TY - JOUR A1 - Caron, Maria Mercedes A1 - De Frenne, Pieter A1 - Brunet, J. A1 - Chabrerie, Olivier A1 - Cousins, S. A. O. A1 - De Backer, L. A1 - Decocq, G. A1 - Diekmann, M. A1 - Heinken, Thilo A1 - Kolb, A. A1 - Naaf, T. A1 - Plue, J. A1 - Selvi, Federico A1 - Strimbeck, G. R. A1 - Wulf, Monika A1 - Verheyen, Kris T1 - Interacting effects of warming and drought on regeneration and early growth of Acer pseudoplatanus and A. platanoides JF - Plant biology N2 - Climate change is acting on several aspects of plant life cycles, including the sexual reproductive stage, which is considered amongst the most sensitive life-cycle phases. In temperate forests, it is expected that climate change will lead to a compositional change in community structure due to changes in the dominance of currently more abundant forest tree species. Increasing our understanding of the effects of climate change on currently secondary tree species recruitment is therefore important to better understand and forecast population and community dynamics in forests. Here, we analyse the interactive effects of rising temperatures and soil moisture reduction on germination, seedling survival and early growth of two important secondary European tree species, Acer pseudoplatanus and A.platanoides. Additionally, we analyse the effect of the temperature experienced by the mother tree during seed production by collecting seeds of both species along a 2200-km long latitudinal gradient. For most of the responses, A.platanoides showed higher sensitivity to the treatments applied, and especially to its joint manipulation, which for some variables resulted in additive effects while for others only partial compensation. In both species, germination and survival decreased with rising temperatures and/or soil moisture reduction while early growth decreased with declining soil moisture content. We conclude that although A.platanoides germination and survival were more affected after the applied treatments, its initial higher germination and larger seedlings might allow this species to be relatively more successful than A.pseudoplatanus in the face of climate change. KW - Acer platanoides KW - Acer pseudoplatanus KW - climate change KW - drought KW - reproduction KW - seed KW - temperature Y1 - 2015 U6 - https://doi.org/10.1111/plb.12177 SN - 1435-8603 SN - 1438-8677 VL - 17 IS - 1 SP - 52 EP - 62 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Sarmento, Juliano Sarmento A1 - Jeltsch, Florian A1 - Thuiller, Wilfried A1 - Higgins, Steven A1 - Midgley, Guy F. A1 - Rebelo, Anthony G. A1 - Rouget, Mathieu A1 - Schurr, Frank Martin T1 - Impacts of past habitat loss and future climate change on the range dynamics of South African Proteaceae JF - Diversity & distributions : a journal of biological invasions and biodiversity N2 - Aim To assess how habitat loss and climate change interact in affecting the range dynamics of species and to quantify how predicted range dynamics depend on demographic properties of species and the severity of environmental change. Location South African Cape Floristic Region. Methods We use data-driven demographic models to assess the impacts of past habitat loss and future climate change on range size, range filing and abundances of eight species of woody plants (Proteaceae). The species-specific models employ a hybrid approach that simulates population dynamics and long-distance dispersal on top of expected spatio-temporal dynamics of suitable habitat. Results Climate change was mainly predicted to reduce range size and range filling (because of a combination of strong habitat shifts with low migration ability). In contrast, habitat loss mostly decreased mean local abundance. For most species and response measures, the combination of habitat loss and climate change had the most severe effect. Yet, this combined effect was mostly smaller than expected from adding or multiplying effects of the individual environmental drivers. This seems to be because climate change shifts suitable habitats to regions less affected by habitat loss. Interspecific variation in range size responses depended mostly on the severity of environmental change, whereas responses in range filling and local abundance depended mostly on demographic properties of species. While most surviving populations concentrated in areas that remain climatically suitable, refugia for multiple species were overestimated by simply overlying habitat models and ignoring demography. Main conclusions Demographic models of range dynamics can simultaneously predict the response of range size, abundance and range filling to multiple drivers of environmental change. Demographic knowledge is particularly needed to predict abundance responses and to identify areas that can serve as biodiversity refugia under climate change. These findings highlight the need for data-driven, demographic assessments in conservation biogeography. KW - biodiversity refugia KW - CFR Proteaceae KW - climate change KW - demographic properties KW - habitat loss KW - local abundances KW - process-based range models KW - range filling KW - range size KW - species distribution models Y1 - 2013 U6 - https://doi.org/10.1111/ddi.12011 SN - 1366-9516 VL - 19 IS - 4 SP - 363 EP - 376 PB - Wiley-Blackwell CY - Hoboken ER - TY - THES A1 - Hornick, Thomas T1 - Impact of climate change effects on diversity and function of pelagic heterotrophic bacteria studied in large-scale mesocosm facilities T1 - Studien zum Einfluss des Klimawandels auf die Diversität und Funktion pelagischer heterotropher Bakterien in Mesokosmen N2 - Seit der Industriellen Revolution steigt die Konzentration von Kohlenstoffdioxid (CO2) und anderen Treibhausgasen in der Erdatmosphäre stetig an, wodurch wesentliche Prozesse im Erdsystem beeinflusst werden. Dies wird mit dem Begriff „Klimawandel“ umschrieben. Aquatische Ökosysteme sind sehr stark davon betroffen, da sie als Integral vieler Prozesse in einer Landschaft fungieren. Ziel dieser Doktorarbeit war zu bestimmen, wie verschiedene Auswirkungen des Klimawandels die Gemeinschaftsstruktur und Aktivität von heterotrophen Bakterien in Gewässern verändert, welche eine zentrale Rolle bei biogeochemischen Prozessen einnehmen. Diese Arbeit konzentriert sich auf zwei Aspekte des Klimawandels: (1) Ozeane nehmen einen Großteil des atmosphärischen CO2 auf, welches im Meerwasser das chemische Gleichgewicht des Karbonatsystems verschiebt („Ozeanversauerung“). (2) Durch kontinuierlichen Anstieg der Erdoberflächentemperatur werden Veränderungen im Klimasystem der Erde vorhergesagt, welche u. a. die Häufigkeit und Heftigkeit von episodischen Wetterereignissen (z.B. Stürme) verstärken wird. Insbesondere Sommer-Stürme sind dabei in der Lage die sommerliche Temperaturschichtung der Wassersäule in Seen zu zerstören. Beide Effekte des Klimawandels können weitreichende Auswirkungen auf Wasserchemie/-physik sowie die Verteilung von Organismen haben, was mittels Mesokosmen simuliert wurde. Dabei untersuchten wir den Einfluss der Ozeanversauerung auf heterotrophe bakterielle Prozesse in der Ostsee bei geringen Konzentrationen an gelösten Nährstoffen. Unsere Ergebnisse zeigen, dass Ozeanversauerungseffekte in Kombination mit Nährstofflimitation indirekt das Wachstum von heterotrophen Bakterien durch veränderte trophische Interaktionen beeinflussen können und potentiell zu einer Erhöhung der Autotrophie des Ökosystems führen. In einer weiteren Studie analysierten wir, wie Ozeanversauerung die Umsetzung und Qualität gelösten organischen Materials (DOM) durch heterotrophe Bakterien beeinflussen kann. Die Ergebnisse weisen jedoch darauf hin, dass Änderungen in der DOM-Qualität durch heterotrophe bakterielle Prozesse mit zunehmender Ozeanversauerung unwahrscheinlich sind. Desweiteren wurde der Einfluss eines starken Sommer-Sturmes auf den stratifizierten, oligotroph-mesotrophen Stechlinsee simuliert. Mittels oberflächlicher Durchmischung in Mesokosmen wurde die bestehende Thermokline zerstört und die durchmischte Oberflächenwasserschicht vergrößert. Dies änderte die physikalischen und chemischen Gradienten innerhalb der Wassersäule. Effekte der Einmischung von Tiefenwasser änderten in der Folge die Zusammensetzung der bakteriellen Gemeinschaftsstruktur und stimulierten das Wachstum filamentöser Cyanobakterien, die zu einer Cyanobakterien-Blüte führte und so maßgeblich die metabolischen Prozesse von heterotrophen Bakterien bestimmte. Unsere Studie gibt ein mechanistisches Verständnis, wie Sommer-Stürme bakterielle Gemeinschaften und Prozesse für längere Zeit während der sommerlichen Stratifizierung beeinflussen können. Die in dieser Arbeit präsentierten Ergebnisse zeigen Veränderungen bakterieller Gemeinschaften und Prozesse, welche mit dem einhergehenden Klimawandel erwartet werden können. Diese sollten bei Beurteilung klimarelevanter Fragen hinsichtlich eines zukünftigen Gewässer-managements Berücksichtigung finden. N2 - The unprecedented increase in atmospheric concentrations of carbon dioxide (CO2) and other greenhouse gases (GHG) by anthropogenic activities since the Industrial Revolution impacts on various earth system processes, commonly referred to as `climate change´ (CC). CC faces aquatic ecosystems with extreme abiotic perturbations that potentially alter the interrelations between functional autotrophic and heterotrophic plankton groups. These relations, however, modulate biogeochemical cycling and mediate the functioning of aquatic ecosystems as C sources or sinks to the atmosphere. The aim of this thesis was therefore to investigate how different aspects of CC influence community composition and functioning of pelagic heterotrophic bacteria. These organisms constitute a major component of biogeochemical cycling and largely determine the balance between autotrophic and heterotrophic processes. Due to the vast amount of potential CC impacts, this thesis focuses on the following two aspects: (1) Increased exchange of CO2 across the atmosphere-water interface and reaction of CO2 with seawater leads to profound shifts in seawater carbonate chemistry, commonly termed as `ocean acidification´ (OA), with consequences for organism physiology and the availability of dissolved inorganic carbon (DIC) in seawater. (2) The increase in atmospheric GHG concentration impacts on the efficiency with which the Earth cools to space, affecting global surface temperature and climate. With ongoing CC, shifts in frequency and severity of episodic weather events, such as storms, are expected that in particular might affect lake ecosystems by disrupting thermal summer stratification. Both aspects of CC were studied at the ecosystem-level in large-volume mesocosm experiments by using the Kiel Off-shore Mesocosms for Future Ocean Simulations (KOSMOS) deployed at different coastal marine locations, and the LakeLab facility in Lake Stechlin. We evaluated the impact of OA on heterotrophic bacterial metabolism in a brackish coastal ecosystem during low-nutrient summer months in the Baltic Sea. There are several in situ experiments that already assessed potential OA-induced changes in natural plankton communities at diverse spatial and seasonal conditions. However, most studies were performed at high phytoplankton biomass conditions, partly provoked by nutrient amendments. Our study highlights potential OA effects at low-nutrient conditions that are representative for most parts of the ocean and of particular interest in current OA research. The results suggest that during extended periods at low-nutrient concentrations, increasing pCO2 levels indirectly impact the growth balance of heterotrophic bacteria via trophic bacteria-phytoplankton interactions and shift the ecosystem to a more autotrophic system. Further work investigated how OA affects heterotrophic bacterial dissolved organic matter (DOM) transformation in two mesocsom studies, performed at different nutrient conditions. We observed similar succession patterns for individual compound pools during a phytoplankton bloom and subsequent accumulation of these compounds irrespective of the pCO2 treatment. Our results indicate that OA-induced changes in the dynamics of bacterial DOM transformation and potential impacts on DOM quality are unlikely. In addition, there have been no indications that in dependence of nutrient conditions, different amounts of photosynthetic organic matter are channelled into the more recalcitrant DOM pool. This provides novel insights into the general dynamics of the marine DOM pool. A fourth enclosure experiment in oligo-mesotrophic Lake Stechlin assessed the impact of a severe summer storm on lake bacterial communities during thermal stratification by artificially mixing. Mixing disrupted and lowered the thermocline, increasing the upper mixed layer and substantially changed water physical-chemical variables. Deep water entrainment and associated changes in water physical-chemical variables significantly affected relative bacterial abundances for about one week. Afterwards a pronounced cyanobacterial bloom developed in response to mixing which affected community assembly of heterotrophic bacteria. Colonization and mineralization of senescent phytoplankton cells by heterotrophic bacteria largely determined C-sequestration to the sediment. About six weeks after mixing, bacterial communities and measured activity parameters converged to control conditions. As such, summer storms have the potential to affect bacterial communities for a prolonged period during summer stratification. The results highlight effects on community assembly and heterotrophic bacterial metabolism that are associated to entrainment of deep water into the mixed water layer and assess consequences of an episodic disturbance event for the coupling between bacterial metabolism and autochthonous DOM production in large volume clear-water lakes. Altogether, this doctoral thesis reveales substantial sensitivities of heterotrophic bacterial metabolism and community structure in response to OA and a simulated summer storm event, which should be considered when assessing the impact of climate change on marine and lake ecosystems. KW - climate change KW - ocean acidification KW - Ozeanversauerung KW - Klimawandel KW - Gewässerökologie KW - heterotrophic bacteria Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-428936 ER - TY - JOUR A1 - Perring, Michael P. A1 - Bernhardt-Roemermann, Markus A1 - Baeten, Lander A1 - Midolo, Gabriele A1 - Blondeel, Haben A1 - Depauw, Leen A1 - Landuyt, Dries A1 - Maes, Sybryn L. A1 - De Lombaerde, Emiel A1 - Caron, Maria Mercedes A1 - Vellend, Mark A1 - Brunet, Joerg A1 - Chudomelova, Marketa A1 - Decocq, Guillaume A1 - Diekmann, Martin A1 - Dirnboeck, Thomas A1 - Doerfler, Inken A1 - Durak, Tomasz A1 - De Frenne, Pieter A1 - Gilliam, Frank S. A1 - Hedl, Radim A1 - Heinken, Thilo A1 - Hommel, Patrick A1 - Jaroszewicz, Bogdan A1 - Kirby, Keith J. A1 - Kopecky, Martin A1 - Lenoir, Jonathan A1 - Li, Daijiang A1 - Malis, Frantisek A1 - Mitchell, Fraser J. G. A1 - Naaf, Tobias A1 - Newman, Miles A1 - Petrik, Petr A1 - Reczynska, Kamila A1 - Schmidt, Wolfgang A1 - Standovar, Tibor A1 - Swierkosz, Krzysztof A1 - Van Calster, Hans A1 - Vild, Ondrej A1 - Wagner, Eva Rosa A1 - Wulf, Monika A1 - Verheyen, Kris T1 - Global environmental change effects on plant community composition trajectories depend upon management legacies JF - Global change biology N2 - The contemporary state of functional traits and species richness in plant communities depends on legacy effects of past disturbances. Whether temporal responses of community properties to current environmental changes are altered by such legacies is, however, unknown. We expect global environmental changes to interact with land-use legacies given different community trajectories initiated by prior management, and subsequent responses to altered resources and conditions. We tested this expectation for species richness and functional traits using 1814 survey-resurvey plot pairs of understorey communities from 40 European temperate forest datasets, syntheses of management transitions since the year 1800, and a trait database. We also examined how plant community indicators of resources and conditions changed in response to management legacies and environmental change. Community trajectories were clearly influenced by interactions between management legacies from over 200 years ago and environmental change. Importantly, higher rates of nitrogen deposition led to increased species richness and plant height in forests managed less intensively in 1800 (i.e., high forests), and to decreases in forests with a more intensive historical management in 1800 (i.e., coppiced forests). There was evidence that these declines in community variables in formerly coppiced forests were ameliorated by increased rates of temperature change between surveys. Responses were generally apparent regardless of sites’ contemporary management classifications, although sometimes the management transition itself, rather than historic or contemporary management types, better explained understorey responses. Main effects of environmental change were rare, although higher rates of precipitation change increased plant height, accompanied by increases in fertility indicator values. Analysis of indicator values suggested the importance of directly characterising resources and conditions to better understand legacy and environmental change effects. Accounting for legacies of past disturbance can reconcile contradictory literature results and appears crucial to anticipating future responses to global environmental change. KW - biodiversity change KW - climate change KW - disturbance regime KW - forestREplot KW - herbaceous layer KW - management intensity KW - nitrogen deposition KW - plant functional traits KW - time lag KW - vegetation resurvey Y1 - 2017 U6 - https://doi.org/10.1111/gcb.14030 SN - 1354-1013 SN - 1365-2486 VL - 24 IS - 4 SP - 1722 EP - 1740 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Grimm-Seyfarth, Annegret A1 - Mihoub, Jean-Baptiste A1 - Henle, Klaus T1 - Functional traits determine the different effects of prey, predators, and climatic extremes on desert reptiles JF - Ecosphere : the magazine of the International Ecology University N2 - Terrestrial reptiles are particularly vulnerable to climate change. Their highest density and diversity can be found in hot drylands, ecosystems which demonstrate extreme climatic conditions. However, reptiles are not isolated systems but part of a large species assemblage with many trophic dependencies. While direct relations among climatic conditions, invertebrates, vegetation, or reptiles have already been explored, to our knowledge, species’ responses to direct and indirect pathways of multiple climatic and biotic factors and their interactions have rarely been examined comprehensively. We investigated direct and indirect effects of climatic and biotic parameters on the individual (body condition) and population level (occupancy) of eight abundant lizard species with different functional traits in an arid Australian lizard community using a 30‐yr multi‐trophic monitoring study. We used structural equation modeling to disentangle single and interactive effects. We then assessed whether species could be grouped into functional groups according to their functional traits and their responses to different parameters. We found that lizard species differed strongly in how they responded to climatic and biotic factors. However, the factors to which they responded seemed to be determined by their functional traits. While responses on body condition were determined by habitat, activity time, and prey, responses on occupancy were determined by habitat specialization, body size, and longevity. Our findings highlight the importance of indirect pathways through climatic and biotic interactions, which should be included into predictive models to increase accuracy when predicting species’ responses to climate change. Since one might never obtain all mechanistic pathways at the species level, we propose an approach of identifying relevant species traits that help grouping species into functional groups at different ecological levels, which could then be used for predictive modeling. KW - Australia KW - climate change KW - Gekkonidae KW - periodic flooding KW - Scincidae KW - species functional traits KW - species interactions KW - structural equation modeling Y1 - 2019 U6 - https://doi.org/10.1002/ecs2.2865 SN - 2150-8925 VL - 10 IS - 9 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Seifert, Linda I. A1 - Weithoff, Guntram A1 - Vos, Matthijs T1 - Extreme heat changes post-heat wave community reassembly JF - Ecology and evolution N2 - Climate forecasts project further increases in extremely high-temperature events. These present threats to biodiversity, as they promote population declines and local species extinctions. This implies that ecological communities will need to rely more strongly on recovery processes, such as recolonization from a meta-community context. It is poorly understood how differences in extreme event intensity change the outcome of subsequent community reassembly and if such extremes modify the biotic environment in ways that would prevent the successful re-establishment of lost species. We studied replicated aquatic communities consisting of algae and herbivorous rotifers in a design that involved a control and two different heat wave intensity treatments (29 degrees C and 39 degrees C). Animal species that suffered heat-induced extinction were subsequently re-introduced at the same time and density, in each of the two treatments. The 39 degrees C treatment led to community closure in all replicates, meaning that a previously successful herbivore species could not re-establish itself in the postheat wave community. In contrast, such closure never occurred after a 29 degrees C event. Heat wave intensity determined the number of herbivore extinctions and strongly affected algal relative abundances. Re-introduced herbivore species were thus confronted with significantly different food environments. This ecological legacy generated by heat wave intensity led to differences in the failure or success of herbivore species re-introductions. Reassembly was significantly more variable, and hence less predictable, after an extreme heat wave, and was more canalized after a moderate one. Our results pertain to relatively simple communities, but they suggest that ecological legacies introduced by extremely high-temperature events may change subsequent ecological recovery and even prevent the successful re-establishment of lost species. Knowing the processes promoting and preventing ecological recovery is crucial to the success of species re-introduction programs and to our ability to restore ecosystems damaged by environmental extremes. KW - Biodiversity KW - climate change KW - conservation KW - ecological restoration KW - extinction KW - extreme temperature events KW - global warming KW - maximum temperature KW - variability Y1 - 2015 U6 - https://doi.org/10.1002/ece3.1490 SN - 2045-7758 VL - 5 IS - 11 SP - 2140 EP - 2148 PB - Wiley-Blackwell CY - Hoboken ER - TY - THES A1 - Kahl, Sandra T1 - Evolutionary adaptive responses to rapid climate change in plants T1 - Evolutionäre Anpassungsstrategien von Pflanzen an den Klimawandel BT - a case study of the widely distributed species Silene vulgaris BT - ein Fallbeispiel der weit verbreiteten Art Silene vulgaris N2 - The ongoing climate change is altering the living conditions for many organisms on this planet at an unprecedented pace. Hence, it is crucial for the survival of species to adapt to these changing conditions. In this dissertation Silene vulgaris is used as a model organism to understand the adaption strategies of widely distributed plant species to the current climate change. Especially plant species that possess a wide geographic range are expected to have a high phenotypic plasticity or to show genetic differentiation in response to the different climate conditions they grow in. However, they are often underrepresented in research. In the greenhouse experiment presented in this thesis, I examined the phenotypic responses and plasticity in S. vulgaris to estimate its’ adaptation potential. Seeds from 25 wild European populations were collected along a latitudinal gradient and grown in a greenhouse under three different precipitation (65 mm, 75 mm, 90 mm) and two different temperature regimes (18°C, 21°C) that resembled a possible climate change scenario for central Europe. Afterwards different biomass and fecundity-related plant traits were measured. The treatments significantly influenced the plants but did not reveal a latitudinal difference in response to climate treatments for most plant traits. The number of flowers per individual however, showed a stronger plasticity in northern European populations (e.g., Swedish populations) where numbers decreased more drastically with increased temperature and decreased precipitation. To gain an even deeper understanding of the adaptation of S. vulgaris to climate change it is also important to reveal the underlying phylogeny of the sampled populations. Therefore, I analysed their population genetic structure through whole genome sequencing via ddRAD. The sequencing revealed three major genetic clusters in the S. vulgaris populations sampled in Europe: one cluster comprised Southern European populations, one cluster Western European populations and another cluster contained central European populations. A following analysis of experimental trait responses among the clusters to the climate-change scenario showed that the genetic clusters significantly differed in biomass-related traits and in the days to flowering. However, half of the traits showed parallel response patterns to the experimental climate-change scenario. In addition to the potential geographic and genetic adaptation differences to climate change this dissertation also deals with the response differences between the sexes in S. vulgaris. As a gynodioecious species populations of S. vulgaris consist of female and hermaphrodite individuals and the sexes can differ in their morphological traits which is known as sexual dimorphism. As climate change is becoming an important factor influencing plant morphology it remains unclear if and how different sexes may respond in sexually dimorphic species. To examine this question the sex of each individual plant was determined during the greenhouse experiment and the measured plant traits were analysed accordingly. In general, hermaphrodites had a higher number of flowers but a lower number of leaves than females. With regards to the climate change treatment, I found that hermaphrodites showed a milder negative response to higher temperatures in the number of flowers produced and in specific leaf area (SLA) compared to females. Synthesis – The significant treatment response in Silene vulgaris, independent of population origin in most traits suggests a high degree of universal phenotypic plasticity. Also, the three European intraspecific genetic lineages detected showed comparable parallel response patterns in half of the traits suggesting considerable phenotypic plasticity. Hence, plasticity might represent a possible adaptation strategy of this widely distributed species during ongoing and future climatic changes. The results on sexual dimorphism show that females and hermaphrodites are differing mainly in their number of flowers and females are affected more strongly by the experimental climate-change scenario. These results provide a solid knowledge basis on the sexual dimorphism in S. vulgaris under climate change, but further research is needed to determine the long-term impact on the breeding system for the species. In summary this dissertation provides a comprehensive insight into the adaptation mechanisms and consequences of a widely distributed and gynodioecious plant species and leverages our understanding of the impact of anthropogenic climate change on plants. N2 - Der derzeitige Klimawandel verändert die Lebensbedingungen für viele Tiere und Pflanzen auf unserem Planeten in nie da gewesenem Maße. Damit Arten überleben, ist es von besonderer Wichtigkeit, dass sich diese an die sich ändernden Klimabedingungen anpassen können. Die vorliegende Dissertation befasst sich mit der Modellpflanze Silene vulgaris und versucht zu ergründen, wie sich solch weit verbreitete Pflanzenarten an den Klimawandel anpassen. Dabei ist zu erwarten, dass sie eine hohe phänotypische Plastizität besitzen, durch die sie sich gut anpassen können oder, dass sie sich durch eine genetische Differenzierung als Antwort auf die vorherrschenden Umweltbedingungen auszeichnen. Im experimentellen Ansatz dieser Dissertation untersuchte ich daher die phänotypischen Anpassungen und die phänotypische Plastizität von S. vulgaris an ein mögliches Klimawandelszenario für Zentraleuropa. Dabei wurden die Samen von 25 europäischen Populationen gesammelt und in einem Gewächshausexperiment unter drei verschiedenen Niederschlagsbedingungen (65 mm, 75 mm, 90 mm) und zwei verschiedenen Temperaturbedingungen (18°C, 21°C) herangezogen. Im Anschluss wurden verschiedene Biomasse- und Fertilitätsmerkmale gemessen. Für ein tiefergehendes Verständnis der Anpassungsmöglichkeiten von S. vulgaris an den Klimawandel ist es zudem wichtig, auch die zugrundeliegende Phylogenie der Populationen zu verstehen. In diesem Zusammenhang nutzte ich eine genomweite Sequenziermethode mittels ddRAD. Die Bedingungen im Gewächshausexperiment beeinflussten die Pflanzen signifikant in ihren phänotypischen Merkmalen, jedoch ließ sich kein Unterschied zwischen Population unterschiedlicher Herkunft erkennen. Lediglich die Anzahl der Blüten zeigte eine größere Plastizität in nördlichen europäischen Populationen, wo sich die Blütenzahl stärker dezimierte unter höheren Temperaturen und stärkerer Trockenheit. Die populationsgenetische Analyse ergab drei distinkte phylogenetische Gruppen für die untersuchten europäischen Populationen von S. vulgaris: eine Gruppe beinhaltete südeuropäische Populationen aus Spanien und Südfrankreich, eine weitere Gruppe bestand aus den gesammelten Individuen der westfranzösischen Populationen, während die dritte Gruppe, die Populationen aus Mittel- und Nordeuropa enthielt. Diese genetischen Gruppen wurden anschließend ebenfalls der Merkmalsanalyse unter den Gewächshausbedingungen unterzogen. Dabei stellte sich heraus, dass sich die genetischen Gruppen in ihren phänotypischen Merkmalen unterschieden, jedoch eine ähnliche Anpassung ihrer Merkmale an die experimentellen Klimawandelbedingungen zeigten. Der dritte Aspekt dieser Dissertation befasste sich mit möglichen Anpassungsunterschieden zwischen den Geschlechtern in S. vulgaris. Als gynodiözische Art bestehen ihre Populationen sowohl aus weiblichen, also auch aus zwittrigen Individuen. Die phänotypischen Merkmale beider Geschlechter können sich dabei unterscheiden, was man als Sexualdimorphismus bezeichnet. Es ist bereits bekannt, dass sich Pflanzenmerkmale durch den anhaltenden Klimawandel bereits verändern, jedoch ist es nicht gut erforscht, ob und wie sich die unterschiedlichen Geschlechter bei einer sexuell dimorphen Art unter diesem Selektionsdruck verhalten. Während des Gewächshausexperiments wurden daher die Geschlechter der Individuen bestimmt und die phänotypischen Unterschiede zwischen weiblichen und zwittrigen Pflanzen analysiert. Allgemein lässt sich sagen, dass zwittrige Individuen mehr Blüten aber weniger Blätter hatten als weibliche. Im Hinblick auf die experimentellen Klimawandelbedingungen konnte ich zudem feststellen, dass Hermaphroditen in ihrer spezifischen Blattfläche und der Blütenanzahl weniger stark negativ auf höhere Temperaturen reagierten. Synthese – Die signifikanten Merkmalsanpassungen an die Gewächshausbedingungen waren unabhängig von der geographischen Herkunft oder genetischen Gruppe der Individuen. Dies lässt ein hohes Maß an universeller, phänotypischer Plastizität vermuten. Dementsprechend kann davon ausgegangen werden, dass phänotypische Plastizität ein möglicher Anpassungsmechanismus für diese weit verbreitete Art an den Klimawandel sein könnte. Im Hinblick auf den Sexualdimorphismus in S. vulgaris lässt sich sagen, dass sich beide Geschlechter vornehmlich in der Anzahl der Blüten unterscheiden und dass weibliche Pflanzen stärker von den Bedingungen des Gewächshausexperiments beeinflusst wurden. Diese Dissertation konnte damit erstmals darüber Aufschluss geben, wie sich S. vulgaris im Hinblick auf ihren Sexualdimorphismus unter Klimawandelbedingungen verhält. Weitere Forschung wird nun benötigt, um auch den Langzeiteffekt des Klimawandels auf das Fortpflanzungssystem dieser Art abschätzen zu können. Zusammenfassend lässt sich sagen, dass die vorliegende Arbeit einen umfassenden Einblick in die Anpassungsmechanismen einer weit verbreiteten Pflanzenart an den anthropogenen Klimawandel gibt. Zudem bestärkt sie unser Verständnis der Auswirkungen, die sich daraus für eine gynodiözische Art, wie S. vulgaris ergeben. KW - Silene vulgaris KW - climate change KW - plant adaptation KW - Silene vulgaris KW - Klimawandel KW - Pflanzenanpassung Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-556483 ER - TY - JOUR A1 - Maes, Sybryn L. A1 - Perring, Michael P. A1 - Vanhellemont, Margot A1 - Depauw, Leen A1 - Van den Bulcke, Jan A1 - Brumelis, Guntis A1 - Brunet, Jorg A1 - Decocq, Guillaume A1 - den Ouden, Jan A1 - Härdtle, Werner A1 - Hedl, Radim A1 - Heinken, Thilo A1 - Heinrichs, Steffi A1 - Jaroszewicz, Bogdan A1 - Kopecký, Martin A1 - Malis, Frantisek A1 - Wulf, Monika A1 - Verheyen, Kris T1 - Environmental drivers interactively affect individual tree growth across temperate European forests JF - Global change biology N2 - Forecasting the growth of tree species to future environmental changes requires abetter understanding of its determinants. Tree growth is known to respond to global‐change drivers such as climate change or atmospheric deposition, as well as to localland‐use drivers such as forest management. Yet, large geographical scale studiesexamining interactive growth responses to multiple global‐change drivers are relativelyscarce and rarely consider management effects. Here, we assessed the interactiveeffects of three global‐change drivers (temperature, precipitation and nitrogen deposi-tion) on individual tree growth of three study species (Quercus robur/petraea, Fagus syl-vatica and Fraxinus excelsior). We sampled trees along spatial environmental gradientsacross Europe and accounted for the effects of management for Quercus. We collectedincrement cores from 267 trees distributed over 151 plots in 19 forest regions andcharacterized their neighbouring environment to take into account potentially confounding factors such as tree size, competition, soil conditions and elevation. Wedemonstrate that growth responds interactively to global‐change drivers, with species ‐specific sensitivities to the combined factors. Simultaneously high levels of precipita-tion and deposition benefited Fraxinus, but negatively affected Quercus’ growth, high-lighting species‐specific interactive tree growth responses to combined drivers. ForFagus, a stronger growth response to higher temperatures was found when precipita-tion was also higher, illustrating the potential negative effects of drought stress underwarming for this species. Furthermore, we show that past forest management canmodulate the effects of changing temperatures on Quercus’ growth; individuals in plotswith a coppicing history showed stronger growth responses to higher temperatures.Overall, our findings highlight how tree growth can be interactively determined by glo-bal‐change drivers, and how these growth responses might be modulated by past for-est management. By showing future growth changes for scenarios of environmentalchange, we stress the importance of considering multiple drivers, including past man-agement and their interactions, when predicting tree growth. KW - basal area increment KW - climate change KW - Fagus KW - Fraxinus KW - historical ecology KW - nitrogen deposition KW - Quercus KW - tree-ring analysis Y1 - 2018 U6 - https://doi.org/10.1111/gcb.14493 SN - 1354-1013 SN - 1365-2486 VL - 25 IS - 1 SP - 201 EP - 217 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Lischke, Betty A1 - Hilt, Sabine A1 - Janse, Jan H. A1 - Kuiper, Jan J. A1 - Mehner, Thomas A1 - Mooij, Wolf M. A1 - Gaedke, Ursula T1 - Enhanced input of terrestrial particulate organic matter reduces the resilience of the clear-water state of shallow lakes: A model study JF - Ecosystems N2 - The amount of terrestrial particulate organic matter (t-POM) entering lakes is predicted to increase as a result of climate change. This may especially alter the structure and functioning of ecosystems in small, shallow lakes which can rapidly shift from a clear-water, macrophyte-dominated into a turbid, phytoplankton-dominated state. We used the integrative ecosystem model PCLake to predict how rising t-POM inputs affect the resilience of the clear-water state. PCLake links a pelagic and benthic food chain with abiotic components by a number of direct and indirect effects. We focused on three pathways (zoobenthos, zooplankton, light availability) by which elevated t-POM inputs (with and without additional nutrients) may modify the critical nutrient loading thresholds at which a clear-water lake becomes turbid and vice versa. Our model results show that (1) increased zoobenthos biomass due to the enhanced food availability results in more benthivorous fish which reduce light availability due to bioturbation, (2) zooplankton biomass does not change, but suspended t-POM reduces the consumption of autochthonous particulate organic matter which increases the turbidity, and (3) the suspended t-POM reduces the light availability for submerged macrophytes. Therefore, light availability is the key process that is indirectly or directly changed by t-POM input. This strikingly resembles the deteriorating effect of terrestrial dissolved organic matter on the light climate of lakes. In all scenarios, the resilience of the clear-water state is reduced thus making the turbid state more likely at a given nutrient loading. Therefore, our study suggests that rising t-POM input can add to the effects of climate warming making reductions in nutrient loadings even more urgent. KW - climate change KW - PCLake KW - bistability KW - alternative stable states KW - critical nutrient loading KW - ecosystem modeling KW - allochthony KW - t-POM Y1 - 2014 U6 - https://doi.org/10.1007/s10021-014-9747-7 SN - 1432-9840 SN - 1435-0629 VL - 17 IS - 4 SP - 616 EP - 626 PB - Springer CY - New York ER - TY - THES A1 - Grimm-Seyfarth, Annegret T1 - Effects of climate change on a reptile community in arid Australia T1 - Auswirkungen von Klimawandel auf eine Reptiliengemeinschaft im ariden Australien BT - exploring mechanisms and processes in a hot, dry, and mysterious ecosystem BT - eine Untersuchung von Mechanismen und Prozessen in einem heißen, trockenen, und rätselhaften Ökosystem N2 - Dies ist eine kumulative Dissertation, die drei Originalstudien umfasst (eine publiziert, eine in Revision, eine eingereicht; Stand Dezember 2017). Sie untersucht, wie Reptilienarten im ariden Australien auf verschiedene klimatische Parameter verschiedener räumlicher Skalen reagieren und analysiert dabei zwei mögliche zugrunde liegende Hauptmechanismen: Thermoregulatorisches Verhalten und zwischenartliche Wechselwirkungen. In dieser Dissertation wurden umfassende, individuenbasierte Felddaten verschiedener trophischer Ebenen kombiniert mit ausgewählten Feldexperimenten, statistischen Analysen, und Vorhersagemodellen. Die hier erkannten Mechanismen und Prozesse können nun genutzt werden, um mögliche Veränderungen der ariden Reptiliengesellschaft in der Zukunft vorherzusagen. Dieses Wissen wird dazu beitragen, dass unser Grundverständnis über die Konsequenzen des globalen Wandels verbessert und Biodiversitätsverlust in diesem anfälligen Ökosystem verhindert wird. N2 - This is a cumulative dissertation comprising three original studies (one published, one in revision, one submitted; Effective December 2017) investigating how reptile species in arid Australia respond to various climatic parameters at different spatial scales and analysing the two potential main underlying mechanisms: thermoregulatory behaviour and species interactions. This dissertation combines extensive individual-based field data across trophic levels, selected field experiments, statistical analyses, and predictive modelling techniques. Mechanisms and processes detected in this dissertation can now be used to predict potential future changes in the community of arid-zone lizards. This knowledge will help improving our fundamental understanding of the consequences of global change and thereby prevent biodiversity loss in a vulnerable ecosystem. KW - Australien KW - Reptilien KW - Australia KW - reptiles KW - Populationsökologie KW - population ecology KW - Thermoregulationsverhalten KW - thermoregulatory behaviour KW - interspezifische Wechselwirkungen KW - interspecific interactions KW - Vorhersagemodelle KW - predictive modelling KW - Klimawandel KW - climate change KW - Wüste KW - desert Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-412655 ER -