TY - JOUR A1 - Carus, Jana A1 - Heuner, Maike A1 - Paul, Maike A1 - Schröder, Boris T1 - Plant distribution and stand characteristics in brackish marshes BT - Unravelling the roles of abiotic factors and interspecific competition JF - Estuarine, Coastal and Shelf Science N2 - Due to increasing pressure on estuarine marshes from sea level rise and river training, there is a growing need to understand how species-environment relationships influence the zonation and growth of tidal marsh vegetation. In the present study, we investigated the distribution and stand characteristics of the two key brackish marsh species Bolboschoenus maritimus and Phragmites australis in the Elbe estuary together with several abiotic habitat factors. We then tested the effect of these habitat factors on plant growth and zonation with generalised linear models (GLMs). Our study provides detailed information on the importance of single habitat factors and their interactions for controlling the distribution patterns and stand characteristics of two key marsh species. Our results suggest that flow velocity is the main factor influencing species distribution and stand characteristics and together with soil-water salinity even affects the inundation tolerance of the two specie investigated here. Additionally, inundation height and duration as well as interspecific competition helped explain the distribution patterns and stand characteristics. By identifying the drivers of marsh zonation and stand characteristics and quantifying their effects, this study provides useful information for evaluating a future contribution of tidal marsh vegetation to ecosystem-based shore protection. KW - Bolboschoenus maritimus KW - Elbe estuary KW - Flow velocity KW - Inundation KW - Phragmites australis KW - Soil-water salinity Y1 - 2017 U6 - https://doi.org/10.1016/j.ecss.2017.06.038 SN - 0272-7714 SN - 1096-0015 VL - 196 SP - 237 EP - 247 PB - Elsevier CY - London ER - TY - THES A1 - Carus, Jana T1 - Plant-habitat interactions in brackish marshes T1 - Pflanzen-Habitat Interaktionen in Tidemarschen BT - coping with, adapting to and modifying the environment N2 - Estuarine marshes are ecosystems that are situated at the transition zone between land and water and are thus controlled by physical and biological interactions. Marsh vegetation offers important ecosystem services by filtrating solid and dissolved substances from the water and providing habitat. By buffering a large part of the arriving flow velocity, attenuating wave energy and serving as erosion control for riverbanks, tidal marshes furthermore reduce the destructive effects of storm surges and storm waves and thus contribute to ecosystem-based shore protection. However, in many estuaries, extensive embankments, artificial bank protection, river dredging and agriculture threaten tidal marshes. Global warming might entail additional risks, such as changes in water levels, an increase of the tidal amplitude and a resulting shift of the salinity zones. This can affect the dynamics of the shore and foreland vegetation, and vegetation belts can be narrowed or fragmented. Against this background, it is crucial to gain a better understanding of the processes underlying the spatio temporal vegetation dynamics in brackish marshes. Furthermore, a better understanding of how plant-habitat relationships generate patterns in tidal marsh vegetation is vital to maintain ecosystem functions and assess the response of marshes to environmental change as well as the success of engineering and restoration projects. For this purpose, three research objectives were addressed within this thesis: (1) to explore the possibility of vegetation serving as self-adaptive shore protection by quantifying the reduction of current velocity in the vegetation belt and the morphologic plasticity of a brackish marsh pioneer, (2) to disentangle the roles of abiotic factors and interspecific competition on species distribution and stand characteristics in brackish marshes, and (3) to develop a mechanistic vegetation model that helps analysing the influence of habitat conditions on the spatio-temporal dynamic of tidal marsh vegetation. These aspects were investigated using a combination of field studies and statistical as well as process-based modelling. To explore the possibility of vegetation serving as self-adaptive coastal protection, in the first study, we measured current velocity with and without living vegetation, recorded ramet density and plant thickness during two growing periods at two locations in the Elbe estuary and assessed the adaptive value of a larger stem diameter of plants at locations with higher mechanical stress by biomechanical measurements. The results of this study show that under non-storm conditions, the vegetation belt of the marsh pioneer Bolboschoenus maritimus is able to buffer a large proportion of the flow velocity. We were furthermore able to show that morphological traits of plant species are adapted to hydrodynamic forces by demonstrating a positive correlation between ramet thickness and cross-shore current. In addition, our measurements revealed that thicker ramets growing at the front of the vegetation belt have a significantly higher stability than ramets inside the vegetation belt. This self-adaptive effect improves the ability of B. maritimus to grow and persist in the pioneer zone and could provide an adaptive value in habitats with high mechanical stress. In the second study, we assessed the distribution of the two marsh species and a set of stand characteristics, namely aboveground and belowground biomass, ramet density, ramet height and the percentage of flowering ramets. Furthermore, we collected information on several abiotic habitat factors to test their effect on plant growth and zonation with generalised linear models (GLMs). Our results demonstrate that flow velocity is the main factor controlling the distribution of Bolboschoenus maritimus and Phragmites australis. Additionally, inundation height and duration, as well as intraspecific competition affect distribution patterns. This study furthermore shows that cross-shore flow velocity does not only directly influence the distribution of the two marsh species, but also alters the plants’ occurrence relative to inun-dation height and duration. This suggests an effect of cross-shore flow velocity on their tolerance to inundation. The analysis of the measured stand characteristics revealed a negative effect of total flow velocity on all measured parameters of B. maritimus and thus confirmed our expectation that flow velocity is a decisive stressor which influences the growth of this species. To gain a better understanding of the processes and habitat factors influencing the spatio-temporal vegetation dynamics in brackish marshes, I built a spatially explicit, mechanistic model applying a pattern-oriented modelling approach. A sensitivity analysis of the para-meters of this dynamic habitat-macrophyte model HaMac suggests that rhizome growth is the key process for the lateral dynamics of brackish marshes. From the analysed habitat factors, P. australis patterns were mainly influenced by flow velocity. The competition with P. australis was of key importance for the belowground biomass of B. maritimus. Concerning vegetation dynamics, the model results emphasise that without the effect of flow velocity the B. maritimus vegetation belt would expand into the tidal flat at locations with present vegetation recession, suggesting that flow velocity is the main reason for vegetation recession at exposed locations. Overall, the results of this thesis demonstrate that brackish marsh vegetation considerably contributes to flow reduction under average flow conditions and can hence be a valuable component of shore-protection schemes. At the same time, the distribution, growth and expansion of tidal marsh vegetation is substantially influenced by flow. Altogether, this thesis provides a clear step forward in understanding plant-habitat interactions in tidal marshes. Future research should integrate studies of vertical marsh accretion with research on the factors that control the lateral position of marshes. N2 - Tidemarschen sind Ökosysteme, die sich am Übergang zwischen Land und Wasser befinden und deshalb von Wechselwirkungen zwischen physikalischen und biologischen Prozessen beherrscht werden. Marschvegetation bietet wichtige Ökosystemleistungen, wie das Filtern von festen und gelösten Stoffen aus dem Wasser und die Bereitstellung von Lebensraum für Tiere. Außerdem verringern Marschen die zerstörerische Wirkung von Sturmfluten und Sturmwellen und tragen so zu einem ökosystembasierten Uferschutz bei. Doch in vielen Fluss­mündungen bedrohen umfangreiche Eindeichungen, künstlicher Uferschutz, Fluss­ver­tiefun­gen und die Landwirtschaft die Tidemarschen. Die globale Erwärmung könnte zusätz­liche Risiken, wie etwa Änderungen der Wasserstände, eine weitere Erhöhung der Gezeiten­amplitude und eine daraus resultierende Verschiebung der Salinitätszonen mit sich bringen. Dies kann die Dynamik der Ufer- und Vorlandvegetation beeinflussen und die Vegetations­gürtel verschmälern oder fragmentieren. Vor diesem Hintergrund ist es entscheidend, ein besseres Verständnis der Prozesse zu erlangen, die der raum-zeitlichen Vegetationsdynamik in Tidemarschen zugrunde liegen. Darüber hinaus ist sind zusätzliche Erkenntnisse darüber, wie Pflanzen-Umwelt-Beziehungen die Muster in Marschen beeinflussen, von entscheidender Bedeutung um Ökosystemfunktionen aufrechtzuerhalten und die Reaktion von Marschen auf Umweltveränderungen sowie den Erfolg von Ingenieur- und Restaurierungsprojekten zu bewerten. Zu diesem Zweck wurden in dieser Arbeit drei Forschungsziele gesetzt: (1) das Erforschen der Möglichkeit der Vegetation als selbstanpassender Uferschutz zu dienen, (2) das Ermitteln der Rolle verschiedener Faktoren auf die Artenverbreitung und verschiedene Pflanzen­merk­male in Tidemarschen und (3) die Entwicklung eines prozess-basierten Vegetations­modells, das die Analyse des Einflusses von Lebensraumbedingungen auf die raum-zeitliche Dynamik der Marschvegetation unterstützt. Diese Aspekte wurden anhand einer Kombination von Feld­studien und statistischer sowie prozessbasierter Modellierung untersucht. Ins­gesamt zeigen die Ergebnisse dieser Arbeit, dass die Marschvegetation erheblich zur Strömungsreduktion unter durchschnittlichen Strömungsverhältnissen beiträgt und somit ein wertvoller Bestandteil von Uferschutzsystemen sein kann. Darüber hinaus konnte Strömung als Hauptfaktor für die Verbreitung, das Wachstum und die Expansion von Marschvegetation identifiziert werden. Diese Arbeit trägt maßgeblich zur Verbesserung des Verständnisses von Pflanzen-Habitat Interaktionen in Tidemarschen bei. Zukünftige Forschung sollte Studien des vertikalen Marschwachstums mit der Analyse der Faktoren, die die laterale Position der Marschen kontrollieren verknüpfen. KW - plant-habitat interactions KW - estuary KW - ecological modelling KW - Pflanzen-Habitat Interaktionen KW - Ästuar KW - ökologische Modellierung Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-404966 ER - TY - JOUR A1 - Müller, Eva Nora A1 - van Schaik, Loes A1 - Blume, Theresa A1 - Bronstert, Axel A1 - Carus, Jana A1 - Fleckenstein, Jan H. A1 - Fohrer, Nicola A1 - Geissler, Katja A1 - Gerke, Horst H. A1 - Gräff, Thomas A1 - Hesse, Cornelia A1 - Hildebrandt, Anke A1 - Hölker, Franz A1 - Hunke, Philip A1 - Körner, Katrin A1 - Lewandowski, Jörg A1 - Lohmann, Dirk A1 - Meinikmann, Karin A1 - Schibalski, Anett A1 - Schmalz, Britta A1 - Schröder-Esselbach, Boris A1 - Tietjen, Britta T1 - Scales, key aspects, feedbacks and challenges of ecohydrological research in Germany JF - Hydrologie und Wasserbewirtschaftung N2 - Ecohydrology analyses the interactions of biotic and abiotic aspects of our ecosystems and landscapes. It is a highly diverse discipline in terms of its thematic and methodical research foci. This article gives an overview of current German ecohydrological research approaches within plant-animal-soil-systems, meso-scale catchments and their river networks, lake systems, coastal areas and tidal rivers. It discusses their relevant spatial and temporal process scales and different types of interactions and feedback dynamics between hydrological and biotic processes and patterns. The following topics are considered key challenges: innovative analysis of the interdisciplinary scale continuum, development of dynamically coupled model systems, integrated monitoring of coupled processes at the interface and transition from basic to applied ecohydrological science to develop sustainable water and land resource management strategies under regional and global change. KW - Coastal regions KW - drylands KW - ecohydrological modelling KW - feedback KW - hyporheic zone KW - meso-scale ecosystems KW - plant-animal-soil-system KW - river networks Y1 - 2014 U6 - https://doi.org/10.5675/HyWa_2014,4_2 SN - 1439-1783 VL - 58 IS - 4 SP - 221 EP - 240 PB - Bundesanst. für Gewässerkunde CY - Koblenz ER - TY - JOUR A1 - Carus, Jana A1 - Paul, Maike A1 - Schroeder, Boris T1 - Vegetation as self-adaptive coastal protection: Reduction of current velocity and morphologic plasticity of a brackish marsh pioneer JF - Ecology and evolution N2 - By reducing current velocity, tidal marsh vegetation can diminish storm surges and storm waves. Conversely, currents often exert high mechanical stresses onto the plants and hence affect vegetation structure and plant characteristics. In our study, we aim at analysing this interaction from both angles. On the one hand, we quantify the reduction of current velocity by Bolboschoenus maritimus, and on the other hand, we identify functional traits of B. maritimus’ ramets along environmental gradients. Our results show that tidal marsh vegetation is able to buffer a large proportion of the flow velocity at currents under normal conditions. Cross-shore current velocity decreased with distance from the marsh edge and was reduced by more than 50% after 15 m of vegetation. We were furthermore able to show that plants growing at the marsh edge had a significantly larger diameter than plants from inside the vegetation. We found a positive correlation between plant thickness and cross-shore current which could provide an adaptive value in habitats with high mechanical stress. With the adapted morphology of plants growing at the highly exposed marsh edge, the entire vegetation belt is able to better resist the mechanical stress of high current velocities. This self-adaptive effect thus increases the ability of B. maritimus to grow and persist in the pioneer zone and may hence better contribute to ecosystem-based coastal protection by reducing current velocity. KW - Adaptive value KW - Bolboschoenus maritimus KW - brackish marsh KW - flow velocity KW - mechanical pressure KW - morphological adaptation KW - phenotypic plasticity KW - pioneer zone Y1 - 2016 U6 - https://doi.org/10.1002/ece3.1904 SN - 2045-7758 VL - 6 SP - 1579 EP - 1589 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Carus, Jana A1 - Heuner, Maike A1 - Paul, Maike A1 - Schröder, Boris T1 - Which factors and processes drive the spatio-temporal dynamics of brackish marshes?-Insights from development and parameterisation of a mechanistic vegetation model JF - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog N2 - Tidal marsh vegetation offers important ecosystem services. However, in many estuaries, extensive embankments, artificial bank protection, river dredging and agriculture threaten tidal marshes. In this study we analysed the processes underlying the spatio-temporal patterns of tidal marsh vegetation in the Elbe estuary and quantified the influence of specific habitat factors by developing and applying the process-based dynamic habitat-macrophyte model HaMac in a pattern-oriented way. In order to develop and parameterise the model, we measured a wide range of biotic and abiotic parameters in two study sites in the Elbe estuary and compared observed and simulated patterns. The final model is able to reproduce the general patterns of vegetation zonation, development and growth and thus helps to understand the underlying processes. By considering the vegetative reproduction of marsh plants as well as abiotic influence factors and intraspecific competition, HaMac allowed to systematically analyse the significance of factors and processes for the dynamic of tidal marsh vegetation. Our results show that rhizome growth is the most important process and that flow velocity, inundation height and duration as well as intraspecific competition are the most important habitat factors for explaining spatio-temporal dynamics of brackish marshes. Future applications of HaMac could support the sustainable development and stabilisation of shore zones and thus contribute to the promotion and planning of ecosystem -based shoreline protection measures. (C) 2017 Elsevier B.V. All rights reserved. KW - Bolboschoenus maritimus KW - Emergent macrophytes KW - Pattern-oriented modelling KW - Phragmites australis KW - Tidal marsh vegetation KW - Vegetative reproduction Y1 - 2017 U6 - https://doi.org/10.1016/j.ecolmodel.2017.08.023 SN - 0304-3800 SN - 1872-7026 VL - 363 SP - 122 EP - 136 PB - Elsevier CY - Amsterdam ER -