Xylobionte Käferfauna alter Eichen, die von dem gefährdeten Bockkäfer Cerambyx cerdo besiedelt sind (Coleoptera: Cerambycidae)

In our present-day landscape in Central Europe major parts of the xylobiontic especially of the saproxylic beetle fauna belong to the group of endangered species assemblages (Speight 1989, Geiser 1994). Oaks, in Central Europe mainly Quercus robur and Q. petraea, are well known for their large number of associated insect species and harbour the highest beetle diversity, especially for dead wood inhabiting species, of all broadleaved tree species in this region (e.g. Palm 1959). A characteristic species associated with oaks in its life-cycle is the endangered Great Capricorn Cerambyx cerdo. C. cerdo is one of the protected species explicitly named in the Habitats Directive of the European Union with the goal of maintaining existing populations and establishing long-term survival (Council of the European Communities 1992). The last remaining colonised areas of this longhorn beetle in Central Europe are well known for the enormous number of very rare xylobiontic beetle species. Thus, we are interested in the following research questions: 1) Are there typical species associated with C. cerdo? 2) If so, what kind of relationship do these associated species have to C. cerdo from a nature conservation point of view?Der Große Eichenbock (Cerambyx cerdo Linnaeus, 1758) hat in Mitteleuropa in den letzten 100 Jahren einen dramatischen Rückgang in der Zahl der Vorkommen und in den Populationsgrößen erfahren. Als Frischholzbesiedler von Eichen beeinflusst die Art durch larvale Fraßtätigkeit die physiologischen Eigenschaften dieser Bäume sowie deren Beschaffenheit als Habitat für andere Organismen. Wir haben die Auswirkungen dieser Veränderungen auf die Zusammensetzung der holzbewohnenden Käferfauna bei verschiedenen taxonomischen und funktionalen Gruppen untersucht. Dabei vergleichen wir die mit Lufteklektoren erzielten Fänge an 10 besiedelten und 10 unbesiedelten Eichen aus einem Untersuchungsgebiet in Niedersachsen. Insbesondere viele seltene Bewohner von Baumhöhlen und Holzmulm profitieren von der Anwesenheit dieser Bockkäferart und den dadurch entstehenden Mikrohabitaten. Besiedelte Bäume beherbergen auch signifikant mehr Arten der Roten Liste. Wir diskutieren die Eigenschaft von C. cerdo als Substratbereiter sowie die davon partizipierenden Arten. Freilich lässt nur ein Teil des Artenspektrums engere Zusammenhänge mit Besiedlung durch den Großen Eichenbock erkennen. Allerdings gehören auch Arten mit loser Beziehung zu Cerambyx cerdo über weite Strecken einer hochgradig bedrohten Käfergemeinschaft alternder Eichen an. Vor diesem Hintergrund sehen wir die unverzichtbare Rolle des Großen Eichenbockes in von Eichen geprägten Ökosystemen, wenn es um die Erhaltung der Artenvielfalt holzbewohnender Insekten geht

Open forest successional stages and landscape heterogeneity promote wild bee diversity in temperate forests

Recent studies have emphasized forests as crucial habitat for wild bees. In Europe, most forests are managed following the principles of close-to-nature silviculture, which combine timber production and nature conservation. How- ever, open late and early successional stages within these forests are largely missing, which could be important for wild bees. This highlights that close-to- nature silviculture alone might not be sufficient to conserve bees within tem- perate forests. Open structures such as canopy gaps and road verges in forests could improve habitat for bees. To provide management recommendations for wild bee conservation in temperate forests, we analyzed how components of bee beta diversity varied between forest management types and tested how open structures, namely clear-cuts, canopy gaps, and forest road verges influ- enced bee abundance, richness, and diversity. In addition, we analyzed the abundance and percent of red-listed bee species at different scales. Bees were sampled using 90 pan traps on 45 (1 ha) plots in 2019 and 2020 in the Black Forest, Germany. Plots were selected in 15 triplets each consisting of three management types related to different successional stages: unmanaged, close- to-nature, and small clear-cut. Beta diversity was not consistently nested highlighting the importance of different management and successional stages within the landscape to support bees in forests. Abundance, species richness, and Shannon diversity of bees were highest on clear-cuts, compared to unmanaged- and close-to-nature plots. At landscape scale, wild bee abundance increased with canopy openness while wild bee diversity increased with land- scape heterogeneity. Abundance- and percent of red-listed bee species increased with the length of forest road verges. We advocate creating habitats at local scales which offer flowering and nesting resources by providing canopy gaps. At landscape scale, heterogeneity created through different forest succes- sional stages is needed to conserve the entire community of wild bees

Determinants and Congruence of Species Richness Patterns across Multiple Taxonomic Groups on a Regional Scale

Applying multiple generalized regression models, we studied spatial patterns in species richness for different taxonomic groups (amphibians, reptiles, grasshoppers, plants, mosses) within the German federal state Rhineland-Palatinate (RP). We aimed (1) to detect their centres of richness, (2) to rate the influence of climatic and land-use parameters on spatial patterns, and (3) to test whether patterns are congruent between taxonomic groups in RP. Centres of species richness differed between taxonomic groups and overall richness was the highest in the valleys of large rivers and in different areas of southern RP. Climatic parameters strongly correlated with richness in all taxa whereas land use was less significant. Spatial richness patterns of all groups were to a certain extent congruent but differed between group pairs. The number of grasshoppers strongly correlated with the number of plants and with overall species richness. An external validation corroborated the generality of our species richness models

An updated checklist of the scarab beetle fauna of Asinara Island, Sardinia, Italy (Coleoptera: Trogidae, Geotrupidae, Scarabaeidae, Aphodiidae, Cetoniidae, Dynastidae, Hybosoridae)

The island of Asinara, located in the northwest of Sardinia, is characterized by a large number of feral grazing mammals belonging to four herbivorous species (horse, donkey, mouflon, and goat) and an omnivorous one (wild boar). Hand-collections of scarabs in 2014 and the examination of unpublished records revealed the presence of five species new for Asinara (Trox nodulosus, Ateuchetus laticollis, Sisyphus schaefferi, Caccobius schreberi and Cetonia carthami). Based on all records (published and unpublished) we present a new checklist of the scarab beetle fauna of Asinara which increased from 30 to 43 species belonging to seven families: 2 Trogidae, 2 Geotrupidae, 13 Scarabaeidae, 19 Aphodiidae, 5 Cetoniidae, 1 Dynastidae, and 1 Hybosorida

Arthropod dark taxa provide new insights into diversity responses to bark beetle infestations

Natural disturbances are increasing around the globe, also impacting protected areas. Although previous studies have indicated that natural disturbances result in mainly positive effects on biodiversity, these analyses mostly focused on a few well established taxonomic groups, and thus uncertainty remains regarding the comprehensive impact of natural disturbances on biodiversity. Using Malaise traps and meta-barcoding, we studied a broad range of arthropod taxa, including dark and cryptic taxa, along a gradient of bark beetle disturbance severities in five European national parks. We identified order-level community thresholds of disturbance severity and classified barcode index numbers (BINs; a cluster system for DNA sequences, where each cluster corresponds to a species) as negative or positive disturbance indicators. Negative indicator BINs decreased above thresholds of low to medium disturbance severity (20%-30% of trees killed), whereas positive indicator BINs benefited from high disturbance severity (76%-98%). BINs allocated to a species name contained nearly as many positive as negative disturbance indicators, but dark and cryptic taxa, particularly Diptera and Hymenoptera in our data, contained higher numbers of negative disturbance indicator BINs. Analyses of changes in the richness of BINs showed variable responses of arthropods to disturbance severity at lower taxonomic levels, whereas no significant signal was detected at the order level due to the compensatory responses of the underlying taxa. We conclude that the analyses of dark taxa can offer new insights into biodiversity responses to disturbances. Our results suggest considerable potential for forest management to foster arthropod diversity, for example by maintaining both closed-canopy forests (>70% cover) and open forests (<30% cover) on the landscape

A comparison of different Malaise trap types

Recent reports on insect decline have highlighted the need for long-term data on insect communities towards identifying their trends and drivers. With the launch of many new insect monitoring schemes to investigate insect communities over large spatial and temporal scales, Malaise traps have become one of the most important tools due to the broad spectrum of species collected and reduced capture bias through passive sampling of insects day and night. However, Malaise traps can vary in size, shape, and colour, and it is unknown how these differences affect biomass, species richness, and composition of trap catch, making it difficult to compare results between studies. We compared five Malaise trap types (three variations of the Townes and two variations of the Bartak Malaise trap) to determine their effects on biomass and species richness as identified by metabarcoding. Insect biomass varied by 20%–55%, not strictly following trap size but varying with trap type. Total species richness was 20%–38% higher in the three Townes trap models compared to the Bartak traps. Bartak traps captured lower richness of highly mobile taxa but increased richness of ground-dwelling taxa. The white roofed Townes trap captured a higher richness of pollinators. We find that biomass, total richness, and taxa group specific richness are all sensitive to Malaise trap type. Trap type should be carefully considered and aligned to match monitoring and research questions. Additionally, our estimates of trap type effects can be used to adjust results to facilitate comparisons across studies

Temperature drives variation in flying insect biomass across a German malaise trap network

1. Among the many concerns for biodiversity in the Anthropocene, recent reports of flying insect loss are particularly alarming, given their importance as pollinators, pest control agents, and as a food source. Few insect monitoring programmes cover the large spatial scales required to provide more generalizable estimates of insect responses to global change drivers. 2. We ask how climate and surrounding habitat affect flying insect biomass using data from the first year of a new monitoring network at 84 locations across Germany comprising a spatial gradient of land cover types from protected to urban and crop areas. 3. Flying insect biomass increased linearly with temperature across Germany. However, the effect of temperature on flying insect biomass flipped to negative in the hot months of June and July when local temperatures most exceeded long-term averages. 4. Land cover explained little variation in insect biomass, but biomass was lowest in forests. Grasslands, pastures, and orchards harboured the highest insect biomass. The date of peak biomass was primarily driven by surrounding land cover, with grasslands especially having earlier insect biomass phenologies. 5. Standardised, large-scale monitoring provides key insights into the underlying processes of insect decline and is pivotal for the development of climate-adapted strategies to promote insect diversity. In a temperate climate region, we find that the positive effects of temperature on flying insect biomass diminish in a German summer at locations where temperatures most exceeded long-term averages. Our results highlight the importance of local adaptation in climate change-driven impacts on insect communities

The conservation status and distribution of Mediterranean saproxylic beetles

The Mediterranean Red List assessment is a review of the conservation status at regional level of approximately 6,000 species of animals and plants. This report summarizes the results for a key group of Mediterranean biodiversity: saproxylic beetles. Despite their key role in the ecosystem´s health and food chain, saproxylic beetles are still largely misunderstood and the current information gaps on these species´ population status, trends, and distribution are a reflection on how little we still know about them. The geographical scope followed for this assessment is the Mediterranean region according to the Mediterranean Basin Biodiversity Hotspot, with the exception of the Macaronesian islands, which have not been included in this study. All the obligate saproxylic beetles endemic or almost endemic to the Mediterranean region – 320 species and 1 subspecies – are included

The ground beetle tribe platynini bonelli, 1810 (Coleoptera, carabidae) in the southern levant: dichotomous and interactive identification tools, ecological traits, and distribution

The carabids of the tribe Platynini from the southern Levant (Egypt: Sinai Peninsula, Israel, Jordan) and adjacent regions of Egypt, Lebanon, Syria, Iraq, and Saudi Arabia are reviewed in terms of species tax-onomy, ecological, distributional traits, and conservation biology. In addition to a classical dichotomous identification key to the 14 species of the region, identification tools are made freely available via the Xper3 knowledge database “Platynini, southern Levant”. Besides an interactive identification key, a matrix with character states for the species and single access identification keys are available. A database includ-ing all available records from the southern Levant is also provided. First faunistic records are recorded for Anchomenus dorsalis infuscatus from Sinai (Egypt), Olisthopus fuscatus from Lebanon and Iraq, and for O. glabricollis from Iraq. Threatened species are discussed, also with regard to the reasons of their decline. The majority of species lives in wetlands, especially on the shore of winter ponds and streams, which have been extremely degraded in the last decades