TY - GEN A1 - Drygala, Frank A1 - Korablev, Nikolay A1 - Ansorge, Hermann A1 - Fickel, Jörns A1 - Isomursu, Marja A1 - Elmeros, Morten A1 - Kowalczyk, Rafał A1 - Baltrunaite, Laima A1 - Balciauskas, Linas A1 - Saarma, Urmas A1 - Schulze, Christoph A1 - Borkenhagen, Peter A1 - Frantz, Alain C. T1 - Homogenous population genetic structure of the non-native raccoon dog (Nyctereutes procyonoides) in Europe as a result of rapid population expansion T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The extent of gene flow during the range expansion of non-native species influences the amount of genetic diversity retained in expanding populations. Here, we analyse the population genetic structure of the raccoon dog (Nyctereutes procyonoides) in north-eastern and central Europe. This invasive species is of management concern because it is highly susceptible to fox rabies and an important secondary host of the virus. We hypothesized that the large number of introduced animals and the species' dispersal capabilities led to high population connectivity and maintenance of genetic diversity throughout the invaded range. We genotyped 332 tissue samples from seven European countries using 16 microsatellite loci. Different algorithms identified three genetic clusters corresponding to Finland, Denmark and a large 'central' population that reached from introduction areas in western Russia to northern Germany. Cluster assignments provided evidence of long-distance dispersal. The results of an Approximate Bayesian Computation analysis supported a scenario of equal effective population sizes among different pre-defined populations in the large central cluster. Our results are in line with strong gene flow and secondary admixture between neighbouring demes leading to reduced genetic structuring, probably a result of its fairly rapid population expansion after introduction. The results presented here are remarkable in the sense that we identified a homogenous genetic cluster inhabiting an area stretching over more than 1500km. They are also relevant for disease management, as in the event of a significant rabies outbreak, there is a great risk of a rapid virus spread among raccoon dog populations. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 540 KW - distance seed dispersial KW - medium-sized carnivores KW - biological invasion KW - Southeast Finland KW - rabies spread KW - F-statistics KW - N-E KW - diversity KW - history KW - colonization Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-410921 SN - 1866-8372 IS - 540 ER - TY - JOUR A1 - Ehrensperger, Kathy T1 - Trajectories and future avenues in Pauline Studies and Jewish–Christian relations BT - the relevance of William S. Campbell’s approach to Paul JF - Journal of beliefs and values : studies in religion & education N2 - William S. Campbell’s research on the apostle Paul has been at the forefront of overcoming anti-Jewish interpretations. His career has been characterised by academic rigour and social and interfaith engagement. His interpretive approach is committed to formulating Christian identity in positive relation to others and thus contributes to provide a vital basis for Jewish-Christian and Interfaith relations in general for the future. KW - Pauline studies KW - Christian identity KW - diversity KW - anti-judaism KW - Jewish-Christian relations KW - interfaith relations Y1 - 2017 U6 - https://doi.org/10.1080/13617672.2017.1314988 SN - 1361-7672 SN - 1469-9362 VL - 38 IS - 2 SP - 153 EP - 158 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Ehrlich, Elias A1 - Kath, Nadja Jeanette A1 - Gaedke, Ursula T1 - The shape of a defense-growth trade-off governs seasonal trait dynamics in natural phytoplankton JF - The ISME journal N2 - Theory predicts that trade-offs, quantifying costs of functional trait adjustments, crucially affect community trait adaptation to altered environmental conditions, but empirical verification is scarce. We evaluated trait dynamics (antipredator defense, maximum growth rate, and phosphate affinity) of a lake phytoplankton community in a seasonally changing environment, using literature trait data and 21 years of species-resolved high-frequency biomass measurements. The trait data indicated a concave defense-growth trade-off, promoting fast-growing species with intermediate defense. With seasonally increasing grazing pressure, the community shifted toward higher defense levels at the cost of lower growth rates along the trade-off curve, while phosphate affinity explained some deviations from it. We discuss how low fitness differences of species, inferred from model simulations, in concert with stabilizing mechanisms, e.g., arising from further trait dimensions, may lead to the observed phytoplankton diversity. In conclusion, quantifying trade-offs is key for predictions of community trait adaptation and biodiversity under environmental change. KW - coexistence KW - community ecology KW - diversity KW - evolution KW - fitness KW - functional traits KW - lake KW - maintenance KW - mechanisms KW - plankton Y1 - 2020 U6 - https://doi.org/10.1038/s41396-020-0619-1 SN - 1751-7362 SN - 1751-7370 VL - 14 IS - 6 SP - 1451 EP - 1462 PB - Nature Publishing Group CY - London ER - TY - GEN A1 - Ehrlich, Elias A1 - Kath, Nadja Jeanette A1 - Gaedke, Ursula T1 - The shape of a defense-growth trade-off governs seasonal trait dynamics in natural phytoplankton T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Theory predicts that trade-offs, quantifying costs of functional trait adjustments, crucially affect community trait adaptation to altered environmental conditions, but empirical verification is scarce. We evaluated trait dynamics (antipredator defense, maximum growth rate, and phosphate affinity) of a lake phytoplankton community in a seasonally changing environment, using literature trait data and 21 years of species-resolved high-frequency biomass measurements. The trait data indicated a concave defense-growth trade-off, promoting fast-growing species with intermediate defense. With seasonally increasing grazing pressure, the community shifted toward higher defense levels at the cost of lower growth rates along the trade-off curve, while phosphate affinity explained some deviations from it. We discuss how low fitness differences of species, inferred from model simulations, in concert with stabilizing mechanisms, e.g., arising from further trait dimensions, may lead to the observed phytoplankton diversity. In conclusion, quantifying trade-offs is key for predictions of community trait adaptation and biodiversity under environmental change. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1390 KW - functional traits KW - community ecology KW - evolution KW - lake KW - mechanisms KW - diversity KW - plankton KW - fitness KW - maintenance KW - coexistence Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-513956 SN - 1866-8372 IS - 6 ER - TY - GEN A1 - Foster, William J. A1 - Garvie, Christopher L. A1 - Weiss, Anna M. A1 - Muscente, A. Drew A1 - Aberhan, Martin A1 - Counts, John W. A1 - Martindale, Rowan C. T1 - Resilience of marine invertebrate communities during the early Cenozoic hyperthermals T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The hyperthermal events of the Cenozoic, including the Paleocene-Eocene Thermal Maximum, provide an opportunity to investigate the potential effects of climate warming on marine ecosystems. Here, we examine the shallow benthic marine communities preserved in the late Cretaceous to Eocene strata on the Gulf Coastal Plain (United States). In stark contrast to the ecological shifts following the end-Cretaceous mass extinction, our data show that the early Cenozoic hyperthermals did not have a long-term impact on the generic diversity nor composition of the Gulf Coastal Plain molluscan communities. We propose that these communities were resilient to climate change because molluscs are better adapted to high temperatures than other taxa, as demonstrated by their physiology and evolutionary history. In terms of resilience, these communities differ from other shallow-water carbonate ecosystems, such as reef communities, which record significant changes during the early Cenozoic hyperthermals. These data highlight the strikingly different responses of community types, i.e., the almost imperceptible response of molluscs versus the marked turnover of foraminifera and reef faunas. The impact on molluscan communities may have been low because detrimental conditions did not devastate the entire Gulf Coastal Plain, allowing molluscs to rapidly recolonise vacated areas once harsh environmental conditions ameliorated. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1410 KW - eocene thermal maximum KW - gulf coastal plain KW - climate-change KW - ocean acidification KW - extinction event KW - carbon-cycle KW - heat-stress KW - origination KW - ecosystems KW - diversity Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-516011 SN - 1866-8372 IS - 1 ER - TY - JOUR A1 - Foster, William J. A1 - Garvie, Christopher L. A1 - Weiss, Anna M. A1 - Muscente, A. Drew A1 - Aberhan, Martin A1 - Counts, John W. A1 - Martindale, Rowan C. T1 - Resilience of marine invertebrate communities during the early Cenozoic hyperthermals JF - Scientific Reports N2 - The hyperthermal events of the Cenozoic, including the Paleocene-Eocene Thermal Maximum, provide an opportunity to investigate the potential effects of climate warming on marine ecosystems. Here, we examine the shallow benthic marine communities preserved in the late Cretaceous to Eocene strata on the Gulf Coastal Plain (United States). In stark contrast to the ecological shifts following the end-Cretaceous mass extinction, our data show that the early Cenozoic hyperthermals did not have a long-term impact on the generic diversity nor composition of the Gulf Coastal Plain molluscan communities. We propose that these communities were resilient to climate change because molluscs are better adapted to high temperatures than other taxa, as demonstrated by their physiology and evolutionary history. In terms of resilience, these communities differ from other shallow-water carbonate ecosystems, such as reef communities, which record significant changes during the early Cenozoic hyperthermals. These data highlight the strikingly different responses of community types, i.e., the almost imperceptible response of molluscs versus the marked turnover of foraminifera and reef faunas. The impact on molluscan communities may have been low because detrimental conditions did not devastate the entire Gulf Coastal Plain, allowing molluscs to rapidly recolonise vacated areas once harsh environmental conditions ameliorated. KW - eocene thermal maximum KW - gulf coastal plain KW - climate-change KW - ocean acidification KW - extinction event KW - carbon-cycle KW - heat-stress KW - origination KW - ecosystems KW - diversity Y1 - 2020 U6 - https://doi.org/10.1038/s41598-020-58986-5 SN - 2045-2322 VL - 10 IS - 1 SP - 1 EP - 11 PB - Springer Nature CY - London ER - TY - JOUR A1 - Guill, Christian A1 - Hülsemann, Janne A1 - Klauschies, Toni T1 - Self-organised pattern formation increases local diversity in metacommunities JF - Ecology letters N2 - Self-organised formation of spatial patterns is known from a variety of different ecosystems, yet little is known about how these patterns affect the diversity of communities. Here, we use a food chain model in which autotroph diversity is described by a continuous distribution of a trait that affects both growth and defence against heterotrophs. On isolated patches, diversity is always lost over time due to stabilising selection, and the local communities settle on one of two alternative stable community states that are characterised by a dominance of either defended or undefended species. In a metacommunity context, dispersal can destabilise these states and complex spatio-temporal patterns in the species' abundances emerge. The resulting biomass-trait feedback increases local diversity by an order of magnitude compared to scenarios without self-organised pattern formation, thereby maintaining the ability of communities to adapt to potential future changes in biotic or abiotic environmental conditions. KW - biomass-trait feedback KW - fitness gradient KW - food chain KW - functional KW - diversity KW - metacommunity KW - self-organisation KW - source-sink dynamics KW - spatio-temporal pattern KW - trait-based aggregate model KW - Turing instability Y1 - 2021 U6 - https://doi.org/10.1111/ele.13880 SN - 1461-023X SN - 1461-0248 VL - 24 IS - 12 SP - 2624 EP - 2634 PB - Wiley-Blackwell CY - Oxford ER - TY - THES A1 - Heise, Janine T1 - Phylogenetic and physiological characterization of deep-biosphere microorganisms in El’gygytgyn Crater Lake sediments T1 - Phylogenetische und physiologische Charakterisierung der Tiefen Biosphäre in El'gygytgyn Kraterseesedimenten N2 - The existence of diverse and active microbial ecosystems in the deep subsurface – a biosphere that was originally considered devoid of life – was discovered in multiple microbiological studies. However, most of the studies are restricted to marine ecosystems, while our knowledge about the microbial communities in the deep subsurface of lake systems and their potentials to adapt to changing environmental conditions is still fragmentary. This doctoral thesis aims to build up a unique data basis for providing the first detailed high-throughput characterization of the deep biosphere of lacustrine sediments and to emphasize how important it is to differentiate between the living and the dead microbial community in deep biosphere studies. In this thesis, up to 3.6 Ma old sediments (up to 317 m deep) of the El’gygytgyn Crater Lake were examined, which represents the oldest terrestrial climate record of the Arctic. Combining next generation sequencing with detailed geochemical characteristics and other environmental parameters, the microbial community composition was analyzed in regard to changing climatic conditions within the last 3.6 Ma to 1.0 Ma (Pliocene and Pleistocene). DNA from all investigated sediments was successfully extracted and a surprisingly diverse (6,910 OTUs) and abundant microbial community in the El’gygytgyn deep sediments were revealed. The bacterial abundance (10³-10⁶ 16S rRNA copies g⁻¹ sediment) was up to two orders of magnitudes higher than the archaeal abundance (10¹-10⁵) and fluctuates with the Pleistocene glacial/interglacial cyclicality. Interestingly, a strong increase in the microbial diversity with depth was observed (approximately 2.5 times higher diversity in Pliocene sediments compared to Pleistocene sediments). The increase in diversity with depth in the Lake El’gygytgyn is most probably caused by higher sedimentary temperatures towards the deep sediment layers as well as an enhanced temperature-induced intra-lake bioproductivity and higher input of allochthonous organic-rich material during Pliocene climatic conditions. Moreover, the microbial richness parameters follow the general trends of the paleoclimatic parameters, such as the paleo-temperature and paleo-precipitation. The most abundant bacterial representatives in the El’gygytgyn deep biosphere are affiliated with the phyla Proteobacteria, Actinobacteria, Bacteroidetes, and Acidobacteria, which are also commonly distributed in the surrounding permafrost habitats. The predominated taxon was the halotolerant genus Halomonas (in average 60% of the total reads per sample). Additionally, this doctoral thesis focuses on the live/dead differentiation of microbes in cultures and environmental samples. While established methods (e.g., fluorescence in situ hybridization, RNA analyses) are not applicable to the challenging El’gygytgyn sediments, two newer methods were adapted to distinguish between DNA from live cells and free (extracellular, dead) DNA: the propidium monoazide (PMA) treatment and the cell separation adapted for low amounts of DNA. The applicability of the DNA-intercalating dye PMA was successfully evaluated to mask free DNA of different cultures of methanogenic archaea, which play a major role in the global carbon cycle. Moreover, an optimal procedure to simultaneously treat bacteria and archaea was developed using 130 µM PMA and 5 min of photo-activation with blue LED light, which is also applicable on sandy environmental samples with a particle load of ≤ 200 mg mL⁻¹. It was demonstrated that the soil texture has a strong influence on the PMA treatment in particle-rich samples and that in particular silt and clay-rich samples (e.g., El’gygytgyn sediments) lead to an insufficient shielding of free DNA by PMA. Therefore, a cell separation protocol was used to distinguish between DNA from live cells (intracellular DNA) and extracellular DNA in the El’gygytgyn sediments. While comparing these two DNA pools with a total DNA pool extracted with a commercial kit, significant differences in the microbial composition of all three pools (mean distance of relative abundance: 24.1%, mean distance of OTUs: 84.0%) was discovered. In particular, the total DNA pool covers significantly fewer taxa than the cell-separated DNA pools and only inadequately represents the living community. Moreover, individual redundancy analyses revealed that the microbial community of the intra- and extracellular DNA pool are driven by different environmental factors. The living community is mainly influenced by life-dependent parameters (e.g., sedimentary matrix, water availability), while the extracellular DNA is dependent on the biogenic silica content. The different community-shaping parameters and the fact, that a redundancy analysis of the total DNA pool explains significantly less variance of the microbial community, indicate that the total DNA represents a mixture of signals of the live and dead microbial community. This work provides the first fundamental data basis of the diversity and distribution of microbial deep biosphere communities of a lake system over several million years. Moreover, it demonstrates the substantial importance of extracellular DNA in old sediments. These findings may strongly influence future environmental community analyses, where applications of live/dead differentiation avoid incorrect interpretations due to a failed extraction of the living microbial community or an overestimation of the past community diversity in the course of total DNA extraction approaches. N2 - Innerhalb der letzten 20 Jahre wurden diverse und aktive mikrobielle Gemeinschaften in zahlreichen Habitaten der tiefen Biosphäre gefunden, in denen zuvor kein Leben denkbar war. Die mikrobiologischen Untersuchungen beschränken sich dabei meist auf marine Ökosysteme, wohingegen das Wissen über die tiefe Biosphäre von Seesystemen und die Anpassung der Mikroorganismen an sich ändernde klimatische Bedingungen noch sehr eingeschränkt ist. Ziel dieser Arbeit ist es, die mikrobielle Gemeinschaftsstruktur der tiefen Biosphäre des El‘gygytgyn Kratersees in Hinblick auf klimatische Veränderungen der vergangenen 1,0 bis 3,6 Millionen Jahre zu charakterisieren, beeinflussende Umweltparameter zu detektieren und dabei zwischen der lebenden und toten mikrobiellen Gemeinschaft zu differenzieren. Die Seesedimente (43-317 m tief) weisen eine erstaunlich hohe Diversität (6910 OTUs) und Mikrobenfülle (10³-10⁶ bakterielle, 10¹-10⁵ archaeale 16S rRNA Kopien g⁻¹ Sediment) auf, wobei eine 2,5-fach höhere Diversität in den pliozänen Sedimenten im Vergleich zu den jüngeren pleistozänen Sedimenten detektiert werden konnte. Der Diversitätsanstieg mit zunehmendem Sedimentalter (und Tiefe) basiert höchstwahrscheinlich auf die erhöhte temperaturinduzierte Bioaktivität im See und dem erhöhten Eintrag von Organik reichen Material innerhalb des Pliozäns (feucht und warm). Die Unterscheidung zwischen der DNA lebender Mikroben (intrazellulare DNA) und freier DNA (extrazellulare DNA, meist von toten Mikroben) wurde durch die Adaption von zwei Extraktionsmethoden, der Behandlung mit Propidium-Monoazid (PMA) und der Zellseparation, erreicht. Dabei wurde ein PMA-Protokoll (130 µM PMA, 5 Min Lichtaktivierung mit blauen LEDs) zur erfolgreichen Behandlung von Reinkulturen methanogener Archaeen etabliert, das auch für sandige Umweltproben (Partikelbeladung ≤ 200 mg mL⁻¹) nutzbar ist. Für die feinporigeren Seesedimente des El’gygytgyn Kratersees wurden die zellseparierten DNA-Pools der iDNA und eDNA mit dem Gesamt-DNA-Extrakt (kommerzielles Kit) verglichen, wobei die DNA-Pools starke Unterschiede in ihrer Zusammensetzung aufzeigten (24,1% Distanz basierend auf relative Häufigkeiten) und der Gesamt-DNA-Extrakt die lebende mikrobielle Gemeinschaft nur unzureichend widerspiegeln konnte. Individuelle Redundanzanalysen (RDA) zeigten, dass die mikrobielle Gemeinschaft der iDNA von lebensbeeinflussenden Parametern abhängig ist (u.a. Sedimentmatrix, Wasserverfügbarkeit), wohingegen die der eDNA maßgeblich durch den Anteil an biogener Kieselerde (silica) beeinflusst wird. Diese Arbeit stellt die erste umfangreiche Datenbasis der Diversität und Verteilung von Mikroorganismengemeinschaften in der tiefen Biosphäre eines Seesystems über mehrere Millionen Jahre dar. Zusätzlich zeigt die Studie, dass die Lebend/Tot-Unterscheidung, mit dem ein höherer Anteil der Varianz innerhalb der Gemeinschaft durch Umweltparameter erklärt werden kann, im Vergleich zur Gesamt-DNA-Extraktion ein wesentlicher Schritt zur genauen Widerspiegelung der mikrobiellen Gemeinschaft und deren Funktion in der Tiefen Biosphäre ist. KW - Mikrobiologie KW - El`gygytgyn Kratersee KW - Tiefe Biosphäre KW - Diversität KW - microbiology KW - El’gygytgyn Crater Lake KW - diversity KW - deep biosphere Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-403436 ER - TY - JOUR A1 - Huang, Sichao A1 - Herzschuh, Ulrike A1 - Pestryakova, Luidmila Agafyevna A1 - Zimmermann, Heike Hildegard A1 - Davydova, Paraskovya A1 - Biskaborn, Boris A1 - Shevtsova, Iuliia A1 - Stoof-Leichsenring, Kathleen Rosemarie T1 - Genetic and morphologic determination of diatom community composition in surface sediments from glacial and thermokarst lakes in the Siberian Arctic JF - Journal of paleolimnolog N2 - Lakes cover large parts of the climatically sensitive Arctic landscape and respond rapidly to environmental change. Arctic lakes have different origins and include the predominant thermokarst lakes, which are small, young and highly dynamic, as well as large, old and stable glacial lakes. Freshwater diatoms dominate the primary producer community in these lakes and can be used to detect biotic responses to climate and environmental change. We used specific diatom metabarcoding on sedimentary DNA, combined with next-generation sequencing and diatom morphology, to assess diatom diversity in five glacial and 15 thermokarst lakes within the easternmost expanse of the Siberian treeline ecotone in Chukotka, Russia. We obtained 163 verified diatom sequence types and identified 176 diatom species morphologically. Although there were large differences in taxonomic assignment using the two approaches, they showed similar high abundances and diversity of Fragilariceae and Aulacoseiraceae. In particular, the genetic approach detected hidden within-lake variations of fragilarioids in glacial lakes and dominance of centric Aulacoseira species, whereas Lindavia ocellata was predominant using morphology. In thermokarst lakes, sequence types and valve counts also detected high diversity of Fragilariaceae, which followed the vegetation gradient along the treeline. Ordination analyses of the genetic data from glacial and thermokarst lakes suggest that concentrations of sulfate (SO42-), an indicator of the activity of sulfate-reducing microbes under anoxic conditions, and bicarbonate (HCO3-), which relates to surrounding vegetation, have a significant influence on diatom community composition. For thermokarst lakes, we also identified lake depth as an important variable, but SO42- best explains diatom diversity derived from genetic data, whereas HCO3- best explains the data from valve counts. Higher diatom diversity was detected in glacial lakes, most likely related to greater lake age and different edaphic settings, which gave rise to diversification and endemism. In contrast, small, dynamic thermokarst lakes are inhabited by stress-tolerant fragilarioids and are related to different vegetation types along the treeline ecotone. Our study demonstrated that genetic investigations of lake sediments can be used to interpret climate and environmental responses of diatoms. It also showed how lake type affects diatom diversity, and that such genetic analyses can be used to track diatom community changes under ongoing warming in the Arctic. KW - diatoms KW - diversity KW - glacial lakes KW - sedimentary DNA KW - Siberian arctic KW - thermokarst Y1 - 2020 U6 - https://doi.org/10.1007/s10933-020-00133-1 SN - 0921-2728 SN - 1573-0417 VL - 64 IS - 3 SP - 225 EP - 242 PB - Springer CY - Dordrecht ER - TY - THES A1 - May, Felix T1 - Spatial models of plant diversity and plant functional traits : towards a better understanding of plant community dynamics in fragmented landscapes T1 - Räumliche Modelle der Diversität und der funktionellen Eigenschaften von Pflanzen : für ein besseres Verständnis der Dynamik von Pflanzengemeinschaften in fragmentierten Landschaften N2 - The fragmentation of natural habitat caused by anthropogenic land use changes is one of the main drivers of the current rapid loss of biodiversity. In face of this threat, ecological research needs to provide predictions of communities' responses to fragmentation as a prerequisite for the effective mitigation of further biodiversity loss. However, predictions of communities' responses to fragmentation require a thorough understanding of ecological processes, such as species dispersal and persistence. Therefore, this thesis seeks an improved understanding of community dynamics in fragmented landscapes. In order to approach this overall aim, I identified key questions on the response of plant diversity and plant functional traits to variations in species' dispersal capability, habitat fragmentation and local environmental conditions. All questions were addressed using spatially explicit simulations or statistical models. In chapter 2, I addressed scale-dependent relationships between dispersal capability and species diversity using a grid-based neutral model. I found that the ratio of survey area to landscape size is an important determinant of scale-dependent dispersal-diversity relationships. With small ratios, the model predicted increasing dispersal-diversity relationships, while decreasing dispersal-diversity relationships emerged, when the ratio approached one, i.e. when the survey area approached the landscape size. For intermediate ratios, I found a U-shaped pattern that has not been reported before. With this study, I unified and extended previous work on dispersal-diversity relationships. In chapter 3, I assessed the type of regional plant community dynamics for the study area in the Southern Judean Lowlands (SJL). For this purpose, I parameterised a multi-species incidence-function model (IFM) with vegetation data using approximate Bayesian computation (ABC). I found that the type of regional plant community dynamics in the SJL is best characterized as a set of isolated “island communities” with very low connectivity between local communities. Model predictions indicated a significant extinction debt with 33% - 60% of all species going extinct within 1000 years. In general, this study introduces a novel approach for combining a spatially explicit simulation model with field data from species-rich communities. In chapter 4, I first analysed, if plant functional traits in the SJL indicate trait convergence by habitat filtering and trait divergence by interspecific competition, as predicted by community assembly theory. Second, I assessed the interactive effects of fragmentation and the south-north precipitation gradient in the SJL on community-mean plant traits. I found clear evidence for trait convergence, but the evidence for trait divergence fundamentally depended on the chosen null-model. All community-mean traits were significantly associated with the precipitation gradient in the SJL. The trait associations with fragmentation indices (patch size and connectivity) were generally weaker, but statistically significant for all traits. Specific leaf area (SLA) and plant height were consistently associated with fragmentation indices along the precipitation gradient. In contrast, seed mass and seed number were interactively influenced by fragmentation and precipitation. In general, this study provides the first analysis of the interactive effects of climate and fragmentation on plant functional traits. Overall, I conclude that the spatially explicit perspective adopted in this thesis is crucial for a thorough understanding of plant community dynamics in fragmented landscapes. The finding of contrasting responses of local diversity to variations in dispersal capability stresses the importance of considering the diversity and composition of the metacommunity, prior to implementing conservation measures that aim at increased habitat connectivity. The model predictions derived with the IFM highlight the importance of additional natural habitat for the mitigation of future species extinctions. In general, the approach of combining a spatially explicit IFM with extensive species occupancy data provides a novel and promising tool to assess the consequences of different management scenarios. The analysis of plant functional traits in the SJL points to important knowledge gaps in community assembly theory with respect to the simultaneous consequences of habitat filtering and competition. In particular, it demonstrates the importance of investigating the synergistic consequences of fragmentation, climate change and land use change on plant communities. I suggest that the integration of plant functional traits and of species interactions into spatially explicit, dynamic simulation models offers a promising approach, which will further improve our understanding of plant communities and our ability to predict their dynamics in fragmented and changing landscapes. N2 - Die Fragmentierung von Landschaften umfasst die Zerschneidung und den Verlust von Flächen mit natürlicher Vegetationsentwicklung und ist eine der Hauptursachen für den gegenwärtigen drastischen Verlust an Biodiversität. Diese Dissertation soll zu einem besseren Verständnis der Vegetationsdynamik in fragmentierten Landschaften beitragen. Damit verbunden ist das Ziel, Vorhersagen über die Reaktion von Pflanzengemeinschaften auf Fragmentierung zu verbessern. Diese Vorhersagen sind notwendig, um gezielte Naturschutzmaßnahmen zur Verminderung eines weiteren Verlustes an Biodiversität umsetzen zu können. In Kapitel 2 der Dissertation wird mit einem Simulationsmodell untersucht, wie sich die Ausbreitungsdistanz von Samen auf die lokale Artenzahl von Pflanzengemeinschaften auswirkt. Dabei zeigte sich, dass längere Ausbreitungsdistanzen die lokale Artenvielfalt sowohl erhöhen, als auch verringern können. Der wichtigste Einflussfaktor war dabei die Artenvielfalt der über-geordneten Pflanzengemeinschaft, in der die betrachtete lokale Gemeinschaft eingebettet war. Im dritten Kapitel wird die Konnektivität zwischen Pflanzengemeinschaften in Habitat-fragmenten, d.h. der Austausch von Arten und Individuen durch Samenausbreitung, im Unter-suchungsgebiet in Israel analysiert. Dafür wurde ein zweites räumliches Simulationsmodell mit statistischen Verfahren an Felddaten angepasst. Der Vergleich des Modells mit den Daten wies auf eine sehr geringe Konnektivität zwischen den Habitatfragmenten hin. Das Modell sagte vorher, dass innerhalb von 1000 Jahren 33% - 60% der Arten aussterben könnten. In Kapitel 4 wird zuerst analysiert, welche Prozesse die Verteilung von funktionellen Eigenschaften in Pflanzengemeinschaften bestimmen. In einem zweiten Schritt wird dann unter-sucht, wie sich funktionelle Eigenschaften von Pflanzengemeinschaften mit dem Niederschlag und der Fragmentierung im Untersuchungsgebiet in Israel verändern. Der Zusammenhang zwischen den Eigenschaften Pflanzenhöhe, sowie spezifischer Blattfläche und der Fragmentierung änderte sich nicht entlang des Niederschlagsgradienten. Im Gegensatz dazu, änderte sich der Zusammenhang zwischen der Samenmasse bzw. der Samenzahl und der Fragmentierung mit dem Niederschlag. Aus den Ergebnissen der ersten Teilstudie wird deutlich, dass Naturschutzmaßnahmen, die natürliche Habitate stärker vernetzen sollen, die Diversität, sowie die Zusammensetzung der übergeordneten Artengemeinschaft berücksichtigen müssen, um Verluste an Biodiversität zu vermeiden. Die Verknüpfung eines räumlichen Simulationsmodells mit Felddaten in der zweiten Teilstudie stellt einen neuen und vielversprechenden Ansatz für die Untersuchung der Auswirkungen verschiedener Management-Szenarien dar. Die dritte Teilstudie ist die erste Analyse der gemeinsamen Auswirkungen von Klima und Fragmentierung auf funktionelle Pflanzen-eigenschaften und zeigt die hohe Bedeutung der Untersuchung von Synergie-Effekten verschiedener Umweltfaktoren. Für zukünftige Forschung legt diese Dissertation nahe, funktionelle Eigenschaften und Konkurrenz zwischen Arten in räumlichen Simulationsmodellen zu berücksichtigen, um das Verständnis von Artengemeinschaften in fragmentierten Landschaften noch weiter zu verbessern. KW - Diversität KW - Ausbreitung KW - Pflanzengemeinschaften KW - Fragmentierung KW - ökologische Modellierung KW - diversity KW - dispersal KW - plant communities KW - fragmentation KW - ecological modelling Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-68444 ER - TY - THES A1 - Meyer-Lucht, Yvonne T1 - Does variability matter? Major histocompatibility complex (MHC) variation and its associations to parasitism in natural small mammal populations T1 - Die Vielfalt der MHC Immungene und ihre Bedeutung in der Parasitenabwehr in natürlichen Kleinsäugerpopulationen N2 - The adaptive evolutionary potential of a species or population to cope with omnipresent environmental challenges is based on its genetic variation. Variability at immune genes, such as the major histocompatibility complex (MHC) genes, is assumed to be a very powerful and effective tool to keep pace with diverse and rapidly evolving pathogens. In my thesis, I studied natural levels of variation at the MHC genes, which have a key role in immune defence, and parasite burden in different small mammal species. I assessed the importance of MHC variation for parasite burden in small mammal populations in their natural environment. To understand the processes shaping different patterns of MHC variation I focused on evidence of selection through pathogens upon the host. Further, I addressed the issue of low MHC diversity in populations or species, which could potentially arise as a result from habitat fragmentation and isolation. Despite their key role in the mammalian evolution the marsupial MHC has been rarely investigated. Studies on primarily captive or laboratory bred individuals indicated very little or even no polymorphism at the marsupial MHC class II genes. However, natural levels of marsupial MHC diversity and selection are unknown to date as studies on wild populations are virtually absent. I investigated MHC II variation in two Neotropical marsupial species endemic to the threatened Brazilian Atlantic Forest (Gracilinanus microtarsus, Marmosops incanus) to test whether the predicted low marsupial MHC class II polymorphism proves to be true under natural conditions. For the first time in marsupials I confirmed characteristics of MHC selection that were so far only known from eutherian mammals, birds, and fish: Positive selection on specific codon sites, recombination, and trans-species polymorphism. Beyond that, the two marsupial species revealed considerable differences in their MHC class II diversity. Diversity was rather low in M. incanus but tenfold higher in G. microtarsus, disproving the predicted general low marsupial MHC class II variation. As pathogens are believed to be very powerful drivers of MHC diversity, I studied parasite burden in both host species to understand the reasons for the remarkable differences in MHC diversity. In both marsupial species specific MHC class II variants were associated to either high or low parasite load highlighting the importance of the marsupial MHC class II in pathogen defence. I developed two alternative scenarios with regard to MHC variation, parasite load, and parasite diversity. In the ‘evolutionary equilibrium’ scenario I assumed the species with low MHC diversity, M. incanus, to be under relaxed pathogenic selection and expected low parasite diversity. Alternatively, low MHC diversity could be the result of a recent loss of genetic variation by means of a genetic bottleneck event. Under this ‘unbalanced situation’ scenario, I assumed a high parasite burden in M. incanus due to a lack of resistance alleles. Parasitological results clearly reject the first scenario and point to the second scenario, as M. incanus is distinctly higher parasitised but parasite diversity is relatively equal compared to G. microtarsus. Hence, I suggest that the parasite load in M. incanus is rather the consequence than the cause for its low MHC diversity. MHC variation and its associations to parasite burden have been typically studied within single populations but MHC variation between populations was rarely taken into account. To gain scientific insight on this issue, I chose a common European rodent species. In the yellow necked mouse (Apodemus flavicollis), I investigated the effects of genetic diversity on parasite load not on the individual but on the population level. I included populations, which possess different levels of variation at the MHC as well as at neutrally evolving genetic markers (microsatellites). I was able to show that mouse populations with a high MHC allele diversity are better armed against high parasite burdens highlighting the significance of adaptive genetic diversity in the field of conservation genetics. An individual itself will not directly benefit from its population’s large MHC allele pool in terms of parasite resistance. But confronted with the multitude of pathogens present in the wild a population with a large MHC allele reservoir is more likely to possess individuals with resistance alleles. These results deepen our understanding of the complex causes and processes of evolutionary adaptations between hosts and pathogens. N2 - In einer sich ständig verändernden Umwelt ist es unverzichtbar, sich fortwährend zu verändern und anzupassen. Dabei gründet sich das Anpassungsvermögen oder das evolutionäre Potential einer Art auf ihre genetische Variabilität. In der Krankheitsabwehr ist die Variabilität der Immungene ein besonders wichtiges und effektives Instrument, weil Pathogene sehr vielfältig sind und schnell evolvieren. Im Rahmen meiner Doktorarbeit habe ich mich mit der Variabilität des Immungen-Komplexes MHC (major histocompatibility complex) beschäftigt, der eine Schlüsselrolle in der Immunabwehr bei Vertebraten einnimmt. Anhand verschiedener Arten und Populationen von Kleinsäugern habe ich den Einfluss der MHC Vielfalt auf den Parasitenbefall unter natürlichen Bedingungen untersucht. Dabei interessierte mich insbesondere das Vorkommen geringer MHC Variabilität in Populationen, das möglicherweise eine Folge von Lebensraum-fragmentierung und Isolation ist. Obwohl Beuteltiere eine zentrale Rolle in der Evolution der Säugetiere spielen, ist über ihren MHC bislang nur sehr wenig bekannt. Einige Studien befassten sich mit Labor- oder Zootieren, und deuteten auf geringe oder sogar gar keine Variation im MHC Klasse II bei Beuteltieren hin. Allerdings gab es bislang nahezu keine Studien an frei lebenden Beuteltieren, deshalb war bislang ein natürliches Ausmaß der MHC Variabilität unbekannt. Anhand von zwei endemischen neotropischen Beuteltieren aus dem brasilianischen Küstenregenwald (Gracilinanus microtarsus, Marmosops incanus) habe ich überprüft, ob sich diese geringe MHC Vielfalt unter natürlichen Freilandbedingungen bestätigt. Erstmals konnte ich zeigen, dass der MHC II bei Beuteltieren charakteristische Merkmale positiver Selektion aufweist, die bisher nur von placentalen Säugern, Vögeln und Fischen bekannt waren: Positive Selektion auf spezifischen Aminosäurepositionen, Rekombination und Trans-Species-Polymorphismus. Darüber hinaus unterschieden sich die beiden Beuteltierarten beträchtlich in ihrer MHC II Variabilität. Während M. incanus sich als relativ wenig divers erwies, zeigte G. microtarsus eine zehnmal höhere Vielfalt und widerlegt damit die generelle Gültigkeit der ursprünglich angenommenen geringen MHC II Variabilität bei Beuteltieren. Um diese beachtlichen Diversitätsunterschiede zwischen den beiden Arten zu erklären, habe ich die Parasitenbelastung untersucht. Bei beiden Arten konnte ich nachweisen, dass bestimmte MHC Varianten mit entweder hoher oder niedriger Parasitenbelastung verknüpft waren. Solche Assoziationen spiegeln Pathogen-vermittelte Selektion wider, untermauern die Funktionalität des MHC Klasse II bei Beuteltieren und weisen auf dieselbe Bedeutsamkeit des MHC wie bei placentalen Säuger, Vögeln und Fischen hin. Ich entwickelte zwei alternative evolutionäre Szenarien, unter denen eine geringe MHC Variabilität denkbar ist. Im Szenario des ‘evolutionären Gleichgewichts’ ist geringe MHC Variabilität die Folge eines verminderten Selektionsdruckes durch wenige Parasiten, sodass eine geringe Parasitendiversität zu erwarten ist. Alternativ könnte eine geringe MHC Variabilität aber auch Folge eines kürzlich erlittenen Verlustes an genetischer Variabilität sein, beispielsweise durch ein Flaschenhalsereignis. Unter diesem Szenario des ‘Ungleichgewichts’ wäre bei M. incanus im Falle eines potentiellen Verlustes von Resistenzallelen eine starke Parasitenbelastung zu erwarten. Die parasitologischen Ergebnisse widersprechen dem ersten und deuten eher auf das zweite Szenario. M. incanus war deutlich stärker parasitiert als G. microtarsus, wohingegen die Parasitendiversität bei beiden Arten ungefähr gleich war. Die hohe Parasitenbelastung bei M. incanus ist offenbar weniger der Auslöser als vielmehr eine Folge seiner geringen MHC Vielfalt zu sein. Üblicherweise werden sowohl die Variabilität des MHC als auch seine Verknüpfung mit Parasitenbelastung innerhalb von einzelnen Populationen untersucht, nur selten wird die Variation zwischen Populationen in Betracht gezogen. Um Erkenntnisse auf dieser Ebene zu gewinnen, habe ich den Zusammenhang zwischen genetischer Vielfalt und Parasitenbelastung nicht auf der Ebene des Individuums, sondern auf der Populationsebene anhand der europäischen Gelbhalsmaus (Apodemus flavicollis) erforscht. Dabei wurden Populationen mit unterschiedlicher genetischer Variabilität am MHC und an neutralen genetischen Markern (Mikrosatelliten) betrachtet. Ich konnte nachweisen, dass Populationen, die über ein großes Spektrum verschiedener MHC Allele verfügen, besser gegen starke Parasitenbelastung gewappnet sind als Populationen mit einer geringen Anzahl MHC Allele. In einer MHC-diversen Population ist die Gegenwart von Individuen mit Resistenzallelen deutlich wahrscheinlicher, und damit die Überlebenswahrscheinlichkeit der Population. Diese Ergebnisse erweitern und vertiefen unsere Erkenntnisse zu die komplexen evolutionären Vorgängen und Mechanismen zwischen Wirt und Parasit in ihrem fortwährenden Wettstreit. KW - Haupthistokompatibilitätskomplex KW - Kleinsäuger KW - Parasitierung KW - Immunsystem KW - Vielfalt KW - major hhistocompatibility complex KW - small mammals KW - parasitism KW - immune system KW - diversity Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-36419 ER - TY - JOUR A1 - Rjosk, Camilla A1 - Richter, Dirk A1 - Luedtke, Oliver A1 - Eccles, Jacquelynne Sue T1 - Ethnic Composition and Heterogeneity in the Classroom: Their Measurement and Relationship With Student Outcomes JF - The journal of educational psychology N2 - This study explores various measures of the ethnic makeup in a classroom and their relationship with student outcomes. We examine whether measures of ethnic diversity are related to achievement (mathematics, reading) and feeling of belonging with one’s peers over and above commonly investigated composition characteristics. Multilevel analyses were based on data from a representative sample of 18,762 elementary school students in 903 classrooms. The proportion of minority students and diversity measures showed negative associations with student outcomes in separate models. Including diversity measures and the proportion of minority students, diversity of minority students mostly lost its significance. However, the results suggest that diversity measures may provide additional information over and above other classroom characteristics for some student outcomes. The various measures of diversity led to comparable results. (PsycINFO Database Record (c) 2017 APA, all rights reserved) KW - ethnic composition KW - diversity KW - multilevel analysis KW - academic achievement KW - classroom Y1 - 2017 U6 - https://doi.org/10.1037/edu0000185 SN - 0022-0663 SN - 1939-2176 VL - 109 SP - 1188 EP - 1204 PB - American Psychological Association CY - Washington ER - TY - GEN A1 - Romero-Munoz, Alfredo A1 - Fandos, Guillermo A1 - Benítez-López, Ana A1 - Kuemmerle, Tobias T1 - Habitat destruction and overexploitation drive widespread declines in all facets of mammalian diversity in the Gran Chaco T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Global biodiversity is under high and rising anthropogenic pressure. Yet, how the taxonomic, phylogenetic, and functional facets of biodiversity are affected by different threats over time is unclear. This is particularly true for the two main drivers of the current biodiversity crisis: habitat destruction and overexploitation. We provide the first long-term assessment of multifaceted biodiversity changes caused by these threats for any tropical region. Focussing on larger mammals in South America's 1.1 million km(2) Gran Chaco region, we assessed changes in multiple biodiversity facets between 1985 and 2015, determined which threats drive those changes, and identified remaining key areas for all biodiversity facets. Using habitat and threat maps, we found, first, that between 1985 and 2015 taxonomic (TD), phylogenetic (PD) and functional (FD) diversity all declined drastically across over half of the area assessed. FD declined about 50% faster than TD and PD, and these declines were mainly driven by species loss, rather than species turnover. Second, habitat destruction, hunting, and both threats together contributed similar to 57%, similar to 37%, and similar to 6% to overall facet declines, respectively. However, hunting pressure increased where TD and PD declined most strongly, whereas habitat destruction disproportionally contributed to FD declines. Third, just 23% of the Chaco would have to be protected to safeguard the top 17% of all three facets. Our findings uncover a widespread impoverishment of mammal species richness, evolutionary history, and ecological functions across broad areas of the Chaco due to increasing habitat destruction and hunting. Moreover, our results pinpoint key areas that should be preserved and managed to maintain all facets of mammalian diversity across the Chaco. More generally, our work highlights how long-term changes in biodiversity facets can be assessed and attributed to specific threats, to better understand human impacts on biodiversity and to guide conservation planning to mitigate them. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1370 KW - biodiversity facets KW - extinction drivers KW - functional diversity KW - functional richness KW - overhunting KW - phylogenetic diversity KW - taxonomic KW - diversity KW - traits Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-567696 SN - 1866-8372 IS - 4 ER - TY - JOUR A1 - Romero-Munoz, Alfredo A1 - Fandos, Guillermo A1 - Benítez-López, Ana A1 - Kuemmerle, Tobias T1 - Habitat destruction and overexploitation drive widespread declines in all facets of mammalian diversity in the Gran Chaco JF - Global change biology N2 - Global biodiversity is under high and rising anthropogenic pressure. Yet, how the taxonomic, phylogenetic, and functional facets of biodiversity are affected by different threats over time is unclear. This is particularly true for the two main drivers of the current biodiversity crisis: habitat destruction and overexploitation. We provide the first long-term assessment of multifaceted biodiversity changes caused by these threats for any tropical region. Focussing on larger mammals in South America's 1.1 million km(2) Gran Chaco region, we assessed changes in multiple biodiversity facets between 1985 and 2015, determined which threats drive those changes, and identified remaining key areas for all biodiversity facets. Using habitat and threat maps, we found, first, that between 1985 and 2015 taxonomic (TD), phylogenetic (PD) and functional (FD) diversity all declined drastically across over half of the area assessed. FD declined about 50% faster than TD and PD, and these declines were mainly driven by species loss, rather than species turnover. Second, habitat destruction, hunting, and both threats together contributed similar to 57%, similar to 37%, and similar to 6% to overall facet declines, respectively. However, hunting pressure increased where TD and PD declined most strongly, whereas habitat destruction disproportionally contributed to FD declines. Third, just 23% of the Chaco would have to be protected to safeguard the top 17% of all three facets. Our findings uncover a widespread impoverishment of mammal species richness, evolutionary history, and ecological functions across broad areas of the Chaco due to increasing habitat destruction and hunting. Moreover, our results pinpoint key areas that should be preserved and managed to maintain all facets of mammalian diversity across the Chaco. More generally, our work highlights how long-term changes in biodiversity facets can be assessed and attributed to specific threats, to better understand human impacts on biodiversity and to guide conservation planning to mitigate them. KW - biodiversity facets KW - extinction drivers KW - functional diversity KW - functional richness KW - overhunting KW - phylogenetic diversity KW - taxonomic KW - diversity KW - traits Y1 - 2020 U6 - https://doi.org/10.1111/gcb.15418 SN - 1354-1013 SN - 1365-2486 VL - 27 IS - 4 SP - 755 EP - 767 PB - Wiley CY - Hoboken ER - TY - THES A1 - Schmider, Stephan T1 - Was ist HipHop? T1 - What is hip-hop? BT - Diskurse, Praktiken und genuine Eigenschaften eines Kulturphänomens BT - discourses, practices and genuine characteristics of a cultural phenomenon N2 - Es handelt sich bei der vorliegenden Dissertation um eine investigative Forschungsarbeit, die sich mit dem dynamisch wandelnden HipHop-Phänomen befasst. Der Autor erläutert hierbei die anhaltende Attraktivität des kulturellen Phänomens HipHop und versucht die Tatsache der stetigen Reproduzierbarkeit des HipHops genauer zu erklären. Daher beginnt er mit einer historischen Diskursanalyse der HipHop-Kultur. Er analysiert hierfür die Formen, die Protagonisten und die Diskurse des HipHops, um diesen besser verstehen zu können. Durch die Herausarbeitung der genuinen Eigenschaft der Mehrfachkodierbarkeit des HipHops werden gängige Erklärungsmuster aus Wissenschaft und Medien relativiert und kritisiert. Der Autor kombiniert in seiner Studie kultur- und erziehungswissenschaftliche Literatur mit diversen aktuellen und historischen Darstellungen und Bildern. Es werden vor allem bildbasierte Selbstinszenierungen von HipHoppern und Selbstzeugnisse aus narrativen Interviews, die er selbst mit verschiedenen HipHoppern in Deutschland geführt hat, ausgewertet. Neben den narrativen Interviews dient vor allem die Bildinterpretation nach Bohnsack als Quelle zur Bildung der These der Mehrfachkodierbarkeit. Hierbei werden zwei Bilder der HipHopper Lady Bitch Ray und Kollegah nach Bohnsack (2014) interpretiert und gezeigt wie HipHop neben der lyrischen und der klanglichen Komponente auch visuell inszeniert und produziert wird. Hieraus wird geschlussfolgert, dass es im HipHop möglich ist konträre Sichtweisen bei gleichzeitiger Anwendung von typischen Kulturpraktiken wie zum Beispiel dem Boasting darzustellen und zu vermitteln. Die stetige Offenheit des HipHops wird durch Praktiken wie dem Sampling oder dem Battle deutlich und der Autor erklärt, dass durch diese Techniken die generative Eigenschaft der Mehrfachkodierbarkeit hergestellt wird. Damit vertritt er eine Art Baukasten-Theorie, die besagt, dass sich prinzipiell jeder aus dem Baukasten HipHop, je nach Vorliebe, Interesse und Affinität, bedienen kann. Durch die Vielfalt an Meinungen zu HipHop, die der Autor durch die Kodierung der geführten narrativen Interviews erhält, wird diese These verdeutlicht und es wird klar, dass es sich bei HipHop um mehr als nur eine Mode handelt. HipHop besitzt die prinzipielle Möglichkeit durch die Offenheit, die er in sich trägt, sich stetig neu zu wandeln und damit an Beliebtheit und Popularität zuzunehmen. Die vorliegende Arbeit erweitert damit die immer größer werdende Forschung in den HipHop-Studies und setzt wichtige Akzente um weiter zu forschen und HipHop besser verständlich zu machen. N2 - The described dissertation is an investigative research paper, covering the dynamic and ever-changing phenomena of hip-hop. The author will explain the continued attraction drawn by the hip-hop culture and will attempt to explain its’ reproduceable impact in more detail. To achieve this, he starts with a historic discourse analysis of the hip-hop culture. In order to give a greater understanding of the subject he analyses the different forms, protagonists as well as the dialogue of hip-hop. The author will show that hip-hop has multi-layered characteristics and through elaboration using scientific tools and media sources he will further qualify and criticize the subject. The research combines cultural and educational science literature with different time-relevant and historic presentations alongside graphic images. Especially self-staged photos of rap artists and personal testimonials from interviews, which the author personally conducted, with a variety of artists throughout Germany, will be analysed. Besides the accounts reflected in the interviews a large emphasis has been focused on imagery interpretation in line with Bohnsack, which will serve as the source to the multi-layering thesis. In this connection two images of artists Lady Bitch Ray and Kollegah are interpreted according to Bohnsack (2014), to show that hip-hop does not only have a lyrical and musical component to it but is also visually staged and produced. This research work will conclude that it is possible in hip-hop culture to present contrasting viewpoints through the use of cultural traditions, such as ‘boasting’. The ongoing open-mindedness of hip-hop will become clear through the analysis of ‘sampling’ and the ‘rap battle’, the author will proof how such traditional techniques create multi-layered hip-hop characteristics. With this conclusion he supports a type of modular theory, stating that principally anybody can take advantage of what hip-hop as to offer, regardless of their preferences, interests, or affections. Through the diversity of opinions in hip-hop culture, which the author is presented with through the interpretation of the interviews, his proposition becomes clear and he is able to conclude that the phenomenon of hip-hop is more than just a temporary fad. Hip-hop has the fundamental potential to continuously change, and through its open-mindedness manages to keep increasing its’ popularity and demand over time. This research paper builds on the continuous interest into the research of hip-hop culture and asks important questions, which validates further research into the topic and aims to make hip-hop more accessible. KW - HipHop KW - Kultur KW - Kulturwissenschaft KW - Gangsta-Rap KW - Authentizität KW - Kollegah KW - Lady Bitch Ray KW - Struggle KW - Battle KW - Rap KW - Musik KW - Jugendkultur KW - Sampling KW - Beat KW - Politik KW - Migrantenkultur KW - HipHop KW - cultural studies KW - Rap KW - Music KW - Sample KW - Track KW - Battle KW - Lady Bitch Ray KW - Kollegah KW - dynamic KW - discourse KW - diversity KW - multi-layered Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-523759 ER - TY - GEN A1 - Stiegler, Jonas A1 - von Hoermann, Christian A1 - Müller, Jörg A1 - Benbow, Mark Eric A1 - Heurich, Marco T1 - Carcass provisioning for scavenger conservation in a temperate forest ecosystem T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Carrion plays an essential role in shaping the structure and functioning of ecosystems and has far‐reaching implications for biodiversity conservation. The change in availability and type of carcasses throughout ecosystems can involve negative effects for scavenging communities. To address this issue, there have been recent conservation management measures of carrion provision in natural systems. However, the optimal conditions under which exposing carcasses to optimize conservation outcomes are still limited. Here, we used camera traps throughout elevational and vegetational gradients to monitor the consumption of 48 deer carcasses over a study period of six years by evaluating 270,279 photographs resulting out of 15,373 trap nights. We detected 17 species visiting carcass deployments, including five endangered species. Our results show that large carcasses, the winter season, and a heterogeneous surrounding habitat enhanced the frequency of carcass visits and the species richness of scavenger assemblages. Contrary to our expectations, carcass species, condition (fresh/frozen), and provision schedule (continuous vs single exposure) did not influence scavenging frequency or diversity. The carcass visitation frequency increased with carcass mass and lower temperatures. The effect of large carcasses was especially pronounced for mesopredators and the Eurasian lynx (Lynx lynx ). Lynx were not too influenced in its carrion acquisition by the season, but exclusively preferred remote habitats containing higher forest cover. Birds of prey, mesopredators, and top predators were also positively influenced by the visiting rate of ravens (Corvus corax ), whereas no biotic or abiotic preferences were found for wild boars (Sus scrofa ). This study provides evidence that any ungulate species of carrion, either in a fresh or in previously frozen condition, attracts a high diversity of scavengers especially during winter, thereby supporting earlier work that carcass provisions may support scavenger communities and endangered species. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 955 KW - anthropogenic food subsidies KW - carrion ecology KW - diversity KW - nature conservation KW - necrobiome KW - vertebrate scavenger KW - wildlife management Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-471099 SN - 1866-8372 IS - 955 ER - TY - JOUR A1 - Stiegler, Jonas A1 - von Hoermann, Christian A1 - Müller, Jörg A1 - Benbow, Mark Eric A1 - Heurich, Marco T1 - Carcass provisioning for scavenger conservation in a temperate forest ecosystem JF - Ecosphere N2 - Carrion plays an essential role in shaping the structure and functioning of ecosystems and has far‐reaching implications for biodiversity conservation. The change in availability and type of carcasses throughout ecosystems can involve negative effects for scavenging communities. To address this issue, there have been recent conservation management measures of carrion provision in natural systems. However, the optimal conditions under which exposing carcasses to optimize conservation outcomes are still limited. Here, we used camera traps throughout elevational and vegetational gradients to monitor the consumption of 48 deer carcasses over a study period of six years by evaluating 270,279 photographs resulting out of 15,373 trap nights. We detected 17 species visiting carcass deployments, including five endangered species. Our results show that large carcasses, the winter season, and a heterogeneous surrounding habitat enhanced the frequency of carcass visits and the species richness of scavenger assemblages. Contrary to our expectations, carcass species, condition (fresh/frozen), and provision schedule (continuous vs single exposure) did not influence scavenging frequency or diversity. The carcass visitation frequency increased with carcass mass and lower temperatures. The effect of large carcasses was especially pronounced for mesopredators and the Eurasian lynx (Lynx lynx ). Lynx were not too influenced in its carrion acquisition by the season, but exclusively preferred remote habitats containing higher forest cover. Birds of prey, mesopredators, and top predators were also positively influenced by the visiting rate of ravens (Corvus corax ), whereas no biotic or abiotic preferences were found for wild boars (Sus scrofa ). This study provides evidence that any ungulate species of carrion, either in a fresh or in previously frozen condition, attracts a high diversity of scavengers especially during winter, thereby supporting earlier work that carcass provisions may support scavenger communities and endangered species. KW - anthropogenic food subsidies KW - carrion ecology KW - diversity KW - nature conservation KW - necrobiome KW - vertebrate scavenger KW - wildlife management Y1 - 2020 U6 - https://doi.org/10.1002/ecs2.3063 SN - 2150-8925 VL - 11 IS - 4 PB - ESA CY - Ithaca, NY ER - TY - THES A1 - Tschöpe, Okka T1 - Managing open habitats for species conservation : the role of wild ungulate grazing, small-scale disturbances, and scale T1 - Offenlandmanagement für den Artenschutz : die Bedeutung von Wildtierbeweidung, kleinräumigen Störungen und der Maßstabsebene N2 - During the last decades, the global change of the environment has caused a dramatic loss of habitats and species. In Central Europe, open habitats are particularly affected. The main objective of this thesis was to experimentally test the suitability of wild megaherbivore grazing as a conservation tool to manage open habitats. We studied the effect of wild ungulates in a 160 ha game preserve in NE Germany in three successional stages (i) Corynephorus canescens-dominated grassland, (ii) ruderal tall forb vegetation dominated by Tanacetum vulgare and (iii) Pinus sylvestris-pioneer forest over three years. Our results demonstrate that wild megaherbivores considerably affected species composition and delayed successional pathways in open habitats. Grazing effects differed considerably between successional stages: species richness was higher in grazed ruderal and pioneer forest plots, but not in the Corynephorus sites. Species composition changed significantly in the Corynephorus and ruderal sites. Grazed ruderal sites had turned into sites with very short vegetation dominated by Agrostis spp. and the moss Brachythecium albicans, most species did not flower. Woody plant cover was significantly affected only in the pioneer forest sites. Young pine trees were severely damaged and tree height was considerably reduced, leading to a “Pinus-macchie”-appearance. Ecological patterns and processes are known to vary with spatial scale. Since grazing by megaherbivores has a strong spatial component, the scale of monitoring success of grazing may largely differ among and within different systems. Thus, the second aim of this thesis was to test whether grazing effects are consistent over different spatial scales, and to give recommendations for appropriate monitoring scales. For this purpose, we studied grazing effects on plant community structure using multi-scale plots that included three nested spatial scales (0.25 m2, 4 m2, and 40 m2). Over all vegetation types, the scale of observation directly affected grazing effects on woody plant cover and on floristic similarity, but not on the proportion of open soil and species richness. Grazing effects manifested at small scales regarding floristic similarity in pioneer forest and ruderal sites and regarding species richness in ruderal sites. The direction of scale-effects on similarity differed between vegetation types: Grazing effects on floristic similarity in the Corynephorus sites were significantly higher at the medium and large scale, while in the pioneer forest sites they were significantly higher at the smallest scale. Disturbances initiate vegetation changes by creating gaps and affecting colonization and extinction rates. The third intention of the thesis was to investigate the effect of small-scale disturbances on the species-level. In a sowing experiment, we studied early establishment probabilities of Corynephorus canescens, a key species of open sandy habitats. Applying two different regimes of mechanical ground disturbance (disturbed and undisturbed) in the three successional stages mentioned above, we focused on the interactive effects of small-scale disturbances, successional stage and year-to-year variation. Disturbance led to higher emergence in a humid and to lower emergence in a very dry year. Apparently, when soil moisture was sufficient, the main factor limiting C. canescens establishment was competition, while in the dry year water became the limiting factor. Survival rates were not affected by disturbance. In humid years, C. canescens emerged in higher numbers in open successional stages while in the dry year, emergence rates were higher in late stages, suggesting an important role of late successional stages for the persistence of C. canescens. We conclude that wild ungulate grazing is a useful tool to slow down succession and to preserve a species-rich, open landscape, because it does not only create disturbances, thereby supporting early successional stages, but at the same time efficiently controls woody plant cover. However, wild ungulate grazing considerably changed the overall appearance of the landscape. Additional measures like shifting exclosures might be necessary to allow vulnerable species to flower and reproduce. We further conclude that studying grazing impacts on a range of scales is crucial, since different parameters are affected at different spatial scales. Larger scales are suitable for assessing grazing impact on structural parameters like the proportion of open soil or woody plant cover, whereas species richness and floristic similarity are affected at smaller scales. Our results further indicate that the optimal strategy for promoting C. canescens is to apply disturbances just before seed dispersal and not during dry years. Further, at the landscape scale, facilitation by late successional species may be an important mechanism for the persistence of protected pioneer species. N2 - Der globale Wandel führte in den letzten Jahrzehnten zu einem drastischen Habitat- und Artenschwund, von dem in Mitteleuropa offene Lebensräume besonders betroffen sind. Hauptziel dieser Arbeit war es, experimentell zu untersuchen, ob Wildtierbeweidung eine geeignete Methode für das Offenlandmanagement ist. Der Wildtiereffekt wurde über drei Jahre in einem 160 ha großen Wildtiergehege im NO Deutschlands in drei Sukzessionsstadien untersucht: (i) Corynephorus canescens-dominierte Kurzgrasrasen, (ii) durch Tanacetum vulgare dominierte ruderale Staudenfluren und (iii) Pinus sylvestris-Vorwälder. Wildtierbeweidung beeinflusste die Artenzusammensetzung entscheidend und verzögerte die Sukzession, wobei sich die Beweidungseffekte zwischen den Sukzessionsstadien unterschieden. Die Artenzahl war in den beweideten Ruderal- und Vorwaldflächen deutlich höher als in den unbeweideten, nicht jedoch in den Corynephorus-Flächen. Die Artenzusammensetzung wurde in den Corynephorus- und den Ruderal-Flächen verändert. Ruderal-Flächen entwickelten sich durch die Beweidung zu einem durch Agrostis spp. dominierten Vegetationstyp mit niedriger Vegetationshöhe, in dem die meisten Arten nicht zur Blüte kamen. Die Gehölzdeckung wurde in den beweideten Vorwaldflächen signifikant reduziert. Junge Kiefern wurden stark geschädigt und in ihrer Wuchshöher reduziert. Analyse und Interpretation einer Untersuchung sind abhängig vom Beobachtungsmaßstab. Das zweite Ziel dieser Arbeit war es, zu testen, ob Beweidungseffekte über verschiedene räumliche Skalen konsistent sind, sowie Empfehlungen für geeignete Monitoring-Maßstäbe zu geben. Der Effekt von Wildtierbeweidung auf die Vegetation dreier Sukzessionsstadien wurde mittels genesteter Dauerflächen untersucht (0.25 m2, 4 m2, 40 m2). Über alle Vegetationstypen zusammen beeinflusste der Beobachtungsmaßstab den Beweidungseffekt auf die Gehölzdeckung sowie auf die floristische Ähnlichkeit, aber nicht auf den Anteil offenen Bodens und die Artenzahl. Betrachtet man die Vegetationstypen getrennt, so zeigte sich der Beweidungseffekt auf kleinen Skalen in den Vorwaldflächen und den ruderalen Flächen hinsichtlich der Ähnlichkeit und in den ruderalen Flächen hinsichtlich der Artenzahl. Die Richtung der Skaleneffekte auf die floristische Ähnlichkeit unterschied sich zwischen den Vegetationstypen: Während sich beweidete und unbeweidete Corynephorus-Flächen auf der mittleren und der großen Skala signifikant voneinander unterschieden, war dies im Kiefernvorwald auf der kleinsten Skala der Fall. Störungen führen zu Vegetationsveränderungen, die die Einwanderungs- und Aussterberaten von Arten beeinflussen. Das dritte Ziel dieser Arbeit war es, den Effekt kleinräumiger Störungen auf der Art-Ebene zu untersuchen sowie deren Interaktion mit dem Sukzessionsstadium und der jährlichen Variabilität. In einem Aussaatexperiment wurde das Etablierungsverhalten von Corynephorus canescens, einer Schlüsselart sandiger Offenhabitate, in drei Sukzessionsstadien und unter zwei Störungsregimes (gestört vs. ungestört) untersucht. In einem feuchten Jahr führten Störungen zu höheren, in einem trockenen Jahr dagegen zu niedrigeren Keimraten. Solange die Bodenfeuchtigkeit hoch genug war, war Konkurrenz der wichtigste limitierende Faktor für die Etablierung von C. canescens, während im trockenen Jahr Wasser zum entscheidenden Faktor wurde. Auf die Überlebensraten hatten Störungen keinen Einfluss. In feuchten Jahren waren die Keimraten in offenen Sukzessionsstadien höher, während sie im trockenen Jahr im späten Sukzessionsstadium höher waren. Spätere Sukzessionsstadien können also für die Persistenz von C. canescens eine wichtige Rolle spielen. Da Wildtierbeweidung sowohl Störungen verursacht und dadurch frühe Sukzessionsstadien fördert, als auch die Gehölzdeckung reduziert, ist sie eine besonders geeignete Maßnahme, um artenreiche, offene Landschaften zu erhalten. Sie kann jedoch zu teilweise drastischen Veränderungen der Landschaft führen, so dass zusätzliche Maßnahmen wie wechselnde Auskoppelungen notwendig sein können, um ein reiches Mosaik verschiedener Sukzessionsstadien mit einer hohen Gesamtartenzahl zu erhalten. Weiterhin ist die Untersuchung von Beweidungseffekten auf verschiedenen Maßstabsebenen von großer Bedeutung, da verschiedene Parameter auf unterschiedlichen Skalen beeinflusst werden. Größere Skalen sind geeignet, um den Beweidungseinfluss auf Strukturparameter wie den Anteil offenen Bodens oder der Gehölzdeckung zu erfassen, während für die Erfassung der Veränderung des Artenreichtums und der floristischen Ähnlichkeit kleinere Skalen besser geeignet sind. Unsere Ergebnisse zeigen außerdem, dass kleinräumige Störungen die Keimung von C. canescens fördern, wobei Störungen direkt vor der Samenausbreitung und nicht in trockenen Jahren durchgeführt werden sollten. Auf Landschaftsebene kann die Förderung durch Arten späterer Sukzessionsstadien ein wichtiger Mechanismus für die Persistenz geschützter Pionierarten sein. KW - Diversität KW - Sukzession KW - Etablierung KW - Corynephorus canescens KW - Maßstabsabhängigkeit KW - diversity KW - succession KW - establishment KW - Corynephorus canescens KW - scale dependence Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13218 ER - TY - THES A1 - Wagner, Dirk T1 - Microbial perspectives of the methane cycle in permafrost ecosystems in the Eastern Siberian Arctic : implications for the global methane budget N2 - The Arctic plays a key role in Earth’s climate system as global warming is predicted to be most pronounced at high latitudes and because one third of the global carbon pool is stored in ecosystems of the northern latitudes. In order to improve our understanding of the present and future carbon dynamics in climate sensitive permafrost ecosystems, the present study concentrates on investigations of microbial controls of methane fluxes, on the activity and structure of the involved microbial communities, and on their response to changing environmental conditions. For this purpose an integrated research strategy was applied, which connects trace gas flux measurements to soil ecological characterisation of permafrost habitats and molecular ecological analyses of microbial populations. Furthermore, methanogenic archaea isolated from Siberian permafrost have been used as potential keystone organisms for studying and assessing life under extreme living conditions. Long-term studies on methane fluxes were carried out since 1998. These studies revealed considerable seasonal and spatial variations of methane emissions for the different landscape units ranging from 0 to 362 mg m-2 d-1. For the overall balance of methane emissions from the entire delta, the first land cover classification based on Landsat images was performed and applied for an upscaling of the methane flux data sets. The regionally weighted mean daily methane emissions of the Lena Delta (10 mg m-2 d-1) are only one fifth of the values calculated for other Arctic tundra environments. The calculated annual methane emission of the Lena Delta amounts to about 0.03 Tg. The low methane emission rates obtained in this study are the result of the used remotely sensed high-resolution data basis, which provides a more realistic estimation of the real methane emissions on a regional scale. Soil temperature and near soil surface atmospheric turbulence were identified as the driving parameters of methane emissions. A flux model based on these variables explained variations of the methane budget corresponding to continuous processes of microbial methane production and oxidation, and gas diffusion through soil and plants reasonably well. The results show that the Lena Delta contributes significantly to the global methane balance because of its extensive wetland areas. The microbiological investigations showed that permafrost soils are colonized by high numbers of microorganisms. The total biomass is comparable to temperate soil ecosystems. Activities of methanogens and methanotrophs differed significantly in their rates and distribution patterns along both the vertical profiles and the different investigated soils. The methane production rates varied between 0.3 and 38.9 nmol h-1 g-1, while the methane oxidation ranged from 0.2 to 7.0 nmol h-1 g-1. Phylogenetic analyses of methanogenic communities revealed a distinct diversity of methanogens affiliated to Methanomicrobiaceae, Methanosarcinaceae and Methanosaetaceae, which partly form four specific permafrost clusters. The results demonstrate the close relationship between methane fluxes and the fundamental microbiological processes in permafrost soils. The microorganisms do not only survive in their extreme habitat but also can be metabolic active under in situ conditions. It was shown that a slight increase of the temperature can lead to a substantial increase in methanogenic activity within perennially frozen deposits. In case of degradation, this would lead to an extensive expansion of the methane deposits with their subsequent impacts on total methane budget. Further studies on the stress response of methanogenic archaea, especially Methanosarcina SMA-21, isolated from Siberian permafrost, revealed an unexpected resistance of the microorganisms against unfavourable living conditions. A better adaptation to environmental stress was observed at 4 °C compared to 28 °C. For the first time it could be demonstrated that methanogenic archaea from terrestrial permafrost even survived simulated Martian conditions. The results show that permafrost methanogens are more resistant than methanogens from non-permafrost environments under Mars-like climate conditions. Microorganisms comparable to methanogens from terrestrial permafrost can be seen as one of the most likely candidates for life on Mars due to their physiological potential and metabolic specificity. N2 - Die Arktis spielt eine Schlüsselrolle im Klimasystem unserer Erde aus zweierlei Gründen. Zum einen wird vorausgesagt, dass die globale Erwärmung in den hohen Breiten am ausgeprägtesten sein wird. Zum anderen ist ein Drittel des globalen Kohlenstoffs in Ökosystemen der nördlichen Breiten gespeichert. Um ein besseres Verständnis der gegenwärtigen und zukünftigen Entwicklung der Kohlenstoffdynamik in klimaempfindlichen Permafrostökosystemen zu erlangen, konzentriert sich die vorliegende Arbeit auf Untersuchungen zur Kontrolle der Methanflüsse durch Mikroorganismen, auf die Aktivität und Struktur der beteiligten Mikroorganismen-gemeinschaften und auf ihre Reaktion auf sich ändernde Umweltbedingungen. Zu diesem Zweck wurde eine integrierte Forschungsstrategie entwickelt, die Spurengasmessungen mit boden- und molekularökologischen Untersuchungen der Mikroorganismengemeinschaften verknüpft. Langzeitmessungen zu den Methanflüssen werden seit 1998 durchgeführt. Diese Untersuchungen zeigten beträchtliche saisonale und räumliche Schwankungen der Methanemissionen auf, die zwischen 0 und 362 mg m-2 d-1 für die untersuchten Landschaftseinheiten schwankten. Für die Bilanzierung der Methanemissionen für das gesamte Delta wurde erstmals eine Klassifikation der unterschiedlichen Landschaftseinheiten anhand von Landsat-Aufnahmen durchgeführt und für eine Hochrechnung der Methandaten genutzt. Die Mittelwerte der regional gewichteten täglichen Methanemissionen des Lenadeltas (10 mg m-2 d-1) sind nur ein Fünftel so hoch wie die berechneten Werte für andere arktische Tundren. Die errechnete jährliche Methanemission des Lenadeltas beträgt demnach ungefähr 0,03 Tg. Die geringen Methanemissionsraten dieser Studie können durch den bisher noch nicht realisierten integrativen Ansatz, der Langzeitmessungen und Landschafts-klassifizierungen beinhaltet, erklärt werden. Bodentemperatur und oberflächennahe atmosphärische Turbulenzen wurden als die antreibenden Größen der Methanfreisetzung identifiziert. Ein Modell, das auf diesen Variablen basiert, erklärt die Veränderungen der Methanflüsse gemäß der dynamischen mikrobiellen Prozesse und der Diffusion von Methan durch den Boden und die Pflanzen zutreffend. Die Ergebnisse zeigen, dass das Lenadelta erheblich zur globalen Methanemission aufgrund seiner weitreichenden Feuchtgebiete beiträgt. Die mikrobiologischen Untersuchungen zeigten, dass Permafrostböden durch eine hohe Anzahl von Mikroorganismen besiedelt wird. Die Gesamtbiomasse ist dabei mit Bodenökosystemen gemäßigter Klimate vergleichbar. Die Stoffwechselaktivitäten von methanogenen Archaeen und methanotrophen Bakterien unterschieden sich erheblich in ihrer Rate und Verteilung im Tiefenprofil sowie zwischen den verschiedenen untersuchten Böden. Die Methanbildungsrate schwankte dabei zwischen 0,3 und 38,9 nmol h-1 g-1, während die Methanoxidation eine Rate von 0,2 bis 7,0 nmol h-1 g-1 aufwies. Phylogenetische Analysen der methanogenen Mikro-organismengemeinschaften zeigten eine ausgeprägte Diversität der methanogenen Archaeen auf. Die Umweltsequenzen bildeten vier spezifische Permafrostcluster aus, die den Gruppen Methanomicrobiaceae, Methanosarcinaceae und Methano-saetaceae zugeordnet werden konnten. Die Ergebnisse zeigen, dass die Methanfreisetzung durch die zugrunde liegenden mikrobiologischen Prozesse im Permafrostboden gesteuert wird. Die beteiligten Mikroorganismen überleben nicht nur in ihrem extremen Habitat, sondern zeigten auch Stoffwechselaktivität unter in-situ-Bedingungen. Ferner konnte gezeigt werden, dass eine geringfügige Zunahme der Temperatur zu einer erheblichen Zunahme der Methanbildungsaktivität in den ständig gefrorenen Permafrostablagerungen führen kann. Im Falle der Permafrostdegradation würde dieses zu einer gesteigerten Freisetzung von Methan führen mit bisher unbekannten Auswirkungen auf das Gesamtbudget der Methanfreistzung aus arktischen Gebieten. Weitere Untersuchungen zur Stresstoleranz von methanogenen Archaeen – insbesondere des neuen Permafrostisolates Methanosarcina SMA-21 - weisen eine unerwartete Widerstandsfähigkeit der Mikroorganismen gegenüber ungünstigen Lebensbedingungen auf. Eine bessere Anpassung an Umweltstress wurde bei 4°C im Vergleich zu 28°C beobachtet. Zum ersten Mal konnte gezeigt werden, dass methanogene Archaeen aus terrestrischem Permafrost unter simulierten Marsbedingungen unbeschadet überleben. Die Ergebnisse zeigen, dass methanogene Archaeen aus Permafrostböden resistenter gegenüber Umweltstress und Marsbedingungen sind als entsprechende Mikroorganismen aus Habitaten, die nicht durch Permafrost gekennzeichnet sind. Mikroorganismen, die den Archaeen aus terrestrischen Permafrosthabitaten ähneln, können als die wahrscheinlichsten Kandidaten für mögliches Leben auf dem Mars angesehen werden. KW - Methankreislauf KW - mikrobielle Prozesse KW - Diversität KW - Spurengasflüsse KW - Permafrostökosysteme KW - methane cycle KW - microbial processes KW - diversity KW - trace gas fluxes KW - permafrost ecosystems Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-15434 ER - TY - GEN A1 - Westbury, Michael V. A1 - Hartmann, Stefanie A1 - Barlow, Axel A1 - Wiesel, Ingrid A1 - Leo, Viyanna A1 - Welch, Rebecca A1 - Parker, Daniel M. A1 - Sicks, Florian A1 - Ludwig, Arne A1 - Dalen, Love A1 - Hofreiter, Michael T1 - Extended and continuous decline in effective population size results in low genomic diversity in the world's rarest hyena species, the brown hyena T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Hyenas (family Hyaenidae), as the sister group to cats (family Felidae), represent a deeply diverging branch within the cat-like carnivores (Feliformia). With an estimated population size of <10,000 individuals worldwide, the brown hyena (Parahyaena brunnea) represents the rarest of the four extant hyena species and has been listed as Near Threatened by the IUCN. Here, we report a high-coverage genome from a captive bred brown hyena and both mitochondrial and low-coverage nuclear genomes of 14 wild-caught brown hyena individuals from across southern Africa. We find that brown hyena harbor extremely low genetic diversity on both the mitochondrial and nuclear level, most likely resulting from a continuous and ongoing decline in effective population size that started similar to 1 Ma and dramatically accelerated towards the end of the Pleistocene. Despite the strikingly low genetic diversity, we find no evidence of inbreeding within the captive bred individual and reveal phylogeographic structure, suggesting the existence of several potential subpopulations within the species. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 589 KW - evolution KW - hyena KW - genomics KW - population genomics KW - diversity Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-414132 SN - 1866-8372 IS - 589 ER - TY - JOUR A1 - Westbury, Michael V. A1 - Hartmann, Stefanie A1 - Barlow, Axel A1 - Wiesel, Ingrid A1 - Leo, Viyanna A1 - Welch, Rebecca A1 - Parker, Daniel M. A1 - Sicks, Florian A1 - Ludwig, Arne A1 - Dalen, Love A1 - Hofreiter, Michael T1 - Extended and continuous decline in effective population size results in low genomic diversity in the world's rarest hyena species, the brown hyena JF - Molecular biology and evolution N2 - Hyenas (family Hyaenidae), as the sister group to cats (family Felidae), represent a deeply diverging branch within the cat-like carnivores (Feliformia). With an estimated population size of <10,000 individuals worldwide, the brown hyena (Parahyaena brunnea) represents the rarest of the four extant hyena species and has been listed as Near Threatened by the IUCN. Here, we report a high-coverage genome from a captive bred brown hyena and both mitochondrial and low-coverage nuclear genomes of 14 wild-caught brown hyena individuals from across southern Africa. We find that brown hyena harbor extremely low genetic diversity on both the mitochondrial and nuclear level, most likely resulting from a continuous and ongoing decline in effective population size that started similar to 1 Ma and dramatically accelerated towards the end of the Pleistocene. Despite the strikingly low genetic diversity, we find no evidence of inbreeding within the captive bred individual and reveal phylogeographic structure, suggesting the existence of several potential subpopulations within the species. KW - evolution KW - hyena KW - genomics KW - population genomics KW - diversity Y1 - 2018 U6 - https://doi.org/10.1093/molbev/msy037 SN - 0737-4038 SN - 1537-1719 VL - 35 IS - 5 SP - 1225 EP - 1237 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Wiesner, Kerstin R. A1 - Loxdale, Hugh D. A1 - Köhler, Günter A1 - Schneider, Anja R. R. A1 - Tiedemann, Ralph A1 - Weisser, Wolfgang W. T1 - Patterns of local and regional genetic structuring in the meadow grasshopper, Chorthippus parallelus (Orthoptera: Acrididae), in Central Germany revealed using microsatellite markers JF - Biological journal of the Linnean Society : a journal of evolution N2 - The meadow grasshopper, Chorthippus parallelus (Zetterstedt), is common and widespread in Central Europe, with a low dispersal range per generation. A population study in Central Germany (Frankenwald and Thuringer Schiefergebirge) showed strong interpopulation differences in abundance and individual fitness. We examined genetic variability using microsatellite markers within and between 22 populations in a short-to long-distance sampling (19 populations, Frankenwald, Schiefergebirge, as well as a southern transect), and in the Erzgebirge region (three populations), with the latter aiming to check for effects as a result of historical forest cover. Of the 671 C. parallelus captured, none was macropterous (functionally winged). All populations showed a high level of expected and observed heterozygosity (mean 0.80-0.90 and 0.60-0.75, respectively), whereas there was evidence of inbreeding (F(IS) values all positive). Allelic richness for all locus-population combinations was high (mean 9.3-11.2), whereas alleles per locus ranged from 15-62. At a local level, genic and genotypic differences were significant. Pairwise F(ST) values were in the range 0.00-0.04, indicating little interpopulation genetic differentiation. Similarly, the calculated gene flow was very high, based on the respective F(ST) (19.5) and using private alleles (7.7). A Neighbour-joining tree using Nei's D(A) and principal coordinate analysis separated two populations that were collected in the Erzgebirge region. Populations from this region may have escaped the effects of the historical forest cover. The visualization of the spatial arrangement of genotypes revealed one geographical barrier to gene flow in the short-distance sampling. KW - adaptation KW - gene flow KW - diversity KW - landscape structure KW - wing polyphenism Y1 - 2011 U6 - https://doi.org/10.1111/j.1095-8312.2011.01698.x SN - 0024-4066 VL - 103 IS - 4 SP - 875 EP - 890 PB - Wiley-Blackwell CY - Malden ER - TY - JOUR A1 - Zimmermann, Heike Hildegard A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Kruse, Stefan A1 - Müller, Juliane A1 - Stein, Ruediger A1 - Tiedemann, Ralf A1 - Herzschuh, Ulrike T1 - Changes in the composition of marine and sea-ice diatoms derived from sedimentary ancient DNA of the eastern Fram Strait over the past 30 000 years JF - Ocean Science N2 - The Fram Strait is an area with a relatively low and irregular distribution of diatom microfossils in surface sediments, and thus microfossil records are scarce, rarely exceed the Holocene, and contain sparse information about past richness and taxonomic composition. These attributes make the Fram Strait an ideal study site to test the utility of sedimentary ancient DNA (sedaDNA) metabarcoding. Amplifying a short, partial rbcL marker from samples of sediment core MSM05/5-712-2 resulted in 95.7 % of our sequences being assigned to diatoms across 18 different families, with 38.6 % of them being resolved to species and 25.8 % to genus level. Independent replicates show a high similarity of PCR products, especially in the oldest samples. Diatom sedaDNA richness is highest in the Late Weichselian and lowest in Mid- and Late Holocene samples. Taxonomic composition is dominated by cold-water and sea-ice-associated diatoms and suggests several reorganisations – after the Last Glacial Maximum, after the Younger Dryas, and after the Early and after the Mid-Holocene. Different sequences assigned to, amongst others, Chaetoceros socialis indicate the detectability of intra-specific diversity using sedaDNA. We detect no clear pattern between our diatom sedaDNA record and the previously published IP25 record of this core, although proportions of pennate diatoms increase with higher IP25 concentrations and proportions of Nitzschia cf. frigida exceeding 2 % of the assemblage point towards past sea-ice presence. KW - last glacial maximum KW - surface temperatures KW - species composition KW - greenland shelf KW - Disko Bay KW - phytoplankton KW - communities KW - variability KW - diversity KW - Svalbard Y1 - 2019 VL - 16 IS - 5 PB - Springer CY - Tokyo ER - TY - GEN A1 - Zimmermann, Heike Hildegard A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Kruse, Stefan A1 - Müller, Juliane A1 - Stein, Ruediger A1 - Tiedemann, Ralf A1 - Herzschuh, Ulrike T1 - Changes in the composition of marine and sea-ice diatoms derived from sedimentary ancient DNA of the eastern Fram Strait over the past 30 000 years T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The Fram Strait is an area with a relatively low and irregular distribution of diatom microfossils in surface sediments, and thus microfossil records are scarce, rarely exceed the Holocene, and contain sparse information about past richness and taxonomic composition. These attributes make the Fram Strait an ideal study site to test the utility of sedimentary ancient DNA (sedaDNA) metabarcoding. Amplifying a short, partial rbcL marker from samples of sediment core MSM05/5-712-2 resulted in 95.7 % of our sequences being assigned to diatoms across 18 different families, with 38.6 % of them being resolved to species and 25.8 % to genus level. Independent replicates show a high similarity of PCR products, especially in the oldest samples. Diatom sedaDNA richness is highest in the Late Weichselian and lowest in Mid- and Late Holocene samples. Taxonomic composition is dominated by cold-water and sea-ice-associated diatoms and suggests several reorganisations – after the Last Glacial Maximum, after the Younger Dryas, and after the Early and after the Mid-Holocene. Different sequences assigned to, amongst others, Chaetoceros socialis indicate the detectability of intra-specific diversity using sedaDNA. We detect no clear pattern between our diatom sedaDNA record and the previously published IP25 record of this core, although proportions of pennate diatoms increase with higher IP25 concentrations and proportions of Nitzschia cf. frigida exceeding 2 % of the assemblage point towards past sea-ice presence. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1195 KW - last glacial maximum KW - surface temperatures KW - species composition KW - greenland shelf KW - Disko Bay KW - phytoplankton KW - communities KW - variability KW - diversity KW - Svalbard Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-525154 SN - 1866-8372 IS - 5 ER -