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Michal Hájek - One of the best experts on this subject based on the ideXlab platform.
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The ratio between bryophyte functional groups impacts vascular plants in rich Fens
Applied Vegetation Science, 2019Co-Authors: Patricia Singh, Daniel Ditě, Jakub Těsitel, Zuzana Pleskova, Tomas Peterka, Petra Hajkova, Pawel Pawlikowski, Michal HájekAbstract:QUESTION: Fens have a well‐developed bryophyte layer covering most of The ground. Non‐sphagnaceous bryophytes, especially The group of so‐called brown mosses, prevail over sphagna under alkaline conditions. In sub‐alkaline conditions, rich Fens allow The co‐occurrence of both These functional groups, but sphagna are competitively superior over non‐sphagnaceous bryophytes and seedlings of vascular plants, and They are currently expanding in some regions. We test wheTher The ratio between The two major bryophyte functional groups (bryo‐ratio) accounts for The species composition of vascular plants in Fens. LOCATION: Central and Eastern Europe. METHODS: Analysis of two existing regional‐ and continental‐scale data sets of The vegetation‐ plot records and measured local factors by Canonical Correspondence Analysis with variation partitioning (community‐level analysis) and Structural Equation Modelling (species‐level analysis). RESULTS: At The community level, The bryo‐ratio accounted significantly for species composition of fen‐specialized vascular plants, more obviously in The regional‐scale data set. At The species level, more fen species (50–67% according to The data set) were significantly directly affected (adjusted p < 0.05) by The bryo‐ratio than by water pH (14–17%) and by measured water table depth (WTD) in The regional data set (12.5%). In The continental data set, The comparable proportions of species were directly affected by The bryo‐ratio and WTD inferred by soil moisture indicator values (50% vs 58%). Most of The species affected significantly by The bryo‐ratio preferred The Fens rich in non‐sphagnaceous bryophytes. They were largely those with a low capability of vegetative reproduction. CONCLUSIONS: The group of species preferring brown moss patches includes mostly rare and endangered species with a great need for generative reproduction (e.g., Primula farinosa, Triglochin palustris, Pedicularis palustris, Saxifraga hirculus). Our findings demonstrate The important role of The bryophyte layer in The structuring of vascular plant communities in Fens and highlight urgent conservation needs for brown moss patches.
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Is species richness of small spring Fens influenced by The spatial mass effect
Community Ecology, 2011Co-Authors: Eva Hettenbergerová, Michal HájekAbstract:Ecological Theory predicts that The species composition of island habitats is, among oThers, shaped by The mass effect of nearby ill-adapted populations, but this has rarely been tested. We investigated small calcareous spring Fens scattered within species-rich grasslands in a region in which particular locations differ in climatic and edaphic conditions. Fens in colder, moister and less calcareous north-eastern (NE) locations harboured more plant species from surrounding grasslands and displayed higher similarity with The surroundings than The Fens in warmer, drier and more calcareous south-western (SW) locations. Fen species richness correlated significantly with surrounding species richness in The NE locations, whereas no correlation was found for The SW locations. Fens in SW locations are characterized by both intense tufa formation, which creates extreme ecological conditions, and The contrasting environmental conditions compared to surrounding grasslands. We demonstrated that The mass effect does not always significantly shape The species composition of island habitats and that The landscape species pool may not influence extreme habitats. This finding accords with The Intermediate difference hypoThesis, which predicts a unimodal relationship between The strength of The spatial mass effect and The ecological similarity between neighbouring plots, and could be utilized in The selection of model habitats for exploring large-scale ecological phenomena without The possibly confounding spatial mass effects.
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modern distribution patterns of snails and plants in The western carpathian spring Fens is it a result of historical development
Journal of Molluscan Studies, 2007Co-Authors: Michal Horsak, Michal Hájek, Daniel Ditě, Lubomir TichýAbstract:The aims of The study were: (1) to investigate The modern distribution pattern of snails in The Western Carpathians (Czech Republic and Slovakia) and compare it with The modern distribution pattern of plants, in which a conspicuous species turnover occurs on The scale of only tens of kilometres; and (2) to construct an hypoThesis explaining why such a steep geographical gradient exists in such a small area, which is homogenous with respect to water chemistry and climate. Snail assemblages of 111 treeless base-rich spring-fen sites were sampled quantitatively from a homogeneous area of 16 m 2 (one sample of 12 l volume) in which a vegetation relevewas also recorded. The result of a partial detrended correspondence analysis of snail data with water pH and conductivity as co-variables confirmed clear differences between snail assemblages of The study area's western and eastern region. The regions differed in Their species pool and The frequencies of particular species. In The eastern region, fen specialists and relics occurred and They were fairly frequent and abundant (e.g. Vertigo geyeri and Pupilla alpicola ). The western region differed by its higher frequency and abundance of woodland and ubiquitous species. The classification of snail species based on Their co-occurrence with plant species reflected The known geographical pattern as well. We found that Western Carpathian fen vegetation as well as The Fens' snail assemblages display a clear geographical gradient within a raTher small area, independently of any climate or oTher environmental variation. Previously published palaeoecological data and both species composition and structure of modern assemblages suggest clear differences in The historical development of The two principal regions. Historical development seems to be one of The most important variables constituting qualitative characters of modern fragmented commu- nities. On a small scale it can influence especially organisms with slower migration rates, such as molluscs.
Jan De Vries - One of the best experts on this subject based on the ideXlab platform.
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Is nutrition science ready for The twenty-first century? Moving towards transdisciplinary impacts in a changing world
European Journal of Nutrition, 2020Co-Authors: Adèle R. Tufford, Edith F. Feskens, Theo Ockhuizen, Jan Sikkema, Pieter Van’t Veer, Philip C Calder, Aletta D Kraneveld, Jan De VriesAbstract:Malnutrition in an obese world was The fitting title of The 13th Federation of European Nutrition Societies (Fens) conference held in October 2019. Many individuals do not eat a healthy, well-balanced diet, and this is now understood to be a major driver of increased disease risk and illness. Moreover, both our current eating patterns and The food system as a whole are environmentally unsustainable, threatening The planetary systems we depend on for survival. As we attempt to feed a growing global population, food systems will increasingly be confronted with Their environmental impacts, with The added challenge of climate change-induced threats to food production. As we move into The third decade of The twenty-first century, These challenges demand that The nutrition research community reconsider its scope, concepts, methods, and societal role. At a pre-meeting workshop held at The Fens conference, over 70 researchers active in The field explored ways to advance The discipline’s capacity to address cross-cutting issues of personal, public and planetary health. Using The world cafe method, four Themed discussion tables explored (a) The breadth of scientific domains needed to meet The current challenges, (b) The nature and definition of The shifting concepts in nutrition sciences, (c) The next-generation methods required and (d) communication and organisational challenges and opportunities. As a follow-up to earlier work [1], here we report The highlights of The discussions, and propose The next steps to advance responsible research and innovation in The domain of nutritional science.
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Is nutrition science ready for The twenty-first century? Moving towards transdisciplinary impacts in a changing world
European Journal of Nutrition, 2020Co-Authors: Adèle R. Tufford, Edith F. Feskens, Theo Ockhuizen, Jan Sikkema, Pieter Van’t Veer, Philip C Calder, Aletta D Kraneveld, Jan De VriesAbstract:Malnutrition in an obese world was The fitting title of The 13th Federation of European Nutrition Societies (Fens) conference held in October 2019. Many individuals do not eat a healthy, well-balanced diet, and this is now understood to be a major driver of increased disease risk and illness. Moreover, both our current eating patterns and The food system as a whole are environmentally unsustainable, threatening The planetary systems we depend on for survival. As we attempt to feed a growing global population, food systems will increasingly be confronted with Their environmental impacts, with The added challenge of climate change-induced threats to food production. As we move into The third decade of The twenty-first century, These challenges demand that The nutrition research community reconsider its scope, concepts, methods, and societal role. At a pre-meeting workshop held at The Fens conference, over 70 researchers active in The field explored ways to advance The discipline’s capacity to address cross-cutting issues of personal, public and planetary health. Using The world cafe method, four Themed discussion tables explored (a) The breadth of scientific domains needed to meet The current challenges, (b) The nature and definition of The shifting concepts in nutrition sciences, (c) The next-generation methods required and (d) communication and organisational challenges and opportunities. As a follow-up to earlier work [1], here we report The highlights of The discussions, and propose The next steps to advance responsible research and innovation in The domain of nutritional science.
Maria Strack - One of the best experts on this subject based on the ideXlab platform.
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effect of environmental factors on production and bioavailability of dissolved organic carbon from substrates available in a constructed and reference Fens in The athabasca oil sands development region
Ecological Engineering, 2015Co-Authors: Bhupesh Khadka, Tariq Muhammad Munir, Maria StrackAbstract:Abstract Fen peatlands cover a large proportion of The landscape in boreal Alberta and thus These ecosystems are likely to be constructed as part of mine closure following oil sands mining. Peatlands are large sources of dissolved organic carbon (DOC); however, little is known about DOC dynamics in constructed peatlands. We investigated DOC production and its bioavailability from substrates collected from a constructed fen and natural Fens (reference ecosystems) in The Athabasca oil sands region near Fort McMurray, Alberta. Dominant vegetation and oTher substrates used in fen construction, like peat, petroleum coke, tailings sand and upland soil, were collected for The study. The effect of substrate type, salinity and temperature on DOC production and bioavailability were analyzed in a laboratory incubation study. Sedges and trees produced The largest amount of DOC, followed by peat and moss in all The Fens, whereas The substrates from The constructed fen such as petroleum coke, tailings sand and upland soil produced very little DOC per unit dry mass. In addition, temperature and salinity were also significant explanatory variables for both initial (30 day) and final (60 day) net DOC production rates. It was also observed that greater production of DOC resulted in lower pH and higher electrical conductivity (EC) in incubation jar water. In addition, The quality of DOC depended upon The type of substrate. Specific ultraviolet absorbance at 254 nm wavelength (SUVA 254 ) indicated that sedges produced DOC having less aromatic humic substances than peat, tailings sand, upland soil and petroleum coke. Substrate, salinity and temperature at which DOC was produced, and interactions among These factors were all found to significantly explain variation in DOC bioavailability. Aromatic content of DOC produced, based on SUVA 254 , had an effect on its bioavailability. As various substrates produced different amounts and quality of DOC, and since construction material like petroleum coke and tailings sand produce very little DOC, it is likely that establishment of The vegetation community and its composition will play an important role in DOC dynamics at The constructed fen in The future.
Aat Barendregt - One of the best experts on this subject based on the ideXlab platform.
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Topographic position and water chemistry of Fens in a Dutch river plain
Journal of Vegetation Science, 1992Co-Authors: Martin J. Wassen, Aat BarendregtAbstract:. On The Vecht river plain (western NeTherlands), small Fens, remnants of a large mesotrophic wetland bordering a moraine, of 1 to 5 ha are found in a man-made matrix of lakes and pastures. The regional position of The Fens, local position of sampling sites, composition of The vegetation and local hydrological variables were measured. Polders in The river plain produce a complex hydrology obscuring The regional zonation between moraine and river. Water supply and species composition are determined more by a site's regional than local position. High-productivity reedlands are abundant close to The river. Carex paniculata reedlands receive large amounts of river water, which gives Their fen water a high K+ concentration. Low-productivity C. diandra Fens and litter Fens have Their optimum closer to The moraine. C. diandra Fens are fed mainly by inflowing nutrient-poor ground- or surface water; litter Fens receive primarily rainwater. Nutrients in fen water and in peat are lowest in C. diandra and C. lasiocarpa Fens, but do not differ significantly between The communities. In both, iron seems to be more important than calcium in reducing phosphate solubility. Iron richness in The C. diandra Fens is caused by present inflows of ground- or surface water, while in C. lasiocarpa Fens, which succeed The former, iron richness is The result of historical inflows.
Susan Faller - One of the best experts on this subject based on the ideXlab platform.
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Decomposition and Peat Accumulation in Rich Fens of Boreal Alberta, Canada
Ecosystems, 2009Co-Authors: Dale H. Vitt, R. Kelman Wieder, Kimberli D. Scott, Susan FallerAbstract:Fens are important components of Canada’s western boreal forests, occupying about 63% of The total peatland area and storing about 65% of The peatland carbon. Rich Fens, dominated by true moss-dominated ground layers, make up more than half of The Fens in The region. We studied organic matter accumulation in three rich Fens that represent The diversity in structural types. We used in situ decomposition socks, a new method that examines actual decomposition throughout The upper peat profile over an extended period of time. We coupled our carbon loss data with macrofossil analyses and dated peat profiles using ^210Pb. Across The three rich Fens and in The top 39 cm of The peat column, dry mass increases on average 3.1 times. From our dry mass loss measurements, we calculate that annual mass loss from The top 39 cm varies from 0.52 to 1.08 kg m^2. Vertical accumulation during The past 50 years has varied from 16 to 32 cm and during These 50 years, organic matter accumulation has averaged 174 g m^−2 y^−1 compared to 527 g m^2 y^−1 dry mass loss, with additional mass losses of 306 g m^2 y^−1 from peat between 50 and 150 years of age. Organic matter accumulation from our rich Fens compares well with literature values from boreal bogs, whereas peat bulk densities increase about three times within The uppermost 40 cm, much more than in bogs. Hence, rich Fens accumulate peat not because The plant material is especially hard to decompose, is acidic, or has The catotelm especially close to The surface, but because dense, rapidly produced inputs outweigh The relatively rapid decomposition process of The upper peat column.