Tomasz Okruszko

Silica uptake in aquatic and wetland macrophytes: a strategic choice between silica, lignin and cellulose?

*Although silica (Si) is not an essential element for plant growth in the classical sense, evidence points towards its functionality for a better resistance against (a)biotic stress. Recently, it was shown that wetland vegetation has a considerable impact on silica biogeochemistry. However, detailed information on Si uptake in aquatic macrophytes is lacking. *We investigated the biogenic silica (BSi), cellulose and lignin content of 16 aquatic/wetland species along the Biebrza river (Poland) in June 2006 and 2007. The BSi data were correlated with cellulose and lignin concentrations. *Our results show that macrophytes contain significant amounts of BSi: between 2 and 28 mg BSi g(-1). This is in the same order of magnitude as wetland species (especially grasses). Significant antagonistic correlations were found between lignin, cellulose and BSi content. Interestingly, observed patterns were opposite for wetland macrophytes and true aquatic macrophytes. *We conclude that macrophytes have an overlooked but potentially vast storage capacity for Si. Study of their role as temporal silica sinks along the land-ocean continuum is needed. This will further understanding of the role of ecosystems on land ocean transport of this essential nutrient.

Low investment in sexual reproduction threatens plants adapted to phosphorus limitation

Plant species diversity in Eurasian wetlands and grasslands depends not only on productivity but also on the relative availability of nutrients, particularly of nitrogen and phosphorus. Here we show that the impacts of nitrogen:phosphorus stoichiometry on plant species richness can be explained by selected plant life-history traits, notably by plant investments in growth versus reproduction. In 599 Eurasian sites with herbaceous vegetation we examined the relationship between the local nutrient conditions and community-mean life-history traits. We found that compared with plants in nitrogen-limited communities, plants in phosphorus-limited communities invest little in sexual reproduction (for example, less investment in seed, shorter flowering period, longer lifespan) and have conservative leaf economy traits (that is, a low specific leaf area and a high leaf dry-matter content). Endangered species were more frequent in phosphorus-limited ecosystems and they too invested little in sexual reproduction. The results provide new insight into how plant adaptations to nutrient conditions can drive the distribution of plant species in natural ecosystems and can account for the vulnerability of endangered species.

A multi-scale hierarchical framework for developing understanding of river behaviour to support river management

This paper introduces this special issue of Aquatic Sciences. It outlines a multi-scale, hierarchical framework for developing process-based understanding of catchment to reach hydromorphology that can aid design and delivery of sustainable river management solutions. The framework was developed within the REFORM (REstoring rivers FOR effective catchment Management) project, funded by the European Union’s FP7 Programme. Specific aspects of this ‘REFORM framework’ and some applications are presented in other papers in this special issue. The REFORM framework is founded on previous hierarchical frameworks, sixteen examples of which are reviewed. However, the REFORM framework has some particular properties that reflect the European context for which it was developed. The framework delineates regional landscapes into nested spatial units at catchment, landscape unit, segment, reach, geomorphic unit and finer scales. Reaches, regardless of their ‘naturalness’, are assigned to a river type based on valley confinement, planform and bed material. Indicators are quantified at each spatial scale to feed three groups of assessments. First, contemporary indicators at reach and geomorphic unit scales investigate present processes, forms and human pressures within each reach. These feed assessments of present reach hydromorphological function/alteration, including whether the reach is functioning appropriately for its type; riparian corridor function and alteration; and hydromorphological adjustment. Second, indicators at catchment to segment scales investigate water and sediment production and delivery to reaches and how these are affected by human pressures now and in the past. These are used to construct an inventory of changes over space and time. Third, historical reach and geomorphic unit scale indicators are used to construct the trajectory of reach-scale changes. Contemporary reach-scale assessments, space–time inventory, and trajectory of changes are then combined to establish how river reaches of different type, subject to different human pressures, and located in different environmental contexts behave in response to changes at all considered spatial scales. These support forecasts of the likely responses of reaches to future scenarios (e.g., changes in climate, land cover, channel interventions).

Eco-Hydrological Functioning of the Biebrza Wetlands: Lessons for the Conservation and Restoration of Deteriorated Wetlands

Human activities have led to the loss of a large proportion of biodiversity in riverine wetlands in western Europe (Van Urk 1984; Cirujano et al. 1996). In the second half of the twentieth century, many floodplains, fens, and riparian woodlands were cultivated for agricultural purposes. In addition, the remain- ing riverine wetlands lost species due to the impact of human activities (Rich and Woodruff 1996; McCollin et al. 2000). Recently, policy has become more focused on conservation of the remaining wetlands and on rehabilitation of disturbed rivers and floodplains (Jongman 1998). The management and reha- bilitation of wetlands is difficult without adequate knowledge of the hydrolog- ical and ecological processes responsible for the functioning and biodiversity of undisturbed wetlands.

Broad-scale ecosystem services of European wetlands—overview of the current situation and future perspectives under different climate and water management scenarios

Abstract An appropriate hydrological regime within a wetland is essential to maintain its goods and services. This regime is related to the source of the water, which differs for particular kinds of wetlands. This paper presents an overview of the ecosystem services of European wetlands, based on a representative sample of 102 protected wetlands larger than 5000 ha, and the implications of hydrological alterations caused by future climate and socio-economic changes. Six major ecosystem services of wetlands were assessed namely: biodiversity in terms of plants and animals, biomass production, nutrient removal, carbon storage and fish production. Data showed that, on average, four services were present in each wetland. The impact of climate change, water management and land-use change was examined under different future scenarios. Major potential changes in hydrological regime (i.e. precipitation, groundwater recharge and river flow) were quantified up to the 2050s using simulated runoff and river flow data of the WaterGAP model driven by the climate input of two different general circulation models (GCMs), IPCM4 and MIMR. Thresholds of hydrological change that would endanger each ecosystem service were identified. The impacts of future scenarios were distributed across Europe with potential threats to ecosystem services of European wetlands resulting in the loss of between 26 and 46% of all identified ecosystem services in 2050. The models and scenarios suggest that the most significant loss of ecosystem services is likely to occur in Central Europe (Hungary, Germany, France, Belarus, Poland). In general, the most fragile services (the largest number lost) are projected to be those connected to the surface water dynamics—mostly the services of wetland birds and fish spawning. Ecosystem services dependent on groundwater dynamics and water balance changes are seemingly more buffered against the expected hydrological stress. Editor D. Koutsoyiannis Citation Okruszko, T., Duel, H., Acreman, M., Grygoruk, M., Flörke, M. and Schneider, C., 2011. Broad-scale ecosystem services of European wetlands—overview of the current situation and future perspectives under different climate and water management scenarios. Hydrological Sciences Journal, 56 (8), 1501–1517.

Importance of water level dynamics for vegetation patterns in a natural percolation mire (Rospuda fen, NE Poland)

Although conservation of percolation mires is very important for the European biodiversity, our understanding of their functioning is still insufficient, as most of the studied sites are to some extent degraded. We present a study on the relationship between vegetation patterns, hydrochemical gradients and water level fluctuations carried out in the Rospuda valley (NE Poland), which was recently discovered for science as a uniquely preserved fully functioning percolation mire. Vegetation composition, mire water chemistry and water level dynamics were studied along five transects perpendicular to the valley. Eight major vegetation types were identified: brown moss-small and slender sedge fens, Sphagnum-small sedge fens, brown moss-tall sedge fens, tall sedge-reed fens, pine-birch fen woodlands and shrublands, spruce fen woodlands, inundated alder woodlands, alder spring fen woodlands. The seasonal dynamics of water table was revealed as the major factor explaining vegetation patterns. The studied chemical parameters were relatively homogeneous in the whole mire—there is a rather uniform type of mineral-rich nutrient-poor subsurface water all across the fen.

Multi-Site Calibration and Validation of the Hydrological Component of SWAT in a Large Lowland Catchment

This study describes an application of a hydrological component of the catchment model, Soil and Water Assessment Tool (SWAT) in the Narew basin (ca. 28,000 km2) situated in the north-east of Poland. The main objective was to perform a multi-site (spatially distributed) calibration and validation of SWAT using daily observed flows from 23 gauging stations as well as to assess the model’s capability to perform reliable simulations at spatial scales that were smaller than those in the calibration phase. A detailed description of the model configuration for the Narew basin upstream from Zambski Kościelne gauge has been given. Building a SWAT project for a large-scale application appeared to be a demanding task, with the most critical part of preparing soil input data. Sensitivity analysis performed using a LH-OAT method indicated which parameters should be used in autocalibration. The ParaSol tool allowed to find the best parameter values from 8D parameter space in 11 calibration areas. The calibrated model generally performed well, with average Nash–Sutcliffe Efficiency for daily data equal to 0.68 for calibration period and 0.57 for validation period. SWAT correctly conserved the mass balance in different parts of the catchment as well as at the main outlet. The model results were significantly better in large basins than in small basins. Spatial validation performed at 12 independent catchments ranging in size from 355 to 1,657 km2 revealed that adapted SWAT model should rather not be used in the Narew basin catchments smaller than ca. 600 km2. It is believed that ensuring reliability of SWAT results at smaller spatial scales, which would be of interest to decision-makers, would require providing better input data and in particular using significantly more precipitation stations.

Evaluating the role of participation in modeling studies for environmental planning

Stakeholder participation in modeling studies is often advocated as a means to enhance the acceptability of these studies. In turn, acceptability of modeling studies is considered as an important factor stimulating their actual use in policy making. Although these hypotheses are generally accepted, to date little empirical evidence is available to support or reject them. This study aims at exploring in more detail whether or not stakeholder participation increases acceptability of modeling studies and the use of their results in policy making, and how that can be understood. For this purpose thirteen projects were analyzed. Methods employed included a review of project reports and further papers on the project, as well as standardized surveys with scientists involved in the cases and open oral interviews with other key figures. A majority of the projects concerned European cases in which land use and exploitation of water resources had to be planned in combination. Our results suggest that acceptability of modeling studies is correlated to the actual use of these studies, although it does not seem to be a prerequisite. In turn, acceptability of modeling studies is positively correlated to a participatory approach. The latter is also correlated to the extent to which policy-oriented learning took place during modeling studies. In addition our study shows that stakeholder participation enhances acceptability of the models by allowing stakeholders to contribute ideas, knowledge, and priorities. Also communication of studies and their results to stakeholders is important for the acceptability of models. Finally, applicability of models seems to be a prerequisite for their acceptability. No evidence was found of the acceptability of models being positively influenced by the models credibility, the extent to which models reduce uncertainties, the insights that models give into the effects of policies, the transparency of models and modeling studies, nor the extent to which they facilitate a mutual understanding of actors with conflicting interests. We recommend further testing of the general validity of our conclusions by evaluating other projects.

Groundwater Modelling and Hydrological System Analysis of Wetlands in the Middle Biebrza Basin

In the presented approach, a three dimensional finite-difference steady-state groundwater model was applied to analyze the groundwater flow system of the Middle Biebrza Basin. Study contains analysis of hydrogeological and morphological outline of the area, as well as the description of developed groundwater model including conceptual model description, model calibration and sensitivity analysis of parameters. Analysis of volumetric water budget of the model within assumed boundary conditions indicated that groundwater resources of the analyzed part of the Middle Biebrza Basin in approximately 80% come from lateral inflow from the adjacent plateaus. Analysis of spatial distribution of groundwater discharge indicated that the most intensive groundwater inflow to the top peat layer is concentrated within the “Czerwone Bagno”, where the peatlands are not degraded and wetland habitats develop naturally, not being directly impacted by drainage ditches and canals.

Hydrological modelling of the Vistula and Odra river basins using SWAT

ABSTRACT This paper presents a large-scale application of the SWAT model for water balance and natural streamflow simulation in the entire basins of the Vistula and the Odra, covering most of the territory of Poland. A tailored calibration approach was designed to achieve satisfactory goodness-of-fit across a range of catchment sizes. Model calibration and evaluation driven by high-resolution climate data showed overall good behaviour for 80 benchmark catchments divided into eight clusters, and spatial evaluation for 30 gauges showed that the designed regionalization scheme performed well (median KGE of 0.76). Basin-averaged estimates of blue and green water flow and green water storage estimated using the calibrated model were 185, 517 and 206 mm, respectively. This study provides a basis for future work, such as assessing climate change impacts on hydrology, assessing flow alterations, and water quality simulation. The model output is publicly available through an online research data archive (doi:10.4121/uuid:b8ab4f5f-f692-4c93-a910-2947aea28f42). EDITOR A. Castellarin ASSOCIATE EDITOR G. Thirel