Wiktor Kotowski

University of Warsaw | UW · Department of Plant Ecology and Environmental Conservation / Research Group for Conservarion and Restoration of Ecosystems

Zmniejszające się zasoby wodne w lasach są efektem wpływu człowieka na klimat i ekosystemy ze szczególnym punktem krytycznym w mijających 50 latach. Tysiąc lat temu Polskę pokrywała pierwotna puszcza. Wraz z rozwojem Państwa Polskiego wzrastało zapotrzebowanie na drewno, przez to następowały progresywne wylesienia. Wraz z utratą drzew postępowała c...

Peatlands have been drained for land use for a long time and on a large scale, turning them from carbon and nutrient sinks into respective sources, diminishing water regulation capacity, causing surface height loss and destroying biodiversity. Over the last decades, drained peatlands have been rewetted for biodiversity restoration and, as it strong...

Baltic Sea is one of the World's most oxygen-depletes seas, so the region requires urgent mitigation measures to significantly reduce nitrogen and phosphorus inputs from land through rivers, which cannot be achieved without large-scale restoration of wetland buffer zones. The manuscript summarises the findings of the discrete choice experiment aime...

Ground- and surface-water-fed peatlands (i.e., fens) of temperate Europe face high anthropogenic nutrient loads from atmospheric deposition, agricultural catchment areas, and from peat decomposition, if drained. As a result, nitrogen loads may exceed a fen's natural nutrient removal capacity, leading to increased eutrophication of adjacent water bo...

Fertiliser use in agriculture increases the non-point pollution of waters with nitrogen (N) and phosphorus (P). Wetland buffer zones (WBZs) are wetland ecosystems between agricultural lands and water bodies that protect surface waters from non-point source pollution. We assessed how vegetation harvesting within WBZs impacts their N and P removal ef...

For more than two decades, wetland restoration has been successfully applied in Denmark as a tool to protect watercourses from elevated nutrient inputs from agriculture, but little is known about how the flora and fauna respond to restoration. The main objective of this study was therefore to: (1) examine plant community characteristics in 10 wetla...

Torfowiska stanowią największy lądowy magazyn węgla organicznego. W stanie naturalnym (bagiennym) pochłaniają dwutlenek węgla z atmosfery, akumulując węgiel w torfie. Jeśli się je osuszy, stają się silnymi źródłami gazów cieplarnianych, przyczyniając się do powiększania efektu cieplarnianego. W skali świata odwodnione torfowiska emitują ok. 2 Gt dw...

Peat formation is a key carbon sequestration process in the terrestrial biosphere. In temperate fens, peat is mainly formed by below‐ground biomass of vascular plants. Nutrient availability in temperate fens is naturally variable, and nowadays increasing due to atmospheric deposition, runoff from agriculture, and mineralization of peat caused by dr...

Mesotrophic rich fens, that is, groundwater-fed mires, may be long-lasting, as well as transient ecosystems, displaced in time by poor fens, bogs, forests or eutrophic reeds. We hypothesized that fen stability is controlled by plant stress caused by waterlogging with calcium-rich and nutrient-poor groundwater, which limits expansion of hummock moss...

Many of the world’s peatlands have been affected by water table drawdown and subsequent loss of organic matter. Rewetting has been proposed as a measure to restore peatland functioning and to halt carbon loss, but its effectiveness is subject to debate. An important prerequisite for peatland recovery is a return of typical microbial communities, wh...

Wetland buffer zones (WBZs) are riparian areas that form a transition between terrestrial and aquatic environments and are well-known to remove agricultural water pollutants such as nitrogen (N) and phosphorus (P). This review attempts to merge and compare data on the nutrient load, nutrient loss and nutrient removal and/or retention from multiple...

Large-scale re-establishment of wetland buffer zones (WBZ) along rivers is regarded as an effective measure in order to reduce non-point source nitrogen (N) and phosphorus (P) pollution in agricultural catchments. We estimated efficiency and costs of a hypothetical establishment of WBZs along all watercourses in an agricultural landscape of the low...

Transformation of organic matter components as a result of decomposition processes during peat formation can be investigated using Fourier transform infrared (FTIR) spectra analysis. This method enables calculation of so-called 'Humification Index' (HI), i.e. the ratio of spectral peak intensity of lignin and phenolic compounds (wavenumbers 1600-16...

Background: In fens, plant species composition is predominantly controlled by two environmental factors: root anoxia and low nutrient availability. Aims: We asked how these filters were reflected to the functional structure of plant communities in natural and drained rich fens. Methods: We analysed traits related to species response to anoxia and n...

In peatland restoration we often lack an information whether re-established ecosystems are functionally similar to non-degraded ones. We re-analysed the long-term outcomes of restoration on vegetation and plant functional traits in 38 European fens restored by rewetting (18 sites) and topsoil removal (20 sites). We used traits related to nutrient a...

Questions Fens are important conservation targets in temperate Europe. When hydrologically undisturbed, fens remain open for millennia. However, unaltered fens are scarce, and today their biodiversity largely depends on conservational mowing applied to prevent successional shifts. However, its effects on community structure and conservation values...

The restoration of grasslands is a key management practice that supports biodiversity across Europe. On species poor grasslands and ex-arable fields, the establishment of plant species is often limited by the availability of habitat niches, in particular space to germinate. We investigated the impacts of full inversion tillage and its interaction w...

Peatlands provide globally important ecosystem services through climate and water regulation or biodiversity conservation. While covering only 3% of the earth's surface, degrading peatlands are responsible for nearly a quarter of carbon emissions from the land use sector. Bringing together world-class experts from science, policy and practice to hi...

We explored the background of differences in long–term stability between two parts in an undisturbed mire system (Rospuda fen, NE Poland). We re-constructed the Holocene history of the mire and compared it with current vegetation, water level dynamics, water chemistry and nutri-ent availability in two basins: A, where the mire terrestrialised a dee...

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 plan...

Ecological restoration has traditionally been evaluated with analyses focused on species identities and abundances. These analyses provide no ecological explanation to why certain species change in abundance. One solution may be a functional trait analysis. We asked whether shifts in functional traits could explain vegetation changes in fens restor...

Top-soil removal followed by species introduction through hay transfer has appeared as a method to restore drained fens. This method addresses abiotic constraints by restoring hydrology and nutrient status, and biotic constraints by removing an unwanted seed bank and counteracting dispersal-limitation. Restoration works by altering environmental fi...

Despite the growing concern about the importance of silicon (Si) in controlling ecological processes in aquatic ecosystems, little is known about its processing in riparian vegetation, especially compared to nitrogen (N) and phosphorus (P). We present experimental evidence that relative plant uptake of N and P compared to Si in riparian vegetation...

Semi-natural grasslands are some of the most threatened habitats on the planet, due to the abandonment of small-scale farming and its replacement with intensive agriculture. The fragmented landscape of today has created dispersal limitation that makes improbable the natural dispersal of target species into the remaining patches of grassland. This p...

We investigated the effects of different restoration treatments on the development of fen meadow communities: (1) depth of topsoil removal, with shallow (circa 20 cm) and deep (circa 40 cm) soil removal applied, (2) transfer of seed-containing hay, and (3) access of large animals. We carried out a full factorial experiment with all combinations of...

We carried out an eco-hydrological analysis to evaluate the most important effects of land use changes on the hydrological functioning of a fen system in Poland. We measured water levels (hydraulic heads) and water flow along a transect through the study area and also analysed land use changes using historical maps. Major hydrological changes occur...

The majority of fens in Europe have been transformed for agricultural purposes and have disappeared or become degraded. Fen meadows that developed under low-intensity management of fens also have become degraded. In this paper, we consider the available restoration methods, biotic constraints for restoration and new prospects and approaches for the...

Topsoil removal is an effective, but also expensive method of nature restoration on fens and fen meadows. The high cost is a factor limiting the application of this method, especially in Central European countries, where investments in nature restoration are low.Can we partly balance the high costs of restoration with the method of topsoil removal,...

Natural evolution of wetlands is strongly dependent on groundwater dynamics, soil aeration and climate. These environmental factors determine the constant development of wetland plant communities and peat forming processes. Depending on spatial distribution of groundwater flow systems and recharge and discharge conditions, shallow groundwater can a...

1. The extent to which seedling recruitment contributes to local functional diversity depends on the environmental filters operating in a plant community. Classical community assembly models assume that habitat constraints and competition act like hierarchical filters with habitat filtering as the dominant one. Alternative models assume a synergic...

Shrub removal is commonly used for management and restoration of species-rich fen meadows. A common problem after initial shrub cutting of willow is a vigorous re-sprouting and quick re-growth. In this paper we test experimentally what is an effective management option, limiting the re-growth of willow after cutting, on peat soils. In this experime...

Fens in Central Europe are characterised by waterlogged organic substrate and low productivity. Human-induced changes due to drainage and mowing lead to changes in plant species composition from natural fen communities to fen meadows and later to over-drained, degraded meadows. Moderate drainage leads to increased vegetation productivity, and sever...

1. The extent to which seedling recruitment contributes to local functional diversity depends on the environmental filters operating in a plant community. Classical community assembly models assume that habitat constraints and competition act like hierarchical filters with habitat filtering as the dominant one. Alternative models assume a synergic...

To provide a reference for wetlands elsewhere we analysed soil nutrients and the vegetation of floodplains and fens in the relatively undisturbed Biebrza-valley, Poland. Additionally, by studying sites along a water-table gradient, and by comparing pairs of mown and unmown sites, we aimed with exploring long-term effects of drainage and annual hay-...

This article was submitted without an abstract, please refer to the full-text PDF file.

This article was submitted without an abstract, please refer to the full-text PDF file.

The Biebrza river valley is one of the largest European high value wetlands that remain in good ecological condition. The dominating wetland type is fen with types including groundwater-fed mire. Other high value habitats include meadows and pastures on wet and mesic sites. Most of the meadows in the valley which occur within the park on wet peat s...

Question: What is the relative importance of competition and physical factors in restricting the occurrence of different fen species to certain zones of the riparian landscape? Location: Biebrza National Park, NE Poland. Methods: We carried out a two-season reciprocal transplantation experiment: sod-blocks were replaced between a low-productive gro...

The main objective of these guidelines is to promote the use of floodplains as natural flood defence measures, while at the same time optimising other compatible functions and values through conservation and restoration. It is intended that these guidelines will be used as a tool primarily by policy-makers and decision-makers who are aware of the p...

Abstract: The major problems in the conservation of fens are desiccation, eutrophication, natural succession and in some cases acidification. Management measures, like mowing and shrub removal, are necessary to stop the succession. However, the impact of these measures is not enough to facilitate the re-development of fen and wet meadow vegetation....

Most of open riparian wetlands used to exist for centuries under a low-intensity mowing management. A decline of this management over several past decades is believed to be the main cause of a rapid vegetation succession observed in wetlands throughout Europe often leading to a decrease of biodiversity. We demonstrate the rate and extent of vegetat...

Questions: 1. To what extent does light availability differ among fen plant communities? 2. To what extent does light coincide with productivity and moisture gradients? 3. Does light act as an important environmental filter in natural and transformed riparian landscapes? Location: Current data from the Biebrza Valley, NE Poland; literature data fro...

Fens belong to the most treatened European ecosystems, being at the same time inhabited by a high number of rare plant species. Together with other types of wetlands, fens used to be widespread in lowland river valleys, but due to agricultural development, commonly accompanied by drainage, their area has decreased dramatically. In addition, fen bio...

Characteristic species of sedge-moss fen communities occur in constantly wet, nutrient-poor sites with a high penetration of light through the vegetation canopy. We studied the effects of water table depth and differences in light intensity on the performance of fen species. Three fen species (Carex curta, Viola palustris, Hydrocotyle vulgaris) and...

The realized habitat of a species can be considered as the product of its physiological requirements and competitive interactions with other species. One may, therefore, expect that the realized habitat differs between areas when a species has to coexist (and hence - compete) with different species. To test this hypothesis, we compared the response...