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Highlights: [•] Flooding drives ecological processes in river floodplains. [•] According to the Flood Pulse Concept, river water connects the entire floodplain. [•] Contrastingly, groundwater and atmospheric water are dominating water sources. [•] These three water sources appear in a spatial pattern in the Biebrza floodplain. [•] Our findings urge for a revision of the Flood Pulse Concept. [ABSTRACT FROM AUTHOR]

Abstract: The effectiveness of measures targeted at the restoration of populations of endangered species in anthropogenically dominated regions is often limited by a combination of insufficient restoration of habitat quality and dispersal failure. Therefore, the joint prediction of suitable habitat and seed dispersal in dependency of management actions is required for effective nature management. Here we demonstrate an approach, which links a habitat suitability and a seed dispersal model. The linked model describes potential species distribution as a function of current species distribution, species-specific dispersal traits, the number of successful dispersal events, dispersal infrastructure and habitat configuration. The last two variables were related to water management actions. We demonstrate the applicability of the model in a strategy analysis of hydrological restoration measures for a large fen area in which still numerous endangered plant species grow. With the aid of the linked model, we were able to optimise the spatial planning of restoration measures, taking into account both the constraints of water management practices on abiotic restoration and the effects of habitat fragmentation on dispersal. Moreover, we could demonstrate that stand-alone habitat suitability models, which assume unlimited dispersal, may considerably overestimate restoration prospects. For these reasons, we conclude that linked habitat suitability and dispersal models can provide useful insights into spatially differentiated potentials and constraints of nature restoration measures targeted at the sustainable conservation of endangered plant populations whose habitats have been deteriorated due to undesirable effects of land and water management on abiotic conditions. These insights may contribute to the design of cost-effective nature restoration and conservation measures. [Copyright &y& Elsevier]

Summary: Knowledge of the hydrological mechanisms that underlie stable plant communities within natural fens is essential for the improvement of current fen restoration and conservation strategies. In this study, steady-state groundwater modelling was performed to quantify the impact of throughflow mechanisms on the presence of exfiltrated, alkaline groundwater across a near-natural fen in the Biebrza River catchment (Poland). Alkaline groundwater is considered essential for the existence of low-productive fen plants. The results indicate that throughflow redistributes exfiltrated groundwater, mixed with locally infiltrated precipitation, in various concentrations across the fen. The throughflow model provides an explanation for the major patterns in the plant alliances that have a preference for minerotrophic or ombrotrophic habitat conditions. These patterns could not be reproduced with groundwater models that did not account for the existence of throughflow on a regional scale. We conclude that throughflow (1) enables a spatially contiguous supply of exfiltrated groundwater across fens, and thereby (2) facilitates abiotic conditions suitable for fen plants outside the zones that are directly supplied by exfiltrated groundwater. These new insights into landscape hydrological mechanisms that drive abiotic conditions within natural fens necessitate the reprioritisation of current hydrological fen restoration strategies. [Copyright &y& Elsevier]

Summary: Knowledge of the anthropogenic impact on the hydrology of low-productive fens that are subject to environmental degradation is essential to improve currently utilized hydrological fen restoration strategies. We analyse the naturally and anthropogenically driven evolution of groundwater systems in an intensively managed fen area in The Netherlands using a series of three-dimensional palaeo-groundwater models at a high spatial and temporal resolution. These palaeo-models are representative for five time slices of the time frame 0–2000 AD (Anno Domini), which are defined according to the timing of the natural and anthropogenic developments that had major impacts on the groundwater system configuration. For each time slice, palaeo-geohydrological conditions are reconstructed, which allowed for the calculation of groundwater discharge patterns, water balances and groundwater flow patterns. Contrary to former studies on the evolution of groundwater systems, our palaeo-hydrological reconstruction indicates that current groundwater discharge flux into managed fens may exceed the late-natural groundwater discharge flux. The increased groundwater discharge flux relates to the development of groundwater systems in the river valley with the establishment of polders since 1350AD. Notably, more recent redirections of groundwater flow due to the reclamation of lakes and the establishment of abstractions wells, as well as the decreased groundwater recharge by anthropogenic land cover change, reduced the groundwater discharge flux only to a minor extent. This finding opposes the hypothesis that a decreased groundwater flux to fens underlies the environmental degradation of fens in intensively managed regions. The palaeo-hydrological reconstruction provides evidence that it is mainly the changes in the spatial configuration, and the shift in the predominant groundwater discharge mechanism, that underlies the environmental degradation of managed low-productive fens. We discuss the consequences of these hydrological changes for the suitability and availability of fen habitat sites. [Copyright &y& Elsevier]