigating biogeographic and ecological traits of the communities living in the Dolomites (Italy)

Long‐term drought triggers severe declines in carabid beetles in a temperate forest

Evidence for widespread declines in arthropods is growing and climate change is one of the suspected drivers. Recent droughts in Europe were unprecedented in the previous centuries and we are only beginning to understand the impacts on ecosystems. We analysed a 24‐year dataset of carabid beetles from a temperate forest area in northeast Germany and investigated linear and non‐linear trends in carabid abundance, biomass, diversity and species traits. We were especially interested if and how these were linked to droughts at different temporal scales using the standardized precipitation evapotranspiration index (SPEI). We found significant linear declines in abundance and biomass with annual rates of −3.1% (0.95 CI [−5.3, −1]) and –4.9% (0.95 CI [−9.4, −1.6]), respectively. Non‐linear trends were closely related to the SPEI when considering the climatic water balance of the previous six years and showed severe declines between 2015 and 2022 (−71% abundance, 0.95 CI [−84, −61] / −89% biomass, 0.95 CI [−97, −59]). However, there remained a significant annual background‐decline of −2.1% (0.95 CI [−5.7, −0.2]) and −3.1% (0.95 CI [−6.5, −0.1]), respectively, which occurred independently of drought. We observed negative trends in standardized carabid diversity metrics and a shift in species assemblage that were less directly linked to droughts. Declining and drought‐sensitive species tended to be larger predators with low dispersal abilities. This study is among the very first to investigate the impacts of the current unprecedented drought on forest insects in central Europe. Our findings add to the concerning amount of evidence for widespread declines in arthropods while pointing towards weather anomalies and climate change as one important driver.

Functional trait composition of carabid beetle communities predicts prey suppression through both mass ratio and niche complementarity mechanisms.

Several components of predator functional diversity have been hypothesized to influence prey suppression through either niche complementarity or mass ratio effects. Nevertheless, most studies have used a functional group approach when assessing the role of these predators in ecosystem functioning. By adopting a trait-based approach, we evaluated the relative contributions of carabid diversity components in predicting prey suppression. Our results highlight the importance of both taxonomic and functional diversity components of carabids as key drivers of prey suppression. Prey suppression was best predicted by carabid densities, with the dominance of Poecilus cupreus potentially driving the positive effect of community total abundance through the mass ratio effect. Prey suppression increased with increasing the density of large carabids. In addition, carabid eye diameter and antennal length were key functional traits for predicting prey suppression. Furthermore, prey suppression increased with increasing carabid functional richness following the niche complementarity effect. In contrast to functional richness, functional evenness and functional divergence of carabid communities were weakly correlated with prey suppression. By identifying which diversity components of carabid communities contribute the most to increase prey suppression, our results can guide efforts aiming to predict the relationship between diversity of these predators and ecosystem functioning.

Do carabids struggle to recolonize restored grasslands in the fragmented landscapes of Northern Belgium?

Abstract Semi‐natural grasslands in Western Europe are degrading and declining. Their plant species diversity and associated fauna, such as arthropods, are decreasing fast making restoration crucial. Carabid beetles are an essential link in ecosystem functioning (e.g., through herbivory and predation) and provide important ecosystem services (e.g., pest control). As a diverse group from different trophic levels, they occupy a variety of ecological niches, making them good indicators of restoration success and habitat quality. To study how different aspects of carabid diversity change along a restoration gradient from degraded grasslands to restored semi‐natural Nardus grasslands, we sampled carabid beetles in grasslands in Northern Belgium. We analysed differences in abundance, diversity and community composition and investigated carabid traits potentially influencing carabids' response to grassland restoration. Species richness did not change along the restoration gradient, but number of individuals decreased as grassland restoration time and effort increased and species composition changed, mostly caused by species turnover. As grassland restoration time and effort increased, carabid body size decreased and the proportion of day‐active carabids increased. Predators and habitat generalists were dominant along the entire gradient. Even though the target vegetation was restored, the carabid communities were not, or at least, did not possess yet traits to be expected from a restored community. The landscape in Northern Belgium might be too fragmented for larger species with low dispersal ability to recolonize restored grasslands. However, restored species‐rich grasslands are beneficial for conservation of meadow birds as day‐active beetles thriving in restored grasslands are an important food source.

Rows make the field: Winter wheat fields with manipulated crop architecture show potential for ecological intensification based on higher natural pest and weed seed control

Ecological intensification aims to reduce environmental costs of agricultural production by increasing biodiversity and using the associated ecosystem services instead of, or in combination with, external inputs, so that yields are maintained at high levels or increased. However, to date there are few measures available for which such benefits have already been demonstrated in the field.In this study, the seeding pattern in winter wheat fields was manipulated to create a diversified crop architecture consisting of ‘unsown-rows’ and ‘densely-sown-rows’ in treatment fields in comparison to ‘conventionally-sown-rows’ in control fields to assess whether (i) in-field structural and microclimatic conditions are more heterogeneous in fields with manipulated crop architecture compared to conventionally managed fields, (ii) a change in crop architecture is related to higher species richness, activity density and altered body size distribution of carabid communities, (iii) this in turn increases natural pest and weed seed control, but (iv) does not lead to yield loss.In-field structural and microclimatic conditions were more heterogeneous in treatment fields compared to control fields, which was associated with significantly increased body sizes of predatory carabids and a trend for increased predatory carabid species richness (in the ‘unsown-rows’ of treatment fields). These changes were related to significantly stronger pest suppression in the ‘densely-sown-rows’ of treatment fields compared to ‘conventionally-sown-rows’ in control fields, with 10 % higher experimental pest predation rates and 56 % reduced crop damage caused by cereal leaf beetles. Moreover, carabids known to consume weed seeds showed significantly higher activity densities in ‘unsown-rows’ compared to ‘conventionally-sown-rows’, which was related to significantly higher experimental weed seed predation in ‘densely-sown-rows’. Wheat yields were not significantly different in fields with or without manipulated crop architecture.The results suggest that the simple measure of manipulating the seeding pattern in winter wheat fields creates a diversified crop architecture, thereby promoting carabid diversity and altering their community composition and activity density such that important ecosystem services are increased without yield losses. Thus, beyond fostering biodiversity, this measure has, although not directly tested here, the potential for being used for ecological replacement of pesticides through enhanced ecosystem services without entailing agronomic and economic disadvantages such as land opportunity costs or increased workload.

The ground beetles (Coleoptera, Carabidae) from the René Jeannel collection of the Babeș-Bolyai University Zoological Museum, Romania

This paper reviews the ground beetles from René Jeannel collection which is preserved in Zoological Museum of Babeș-Bolyai University. The illustrious coleopterologist, René Jeannel was a French entomologist, who worked between 1920-1930 as Deputy Director of the Institute of Speleology founded by Emil Racovitza, the first institute of its kind in the world. He was also a professor of general biology at the Faculty of Sciences of the University of Cluj Napoca. As well, in that period he published numerous articles on the systematics, phylogeny, biogeography and evolution of cave and endogenous beetles. In 1931, R. Jeannel left Romania to start working at the Muséum National d'histoire naturelle, whose director he was between 1945 -1951. During the 10 years of activity in Romania, he created and organized an important collection of ground beetles (Coleoptera, Carabidae). The total number of prepared and labeled specimens is 1672. The material was collected between 1921-1927, mostly in Transylvania, Romania. The collection includes 182 species from 56 genera and contains rare or endemic species. Among the endemic species we list: Pterostichus bielzii (Fuss, 1858), endemic to the Apuseni mountains, is present in the collection from 13 different locations; Nebria (Nebria) transsylvanica Germar, 1823, an endemic species in the Romanian Carpathians and in the southern part of the Carpathians in Ukraine; Platynus (Batenus) banaticus (I.Frivaldszky von Frivald, 1865) present in the collection from 3 locations. For the genus Carabus, representative species are Carabus (Megodontus) planicollis Küster, 1846, endemic species in Romania, and the Natura 2000 species Carabus variolosus Fabricius, 1787 and Carabus (Procerus) gigas (Creutzer, 1799). Among the Trechinae the most representative are the genus Duvalius, with four species: Duvalius cognatus subsp. longicollis Jeannel, 1928, D. laevigatus (Bokor, 1913), D. budae subsp. dioszeghyi Mallasz, 1928 and D. hegeduesii subsp. jonescoi (Jeannel, 1919), and the genus Trechus with 7 species, of which 3 are endemic in Romania: T. bannaticus Dejean, 1831, T. biharicus Meixner, 1912, and T. marginalis Schaum, 1862. The collection is a very valuable one, both from a historical and scientific point of view, because it offers an overview of the diversity and distribution of carabids in the karst areas of Romania, at the beginning of the 20th century.

Ground beetles in Romanian oilseed rape fields and adjacent grasslands (Coleoptera: Carabidae)

Abstract This study aimed at clarifying species composition and ecological structure of the ground beetles associated with oilseed rape fields during flowering, ripening and post-harvest, as well as pastures adjacent to them. Field work was carried out in 2017. Pitfall traps (5 in each site) were set in 20 sampling sites in the Transylvania region, Cluj County. A total of 8,151 individuals were collected (7,576 in rapeseed fields and 575 in pastures) belonging to 82 species from 29 genera. The richest tribes were Harpalini (25 species), Zabrini (12 species), Pterostichini (10 species), and Carabini (9 species). The most species-rich were the genera Harpalus (13 species), Amara (11 species), Carabus and Ophonus (8 species each). The most abundant species in the rape fields were Poecilus cupreus (1,760 ind.), Brachinus explodens (1,500 ind.), Brachinus elegans (1206 ind.), and Anchomenus dorsalis (875 ind.). The most abundant in the grasslands were Pterostichus hungaricus (101 ind.), Calathus fuscipes (74 ind.), Harpalus caspius (67 ind.), and Cylindera germanica (64 ind.). The species found only in rape fields were 36 while 13 species were exclusive to pastures; 34 species were discovered in both types of habitats. The investigation acquired some new data on carabid diversity in Romania, including two new country records.

Effects of urbanization on carabid beetles in an urban riparian area

AbstractUrban rivers and riparian areas serve as corridors that move matter, organisms, and energy to urban areas from adjacent landscapes. However, anthropogenic disturbances and obstructions in river basins have severely impeded the function of many urban rivers as ecological corridors. Here, we used carabid beetles to assess the impact of urbanization on a river and its riparian areas. We identified carabid diversity and composition along an urbanization gradient. We classified 1,855 individuals in 17 species along a river. The carabid communities in riparian areas reflected critically disturbed habitats, and their composition markedly differed between the riparian areas and their adjacent habitats. Carabid beetle diversity sharply decreased with increasing urbanization. Flight capacity and feeding type varied along the urbanization gradient. Environmental variables associated with urbanization such as riparian quality and disturbance level significantly influenced carabid diversity. Land use type in increasingly urbanized areas was correlated with decreased carabid diversity and increased carabid dominance. Patch density, patch size, and interspersion metrics revealed that fragmentation and isolation influenced carabid diversity. Mitigation of disturbances and conservation of riparian microhabitats are required to improve biodiversity in riparian areas.

Effects of Ground Cover Management, Landscape Elements and Local Conditions on Carabid (Coleoptera: Carabidae) Diversity and Vine Vitality in Temperate Vineyards

Sustainable vineyard management in inter-rows may improve biodiversity and ecosystem service provision in landscapes with a high density of vineyards. The current work investigates the effect of three inter-row ground cover treatments (bare soil by tillage, alternating and complete vegetation cover) on carabid beetle communities and vine vitality, in relation to climatic, soil and landscape parameters. Pitfall traps were used to collect carabids in the spring and autumn of 2016 from nine Austrian vineyards, with all three ground cover treatments established in each vineyard. Additionally, grape berry samples were collected before harvest in order to determine juice quality parameters. Generalized linear mixed models revealed that complete vegetation cover, the most extensive vineyard inter-row management, decreased both carabid density and species richness. The variables hours of sunshine, vineyard cover at the landscape scale and mesofauna abundance had negative impacts on species richness. The largest differentiator of carabid communities was the sampling timepoint, and we observed clustering associated to vineyard manager, whereas ground cover treatment played no significant role. The importance of treatment on vine vitality parameters was low; however, complete vegetation cover was detrimental to vine vegetative growth and berry weight. On the basis of our results, we conclude that although community composition may be influenced by pedo-climatic conditions and landscape components, alternating vegetation cover is an option for maintaining both carabid diversity and high-quality berries in vineyards.

Positive effects of organic viticulture on carabid beetles depend on landscape and local habitat conditions

AbstractAgricultural intensification is a major cause of biodiversity loss. Organic farming may counteract the loss of species, however, knowledge about its benefits for perennial agroecosystems such as vineyards is incomplete. We, therefore, analysed the effects of organic viticulture on carabid beetles, a frequently used indicator group in agroecology. We investigated organic and conventional vineyards in two different landscapes (‘simple’ vs. ‘complex’) in SW Germany using a paired design. As a key result we found positive effects of organic viticulture on carabid diversity only in the simple landscape while such an effect was not obvious in the more complex landscape. Moreover, the species composition was differently influenced by organic management between the two landscapes indicating context‐dependent responses of carabid species towards the farming practice. We conclude that positive effects of organic viticulture on carabid beetle diversity differ with landscape context and depend on local habitat conditions such as slope inclination and the inter‐row vegetation. Our results therefore indicate that organic viticulture benefits are not only highly variable among taxonomic groups, but can have even varying effects within one insect family.

Changes in carabid diversity indicate successful restoration of riparian habitats

AbstractNatural rivers offer riparian habitats to many highly specialised, rare, and endangered insect species and are extremely important for ecosystem services. In the past, these ecosystems have been heavily degraded by anthropogenic use and run the risk of losing their favourable ecological conditions. For this reason, restoration measures are urgently needed and strongly demanded politically as well as legally, for instance, through the European Union Water Framework Directive. This is also important because nowadays, we are confronted with increasing insect declines. Using a Before‐After‐Control‐Impact approach, we studied the effects of a riverbank restoration (complete removal of a large gravel embankment) on carabid assemblages of riparian habitats along the Mulde River in central Germany in 2017 and 2019. We collected 86 species in three site types (managed, natural, and restored) by pitfall trapping and found numerous species of conservation concern. Our analyses showed that the percentage of species of conservation concern was significantly higher after restoration in restored compared to managed sites. Furthermore, after restoration, the percentage of indicator species for natural sites increased significantly in restored sites while the abundance of indicator species characteristic for managed sites decreased in these sites. Species assemblage composition significantly changed in response to restoration approaching near‐natural conditions. The creation of habitat mosaics with open gravel and sand patches as well as the re‐establishment of river dynamics were likely the most significant drivers for restoration success. We were able to show how important the restoration of riparian habitats is to promote populations of endangered, rare, and specialised species. Our results highlight that positive effects of a river restoration measure can be observed after a relatively short time. Ground beetles can thus be viewed as early indicators for restoration success, but we see a need for long‐term monitoring to evaluate long‐term effects reliably.

Ground beetle (Coleoptera: Carabidae) communities and microhabitat diversity in a mountain village house yard – a case study from the Western Rhodope Mountains in Bulgaria

This study explores the ground beetle (Coleoptera: Carabidae) diversity from an uncultivated house yard in a mountain hamlet in the Western Rhodope Mountains in southern Bulgaria. The sampling site was located at an altitude of 1340 m. A total of 2512 carabid specimens of 76 species were collected with only six pitfall traps between May 2016 and April 2021. They belong to 31 genera, 13 tribes, 21 zoogeographical categories and 15 life forms. Two species (Olisthopus rotundatus and Ophonus brevicollis) are new for the Rhodope Mountains. The findings reveal new highest altitude records for two species (Ophonus brevicollis and Philorhizus notatus). Along with the typical montane forest fauna, many ecotone and open habitat species were found. Nevertheless, carabid life forms and wing morphology structure indicate a stable environment in comparison with other regions in Bulgaria. Furthermore, this research demonstrates that even small natural habitat patches can keep a remarkable carabid diversity. Over the five-year study period, the carabid fauna in the studied house yard experienced some, both qualitative and quantitative, impoverishment, indicating some ecological “exhaustion”.

The effects of trapping effort and sources of variability on the estimation of activity-density and diversity of carabids in annual field crops by pitfall trapping; a meta-analysis

The effects of trapping effort and sources of variability on the estimation of activity-density and diversity of carabids in annual field crops by pitfall trapping; a meta-analysis

Direct and indirect effects of landscape and field management intensity on carabids through trophic resources and weeds

Abstract Carabids are important biological control agents of weeds and other pests in agricultural fields. The carabid community is built upon direct and indirect ecological effects of landscape complexity, field management intensity and biotic components that in interaction make any prediction of community size and composition challenging. We analyse a large‐scale sample of 60 European cereal fields using structural equation modelling to quantify the direct effects of field management intensity and the surrounding landscape, and their indirect effect via biotic components, on carabid diversity. Our results highlight that direct and indirect effects of increasing landscape complexity, mediated by trophic resources, mainly affect carabids positively. Field management intensity only ever affects carabids through indirect effects that are generally negative, by suppressing standing weeds and weed seeds. Indirect effects on granivore carabid species depended on weed seed availability, whereas omnivores depended on the availability of both weed seeds and animal prey. Synthesis and applications. A consideration of both the direct and indirect effects of landscape and field management is necessary for predicting carabid communities. These indirect effects, mediated via trophic resources, supports the diversity and abundance of carabid communities and their provision of ecosystem services. Our results show that promoting crop diversity and connectivity to semi‐natural habitats will directly enhance carabid communities in farmland by manipulating their migration from source habitats and indirectly by promoting the presence and diversity of their trophic resources. A reduction in field management intensity will preserve local standing weeds and weed seeds, and indirectly support carabid communities. These local and landscape modifications could contribute to improve the natural regulation of pests and weeds by carabids.

Taxon- and functional group-specific responses of ground beetles and spiders to landscape complexity and management intensity in apple orchards of the North China Plain

Agricultural intensification has caused severe declines in ground-dwelling arthropods and associated ecosystem services. The conservation and re-establishment of semi-natural habitats in agricultural landscapes represent widely accepted measures to counter these declines. The effectiveness of these measures nonetheless varies between target taxa and their functional traits, while also being affected by local management. Here, we studied how species richness and abundance of different functional groups of carabid beetles and spiders in apple orchards were affected by landscape complexity (% semi-natural habitat) and local management intensity (mowing and soil total nitrogen (STN) content). Both abundance and species richness of non-carnivorous carabids and carabids overall were negatively affected by STN, while the abundance of carnivorous carabids and carabids overall was affected by interactive effects of mowing and landscape complexity, showing a positive response to mowing where semi-natural habitats are scarce, but negative responses in landscapes with a higher proportion of semi-natural habitats. The abundance of ground-hunting spiders and spiders overall was generally positively related to % semi-natural habitats, while the abundance of web-building spiders and the species richness of ground-hunting spiders showed a positive correlation with STN at landscapes with a low or medium abundance of semi-natural habitats, but a negative correlation where semi-natural habitats were more abundant. Non-carnivorous carabid diversity benefitted from low nitrogen application, while carnivorous carabid abundance benefitted from mowing intensity especially in simple and structurally homogenous agricultural landscapes. Both web-building and ground-hunting spiders positively responded to low nitrogen applications and intermediate landscape complexity. Overall, a low local management intensity promoted carabid beetles, while spiders were favored by increasing landscape complexity. We conclude that taxon- and functional group-specific, multi-scale conservation strategies are therefore required to conserve invertebrate predators in apple orchards.

Fallows and permanent grasslands conserve the species composition and functional diversity of carabid beetles and linyphiid spiders in agricultural landscapes

Abstract The European Union reformed the Common Agricultural Policy (CAP 2013) to include greening measures with the aim to decrease negative impacts of farming on the environment and biodiversity. The degree to which greening measures such as permanent grassland or fallows of different ages enhance biodiversity is still debated. We investigate the effect of fallows in two different age classes and permanent grassland in the surrounding landscape on the taxonomic and functional diversity of two numerically dominant groups of natural enemies in cereal fields: soil‐emerging carabid beetles (Family Carabidae, Order Coleoptera) and ground‐active linyphiid spiders (Family Linyphiidae, Order Araneae). The species richness, abundance and Hill–Shannon diversity of carabids and linyphiids did not differ significantly between fallows and cereal fields and was not significantly related to the proportion of permanent grassland in the surrounding landscape. The species composition of both communities differed significantly between cereal fields and fallows. The functional distinctness, as an index reflecting the similarity among species in terms of functional traits, of linyphiids was significantly higher in fallows than in cereal fields. The trait composition of carabids was significantly related to the proportion of permanent grassland depending on field type (cereal or fallow). Our results document considerable species turnover in natural enemy communities of adjacent cereal fields and fallows, and support the assumption that older fallows (>8 years) produce functionally more diverse natural enemy communities. Maintaining fallows for a long period is an important measure to promote the functional diversity in predaceous arthropod communities.

Responses of ground beetle (Coleoptera: Carabidae) assemblages to stand characteristics and landscape structure in riparian poplar forests

Abstract Many carabid beetles are among the most important biocontrol agents and are biological indicators of environmental change, although relatively little is known about how local and landscape factors affect forest ground beetle assemblages. Understanding such effects of multi‐scale environmental drivers on ground beetles can promote carabid diversity and conservation. Ground beetles were sampled by pitfall trapping in 40 poplar forest stands (sampling plots) along the Irtysh River in Northwestern China. We investigated responses of carabid activity density, species diversity and functional diversity (FD) to stand characteristics and surrounding landscape structure (the overall diversity and percentage cover of vegetation productivity classes in the surrounding area of each sampling plot based on normalised difference vegetation index). While carabid activity density only responded positively to the overall diversity of vegetation productivity classes, carabid species diversity was positively associated with this landscape factor as well as vegetation cover but negatively associated with the nearest distance from sampling plot to the river. Only carabid FD responded significantly to percentage cover of vegetation productivity classes, showing a positive correlation with the proportion of medium vegetation productivity. Furthermore, overall carabid FD declined with increasing tree canopy cover. Our results can help predicting spatial patterns of ground beetles according to landscape diversity and proportions of surrounding vegetation types and improve the design of conservation strategies (such as altering canopy cover) of carabids, especially forest specialist species. Any forest management strategies for promoting carabid diversity should consider the pervasive effects of landscape composition and configuration besides local stand characteristics.

Perennial crops can complement semi-natural habitats in enhancing ground beetle (Coleoptera: Carabidae) diversity in agricultural landscapes

Agricultural intensification has caused losses of global biodiversity and associated ecological services. Agroecological landscape assessments are therefore often based on the area of remaining semi-natural habitats due to their ability to promote biodiversity. Due to their structural diversity and often less intensive management in comparison to annual crops, perennial cropland could fulfil similar roles. However, comparisons of the ability of perennial cropland versus semi-natural habitat to maintain agricultural diversity are scarce. Here, we conduct such an assessment, in comparing functional group-specific patterns in ground beetles (Coleoptera: Carabidae) as indicators of anthropogenic land-use impacts on biodiversity and biological pest control. Carabid assemblages were compared between annual cropland (56 plots), perennial cropland (24 plots) and semi-natural habitats (74 plots) of varying plant diversity across nine study regions situated in Eastern China. Our results indicated that perennial crops sustained a greater carabid species richness than semi-natural habitats, whereas assemblages of semi-natural habitats contained greater proportions of large and predatory carabids. Plant species richness positively affected the overall diversity of carabids, with the strongest effects again observed in perennial cropland. Abundance-based and species-based proportions of large carabids were positively linked to plant diversity in perennial cropland and semi-natural habitats, but negatively in annual cropland. A similar response was observed for predatory carabid abundance. Perennial crops might therefore fulfil complementary roles to semi-natural habitats in agricultural biodiversity conservation. Given common trade-offs between biodiversity conservation and agricultural production, promoting perennial cropland in particular in combination with management that increases plant diversity, could enable increases in the sustainability of agricultural production systems particularly in areas with high food demand, but limited availability of arable land. Notwithstanding, semi-natural habitats remain crucial particularly with view of enhancing biological pest control services.

Surface temperature and shrub cover drive ground beetle (Coleoptera: Carabidae) assemblages in short‐rotation coppices

Increasing demand for biomass has led to an on‐going intensification of fuel wood plantations with possible negative effects on open land biodiversity. Hence, ecologists increasingly call for measures that reduce those negative effects on associated biodiversity. However, our knowledge about the efficiency of such measures remains scarce. We investigated the effects of gap implementation in short rotation coppices (SRCs) on carabid diversity and assemblage composition over 3 years, with pitfall traps in gaps, edges and interiors. In parallel, we quantified soil surface temperature, shrub‐ and herb cover. Edges had the highest number of species and abundances per trap, whereas rarefied species richness was significantly lower in short rotation coppice interiors than in other habitat types. Carabid community composition differed significantly between habitat types. The main environmental drivers were temperature for number of species and abundance and shrub cover for rarefied species richness. We found significantly higher rarefied species richness in gaps compared with interiors. Hence, we argue that gap implementation benefits overall diversity in short rotation coppices. Furthermore, the differences in species community composition between habitat types through increased species turnover support carabid diversity in short rotation coppices. These positive effects were largely attributed to microclimate conditions. However, to maintain positive effects, continuous management of herb layer might be necessary.

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.