TY - JOUR A1 - Hagge, Jonas A1 - Müller, Jörg A1 - Birkemoe, Tone A1 - Buse, Jörn A1 - Christensen, Rune Haubo Bojesen A1 - Gossner, Martin M. A1 - Gruppe, Axel A1 - Heibl, Christoph A1 - Jarzabek‐Müller, Andrea A1 - Seibold, Sebastian A1 - Siitonen, Juha A1 - Soutinho, João Gonçalo A1 - Sverdrup‐Thygeson, Anne A1 - Thorn, Simon A1 - Drag, Lukas T1 - What does a threatened saproxylic beetle look like? Modelling extinction risk using a new morphological trait database JF - Journal of Animal Ecology N2 - The extinction of species is a non‐random process, and understanding why some species are more likely to go extinct than others is critical for conservation efforts. Functional trait‐based approaches offer a promising tool to achieve this goal. In forests, deadwood‐dependent (saproxylic) beetles comprise a major part of threatened species, but analyses of their extinction risk have been hindered by the availability of suitable morphological traits. To better understand the mechanisms underlying extinction in insects, we investigated the relationships between morphological features and the extinction risk of saproxylic beetles. Specifically, we hypothesised that species darker in colour, with a larger and rounder body, a lower mobility, lower sensory perception and more robust mandibles are at higher risk. We first developed a protocol for morphological trait measurements and present a database of 37 traits for 1,157 European saproxylic beetle species. Based on 13 selected, independent traits characterising aspects of colour, body shape, locomotion, sensory perception and foraging, we used a proportional‐odds multiple linear mixed‐effects model to model the German Red List categories of 744 species as an ordinal index of extinction risk. Six out of 13 traits correlated significantly with extinction risk. Larger species as well as species with a broad and round body had a higher extinction risk than small, slim and flattened species. Species with short wings had a higher extinction risk than those with long wings. On the contrary, extinction risk increased with decreasing wing load and with higher mandibular aspect ratio (shorter and more robust mandibles). Our study provides new insights into how morphological traits, beyond the widely used body size, determine the extinction risk of saproxylic beetles. Moreover, our approach shows that the morphological characteristics of beetles can be comprehensively represented by a selection of 13 traits. We recommend them as a starting point for functional analyses in the rapidly growing field of ecological and conservation studies of deadwood. KW - deadwood KW - extinction risk KW - forest biodiversity KW - forestry KW - functional traits KW - morphometry KW - red lists KW - saproxylic beetles Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-244717 VL - 90 IS - 8 SP - 1934 EP - 1947 ER - TY - JOUR A1 - Thorn, Simon A1 - Seibold, Sebastian A1 - Leverkus, Alexandro B A1 - Michler, Thomas A1 - Müller, Jörg A1 - Noss, Reed F A1 - Stork, Nigel A1 - Vogel, Sebastian A1 - Lindenmayer, David B T1 - The living dead: acknowledging life after tree death to stop forest degradation JF - Frontiers in Ecology and the Environment N2 - Global sustainability agendas focus primarily on halting deforestation, yet the biodiversity crisis resulting from the degradation of remaining forests is going largely unnoticed. Forest degradation occurs through the loss of key ecological structures, such as dying trees and deadwood, even in the absence of deforestation. One of the main drivers of forest degradation is limited awareness by policy makers and the public on the importance of these structures for supporting forest biodiversity and ecosystem function. Here, we outline management strategies to protect forest health and biodiversity by maintaining and promoting deadwood, and propose environmental education initiatives to improve the general awareness of the importance of deadwood. Finally, we call for major reforms to forest management to maintain and restore deadwood; large, old trees; and other key ecological structures. KW - forest degradation KW - biodiversity KW - deadwood Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218575 VL - 18 IS - 9 SP - 505 EP - 512 ER - TY - JOUR A1 - Graf, Marlene A1 - Lettenmaier, Ludwig A1 - Müller, Jörg A1 - Hagge, Jonas T1 - Saproxylic beetles trace deadwood and differentiate between deadwood niches before their arrival on potential hosts JF - Insect Conservation and Diversity N2 - Deadwood provides a variety of habitats for saproxylic beetles. Whereas the understanding of the drivers promoting saproxylic beetle diversity has improved, the process of deadwood colonisation and beetle's potential to trace resources is poorly understood. However, the mechanisms facilitating deadwood detection by saproxylic beetles appears to be essential for survival, as deadwood is usually scattered in time and space. To investigate whether saproxylic beetles distinguish before their arrival on potential hosts between alive trees and deadwood (lying, stumps, standing), deadwood arrangement (aggregated, distributed) and different heights on standing resources (bottom = 0.5 m, middle = 4–5 m, top = 7.30–11.60 m), we sampled saproxylic beetles with sticky traps in a deadwood experiment. We found on average 67% higher abundance, 100% higher species numbers and 50–130% higher species diversity of colonising saproxylic beetles consistently for all deadwood types compared to alive trees with a distinct community composition on lying deadwood compared to the other resource types. Aggregated deadwood arrangement, which is associated with higher sun‐exposure, had a positive effect on species richness. The abundance, species number and diversity, was significantly higher for standing deadwood and alive trees at the bottom section of tree trunks. In contrast to living trees, however, the vertical position had an additional effect on the community composition on standing deadwood. Our results indicate that saproxylic beetles are attracted to potential deadwood habitats and actively select specific trunk sections before arriving on potential hosts. Furthermore, this study highlights the importance of sun‐exposed resources for species richness in saproxylic beetles. KW - deadwood KW - experiment KW - host discrimination KW - host selection KW - microclimate KW - saproxylic beetles KW - vertical stratification Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262507 VL - 15 IS - 1 SP - 48 EP - 60 ER - TY - JOUR A1 - Zielewska-Büttner, Katarzyna A1 - Heurich, Marco A1 - Müller, Jörg A1 - Braunisch, Veronika T1 - Remotely Sensed Single Tree Data Enable the Determination of Habitat Thresholds for the Three-Toed Woodpecker (Picoides tridactylus) JF - Remote Sensing N2 - Forest biodiversity conservation requires precise, area-wide information on the abundance and distribution of key habitat structures at multiple spatial scales. We combined airborne laser scanning (ALS) data with color-infrared (CIR) aerial imagery for identifying individual tree characteristics and quantifying multi-scale habitat requirements using the example of the three-toed woodpecker (Picoides tridactylus) (TTW) in the Bavarian Forest National Park (Germany). This bird, a keystone species of boreal and mountainous forests, is highly reliant on bark beetles dwelling in dead or dying trees. While previous studies showed a positive relationship between the TTW presence and the amount of deadwood as a limiting resource, we hypothesized a unimodal response with a negative effect of very high deadwood amounts and tested for effects of substrate quality. Based on 104 woodpecker presence or absence locations, habitat selection was modelled at four spatial scales reflecting different woodpecker home range sizes. The abundance of standing dead trees was the most important predictor, with an increase in the probability of TTW occurrence up to a threshold of 44–50 dead trees per hectare, followed by a decrease in the probability of occurrence. A positive relationship with the deadwood crown size indicated the importance of fresh deadwood. Remote sensing data allowed both an area-wide prediction of species occurrence and the derivation of ecological threshold values for deadwood quality and quantity for more informed conservation management. KW - deadwood KW - standing deadwood KW - dead tree KW - snags KW - three-toed woodpecker (Picoides tridactylus) KW - habitat suitability model (HSM) KW - habitat requirements KW - airborne laser scanning (ALS) KW - CIR aerial imagery Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-197565 SN - 2072-4292 VL - 10 IS - 12 ER - TY - JOUR A1 - Vogel, Sebastian A1 - Bussler, Heinz A1 - Finnberg, Sven A1 - Müller, Jörg A1 - Stengel, Elisa A1 - Thorn, Simon T1 - Diversity and conservation of saproxylic beetles in 42 European tree species: an experimental approach using early successional stages of branches JF - Insect Conservation and Diversity N2 - Tree species diversity is important to maintain saproxylic beetle diversity in managed forests. Yet, knowledge about the conservational importance of single tree species and implications for forest management and conservation practices are lacking. We exposed freshly cut branch‐bundles of 42 tree species, representing tree species native and non‐native to Europe, under sun‐exposed and shaded conditions for 1 year. Afterwards, communities of saproxylic beetles were reared ex situ for 2 years. We tested for the impact of tree species and sun exposure on alpha‐, beta‐, and gamma‐diversity as well as composition of saproxylic beetle communities. Furthermore, the number of colonised tree species by each saproxylic beetle species was determined. Tree species had a lower impact on saproxylic beetle communities compared to sun exposure. The diversity of saproxylic beetles varied strongly among tree species, with highest alpha‐ and gamma‐diversity found in Quercus petraea. Red‐listed saproxylic beetle species occurred ubiquitously among tree species. We found distinct differences in the community composition of broadleaved and coniferous tree species, native and non‐native tree species as well as sun‐exposed and shaded deadwood. Our study enhances the understanding of the importance of previously understudied and non‐native tree species for the diversity of saproxylic beetles. To improve conservation practices for saproxylic beetles and especially red‐listed species, we suggest a stronger incorporation of tree species diversity and sun exposure of into forest management strategies, including the enrichment of deadwood from native and with a specific focus on locally rare or silviculturally less important tree species. KW - deadwood KW - deadwood enrichment KW - decay KW - forest management KW - host specificity Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218401 VL - 14 IS - 1 SP - 132 EP - 143 ER - TY - JOUR A1 - Vogel, Sebastian A1 - Prinzing, Andreas A1 - Bußler, Heinz A1 - Müller, Jörg A1 - Schmidt, Stefan A1 - Thorn, Simon T1 - Abundance, not diversity, of host beetle communities determines abundance and diversity of parasitoids in deadwood JF - Ecology and Evolution N2 - Most parasites and parasitoids are adapted to overcome defense mechanisms of their specific hosts and hence colonize a narrow range of host species. Accordingly, an increase in host functional or phylogenetic dissimilarity is expected to increase the species diversity of parasitoids. However, the local diversity of parasitoids may be driven by the accessibility and detectability of hosts, both increasing with increasing host abundance. Yet, the relative importance of these two mechanisms remains unclear. We parallelly reared communities of saproxylic beetle as potential hosts and associated parasitoid Hymenoptera from experimentally felled trees. The dissimilarity of beetle communities was inferred from distances in seven functional traits and from their evolutionary ancestry. We tested the effect of host abundance, species richness, functional, and phylogenetic dissimilarities on the abundance, species richness, and Shannon diversity of parasitoids. Our results showed an increase of abundance, species richness, and Shannon diversity of parasitoids with increasing beetle abundance. Additionally, abundance of parasitoids increased with increasing species richness of beetles. However, functional and phylogenetic dissimilarity showed no effect on the diversity of parasitoids. Our results suggest that the local diversity of parasitoids, of ephemeral and hidden resources like saproxylic beetles, is highest when resources are abundant and thereby detectable and accessible. Hence, in some cases, resources do not need to be diverse to promote parasitoid diversity. KW - barcoding KW - deadwood KW - experiment KW - host–parasitoid interaction KW - natural enemy KW - specialization Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238892 VL - 11 IS - 11 SP - 6881 EP - 6888 ER -