TY - JOUR A1 - Zupanc, Günther K. H. A1 - Rössler, Wolfgang T1 - Government funding of research beyond biomedicine: challenges and opportunities for neuroethology JF - Journal of Comparative Physiology A N2 - Curiosity-driven research is fundamental for neuroethology and depends crucially on governmental funding. Here, we highlight similarities and differences in funding of curiosity-driven research across countries by comparing two major funding agencies—the National Science Foundation (NSF) in the United States and the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG). We interviewed representatives from each of the two agencies, focusing on general funding trends, levels of young investigator support, career-life balance, and international collaborations. While our analysis revealed a negative trend in NSF funding of biological research, including curiosity-driven research, German researchers in these areas have benefited from a robust positive trend in DFG funding. The main reason for the decrease in curiosity-driven research in the US is that the NSF has only partially been able to compensate for the funding gap resulting from the National Institutes of Health restricting their support to biomedical research using select model organisms. Notwithstanding some differences in funding programs, particularly those relevant for scientists in the postdoctoral phase, both the NSF and DFG clearly support curiosity-driven research. KW - German Research Foundation KW - Government research funding KW - National Science Foundation KW - Deutsche Forschungsgemeinschaft KW - neuroethology Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-325113 VL - 208 IS - 3 ER - TY - JOUR A1 - Ziegler, Alice A1 - Meyer, Hanna A1 - Otte, Insa A1 - Peters, Marcell K. A1 - Appelhans, Tim A1 - Behler, Christina A1 - Böhning-Gaese, Katrin A1 - Classen, Alice A1 - Detsch, Florian A1 - Deckert, Jürgen A1 - Eardley, Connal D. A1 - Ferger, Stefan W. A1 - Fischer, Markus A1 - Gebert, Friederike A1 - Haas, Michael A1 - Helbig-Bonitz, Maria A1 - Hemp, Andreas A1 - Hemp, Claudia A1 - Kakengi, Victor A1 - Mayr, Antonia V. A1 - Ngereza, Christine A1 - Reudenbach, Christoph A1 - Röder, Juliane A1 - Rutten, Gemma A1 - Schellenberger Costa, David A1 - Schleuning, Matthias A1 - Ssymank, Axel A1 - Steffan-Dewenter, Ingolf A1 - Tardanico, Joseph A1 - Tschapka, Marco A1 - Vollstädt, Maximilian G. R. A1 - Wöllauer, Stephan A1 - Zhang, Jie A1 - Brandl, Roland A1 - Nauss, Thomas T1 - Potential of airborne LiDAR derived vegetation structure for the prediction of animal species richness at Mount Kilimanjaro JF - Remote Sensing N2 - The monitoring of species and functional diversity is of increasing relevance for the development of strategies for the conservation and management of biodiversity. Therefore, reliable estimates of the performance of monitoring techniques across taxa become important. Using a unique dataset, this study investigates the potential of airborne LiDAR-derived variables characterizing vegetation structure as predictors for animal species richness at the southern slopes of Mount Kilimanjaro. To disentangle the structural LiDAR information from co-factors related to elevational vegetation zones, LiDAR-based models were compared to the predictive power of elevation models. 17 taxa and 4 feeding guilds were modeled and the standardized study design allowed for a comparison across the assemblages. Results show that most taxa (14) and feeding guilds (3) can be predicted best by elevation with normalized RMSE values but only for three of those taxa and two of those feeding guilds the difference to other models is significant. Generally, modeling performances between different models vary only slightly for each assemblage. For the remaining, structural information at most showed little additional contribution to the performance. In summary, LiDAR observations can be used for animal species prediction. However, the effort and cost of aerial surveys are not always in proportion with the prediction quality, especially when the species distribution follows zonal patterns, and elevation information yields similar results. KW - biodiversity KW - species richness KW - LiDAR KW - elevation KW - partial least square regression KW - arthropods KW - birds KW - bats KW - predictive modeling Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-262251 SN - 2072-4292 VL - 14 IS - 3 ER - TY - JOUR A1 - Wunder, Juliane A1 - Pemp, Daniela A1 - Cecil, Alexander A1 - Mahdiani, Maryam A1 - Hauptstein, René A1 - Schmalbach, Katja A1 - Geppert, Leo N. A1 - Ickstadt, Katja A1 - Esch, Harald L. A1 - Dankekar, Thomas A1 - Lehmann, Leane T1 - Influence of breast cancer risk factors on proliferation and DNA damage in human breast glandular tissues: role of intracellular estrogen levels, oxidative stress and estrogen biotransformation JF - Archives of Toxicology N2 - Breast cancer etiology is associated with both proliferation and DNA damage induced by estrogens. Breast cancer risk factors (BCRF) such as body mass index (BMI), smoking, and intake of estrogen-active drugs were recently shown to influence intratissue estrogen levels. Thus, the aim of the present study was to investigate the influence of BCRF on estrogen-induced proliferation and DNA damage in 41 well-characterized breast glandular tissues derived from women without breast cancer. Influence of intramammary estrogen levels and BCRF on estrogen receptor (ESR) activation, ESR-related proliferation (indicated by levels of marker transcripts), oxidative stress (indicated by levels of GCLC transcript and oxidative derivatives of cholesterol), and levels of transcripts encoding enzymes involved in estrogen biotransformation was identified by multiple linear regression models. Metabolic fluxes to adducts of estrogens with DNA (E-DNA) were assessed by a metabolic network model (MNM) which was validated by comparison of calculated fluxes with data on methoxylated and glucuronidated estrogens determined by GC- and UHPLC-MS/MS. Intratissue estrogen levels significantly influenced ESR activation and fluxes to E-DNA within the MNM. Likewise, all BCRF directly and/or indirectly influenced ESR activation, proliferation, and key flux constraints influencing E-DNA (i.e., levels of estrogens, CYP1B1, SULT1A1, SULT1A2, and GSTP1). However, no unambiguous total effect of BCRF on proliferation became apparent. Furthermore, BMI was the only BCRF to indeed influence fluxes to E-DNA (via congruent adverse influence on levels of estrogens, CYP1B1 and SULT1A2). KW - metabolic network model KW - estrogens KW - human breast KW - multiple linear regression Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265343 SN - 1432-0738 VL - 96 IS - 2 ER - TY - JOUR A1 - Widder, Anna A1 - Kelm, Matthias A1 - Reibetanz, Joachim A1 - Wiegering, Armin A1 - Matthes, Niels A1 - Germer, Christoph-Thomas A1 - Seyfried, Florian A1 - Flemming, Sven T1 - Robotic-assisted versus laparoscopic left hemicolectomy — postoperative inflammation status, short-term outcome and cost effectiveness JF - International Journal of Environmental Research and Public Health N2 - Robotic-assisted colon surgery may contain advantages over the laparoscopic approach, but clear evidence is sparse. This study aimed to analyze postoperative inflammation status, short-term outcome and cost-effectiveness of robotic-assisted versus laparoscopic left hemicolectomy. All consecutive patients who received minimal-invasive left hemicolectomy at the Department of Surgery I at the University Hospital of Wuerzburg in 2021 were prospectively included. Importantly, no patient selection for either procedure was carried out. The robotic-assisted versus laparoscopic approaches were compared head to head for postoperative short-term outcomes as well as cost-effectiveness. A total of 61 patients were included, with 26 patients having received a robotic-assisted approach. Baseline characteristics did not differ among the groups. Patients receiving a robotic-assisted approach had a significantly decreased length of hospital stay as well as lower rates of complications in comparison to patients who received laparoscopic surgery (n = 35). In addition, C-reactive protein as a marker of systemic stress response was significantly reduced postoperatively in patients who were operated on in a robotic-assisted manner. Consequently, robotic-assisted surgery could be performed in a cost-effective manner. Thus, robotic-assisted left hemicolectomy represents a safe and cost-effective procedure and might improve patient outcomes in comparison to laparoscopic surgery. KW - robotic surgery KW - colon resection KW - postoperative inflammation KW - cost-effectiveness KW - left hemicolectomy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286203 SN - 1660-4601 VL - 19 IS - 17 ER - TY - JOUR A1 - Wegener, Christian A1 - Chen, Jiangtian T1 - Allatostatin A signalling: progress and new challenges from a paradigmatic pleiotropic invertebrate neuropeptide family JF - Frontiers in Physiology N2 - Neuropeptides have gained broad attraction in insect neuroscience and physiology, as new genetic tools are increasingly uncovering their wide-ranging pleiotropic functions with high cellular resolution. Allatostatin A (AstA) peptides constitute one of the best studied insect neuropeptide families. In insects and other panarthropods, AstA peptides qualify as brain-gut peptides and have regained attention with the discovery of their role in regulating feeding, growth, activity/sleep and learning. AstA receptor homologs are found throughout the protostomia and group with vertebrate somatostatin/galanin/kisspeptin receptors. In this review, we summarise the current knowledge on the evolution and the pleiotropic and cell-specific non-allatostatic functions of AstA. We speculate about the core functions of AstA signalling, and derive open questions and challengesfor future research on AstA and invertebrate neuropeptides in general. KW - neuropeptide signalling KW - feeding KW - intestinal control KW - sleep/activity KW - kisspeptin/galanin/spexin signalling KW - metabolism and growth KW - learning KW - cardioactive factor Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-278749 SN - 1664-042X VL - 13 ER - TY - JOUR A1 - Wech, Tobias A1 - Ankenbrand, Markus Johannes A1 - Bley, Thorsten Alexander A1 - Heidenreich, Julius Frederik T1 - A data-driven semantic segmentation model for direct cardiac functional analysis based on undersampled radial MR cine series JF - Magnetic Resonance in Medicine N2 - Purpose Image acquisition and subsequent manual analysis of cardiac cine MRI is time-consuming. The purpose of this study was to train and evaluate a 3D artificial neural network for semantic segmentation of radially undersampled cardiac MRI to accelerate both scan time and postprocessing. Methods A database of Cartesian short-axis MR images of the heart (148,500 images, 484 examinations) was assembled from an openly accessible database and radial undersampling was simulated. A 3D U-Net architecture was pretrained for segmentation of undersampled spatiotemporal cine MRI. Transfer learning was then performed using samples from a second database, comprising 108 non-Cartesian radial cine series of the midventricular myocardium to optimize the performance for authentic data. The performance was evaluated for different levels of undersampling by the Dice similarity coefficient (DSC) with respect to reference labels, as well as by deriving ventricular volumes and myocardial masses. Results Without transfer learning, the pretrained model performed moderately on true radial data [maximum number of projections tested, P = 196; DSC = 0.87 (left ventricle), DSC = 0.76 (myocardium), and DSC =0.64 (right ventricle)]. After transfer learning with authentic data, the predictions achieved human level even for high undersampling rates (P = 33, DSC = 0.95, 0.87, and 0.93) without significant difference compared with segmentations derived from fully sampled data. Conclusion A 3D U-Net architecture can be used for semantic segmentation of radially undersampled cine acquisitions, achieving a performance comparable with human experts in fully sampled data. This approach can jointly accelerate time-consuming cine image acquisition and cumbersome manual image analysis. KW - undersampling KW - cardiovascular magnetic resonance (CMR) KW - deep learning KW - radial KW - semantic segmentation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257616 VL - 87 IS - 2 ER - TY - THES A1 - Wagner, Martin T1 - Zyto- und Gentoxizität von Zinkoxid-Nanopartikeln in humanen mesenchymalen Stammzellen nach repetitiver Exposition und im Langzeitversuch T1 - Time-Dependent Toxic and Genotoxic Effects of Zinc Oxide Nanoparticles after Long-Term and Repetitive Exposure to Human Mesenchymal Stem Cells N2 - Zinkoxid-Nanopartikel (ZnO-NP) finden in vielen Produkten des täglichen Verbrauchs Verwendung. Daten über die toxikologischen Eigenschaften von ZnO-NP werden kontrovers diskutiert. Die menschliche Haut ist in Bezug auf die ZnO-NP Exposition das wichtigste Kontakt-Organ. Intakte Haut stellt eine suffiziente Barriere gegenüber NP dar. Bei defekter Haut ist ein Kontakt zu den proliferierenden Stammzellen möglich, sodass diese als wichtiges toxikologische Ziel für NP darstellen. Das Ziel dieser Dissertation war die Bewertung der genotoxischen und zytotoxischen Effekte an humanen mesenchymalen Stammzellen (hMSC) durch niedrig dosierte ZnO-NP nach 24 stündiger Exposition, repetitiven Expositionen und im Langzeitversuch bis zu 6 Wochen. Zytotoxische Wirkungen von ZnO-NP wurden mit 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid-Test (MTT) gemessen. Darüber hinaus wurde die Genotoxizität durch den Comet-Assay bewertet. Zur Langzeitbeobachtung bis zu 6 Wochen wurde die Transmissionselektronenmikroskopie (TEM) verwendet. Zytotoxizität nach 24-stündiger ZnO-NP-Exposition war ab einer Konzentration von 50 µg/ml nachweisbar. Genotoxizität konnten bereits bei Konzentrationen von 1 und 10 µg/ml ZnO-NP beschrieben werden. Wiederholte Exposition verstärkte die Zyto-, aber nicht die Genotoxizität. Eine intrazelluläre NP-Akkumulation mit Penetration der Zellorganelle wurde bei einer Exposition bis zu 6 Wochen beobachtet. Die Ergebnisse deuten auf zytotoxische und genotoxisches Effekte von ZnO-NP hin. Bereits geringe Dosen von ZnO-NP können bei wiederholter Exposition toxische Wirkungen hervorrufen sowie eine langfristige Zellakkumulation. Diese Daten sollten bei der Verwendung von ZnO-NP an geschädigter Haut berücksichtigt werden. N2 - Zinc oxide nanoparticles (ZnO-NP) are widely used in many products of daily consumption. Data on the toxicological properties of the ZnO-NP used are discussed controversially. Human skin is the most important organ in terms of ZnO-NP exposure. Intact skin has been shown to provide an adequate barrier against NPs, while defective skin allows NP contact with proliferating cells. Among proliferating cells, stem cells are the main toxicological target for NPs. Therefore, the aim of this dissertation was to evaluate the genotoxic and cytotoxic effects of human mesenchymal stem cells (hMSC) by low-dose ZnO-NP after 24 hours of exposure, repetitive exposures and in long-term experiments up to 6 weeks. Cytotoxic effects of ZnO-NP were measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test (MTT). In addition, genotoxicity was assessed by the comet assay. Transmission electron microscopy (TEM) was used for long-term observation after 6 exposure periods. The results of the study show that ZnO-NP has a cytotoxic effect starting at high concentrations of 50 µg/mL and could demonstrate genotoxic effects in hMSC exposed to 1 and 10 µg/ml ZnO-NP. Repeated exposure enhanced cytotoxicity but not genotoxicity. Intracellular NP accumulation with penetration of the cell organelles was observed at exposure up to 6 weeks. The results indicate the cytotoxic and genotoxic potential of ZnO-NP. Even small doses of ZnO-NP can cause toxic effects with repeated exposure and long-term cell accumulation. These data should be considered when using ZnO-NP on damaged skin. KW - nanoparticle KW - zinc oxid KW - stem cells KW - nanotoxicology KW - human skin KW - Nanopartikel KW - humane mesenchymale Stammzellen KW - Genotoxizität KW - Zytotoxizität KW - Repetitive Exposition KW - Elektronenmikroskopie Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-275726 ER - TY - JOUR A1 - Vollmuth, Nadine A1 - Schlicker, Lisa A1 - Guo, Yongxia A1 - Hovhannisyan, Pargev A1 - Janaki-Raman, Sudha A1 - Kurmasheva, Naziia A1 - Schmitz, Werner A1 - Schulze, Almut A1 - Stelzner, Kathrin A1 - Rajeeve, Karthika A1 - Rudel, Thomas T1 - c-Myc plays a key role in IFN-γ-induced persistence of Chlamydia trachomatis JF - eLife N2 - Chlamydia trachomatis (Ctr) can persist over extended times within their host cell and thereby establish chronic infections. One of the major inducers of chlamydial persistence is interferon-gamma (IFN-γ) released by immune cells as a mechanism of immune defence. IFN-γ activates the catabolic depletion of L-tryptophan (Trp) via indoleamine-2,3-dioxygenase (IDO), resulting in persistent Ctr. Here, we show that IFN-γ induces the downregulation of c-Myc, the key regulator of host cell metabolism, in a STAT1-dependent manner. Expression of c-Myc rescued Ctr from IFN-γ-induced persistence in cell lines and human fallopian tube organoids. Trp concentrations control c-Myc levels most likely via the PI3K-GSK3β axis. Unbiased metabolic analysis revealed that Ctr infection reprograms the host cell tricarboxylic acid (TCA) cycle to support pyrimidine biosynthesis. Addition of TCA cycle intermediates or pyrimidine/purine nucleosides to infected cells rescued Ctr from IFN-γ-induced persistence. Thus, our results challenge the longstanding hypothesis of Trp depletion through IDO as the major mechanism of IFN-γ-induced metabolic immune defence and significantly extends the understanding of the role of IFN-γ as a broad modulator of host cell metabolism. KW - Chlamydia trachomatis Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-301385 VL - 11 ER - TY - JOUR A1 - Volland, Julian Manuel A1 - Kaupp, Johannes A1 - Schmitz, Werner A1 - Wünsch, Anna Chiara A1 - Balint, Julia A1 - Möllmann, Marc A1 - El-Mesery, Mohamed A1 - Frackmann, Kyra A1 - Peter, Leslie A1 - Hartmann, Stefan A1 - Kübler, Alexander Christian A1 - Seher, Axel T1 - Mass spectrometric metabolic fingerprinting of 2-Deoxy-D-Glucose (2-DG)-induced inhibition of glycolysis and comparative analysis of methionine restriction versus glucose restriction under perfusion culture in the murine L929 model system JF - International Journal of Molecular Sciences N2 - All forms of restriction, from caloric to amino acid to glucose restriction, have been established in recent years as therapeutic options for various diseases, including cancer. However, usually there is no direct comparison between the different restriction forms. Additionally, many cell culture experiments take place under static conditions. In this work, we used a closed perfusion culture in murine L929 cells over a period of 7 days to compare methionine restriction (MetR) and glucose restriction (LowCarb) in the same system and analysed the metabolome by liquid chromatography mass spectrometry (LC-MS). In addition, we analysed the inhibition of glycolysis by 2-deoxy-D-glucose (2-DG) over a period of 72 h. 2-DG induced very fast a low-energy situation by a reduced glycolysis metabolite flow rate resulting in pyruvate, lactate, and ATP depletion. Under perfusion culture, both MetR and LowCarb were established on the metabolic level. Interestingly, over the period of 7 days, the metabolome of MetR and LowCarb showed more similarities than differences. This leads to the conclusion that the conditioned medium, in addition to the different restriction forms, substantially reprogramm the cells on the metabolic level. KW - amino acid restriction KW - glucose restriction KW - mass spectrometry KW - low carb KW - 2-deoxy-D-glucose KW - 2-DG KW - methionine KW - perfusion culture KW - energy restriction KW - caloric restriction Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286007 SN - 1422-0067 VL - 23 IS - 16 ER - TY - THES A1 - Vogel, Sebastian T1 - Determinants of saproxylic biodiversity and conclusions for conservation T1 - Einflussfaktoren auf xylobionte Artenvielfalt und Rückschlüsse für den Naturschutz N2 - Over the past centuries, anthropogenic utilization has fundamentally changed the appearance of European forest ecosystems. Constantly growing and changing demands have led to an enormous decline in ecological key elements and a structural homogenization of most forests. These changes have been accompanied by widespread declines of many forest-dwelling and especially saproxylic, i.e. species depending on deadwood. In order to counteract this development, various conservation strategies have been developed, but they primarily focus on a quantitative deadwood enrichment. However, the diversity of saproxylic species is furthermore driven by a variety of abiotic and biotic determinants as well as interactions between organisms. A detailed understanding of these processes has so far been largely lacking. The aim of the present thesis was therefore to improve the existing ecological knowledge of determinants influencing saproxylic species and species communities in order to provide the basis for evidence-based and adapted conservation measures. In chapter II of this thesis, I first investigated the impact of sun exposure, tree species, and their combination on saproxylic beetles, wood-inhabiting fungi, and spiders. Therefore, logs and branches of six tree species were set up under different sun exposures in an experimental approach. The impact of sun exposure and tree species strongly differed among single saproxylic taxa as well as diameters of deadwood. All investigated taxa were affected by sun exposure, whereby sun exposure resulted in a higher alpha-diversity of taxa recorded in logs and a lower alpha-diversity of saproxylic beetles reared from branches compared to shading by canopy. Saproxylic beetles and wood-inhabiting fungi as obligate saproxylic species were additionally affected by tree species. In logs, the respective impact of both determinants also resulted in divergent community compositions. Finally, a rarefaction/extrapolation method was used to evaluate the effectiveness of different combinations of tree species and sun exposure for the conservation of saproxylic species diversity. Based on this procedure, a combination of broadleaved and coniferous as well as hard- and softwood tree species was identified to support preferably high levels of saproxylic species diversity. The aim of chapter III was to evaluate the individual conservational importance of tree species for the protection of saproxylic beetles. For this, the list of tree species sampled for saproxylic beetles was increased to 42 different tree species. The considered tree species represented large parts of taxonomic and phylogenetic diversity native to Central Europe as well as the most important non-native tree species of silvicultural interest. Freshly cut branches were set up for one year and saproxylic beetles were reared afterwards for two subsequent years. The study revealed that some tree species, in particular Quercus sp., host a particular high diversity of saproxylic beetles, but tree species with a comparatively medium or low overall diversity were likewise important for red-listed saproxylic beetle species. Compared to native tree species, non-native tree species hosted a similar overall species diversity of saproxylic beetles but differed in community composition. In chapter IV, I finally analysed the interactions of host beetle diversity and the diversity of associated parasitoids by using experimentally manipulated communities of saproxylic beetles and parasitoid Hymenoptera as a model system. Classical approaches of species identification for saproxylic beetles were combined with DNA-barcoding for parasitoid Hymenoptera. The diversity of the host communities was inferred from their phylogenetic composition as well as differences in seven functional traits. Abundance, species richness, and Shannon-diversity of parasitoid Hymenoptera increased with increasing host abundance. However, the phylogenetic and functional dissimilarity of host communities showed no influence on the species communities of parasitoid Hymenoptera. The results clearly indicate an abundance-driven system in which the general availability, not necessarily the diversity of potential hosts, is decisive. In summary, the present thesis corroborates the general importance of deadwood heterogeneity for the diversity of saproxylic species by combining different experimental approaches. In order to increase their efficiency, conservation strategies for saproxylic species should generally promote deadwood from different tree species under different conditions of sun exposure on landscape-level in addition to the present enrichment of a certain deadwood amount. The most effective combinations of tree species should consider broadleaved and coniferous as well as hard- and softwood tree species. Furthermore, in addition to dominant tree species, special attention should be given to native, subdominant, silviculturally unimportant, and rare tree species. N2 - Während der letzten Jahrhunderte hat die anthropogene Nutzung das Erscheinungsbild der Waldökosysteme in Europa grundlegend verändert. Stetig wachsende und wandelnde Ansprüche führten zu einem enormen Rückgang ökologischer Schlüsselelemente und einer strukturellen Homogenisierung der meisten Wälder. In der Folge kam es zu Rückgängen vieler waldbewohnender und insbesondere xylobionter, d.h. von Totholz abhängigen, Arten. Um dieser Entwicklung entgegenzuwirken, wurden verschiedene Schutzstrategien entwickelt, welche jedoch vor allem auf eine quantitative Totholzanreicherung abzielen. Die Vielfalt xylobionter Arten wird aber weiterhin durch unterschiedliche abiotische und biotische Einflussfaktoren sowie durch Wechselwirkungen zwischen den Arten beeinflusst. Ein detailliertes Verständnis der genauen Vorgänge fehlt jedoch bislang größtenteils. Ziel der vorliegenden Promotionsarbeit war es deshalb, das diesbezüglich bestehende Wissen zu verbessern, um die Basis für evidenzbasierte und angepasste Naturschutzmaßnahmen zu schaffen. In Kapitel II dieser Arbeit habe ich zunächst den Einfluss der Besonnung und Baumart sowie deren Kombination im Vergleich auf xylobionte Käfer, holzbesiedelnde Pilze und Spinnen untersucht. Für die zugehörige Studie wurden dabei Stämme und Äste von sechs Baumarten bei unterschiedlicher Besonnung in einem experimentellen Ansatz ausgebracht. Der Einfluss der Besonnung und Baumart unterschied sich deutlich zwischen den einzelnen Artengruppen und Totholzdurchmessern. Alle Artengruppen wurden durch die Besonnung beeinflusst, wobei Besonnung im Vergleich zur Beschattung durch Baumkronen bei allen Artengruppen an Stämmen zu einer höheren alpha-Diversität führte und zu einer niedrigeren alpha-Diversität von xylobionten Käfern in Ästen. Xylobionte Käfer und holzbesiedelnde Pilze als obligat xylobionte Arten wurden weiterhin von der Baumart beeinflusst. Für die Artengruppen an Stämmen führten die jeweiligen Auswirkungen von Besonnung und Baumarten ebenfalls zu Unterschieden in der Zusammensetzung der Artgemeinschaften. Abschließend wurden Art-Akkumulationskurven genutzt, um die Effektivität unterschiedlicher Kombinationen aus Baumart und Besonnung für den Erhalt der xylobionten Diversität zu evaluieren. Um eine möglichst hohe Artenvielfalt zu fördern, wurde darauf basierend eine Kombination aus Laub- und Nadelholz einschließlich Weich- und Hartholzarten identifiziert. Ziel meiner Studie in Kapitel III war es den individuellen Beitrag einzelner Baumarten zum Schutz xylobionter Käfer zu identifizieren. Dafür wurde die Zahl untersuchter Baumarten auf 42 erhöht. Die untersuchten Baumarten umfassten dabei große Teile der taxonomischen und phylogenetischen Diversität, die in Mitteleuropa heimisch ist, sowie die wichtigsten, nicht-heimischen Baumarten von waldbaulichem Interesse. Frisch geschnittene Äste wurden für ein Jahr ausgebracht und xylobionte Käfer im Anschluss für zwei aufeinanderfolgende Jahre ausgezüchtet. Im Rahmen der Studie konnte gezeigt werden, dass einige Baumarten, insbesondere Quercus sp., eine besonders hohe Artenvielfalt aufweisen, aber auch Arten mit einer vergleichsweise geringen Gesamtartenzahl für Arten der Roten Liste von Bedeutung sind. Nicht-heimische Baumarten beherbergten insgesamt keine geringere Artenvielfalt von xylobionten Käfern, unterschieden sich aber in der Zusammensetzung ihrer Artgemeinschaften. Die Studie in Kapitel IV analysiert schließlich die Wechselwirkungen zwischen Wirtsdiversität und der Diversität assoziierter Parasitoide unter Verwendung experimentell manipulierter Gemeinschaften von xylobionten Käfern und parasitoiden Hymenopteren als Modellsystem. Klassische Ansätze zur Artidentifizierung für xylobionte Käfer wurden dabei mit DNA-Barcoding für die parasitoiden Hymenopteren kombiniert. Die Vielfalt der Wirtsgemeinschaften wurde aus ihrer phylogenetischen Zusammensetzung sowie Unterschieden in sieben funktionellen Merkmalen abgeleitet. Abundanz, Artenvielfalt und Shannon-Diversität nahmen mit zunehmender Abundanz der Wirte zu. Hingegen zeigten die phylogenetische und funktionelle Ähnlichkeit der Wirtsgemeinschaften insgesamt keinen Einfluss auf die Artgemeinschaften der parasitoiden Hymenopteren. Die Ergebnisse weisen damit klar auf ein abundanz-getriebenes System hin, in dem die generelle Verfügbarkeit und nicht unbedingt die Diversität potentieller Wirte entscheidend ist. Zusammenfassend betont die vorliegende Promotionsarbeit durch die Kombination verschiedener experimenteller Ansätze die generelle Bedeutung der Totholzheterogenität für die Vielfalt xylobionter Arten. Um ihre Effizienz zu steigern, sollten Schutzstrategien für xylobionte Arten neben einer bestimmten Totholzmenge daher generell Totholz verschiedener Baumarten bei unterschiedlicher Besonnung auf Landschaftsebene anreichern. Die effektivsten Baumarten-Kombinationen sollten dabei Laub- und Nadelholz sowie Weich- und Hartholzarten berücksichtigen. Neben den dominierenden Baumarten sollte zudem ein besonderes Augenmerk auf heimischen, subdominanten, wirtschaftlich irrelevanten und seltenen Baumarten liegen. KW - deadwood enrichment KW - saproxylic KW - beetles KW - spiders KW - woodinhabiting-fungi KW - tree species KW - forest conservation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-289266 ER -