@phdthesis{Heitmann2024, author = {Heitmann, Nadja}, title = {Ground-dwelling arthropods as mobile linkers for the phytopathogenic fungi Fusarium and Alternaria}, doi = {10.26127/BTUOpen-6917}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-69179}, school = {BTU Cottbus - Senftenberg}, year = {2024}, abstract = {Actively moving animals connect populations by transporting other organisms and their propagules, such as seeds or spores. These animals are also known as genetic mobile linkers and can alter the genetic structure of populations. So far, the mobile link concept is rarely considered in studying the spatio-temporal patterns of plant diseases, although many of the causal agents are dispersed by arthropods. This study identifies the potential of ground-dwelling arthropods, especially carabid beetles, as mobile linkers for Fusarium, Alternaria and other filamentous fungi between crop fields and kettle holes. These small water bodies are surrounded by permanent semi-natural vegetation and are essential habitats for many arthropod groups. Many Fusarium and Alternaria species are relevant crop pathogens but are also often found in the litter layer and on weeds. Both fungal genera are often associated with various arthropod species and some Fusarium species are spread by arthropods in different cropping systems. However, it is not known whether beneficial arthropods also spread Fusarium and Alternaria, although an interaction within the litter layer is highly likely. Furthermore, carabid beetles are highly mobile and frequently move between arable and semi-natural habitats. At first, I quantified the interaction of carabid beetles and fungi by using pitfall traps in wheat fields close to the kettle hole margins and screened the beetles with molecular and microbiological approaches for fungal propagules (Chapter 3). The results showed that, carabid beetles frequently interacted with Fusarium, Alternaria and always with filamentous fungi in general. Furthermore, smaller carabid species showed a lower fungal load than larger ones. Thereupon, I aimed to identify the limitations of this dispersal mechanism by comparing the Fusarium community composition in the litter of the kettle hole margin, the crop field soil and the body surface of ground-dwelling arthropods. (Chapter 4). I detected three distinct Fusarium communities with the highest Fusarium species richness on the arthropods, which consisted of Fusarium species from both habitats. Therefore, the results indicate a non-selective transport mechanism of Fusarium propagules that neither promotes nor hinders certain species. At last, we analyzed the spillover effects of carabid beetles from kettle holes into adjacent crop fields with directional pitfall traps (Chapter 5). The distance to the kettle hole and the beetles' ingoing or outgoing movement direction did not significantly affect the carabid community. In contrast, the activity density was 1.6 and species richness was 1.1 times higher in early summer than in late spring. The taxonomical and functional composition also differed between the seasons. These results indicate that carabid beetles and other ground -welling arthropods might be relevant mobile linkers for Fusarium, Alternaria and other fungi and that seasonality might affect this mechanism.}, subject = {Ground-dwelling arthropods; Mobile linker; Mycobiota; Spillover; Semi-natural habitats; Bodenbewohnende Arthropoden; Mobile linker; Pilzgemeinschaft; Ausbreitung; Naturnahe Habitate; Bodenarthropoda; Fusarium; Habitat; Soll ; Verbreitungs{\"o}kologie}, language = {en} } @phdthesis{Preusser2024, author = {Preußer, Daniel}, title = {Effects of the antibiotics ceftriaxone and levofloxacin on the growth of forensically relevant blow flies (Diptera, Fam. Calliphoridae) and effects on the determination of the post-mortem interval}, doi = {10.26127/BTUOpen-6893}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-68936}, school = {BTU Cottbus - Senftenberg}, year = {2024}, abstract = {Forensic entomology is a subfield of entomology in which the time of death is determined based on the species composition and age of the maggots found. Entomotoxicology combines forensic entomology and toxicology by investigating the effects of toxic substances on forensic relevant species. Ceftriaxone is a cephalosporin and belongs to the β-lactam antibiotics and levofloxacin is a quinolone antibiotic. Because of endogenous bactericidal secretions, maggots are adapted to live on surfaces with a high density of potential bacterial pathogens such as corpses, carcasses, excrements, or other decaying materials. This property is utilised in medicine to treat bacterial infections and in forensic sciences to determine the time of death and raises the question of the extent to which an additional bactericidal source influences the development of maggots. To answer this question experiments were carried out for three different species in the family Calliphoridae (blow flies). The species Lucilia sericata, Calliphora vomitoria and Protophormia terraenovae were selected for the study to remain within one family of Diptera. For each test procedure, 8 samples were prepared. A control treatment without antibiotics, one treatment each with a ceftriaxone concentration of 28.57 μg/g, 14.3 μg/g and 7.14 μg/g, one treatment each with a levofloxacin concentration of 3.57 μg/g, 1.79 μg/g and 0.89 μg/g and a mixed treatment. Additional tests were conducted in the microbiology department of the Medizinische Universit{\"a}t Lausitz - Carl-Thiem to test the duration of the effects of antibiotics in the culture medium. Both antibiotics are significantly longer active in the nutritional basis without natural elimination. The antibacterial effects of levofloxacin were observed at all examined concentrations during all 10 days of the tests and antibacterial effects of ceftriaxone were observed for 6, 7 and 8 days respectively. The maggot development of Calliphora vomitoria was significantly delayed by 24 - 48 hours depending on the concentration of the antibiotics, which could result in an underestimation of the post-mortem interval. The maggot development of Lucilia sericata was not significantly altered by the used antibiotics, errors in the determination of the time of death are therefore unlikely. Depending on the concentration of the antibiotics, the development time of Protophormia terraenovae was significantly reduced by 24 - 48 hours. The reduced development time could result in an overestimation of the post-mortem interval. As Protophormia terraenovae is considered to be a medically utilised species, the improved growth conditions could be relevant for both forensic investigations and medical treatments. The significantly different effects of the tested antibiotics on the three species highlight that it is impossible to draw conclusions and generalise about effects on other untested species.}, subject = {Entomotoxicology; Entomotoxikologie; Antibiotika; Schmeißfliegen; Entomologie; Leichenliegezeit; Antibiotics; Blowflies; Entomology; Post-mortem interval; Schmeißfliegen ; medizinische Entomologie; Ceftriaxon; Levofloxacin; Todeszeitbestimmung}, language = {en} } @phdthesis{Feng2024, author = {Feng, Lanya}, title = {Beetle Communities in Disturbed Landscapes}, doi = {10.26127/BTUOpen-6813}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-68135}, school = {BTU Cottbus - Senftenberg}, year = {2024}, abstract = {Disturbances can be any discrete events that significantly affect ecosystem components, they can be natural events such as wildfires and floods, or anthropogenic events like farming, mining, and deforestation. Disturbances are the most important source of temporal and spatial heterogeneity and shape the composition and dynamics of natural communities. However, after many years of research, it is still difficult to predict the response patterns of natural communities to disturbances accurately. This dissertation aimed to investigate the taxonomic, functional, and trophic response of beetle communities to three types of disturbances in field studies. Chapter 3 is based on an experiment in an unmanaged heathland area that was affected by a severe wildfire (natural disturbance). Emergence tents and wild boar carcasses were used to analyse the impact of wildfires on re-colonization and emergence of carrion-associated scavenging beetle species from local soils. Chapter 4 focused on effects of fallows at the local scale and proportions of permanent agricultural grasslands at the landscape scale on the taxonomic and functional diversity of the emerging ground beetles in intensively managed cereal fields (anthropogenic disturbance). Chapter 5 addressed the trophic links between the prey (dipterans emerging from lakes or terrestrial collembolans) and predators (ground beetles) at a post-mining lakeshore (anthropogenic disturbance) and compared the patterns of their isotopic niches (δ13C and δ15N) with data from a natural lakeshore. Overall, species composition, trait diversity and trophic interactions were more sensitive to indicate the disturbance conditions than traditional diversity indices, independent on the nature of disturbance (natural or anthropogenic). When the intensity and frequency of disturbance is moderate, the habitat complexity can be maintained, and the taxonomic and functional diversity of beetle communities could even be promoted by the disturbance, rare species with specialized preferences could be conserved. Disturbances, however, do not just affect consumers at higher trophic levels (e.g. predators or scavengers), but may have even greater impact on communities at basal trophic levels (e.g. aquatic dipterans, Collembola, herbivorous beetles) and could further affect the feeding preferences of predatory beetles that utilize such organisms as prey. The findings not only provided unique data and novel insights to effects of land-use and management on the conservation of beetle communities in disturbed landscapes, but also highlighted the need to better understand the impacts of disturbances on integrated aspects of the ecological communities.}, subject = {Trophic interaction; Beetles; Disturbances; Taxonomic diversity; Functional diversity; K{\"a}fer; St{\"o}rungen; Taxonomische Vielfalt; Funktionelle Vielfalt; Trophische Interaktion}, language = {en} } @phdthesis{deTomasMarin2024, author = {de Tom{\´a}s Mar{\´i}n, Sergio}, title = {Analysis of the functional structure of plant communities from the sub-Mediterranean ecotone}, doi = {10.26127/BTUOpen-6804}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-68044}, school = {BTU Cottbus - Senftenberg}, year = {2024}, abstract = {Ecotones are transitional regions between two areas with contrasting ecological features, where elements from the adjacent systems as well as unique species coexist. They are ideal systems to study community assembly mechanisms along environmental gradients. The Iberian Peninsula is one of the largest ecotones in Europe, with Mediterranean climate in the south and Temperate in the north, area known as the sub-Mediterranean region. The broad aim of this thesis is to understand the mechanisms driving plant community assembly in the Iberian sub-Mediterranean ecotone from a functional trait-based approach. In chapter 3 we focused on the two main tree species in a sub-Mediterranean forest of central Spain known as Hayedo de Montejo (UNESCO World Heritage Site): Fagus sylvatica L., a typical Eurosiberian species, and Quercus pyrenaica Willd., a typical Mediterranean species. We quantified functional niche partitioning by estimating the hypervolume of nine traits related to resource acquisition plus relative growth rate as an additional trait. We also estimated environmental niche similarity between both species. While both species shared the environmental niche, they showed notably different functional resource-use strategies, promoting a high complementarity between them. In chapter 4 we studied the mechanisms driving the assembly of 19 woody species in six communities of the Hayedo de Montejo forest. We analysed functional structure variations among communities by estimating the community-weighted mean (CWM), skewness (CWS) and kurtosis (CWK) at whole-plant level. Additionally, we estimated the relative contribution of species turnover and intraspecific trait variability (ITV) to variation in CWM. We detected three axes of variation: Leaf and Root Economics Spectrum, and plant hydraulic architecture, respectively. CWM strongly differed among communities according to their biogeographic origin (Eurosiberian vs Mediterranean). Differences in CWS and CWK indicated different trends in the functional structure among communities and the coexistence of different functional strategies, respectively. Variation in CMW among communities was mainly due to ITV. In chapter 5 we analyzed the taxonomic, phylogenetic and functional diversity of four sub-Mediterranean grasslands of contrasting biogeographic origin (Eurosiberian vs Mediterranean). Further, we decoupled phylogeny and traits to uncover potentially hidden patterns. Communities segregated by their biogeographic origin (Eurosiberian vs Mediterranean) along a soil recourse gradient in line with the Economics Spectrum; however, some traits varied independently from this axis. Assembly patterns showed a general phylogenetic over-dispersion together with functional clustering when decoupling phylogeny and traits. Our results support the idea that the sub-Mediterranean ecotone is a highly diverse and fragile habitat, where even minor environmental changes can lead to strong changes in the functional structure of the ecosystem.}, subject = {Functional Ecology; Sub-Mediterranean Ecotone; Community Aseembly; Plant Ecology; Umweltnische; Sub-Mediterrane {\"O}kotone; Funktionelle Struktur; Intraspezifische Variabilit{\"a}t; Gemeinschaftliche Versammlung; Iberische Halbinsel; {\"O}koton; Waldgesellschaft; Gr{\"u}ndlandgesellschaft; {\"O}kologische Nische}, language = {en} } @article{MenaresSaizSchenketal.2024, author = {Menares, Esteban and Sa{\´i}z, Hugo and Schenk, No{\"e}lle and Riva, Enrique G. de la and Kraus, Jochen and Birkhofer, Klaus}, title = {Co-occrrence patterns do not predict mutualistic interactions between plant and butterfly species}, series = {Ecology and Evolution}, volume = {14}, journal = {Ecology and Evolution}, number = {11}, publisher = {Wiley}, address = {London}, issn = {2045-7758}, doi = {10.1002/ece3.70498}, year = {2024}, abstract = {Biotic interactions are crucial for determining the structure and dynamics of communities; however, direct measurement of these interactions can be challenging in terms of time and resources, especially when numerous species are involved. Inferring species interactions from species co-occurrence patterns is increasingly being used; however, recent studies have highlighted some limitations. To our knowledge, no attempt has been made to test the accuracy of the existing methods for detecting mutualistic interactions in terrestrial ecosystems. In this study, we compiled two literature-based, long-term datasets of interactions between butterflies and herbaceous plant species in two regions of Germany and compared them with observational abundance and presence/absence data collected within a year in the same regions. We tested how well the species associations generated by three different co-occurrence analysis methods matched those of empirically measured mutualistic associations using sensitivity and specificity analyses and compared the strength of associations. We also checked whether flower abundance data (instead of plant abundance data) increased the accuracy of the co-occurrence models and validated our results using empirical flower visitation data. The results revealed that, although all methods exhibited low sensitivity, our implementation of the Relative Interaction Intensity index with pairwise null models performed the best, followed by the probabilistic method and Spearman's rank correlation method. However, empirical data showed a significant number of interactions that were not detected using co-occurrence methods. Incorporating flower abundance data did not improve sensitivity but enhanced specificity in one region. Further analysis demonstrated incongruence between the predicted co-occurrence associations and actual interaction strengths, with many pairs exhibiting high interaction strength but low co-occurrence or vice versa. These findings underscore the complexity of ecological dynamics and highlight the limitations of current co-occurrence methods for accurately capturing species interactions.}, subject = {Biodiversity exploratories; Co-occurrence analysis; Flower visitations; Mutualistic interactions; Species associations}, language = {en} }