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1

Winter methane emission from an alpine open fen on Tibetan Plateau

Zhu D., Chen H., Wu N., Wang Y., Luo P.

Polish Journal of Ecology

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2011

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Vol. 59, nr 1

87-94

EN

Methane (CH4) emission was measured from an open fen on the Zoige Plateau (3500 m a.s.l.) (the eastern edge of the QinghaiTibetan Plateau) during two winters of 2006 and 2007. Three dominant plant stands, including Carex muliensis Hand-Mazz. (CM), Eleocharis valleculosa Ohwif. setosa (Ohwi) Kitagawa.(EV) and Kobresia tibetica Maxim (KT) were chosen to be monitored. Winter CH4 emissions were roughly estimated to be 0.94 mg CH4 m[^-2] h[^-1]. High spatialtemporal variations of the emission were found in this fen (the sequence of CM> EV> KT; 0.63 and 1.24 mg CH4 m[^-2] h[^-1] for 2006 and 2007, respectively). Factors involved in the spatial-temporal variation were: 1) water table in summer determining the winter amount of "old" CH4 stored in peat; 2) ice layer determining the release of CH4; 3) plant growth determining both the quantity of CH4 stored in peat and available substrates for CH4 production in winter. However, due to the homogeneity of freezing in winters, predictive factors such as plant growth and water table in summer could contribute more to winter CH4 emission than in situ freezing conditions. Considering that plant growth and water table are also the key factors controlling the spatial-temporal variation of CH4 emission in summer, we therefore suggested that winter CH4 emission represents the "inertia" of summer CH4 emission.

2

The dynamics of phosphorus in lacustrine sediments : contents and fractions in relation to lake trophic state and chemical composition of bottom deposits

Rzepecki M.

Polish Journal of Ecology

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2010

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Vol. 58, nr 3

409-427

EN

Phosphorus is still recognized as the element driving the matter cycling in freshwater ecosystems. It is the key nutrient in productivity and eutrophication process of lakes and reservoirs. The bottom sediments cumulatively formed inside and in-shore of lakes play a crucial role in accumulation/sorption of phosphorus organic compounds, as well as in release/desorption of the compounds available for uptake by producers and microbial heterotrophs. These two opposite processes are dependent on the chemical composition of sediments and on the site conditions (like oxygen, pH) in over-bottom layers. About three hundred of the sediment surface layer samples were taken from the lacustrine habitats in a variety of lakes typical for postglacial landscape (Masurian Lakeland, Poland): profundal and littoral zones in lakes forming a trophic gradient including a humic lake, river/lake ecotone zone and wetland sites adjacent to lake shoreline. The contents of Ca, Fe, Mg, Mn and Al were analysed as well as the amount of total P (TP) and its three basic groups i.e. easily exchangeable, hardly exchangeable and non-exchangeable fractions. It was found that the sediments of humic lake had the most different, distinct chemical composition and contained very small amounts of Fe, Mn, Mg and Ca - nearly 30 times less than sediments of other, non-humic lakes. These sediments contained the most of organic matter and similar (as in non-humic lakes) amounts of TP whose dominant part (80%) consists of hardly exchangeable organic fraction. Sediments of lakes forming the trophic gradient along the small (15 km long) river (Jorka River) showed consistent changes in the chemical composition. Sediments of lakes situated up the river system (meso- and meso-eutrophic lakes) had higher content of organic matter and Ca but lower content of TP, Fe and Mg than sediments of lakes in the lower part of the river system (eutrophic and hypertrophic lakes). The content of these elements was also higherin profundal than in littoral sediments. Significantly higher content (40-70%) of non-exchangeable P was found in sediments of eutrophic and hypertrophic lakes than in sediments of meso- and meso-eutrophic lakes (30-60%) in both the littoral and profundal zones. Sediments of the river-lake-river ecotones (Krutynia River) showed also the consistent changes of element content along the river flow through the lake. The amount of TP was lower in riverine sediments down and upstream the lake than in lake sediments. Organic matter and Fe contents were lower and Ca, Mg, Mn and Al contents were higher in river-lake-river ecotones or similar to those in sediments of the lakes from the trophic gradient. Easily exchangeable phosphorus prevailed in lake sediments; TP in riverine sediments was dominated by hardly exchangeable and non-exchangeable forms and was similar to that found in littoral sediments of lakes from the trophic gradient. Inshore wetland sediments were characterized by a highcontent of organic matter - higher than in littoral and profundal sediments of lakes forming the trophic gradient. The content of Ca, Mg, Mn and Fe was two to five times lower than in sediments of lakes from the trophic gradient but similar to sediments of humic lake. They also contained less TP than profundal sediments from the trophic gradient and humic lakes but had similar content to littoral and riverine sediments. As in the case of profundal and riverine sediments, non-exchangeable and hardly exchangeable P fractions dominated TP content in wetland inshore sediments. Almost all phosphorus a ccumulated in these sediments is associated with a high organic matter deposition. The study results concern the basic types of lake and lacustrine habitats representative for the postglacial landscape of north and north-east Europe. A significant diversity of sediment origin, chemical composition and phosphorus amount and its potential mobility was found among the sediment types. The wetland and humic sediments appeared to be active in cumulation and stabilisation of P resources while sediment of nonhumic, trophic lakes (especially in profundal zoners) are the active sites for P release and sorption processes.

3

Soil seed banks in lakeshore wetlands : relation to the extant vegetation

Peng Y., Wu N., Gao X., Fang Z., Xiao W.

Polish Journal of Ecology

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2010

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Vol. 58, nr 3

449-457

EN

Seed bank composition and germination characteristics are necessary for modeling wetland vegetation composition. Yet there are few studies about the seed bank difference between plant communities in lakeshore wetlands. Seed banks are also known to play important roles in the vegetation restoration process. Environmental factors such as water level, temperature, or nutrient levels can affect vegetation composition and seed bank composition. The relationships between environmental factors and seed banks of wetlands in the field are still unknown. The Jiuzhaigou Nature Reserve is located at the eastern edge of Qinghai-Xizang Plateau. The lakeshore wetland vegetation is dominated by Phragmites australis (Cav.)Trin. ex Steud., Typha latifolia L., Carex pamirensis C. B. Clarke, Equisetum fluviatile L. The wetlands in Jiuzhaigou (118 lakes) are under strong pressure such as trampling and enhanced construction for travel. Plant restoration is necessary for protection of these areas. We investigated the soil seed bank in six lakeshore wetlands in this area using the seedling emergence method. Sediment samples (0-2 cm, 2-5 cm, 5-10 cm intervals from surface to bottom) were taken with core (diameter 5 cm) in April and from each replicate samples were spread on two plastic trays. Trays were randomly arranged in the greenhouse and watered daily. Seedlings were counted weekly after emergence, and removed as soon as they could be identified. Our study showed that seed density in all soil layers samples was negatively correlated to water depth. Water depth can explain 45% variance of species richness in surface layer in sediment. Species richness in extant vegetation can explain 45, 48, 25% variance of species richness in total 10 cm and in 2-5 cm and 5-10 cm layer sediment respectively. Dominant species cover in extant vegetation, site altitude, total nitrogen, total phosphorus and total organic carbon in soil showed no correlation with species richness in seed bank. Mean seed densities in wetlands ranged from 0 to 15945 m[^-2]. A total of 23 species germinated in seed bank, while 85 species were found in extant vegetation. The dominant species in seed bank and extant vegetation showed great difference. The total number of species and seedlings that germinated in different layers was not significantly different. But the second layer had the greatest seed density. The relationship between seed bank and extant vegetation differed from one species to another. We should use different restoration strategies for different plant communities.

4

Seasonal bird assemblages in a Mediterranean patchy wetland : corroborating the intermediate disturbance hypothesis

Malavasi R., Battisti C., Carpaneto G.

Polish Journal of Ecology

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2009

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Vol. 57, nr 1

171-179

EN

The structure of bird assemblages recorded in breeding and wintering period in a Mediterranean wetland of Central Italy was studied in order to evaluate their seasonal changes and the influence of land cover on their parameters. We identified three habitat macro-types, according to a man-disturbed gradient (from natural to man-made macro-types). Bird assemblages showed differences in relation to season and habitat type, either at quantitative (species richness, diversity index) or qualitative level (species composition and turnover, similarity). In winter, we obtained the higher values of mean species richness, Margalef richness, Shannon diversity, and [Beta]-diversity. The dendrogram of similarity showed a major clear-cut division between seasons, and a secondary division among habitat macro-types. In winter, assemblages were more rich and diverse, with a high turnover among point counts. The semi-natural habitat macro-types showed always the higher values of these indexes, with the exception of the [Beta]-diversity, which showed the highest value in winter but the lowest in the breeding period. The high mean values of richness ([alpha]-diversity) of the semi-natural habitat macro-types, especially in the breeding period could be mainly explained by the 'intermediate disturbance hypothesis'; on the contrary, differences in turn-over ([Beta]-diversity) between the seasons are mainly due to seasonal changes in habitat heterogeneity of this habitat macro-type (from an arid homogeneous pasture to a patchy flooded one). A pattern of intermediate disturbance was evident at mean species richness level (significant values) but not at diversity index level (not significant values). These results could imply specific strategies for the management of small wetlands, focused on maintaining a regime of natural (flooding) and man-made (grazing) disturbances.

5

A protection strategy for the floodplains of the River Yzer (Flanders, Belgium)

Rycke A. de, Devos K., Samain B., Sas M., Decleer K.

Journal of Water and Land Development

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2004

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no. 8

35-48

EN

The Yzer is a lowland river, which rises in Northern France and discharges into the North Sea in western Flanders (Belgium) with a catchment area of 1101 km². In the downstream part, the river has been canalised and embanked for navigation. Along the middle section of the river the original, wide floodplain was preserved and still floods several times every winter. This floodplain area has a high ecological value and was designated as Ramsar and Special Protection Area under the EU Bird Directive. Due to large peak run-offs during the last decade, several times also houses and farms were endangered. An integrated project for flood protection of houses and nature restoration was elaborated. Aiming at a policy of integrated water management, the Flemish Waterways and Maritime Affairs Administration (AWZ) spends more attention for nature conservation and restoration than in the past. The Institute of Nature Conservation was contracted to elaborate nature rehabilitation scenarios for the different Flemish waterways. Within social, economic and ecological preconditions, realistic targets for nature restoration and development are formulated. Basic principle is to develop a sustainable ecosystem, neutralizing the bottlenecks as much as possible, providing (more) space for dynamic fluvial processes, and restoring the relation between river and floodplain. The aim is to (re)create and restore diverse wetland, floodplain and river habitats. This article focuses on the hydrological and ecological features of the River Yzer and describes the protection strategy for the river and its wetlands within the framework of integrated water management.

PL

Ijzer jest nizinną rzeką, która bierze początek w północnej Francji i uchodzi do Morza Północnego w zachodniej Flandrii (Belgia). Powierzchnia zlewni rzeki wynosi 1101 km². Rzeka została skanalizowana i obwałowana w swym dolnym biegu w celu umożliwienia żeglugi. W środkowym odcinku rzeka zachowała naturalną szeroką dolinę zalewową i wylewa kilka razy każdej zimy. Dolina zalewowa ma dużą wartość przyrodniczą i została wyznaczona jako siedlisko konwencji Ramsar i obszar szczególnej ochrony w ramach Dyrektywy Ptasiej UE. Z powody wysokich przepływów jakie miały miejsce w ostatnim dziesięcioleciu domy i gospodarstwa rolne były kilkakrotnie zagrożone. Opracowano zintegrowany projekt ochrony zabudowań przed powodzią i przywrócenia naturalnych walorów środowiska. Mając na względzie zintegrowaną gospodarkę wodną, Flamandzki Zarząd Dróg Wodnych i Spraw Morskich (AWZ) przykłada większą niż w przeszłości wagę do czynnej i biernej ochrony przyrody. Instytut Ochrony Przyrody opracował scenariusze rekultywacji dolin rzecznych Flandrii. W ramach wstępnie założonych uwarunkowań społecznych, ekonomicznych i ekologicznych sformułowano realistyczne cele restytucji i rozwoju środowiska przyrodniczego. Podstawową zasadą było rozwijanie zrównoważonego ekosystemu przez likwidowanie, na ile to możliwe, wszelkich ograniczeń, zapewnienie większej przestrzeni dla dynamicznych procesów fluwialnych i odtworzenie związków między rzeką a doliną zalewową. Celem było odtworzenie zróżnicowanych środowisk podmokłych, doliny zalewowej i siedlisk rzecznych. Artykuł jest poświęcony hydrologicznym i ekologicznym cechom rzeki Ijzer i opisuje strategię ochrony doliny rzeki i jej podmokłych obszarów w ramach zintegrowanej gospodarki wodnej.