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1. Species-rich communities exhibit higher levels of ecosystem functioning compared to species-poor ones, and this positive relationship strengthens over time. One proposed explanation for this phenomenon is the reduction of niche overlap among plants or animals, which corresponds to increased complementarity and reduced competition. 2. In order to examine the potential of increased complementarity among plants or animals to strengthen the relationship between diversity and ecosystem functions, we integrated models of bio-energetic population dynamics and food-web assembly. Through the simulation of various scenarios of plant and animal complementarity change, we sought to elucidate the mechanisms underlying the observed increases in (1) primary productivity, (2) control of herbivores by predators, and (3) reduction of herbivore pressure on plants in species-rich communities. 3. Our findings reveal that increased niche complementarity of plants can steepen the diversity-function relationships if it does not increase their intraspecific competition, while increasing complementarity among animals during community assembly can also have a positive effect but with considerable variability. 4. The study highlights the importance of trait variation both among and within species, and the interplay between intra- and interspecific competition strength in shaping the functioning of ecosystems over time. These results offer insights into the mechanisms underpinning the diversity-functioning relationship, and have practical implications for ecosystem management and conservation efforts.

In the last years, gender-sensitive language use has become an important issue of public debate in Germany and many other countries. The generic use of masculine forms in particular has been widely criticised. How, for example, public figures and politicians, both in government and of the opposition, refer to groups comprised of diverse genders is therefore scrutinised by the general public and routinely commented on in the media. In this paper, we analyse the language use of candidates for German chancellor and federal state prime minister, respectively, in televised pre-election debates – i. e. the most important single campaign event – from 1997 to 2020. Focussing on references to voters (Wählerinnen[FEM] orWähler[MASC]) and to citizens (Bürgerinnen[FEM] orBürger[MASC]), we quantitatively investigate the following research questions: Has the use of gender-sensitive expressions increased over the years? Are female candidates more likely to use gender-sensitive language than male candidates? Is there a preference for gender-sensitive language (as opposed to using the generic masculine) among candidates on the left of the political spectrum compared to conservative candidates?

Leaf functional traits provide important insights into plants’ responses to different environments. Leaf traits have been increasingly studied within-species in the last decade, following the growing realisation that neglecting the intra-specific scale can result in misreading plants’ response to environmental change. However, while likely to lead to similar pitfalls, within-individual leaf traits are under-researched despite being the scale at which elementary interactions shape ecosystem processes.To address this critical lack of understanding at the local scale, we assessed leaf trait variation in a large biodiversity-ecosystem functioning experiment in subtropical China. We used optical spectroscopy to determine nine morphological and biochemical traits of >5800 leaves from 414 trees representing 14 species. We evaluated the relative importance of the intra-individual level for total leaf trait variation, and the interacting effect of two trait variation’s drivers, soil nutrient availability, and a local species richness gradient.Comparing the amount of trait variation at the between-species, between-individuals and intra-individual levels, we found that intra-individual variation accounted on average for >25% of total trait variation. Additionally, intra-individual variation was the most prominent component of intra-specific variation. We found partial support for positive effects of soil nutrient availability and species diversity on intra-individual trait variation, and a strong interdependence of both effects. Contrary to the amplifying effects we expected, trait variation increased with soil nutrient availability at intermediate diversity, but decreased at low and high diversity.Our findings quantify the relevance of intra-individual level for leaf trait variation, and expose a complex interaction between its drivers. In particular, interactive effects of soil nutrient availability and local species diversity on trait variation suggest responses ranging from alleviating competition to enhancing complementarity. Taken together, our work highlights the importance of integrating an intra-individual perspective to understand trait-based mechanisms in biodiversity-ecosystem functioning relationships.

Overfishing to feed the world's growing population is depleting fish stocks. As these species are embedded in complex food webs, single-species management plans must be replaced with models integrating multispecies fisheries, economic market feedbacks, and fisher behaviour into complex ecological interaction networks to promote sustainable resource use. Here, we integrate three open-access fisheries in a dynamic model of complex food webs and find that selectively choosing similar species is more beneficial than harvesting species balanced across different network positions. Targeting low or high trophic levels risks reducing basal biomass or unchaining trophic cascades, respectively, undermining first ecological stability (biodiversity and biomass) and then economic sustainability (catch and revenue). A sustainable solution with high economic gain and low ecological impact arises when similar mid-trophic level species are caught. Our study demonstrates the importance of complex system analyses to balance ecological stability and multispecies fisheries to achieve a sustainable global food supply.

Plant community productivity generally increases with biodiversity, but the strength of this relationship exhibits strong empirical variation. In meta-food-web simulations, we addressed if the spatial overlap in plants’ resource access and movement of animals can explain such variability. We found that spatial overlap of plant resource access is a prerequisite for positive diversity-productivity relationships, but causes exploitative competition that can lead to competitive exclusion. Movement of herbivores causes apparent competition among plants, resulting in negative relationships. However, movement of larger top predators integrates sub-food-webs composed of smaller species, offsetting the negative effects of exploitative and apparent competition and leading to strongly positive diversity-productivity relationships. Overall, our results show that spatial overlap of plant resource access and animal movement can greatly alter the strength and sign of such relationships. In particular, the scaling of animal movement effects opens new perspectives for linking landscape processes without effects on biodiversity to productivity patterns.

Elektronische Reproduktion von: De variis speciebus strangulationis canalis intestinalis internae / Georg. Alb. Ed. Neussel. - Marburgi Cattorum : Elwert, 1841. - 29 S. - Hochschulschrift: Marburg, Univ., Diss., 1841. - Standort: Universität Marburg, Universitätsbibliothek. - Signatur: 085 1 2022/00071,12. - Bemerkungen: Provenienz: Bünger, Christian Heinrich (1782-1842). Digitalisiert 2023

On a global scale, fisheries harvest an estimated 96 million tonnes of fish biomass annually, making them one of the most important drivers of marine ecosystem biodiversity. Yet little is known about the interactions between fisheries and the dynamics of complex food webs in which the harvested species are embedded. We have developed a synthetic model that combines resource economics with complex food webs to examine the direct effects of fishing on exploited species and the indirect impact on other species in the same community. Our model analyses show that the sensitivity of the targeted species increases with its trophic level and decreases with its local interaction complexity (i.e. its number of interactions with prey, predators, and competitors). In addition, we also document a strikingly positive effect of community species richness on the resilience of the harvested species to this disturbance. The indirect effects on other species show specific patterns of spreading across trophic modules that differ systematically from how other disturbances spread across ecological networks. While these results call for further research on how human resource exploitation in general and fishery in particular affect ecological dynamics and biodiversity in naturally complex systems, they also allow for some cautious conclusions. Taken together, our results suggest that the sustainability concerning fishery yield and ecosystem integrity can be maximised by focusing the harvest on low trophic level species with a high local interaction complexity in high biodiversity ecosystems. In this sense, our complex network approach offers a promising avenue for integrating the necessities of generating economic revenue with the protection of natural biodiversity.

Resource-use complementarity of producer species is often invoked to explain the generally positive diversity-productivity relationships. Additionally, multi-trophic interactions that link processes across trophic levels have received increasing attention as a possible key driver. Given that both are integral to natural ecosystems, their interactive effect should be evident but has remained hidden. We address this issue by analysing diversity-productivity relationships in a simulation experiment of producer communities nested within complex food-webs, manipulating resource-use complementarity and multi-trophic animal richness. We show that these two mechanisms interactively create diverse communities of complementary producer species. This shapes diversity-productivity relationships such that their joint contribution generally exceeds their individual effects. Specifically, multi-trophic interactions in animal-rich ecosystems facilitate producer coexistence by preventing competitive exclusion despite overlaps in resource-use, which increases the realised complementarity. The interdependence of food-webs and producer complementarity in creating biodiversity-productivity relationships highlights the importance to adopt a multi-trophic perspective on biodiversity-ecosystem functioning relationships.

Aims Ecological theories predict that assembly processes shape communities so that co‐existing species may either be functionally more dissimilar ("divergence") or more similar ("convergence") than expected by chance. Two important factors that are rarely considered in combination are spatial scale and successional stage. Our aim is to identify different functional patterns during succession across spatial scales and to discuss the likely underlying assembly processes. We expect to find convergence due to environmental filtering at early succession, especially at the largest scales, and a tendency towards divergence driven by competitive interactions as succession unfolds and at smaller spatial scales. Location Protected Landscape Area “Bohemian Karst”, Czech Republic. Methods We studied three succession stages (two, eight and 55 years after abandonment). Each field was sampled using 40 1‐m2 quadrats containing 100 pins in a regular grid. We analysed trait dispersion at several combinations of grain and extent and characterised trait similarity using phylogeny and four traits: specific leaf area, leaf dry matter content, height, and seed mass analysed individually and combined using Gower distance (multi‐trait dissimilarity). Results In the youngest field, three of the traits individually and the multi‐trait dissimilarity showed convergence regardless of scale. Phylogeny showed convergence at most spatial scales of the youngest stage. The other two fields showed greater divergence predominantly in the oldest field at the smallest spatial scale. Conclusions The results are mainly congruent with theoretical expectations and provide a valuable example of directional changes from trait convergence to divergence along succession. The scale‐invariant convergence in the early stages of succession seems to be the result of environmental filtering and weaker competitive exclusion. At later stages and particularly at smaller scales, divergence becomes more common, likely because competition limits the trait similarity of species. These results highlight the importance of predictable (non‐random) changes in ecological succession.

While mature forests are declining worldwide, tree plantations could provide habitats of conservation value for forest-adapted species. However, to what degree the fauna in tree plantations matches the diversity and composition of mature forest communities is still debated. In this meta-analysis, we used beetle species (Coleoptera) as biodiversity indicators to assess the conservation value (i.e. the log response ratio in species richness and abundance and the Soerensen similarity) of tree plantations versus reference old-growth forests. We tested the effects of biome, plantation age, tree species richness and origin, surrounding habitat and the trophic position of the focal guild on the diversity and composition of beetle communities. Our results showed that tree plantations generally harboured communities with 47% less individuals, 33% less species and a significantly distinct composition than old-growth forests. In the case that tree plantations had a similar number of species or individuals as old-growth forests, those plantations still displayed a 40% difference in species composition. Beetle abundance was significantly lower in tropical/subtropical plantations and for detrivorous species. We found no further significant drivers of beetle diversity and community composition in tree plantations. We conclude that, although tree plantations can provide crucial habitats for forest-adapted species, they generally harbour less diverse and significantly different communities, highlighting the conservation value of old-growth forests as biodiversity refuges. To properly assess the conservation value of plantations in different taxa, we propose the use of species composition instead of single diversity indices.

10. Internationales Laser- und Fügesymposium, LFS18, Dresden, Germany, 27 Feb 2018 - 28 Feb 2018; Aachen, (2018)., Published by Aachen

We investigated the macrophyte community in a free flowing stretch of the Danube downstream ofVienna, Austria. Aim of the study was to analyze the macrophyte - habitat relationship with respect to depth andconnectivity. Habitat types (HT-1 to HT-5) paralleled those introduced within the Floodplain Index, i.e. they represent a gradient from permanent and lotic to temporary and lentic environments, which were all represented by water bodies inour survey reach. Species number decreased with increasing connectivity to the main channel and temporary waters showed a diminished diversity. Based on community analysis our data confirmed that the macrophyte vegetation can be used as an indicator that separates all the HTs from each other. A high number of indicator species was observed in HT-3, HT-4, and HT-5, indicating the stress on aquatic plants by the water flow in the main channel (HT-1) and in permanently connected side channels (HT-2). With respect to the EC Water Framework Directive, our study partly fills the gap which is still present as regards the deeper knowledge of macrophyte composition in floodplain waters. We also gave numerical proof to the common knowledge that there is a rather great diversity in floodplain water vegetation, determined by connectivity with the main river channel.

Drosophila paulistorum ist eine neotropische Fruchtfliegenart in statu nascendi, d.h., sie spaltet sich derzeit in mehrere neue Spezies auf. Bisher werden auf Grund von Kreuzungsinkompabilitäten sechs beschriebene Semispezies zu dem D. paulistorum Spezieskomplex gezählt. Deren Unterscheidung und phylogenetische Klassifizierung stellen eine große Herausforderung dar, da sie keine morphologischen Eigenheiten besitzen und bisher keine zuverlässigen molekularen Marker veröffentlicht wurden. Darüber hinaus weisen die publizierten mitochondrialen und nukleären Phylogenien Widersprüche auf. Jede der beschriebenen Semispezies besitzt einen eigenen Stamm an Wolbachia maternal vererbte, intrazelluläre Bakterien, die in mutualistischer Symbiose mit den Fliegen leben und reproduktive Phänotypen in ihren Wirten exprimieren. Diese führen zu sexueller Isolation sympatrischer Populationen unterschiedlicher Semispezies. Männliche Hybride, welche ausschliesslich unter Laborbedingungen durch Kreuzung verschiedener Semispezies erzeugt werden können, sind steril. Durch Behandlung der Fliegen mit Antibiotika können der Wolbachia Titer auf ein Minimum gesenkt und somit die reproduktiven Phänotypen teilweise umgangen werden. Unter solchen Bedingungen wurden in vorrangegangenen Studien stabile Hybridlinien von D. paulistorum Semispezies generiert, die Signaturen einer paternalen Vererbung der Wolbachien aufwiesen. Das erste Ziel dieser Arbeit war es, hochinformative nukleäre und mitochondriale Marker zu finden um die Phylogenie des D. paulistorum-Komplexes zu verbessern und die Widersprüche zwischen den publizierten mitochondrialen und nukleären Daten zu klären. Zu diesem Zweck wurden Gene für antimikrobielle Peptide (AMPs) als nukleäre Marker ausgesucht, da vorangegangene Studien gezeigt haben, dass diese Gene erhöhte Evolutionsraten in Drosophila-Spezies aufweisen. Als mitochondrieller Marker wurde das Gen für die NADH Dehydrogenase Untereinheit 4 ausgewählt. Das zweite Ziel dieser Arbeit war das Erstellen eines genetischen Typisierungssystems, um mit Hilfe der oben beschriebenen Markergene neu gesammelte oder unklassifizierte D. paulistorum Stämme in das System der sechs beschriebenen Semispezies genotypisch einzuordnen. Zudem sollte das Gen für Attacin D, ein AMP welches potentiell intrazellulär wirkt, auf Hinweise für eine Koevolution mit Wolbachien untersucht werden. Als letztes Ziel sollte die mitochondrielle Vererbung in den oben erwähnten stabilen Hybridlinien untersucht werden, da Wolbachien gemeinsam mit Mitochondrien vererbt werden, was eine paternale Übertragung der Mitochondrien in diesen Hybriden vermuten lässt. Die Sequenzanalyse der sechs AMP-Gene Attacin A, -C, -D, und Diptericin-B und Drosocin zeigte eine hohe Rate (2.4 - 7.9%) an unterschiedlichen Nukleotiden innerhalb der D. paulistorum Semispezies. Für drei dieser AMPs wurden mehrere Paraloge in manchen Semispezies entdeckt. Die unterschiedlichsten Nukleotidsequenzen und die meisten Paraloge fanden sich für Attacin D. Obwohl eine Analyse der Ka/Ks-Verhältnisse dieses Gens Hinweise auf negative Selektion hervorbrachte, kann die Aufrechterhaltung der hohen Nukleotiddiversität und der unterschiedlichen Paralogen als eine Adaption an Semispezies-spezifische Symbionten gedeutet werden. Die Sequenzierung und Restriktionsfragmentslängen-polymorphismus- (RFLP-) Analyse durch P32- markierte Southern-Blot-Hybridisierung des mitochondriellen ND4-Gens ergab, dass manche Semispezies mehrere mitochondrielle Haplotypen besitzen. Mit Hilfe der ND4-, Attacin C- und –D- Datensätze wurde ein molekulares Markersystem erstellt, welches die eindeutige Zuordnung dreier unklassifizierter Stämme in das System der sechs Semispezies erlaubte. Darüberhinaus konnten in dieser Studie phylogenetische Bäume mit höherer Auflösung erstellt werden als die der bisher veröffentlichten D. paulistorum Phylogenien. Es traten aber ebenfalls Widersprüche zwischen nukleären und mitochondriellen Daten auf. Die Entdeckung von mehreren Mitotypen und der in dieser Studie erbrachte Beweis der paternalen Vererbung von Mitochondrien in D. paulistorum-Hybriden kann als eine mögliche Erklärung für diese Widersprüche herangezogen werden., Drosophila paulistorum is a neotropical fruit fly in statu nascendi, i.e. under on-going evolutionary segregation into multiple new species. Six described D. paulistorum semispecies are currently assigned to this species complex based on mating compatibilities. The distinction and the phylogenetic classification of these semispecies provide a big challenge, as they are morphologically indistinguishable and no reliable molecular marker system has been published yet. In addition, the existing phylogeny of D. paulistorum is conflicting at nuclear and mitochondrial level. All of the described semispecies harbour distinct strains of Wolbachia, maternally transmitted intracellular bacteria, living in mutualistic symbiosis and expressing reproductive phenotypes in their hosts. These phenotypes induce pre- and postmating isolation of sympatric populations of different semispecies. Male hybrids of the semispecies, hatching only under laboratory conditions, are completely sterile. Antibiotic treatment of the flies reduces the Wolbachia titer to a minimum and can partially rescue those reproductive phenotypes. Under those conditions, hybrid lines of D. paulistorum semispecies were generated in previous studies. Remarkably, such intersemispecies hybrids showed signatures of paternal Wolbachia transmission. The first aim of this thesis was to find and examine highly informative nuclear and mitochondrial genes to improve the phylogeny of the D. paulistorum species complex and to resolve the conflicts between the published nuclear and mitochondrial data. For this purpose, genes for antimicrobial peptides (AMPs) were chosen at nuclear level, as previous studies showed that their rate of evolution is elevated in Drosophila species. As a mitochondrial marker gene, NADH dehydrogenase subunit 4 (ND4) was selected. The second aim was to create with those sequences a genetic strain typing system in order to group newly collected and unclassified D. paulistorum strains in the system of described semispecies. Additionally, the gene for Attacin D, an AMP potentially acting intracellularly, was examined for signs of coevolution with Wolbachia. Finally, we wanted to investigate the mitochondrial transmission mode in hybrid lines mentioned above, as their paternally inherited Wolbachia are potentially hitchhiking with the paternal mitotype. Sequence analysis of the six AMP genes Attacin A, -C, -D, Diptericin, Diptericin-B and Drosocin revealed high levels (2.4% - 7.9%) of nucleotide diversity within the D. paulistorum semispecies. Three of those AMP genes showed multiple paralogues in some semispecies. The highest nucleotide divergence and paralogue abundance was found in Attacin D. Although Ka/Ks ratio analysis of this gene provided signs of negative selection, the maintenance of the divergent paralogues and the high level of nucleotide divergence of this gene were interpreted as an adaptation to a divergent set of symbionts. ND4 sequencing and Restriction fragment length polymorphism (RFLP) analysis via P32-labelled Southern blot hybridization showed that some semispecies harbour multiple mitochondrial haplotypes. By using the ND4 data and the nuclear Attacin C, and - D sequences, a molecular marker system was established. It allowed the unambiguous integration of three unclassified strains into the system of described semispecies. Phylogenetic trees established in this study provide a higher resolution than the previously published D. paulistorum phylogenies. However, they are also inconsistent at nuclear and mitochondrial level. The finding of multiple mitotypes and the proof of paternal transmission of mitochondria in D. paulistorum hybrids, produced in this work, serve as a possible explanation for these incongruence.