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 - JOUR A1 - Lehr, Christian A1 - Dannowski, Ralf A1 - Kalettka, Thomas A1 - Merz, Christoph A1 - Schröder, Boris A1 - Steidl, Jörg A1 - Lischeid, Gunnar T1 - Detecting dominant changes in irregularly sampled multivariate water quality data sets JF - Hydrology and earth system sciences : HESS N2 - Time series of groundwater and stream water quality often exhibit substantial temporal and spatial variability, whereas typical existing monitoring data sets, e.g. from environmental agencies, are usually characterized by relatively low sampling frequency and irregular sampling in space and/or time. This complicates the differentiation between anthropogenic influence and natural variability as well as the detection of changes in water quality which indicate changes in single drivers. We suggest the new term "dominant changes" for changes in multivariate water quality data which concern (1) multiple variables, (2) multiple sites and (3) long-term patterns and present an exploratory framework for the detection of such dominant changes in data sets with irregular sampling in space and time. Firstly, a non-linear dimension-reduction technique was used to summarize the dominant spatiotemporal dynamics in the multivariate water quality data set in a few components. Those were used to derive hypotheses on the dominant drivers influencing water quality. Secondly, different sampling sites were compared with respect to median component values. Thirdly, time series of the components at single sites were analysed for long-term patterns. We tested the approach with a joint stream water and groundwater data set quality consisting of 1572 samples, each comprising sixteen variables, sampled with a spatially and temporally irregular sampling scheme at 29 sites in northeast Germany from 1998 to 2009. The first four components were interpreted as (1) an agriculturally induced enhancement of the natural background level of solute concentration, (2) a redox sequence from reducing conditions in deep groundwater to post-oxic conditions in shallow groundwater and oxic conditions in stream water, (3) a mixing ratio of deep and shallow groundwater to the streamflow and (4) sporadic events of slurry application in the agricultural practice. Dominant changes were observed for the first two components. The changing intensity of the first component was interpreted as response to the temporal variability of the thickness of the unsaturated zone. A steady increase in the second component at most stream water sites pointed towards progressing depletion of the denitrification capacity of the deep aquifer. Y1 - 2018 U6 - https://doi.org/10.5194/hess-22-4401-2018 SN - 1027-5606 SN - 1607-7938 VL - 22 IS - 8 SP - 4401 EP - 4424 PB - Copernicus CY - Göttingen 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 -