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  • 1.
    Kallner Bastviken, Sofia
    et al.
    IFM Biology, Linköping University, Campus Valla, Sweden.
    Weisner, Stefan E.B.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Thiere, Geraldine
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Svensson, Jonas M.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Ehde, Per Magnus
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Tonderski, Karin S.
    IFM Biology, Linköping University, Campus Valla, Sweden.
    Effects of vegetation and hydraulic load on seasonal nitrate removal in treatment wetlands2009Inngår i: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 35, nr 5, s. 946-952Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Optimising nitrate removal and identifying critical factors for nitrate removal in wetlands is an important environmental task in the effort to achieve better surface water quality. In this study, eighteen free water surface wetlands with similar shape and size (22 m2 each) received groundwater with a high nitrate-N concentration (about 11 mg l−1). The effects of two hydraulic loads, 0.13 m d−1 and 0.39 m d−1, and three vegetation types – emergent, submersed and freely developing vegetation – on the nitrate-N removal were investigated through mass inflow and outflow measurements.

    No significant difference in nitrate removal between the different hydraulic loads could be detected. Significantly higher area-specific nitrate removal and first-order area-based rate coefficients were found in the basins with emergent vegetation, with no difference between the basins with submersed and freely developing vegetation. The nitrate-N removal increased as the wetlands matured and the vegetation grew denser, emphasizing the role of dense emergent vegetation for nitrate removal at high nitrate concentrations.

  • 2. Milenkovski, S
    et al.
    Thiere, Geraldine
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Samuelsson, K
    Weisner, Stefan
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Berglund, O
    Lindgren, P-E
    Denitrification in constructed wetlands in southern Sweden2007Inngår i: 2nd International Symposium on Wetland Pollutant Dynamics and Control - WETPOL 2007: Extended abstracts / [ed] Ülo Mander, Margit Kõiv, Christina Vohla, Institute of Geography, 2007, s. 220-222Konferansepaper (Annet vitenskapelig)
  • 3.
    Milenkovski, Susann
    et al.
    Department of Chemical Ecology/Ecotoxicology, Lund University, Lund, Sweden.
    Berglund, Olof
    Department of Chemical Ecology/Ecotoxicology, Lund University, Lund, Sweden.
    Thiere, Geraldine
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Samuelsson, Kristina
    Swedish County Administrative Board, Länsstyrelsen Kalmar län, Kalmar, Sweden.
    Weisner, Stefan
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Lindgren, Per-Eric
    Department of Clinical and Experimental Medicine, Division of Medical Microbiology, Linköping University, Linköping, Sweden.
    Composition of denitrifying bacterial enzyme genes nirS, nirK and nosZ in constructed wetlandsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    In this study the composition of the denitrifying bacterial community among constructed wetlands in agricultural areas was investigated. Thirty-two constructed wetlands located in Southern Sweden were surveyed, and biofilm samples from each were analyzed by applying denaturing gradient gel electrophoresis, to investigate the community composition of the three denitrifying bacterial enzyme genes nirK, nirS and nosZ. The DNA sequences of the enzyme genes were compared to known DNA sequences in GeneBank using BLAST. The results of the denitrifying bacterial enzyme genes indicated that these habitats may harbour a heterogeneous denitrifying bacterial community. Individual analysis of the enzyme genes revealed that nirS was more heterogeneous than both nirK and nosZ. Most sequences from the present study clustered with known sequences from species belonging to the group of α-Proteobacteria, and to a lesser extent with β- Proteobacteria and γ-Proteobacteria, and only nirS clustered with a member of gram-positive bacteria.

  • 4.
    Milenkovski, Susann
    et al.
    Department of Chemical Ecology/Ecotoxicology, Lund University, Lund, Sweden.
    Thiere, Geraldine
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Weisner, Stefan
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Berglund, Olof
    Department of Chemical Ecology/Ecotoxicology, Lund University, Lund, Sweden.
    Lindgren, Per-Eric
    Department of Clinical and Experimental Medicine, Division of Medical Microbiology, Linköping University, Linköping, Sweden.
    Variation of eubacterial and denitrifying bacterial biofilm communities among constructed wetlandsManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Bacteria play important roles in the transformation of nutrients in wetlands, but few studies have examined parameters affecting variation in bacterial community composition between wetlands. We compared the composition of eubacterial and denitrifying bacterial biofilm communities in 32 agricultural constructed wetlands in southern Sweden, and the extent to which wetland environmental parameters could explain the observed variation. Structure and richness of the eubacterial 16S rRNA gene and three denitrifying bacterial enzyme genes (nirK, nirS and nosZ), analysed by molecular fingerprinting methods, varied among the constructed wetlands, which could be partly explained by different environmental parameters. Results from the enzyme gene analyses were also compared to determine whether the practice of using a single denitrifying bacterial gene could characterize the overall community composition of denitrifying bacteria. We found that nirK was more diverse than both nirS and the nosZ, and the band structure and richness of the three genes were not related to the sam environmental parameters. This suggests that using a single enzyme gene may not suffice to characterize the community composition of denitrifying bacteria in constructed agricultural wetlands.

  • 5.
    Schulz, Ralf
    et al.
    Department of Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa; Syngenta Crop Protection AG, Ecological Sciences, Jealott's Hill Intl. Research Centre, Bracknell, Berkshire, United Kingdom.
    Hahn, Christina
    Department of Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa.
    Bennett, Erin R.
    Department of Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa.
    Dabrowski, James M.
    Department of Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa.
    Thiere, Geraldine
    Department of Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa.
    Peall, Sue K.C.
    Forensic Chemistry Laboratory, Department of Health, Cape Town 8000, South Africa.
    Fate and Effects of Azinphos-Methyl in a Flow-Through Wetland in South Africa2003Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 37, nr 10, s. 2139-2144Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Our knowledge about the effectiveness of constructed wetlands in retaining agricultural nonpoint-source pesticide pollution is limited. A 0.44-ha vegetated wetland built along a tributary of the Lourens River, Western Cape, South Africa, was studied to ascertain the retention, fate, and effects of spray drift-borne azinphos-methyl (AZP). Composite water samples taken at the inlet and outlet during five spray drift trials in summer 2000 and 2001 revealed an overall reduction of AZP levels by 90 ± 1% and a retention of AZP mass by 61 ± 5%. Samples were collected at the inlet, outlet, and four platforms within the wetland to determine the fate and effect of AZP in the wetland after direct spray drift deposition in the tributary 200 m upstream of the inlet. Peak concentrations of AZP decreased, and the duration of exposure increased from inlet (0.73 µg/L; 9 h) via platforms 1 and 4 to outlet (0.08 µg/L; 16 h). AZP sorbed to plants or plant surfaces, leading to a peak concentration of 6.8 µg/kg dw. The living plant biomass accounted for 10.5% of the AZP mass initially retained in the wetland, indicating processes such as volatilization, photolysis, hydrolysis, or metabolic degradation as being very important. AZP was not detected in sediments. Water samples taken along two 10-m transects situated perpendicular to the shore indicated a homogeneous horizontal distribution of the pesticide: 0.23±0.02 and 0.14±0.04 µg/L (n = 5), respectively. Both Copepoda (p = 0.019) and Cladocera (p = 0.027) decreased significantly 6 h postdeposition and remained at reduced densities for at least 7 d. In parallel, the chlorophyll a concentration showed an increase, although not significant, within 6 h of spray deposition. The study highlights the potential of constructed wetlands as a risk-mitigation strategy for spray drift-related pesticide pollution.

  • 6.
    Schulz, Ralf
    et al.
    Department of Zoology, University of Stellenbosch, South Africa.
    Thiere, Geraldine
    Department of Zoology, University of Stellenbosch, South Africa.
    Dabrowski, James M.
    Department of Zoology, University of Stellenbosch, South Africa.
    A combined microcosm and field approach to evaluate the aquatic toxicity of azinphos-methyl to stream communities2002Inngår i: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 21, nr 10, s. 2172-2178Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We evaluated the potential effects of the organophosphate insecticide azinphosmethyl (AZP) in a combined microcosm and field approach. The upper regions of the Lourens River, South Africa, are free of contamination (control site), whereas the subsequent stretches flowing through a 400-ha orchard area receive transient insecticide pollution (e.g., 0.82 μg/L AZP, 344 μg/kg chlorpyrifos) following spray drift and runoff (contaminated site). Stones taken from the control site were transferred to outdoor microcosms (1.5 × 0.2 × 0.2 m), providing 12 core species and approximately 350 individuals per microcosm. Microcosms were contaminated for 1 h with AZP (control, 0.2, 1, 5, and 20 μg/L; three replicates each), and acute effects on survival were evaluated 6 d following exposure. The two strongest treatments (measured concentrations: 19.2 ± 1.0 and 4.9 ± 0.3 μg/L, respectively) resulted in a significantly (analysis of variance) reduced invertebrate density, attributed mainly to various insect taxa, such as Demoreptus sp., Castanophlebia sp., Simuliidae, and Chironomidae. In contrast, Aeshna sp., Dugesia sp., Ceratopogonidae, and Cheumatopsyche sp. were unaffected. In parallel, we conducted a quantitative macroinvertebrate survey at the control site and the contaminated site of the Lourens River after the seasonal pesticide application period. The two sites contained a similar number of species but differed considerably in their species composition and abundances. Five of the eight species that were affected by AZP in the microcosm study occurred in the field at significantly lower densities at the contaminated than at the control site or were absent at the contaminated site. All of the four species that were unaffected in the microcosm occurred at significantly higher densities at the contaminated field site. Only 3 of the 12 species reacted differently in the microcosm and the field study. We conclude that microcosm studies employing a field-relevant design could be linked successfully to field studies and our results suggest that transient pesticide contamination affects the aquatic communities of the Lourens River.

  • 7.
    Thiere, G.
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Stadmark, J.
    Lund University.
    Weisner, Stefan
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Retention capacity achievements versus climate gas emission by constructed agricultural wetlands2007Inngår i: 2nd International Symposium on Wetland Pollutant Dynamics and Control - WETPOL 2007: Extended abstracts / [ed] Ülo Mander, Margit Kõiv, Christina Vohla, Institute of Geography, University of Tartu , 2007, s. 302-304Konferansepaper (Annet vitenskapelig)
  • 8.
    Thiere, Geraldine
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Biodiversity and ecosystem functioning in created agricultural wetlands2009Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This doctoral dissertation was produced in a cooperation between Halmstad University (Wetland Research Centre, School of Business and Engineering) and Lund University (Limnology & Marine Biology, Department of Ecology).

    Abstract . Wetland creation at large, regional scales is implemented as a measure to abate the biodiversity loss in agricultural landscapes and the eutrophication of watersheds and coastal areas by non-point source nutrient pollution (mainly nitrogen). The consequences of creating many new wetlands for biodiversity conservation and nutrient reten- tion (ecosystem functioning) in agricultural landscapes are still relatively unknown, both on local (per wetland) and regional (per landscape) scales. In Sweden, wetland creation has progressed already since the 1990s, and by now larger numbers of created wetlands are present, mainly in the intensively farmed landscapes of southwestern Sweden. This thesis aimed to investigate the following aspects in these systems: (i) their large-scale effects on biodiversity, (ii) their functional diversity of bacterial denitrifiers, (iii) the abiotic and biotic influences on wetland ecosystem functioning, (iv) the potential for biodiversity-function links, and (v) the potential for functional links and joint functioning.(i) Created wetlands hosted diverse assemblages of macroinvertebrates and plants. They maintained a similar com- position and diversity as natural ponds in agricultural landscapes. The environmental conditions per wetland did hardly affect macroinvertebrate and plant assemblages, and the prerequisites for nutrient retention did neither. In landscapes were wetland creation efforts had increased the total density of small water bodies by more than 30%, macroinver- tebrate diversity of created wetlands was facilitated on both local and regional scales. (ii) Diverse communities of denitrifying bacteria with the capacity for conducting different denitrification steps (functional types) were present in all investigated wetlands. The richness of denitrifying bacteria communities was affected by nitrate concentration and hydraulic loading rate, which may potentially be relevant for the nitrogen retention function of created wetlands. The diversity across different functional types of bacterial denitrifiers increased with nitrate concentration. (iii) Both abiotic and biotic factors influenced ecosystem functions of created wetlands. Variation in nitrogen retention was associated to nitrate load, but even to vegetation parameters. In wetlands with constant nitrate load, planted emergent vegetation facilitated nitrogen retention compared to other vegetation types. In wetlands with variable loads, nitrogen retention was facilitated if nitrate load was high and many different vegetation types were present; nitrogen load could explain the majority of the variation in nitrogen retention compared to vegetation parameters. Phosporus retention of created wetlands was best explained by vegetation parameters. Litter decomposition was inhibited at high nitrate to phosphorus ratios. Methane production increased with age and decreased with plant cover. (iv) Biodiversity may facilitate wetland ecosystem functions, particularly in dynamic wetland ecosystems. Nitrogen retention increased with vegetation type diversity, phosphorus retention capacity with plant richness, and litter decomposition with macroinvertebrate diversity. (v) Created wetlands have the capacity of sustaining several parallel ecosystem services. Some wetland functions were coupled; nitrogen retention increased with fast litter decomposition. On the other hand, methane emission and nitro- gen retention were independent of each other, as were nitrogen and phosphorus retention.In conclusion, created wetlands have the potential to at least partly abate the lost biodiversity and multifunctionality caused by the past extensive destruction of natural wetlands in agricultural landscapes.

  • 9.
    Thiere, Geraldine
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Milenkovski, Susann
    Department of Ecology, Ecology Building, Lund University, Lund, Sweden.
    Lindgren, Per-Eric
    Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
    Sahlén, Göran
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS).
    Berglund, Olof
    Department of Ecology, Ecology Building, Lund University, Lund, Sweden.
    Weisner, Stefan E.B.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Wetland creation in agricultural landscapes: Biodiversity benefits on local and regional scales2009Inngår i: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 142, nr 5, s. 964-973Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wetland creation aiming at a simultaneous increase in nutrient retention and species diversity in agricultural landscapes has recently become applied as a catchment-scale compensation measure for past wetland losses. Here, we evaluate if, and to what extend, dual-purpose wetlands benefit local and regional diversity of agricultural landscapes. We analysed composition and α, β, and γ diversity of aquatic macroinvertebrate assemblages among dual-purpose wetlands in an agricultural region in southwest Sweden in relation to local (water quality, wetland morphology, succession stage, proximity to other aquatic habitats) and landscape parameters (regional connectivity, wetland density). Diversity of mature agricultural ponds was used as a standard to evaluate the value of dual-purpose wetlands. Dual-purpose wetlands sustained α, β, and γ diversity similar to that of natural lentic water bodies in agricultural landscapes in the region and elsewhere. Over 80% of the overall species richness was attributed to β diversity, and each created wetland contributed to overall species accumulation. Ecosystem parameters explained 19% of the compositional variation among assemblages, but were only marginally related to diversity. Wetland density promoted α and γ diversity, while spatial heterogeneity (β) remained equally high, independent of wetland density. Our results indicate that catchment-scale wetland creation for simultaneous retention and diversity purposes benefits the biodiversity of agricultural landscapes, particularly if the density of aquatic habitats is increased by at least 30%.

  • 10.
    Thiere, Geraldine
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Miljövetenskap, Våtmarkscentrum.
    Schulz, Ralf
    Department of Zoology, University of Stellenbosch, South Africa.
    Runoff simulation with particle-associated azinphosmethyl in multispecies stream microcosms: implications for the field2004Inngår i: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 23, nr 8, s. 1984-1990Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigated the acute (5 d) effects of particle-associated azinphosmethyl (AZP) in multispecies microcosms and assessed the results in the context to data obtained from a parallel field study undertaken in the Lourens River, South Africa. A runoff simulation was carried out in stream microcosms containing the macroinvertebrate fauna of an uncontaminated Lourens River site exposed to particle-associated AZP (control and 200, 1,000, 5,000, 20,000 μg/kg; three replicates each) for 1 h. Measured AZP concentrations in filtered microcosm water resulted in the following values: Not detectable (control) and 0.03, 0.2, 1.1, and 6.9 μg/L, respectively. The two highest treatments resulted in significantly (analysis of variance [ANOVA]) reduced total numbers of individuals, while the number of taxa was affected in the 20,000 μg/kg treatment only. A comparison with previous data suggests that observed effects partly resulted from particle-associated AZP. Particularly affected were six out of 14 macroinvertebrate taxa such as mayfly and stonefly taxa. In parallel, the distribution of macroinvertebrates at a pesticide-free and a contaminated stretch of the Lourens River was monitored five times during the spraying season in 2001 and 2002. Out of the 14 core taxa found in the microcosm study as well as in the field approach, 10 showed comparable reactions in the microcosm experiment and in their field distribution; they were either classified as affected or unaffected in both studies. Thus, we conclude that particle-associated AZP has the potential to affect the invertebrate community structure of the Lourens River and that microcosm studies employing field-relevant exposure scenarios may be valuable for a local risk assessment of pesticide-related community disruptions in the Lourens River.

  • 11.
    Thiere, Geraldine
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Miljövetenskap, Våtmarkscentrum.
    Schulz, Ralf
    Department of Zoology, University of Stellenbosch, South Africa .
    Runoff-related agricultural impact in relation to macroinvertebrate communities of the Lourens River, South Africa2004Inngår i: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 38, nr 13, s. 3092-3102Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A field study at the Lourens River, South Africa, was undertaken during the pesticide application period between November 2001 and January 2002 in order to investigate the potential relation of agricultural pollution to the aquatic macroinvertebrate fauna. The upper regions of the Lourens River were free of contamination (LR1), whereas subsequent stretches flowing through a 400-ha orchard area (LR2) received transient insecticide peaks. Continuously operating suspended-particle samplers as well as flood samplers operating during runoff events were used to measure pesticide contamination. In addition, various physicochemical and morphological parameters were examined. A survey of the macroinvertebrate communities associated with the rocky substrates was carried out every three weeks. Community indices were calculated using the South African Scoring System (SASS 5) for bioassessment of water quality in rivers.

    The two sites differed in pesticide pollution as well as in average turbidity levels (LR1 5.5 mg/L; LR2 64.3 mg/L), but were similar in bottom substrate composition and most other abiotic factors. At the downstream site (LR2), pesticide values of 0.05 μg/L azinphos-methyl in water as well as 49 μg/kg azinphos-methyl, 94 μg/kg chlorpyrifos and 122 μg/kg total endosulfan in suspended particles were found during runoff conditions. The macroinvertebrate communities of the two sampling sites were similar in terms of number of total individuals, but differed significantly (ANOVA) in average number of taxa (LR1 11.7, LR2 8.9). Seven out of 17 investigated taxa occurred in significantly reduced numbers or were even absent at the downstream site LR2. The community characteristics determined by SASS 5 showed a significantly less sensitive community structure at the downstream site (TS 41; ASPT 4.6), indicating continuously lower water quality compared to site LR1 (TS 80; ASPT 6.9). It is concluded that the Lourens River macroinvertebrate communities are affected by agricultural pollution, with pesticides and increased turbidity as the most important stressors.

  • 12.
    Thiere, Geraldine
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Stadmark, Johanna
    Department of Ecology, Limnology, Lund University, Ecology Building, SE-223 62 Lund, Sweden.
    Weisner, Stefan E. B.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Nitrogen retention versus methane emission: Environmental benefits and risks of large-scale wetland creation2011Inngår i: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 37, nr 1, s. 6-15Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Coastal eutrophication by nutrient fluxes from agricultural land to marine recipients is presently combated by measures such as the implementation of watershed-scale wetland creation programs aimed at nitrogen removal. Such created agricultural wetlands – termed ‘nitrogen farming wetlands’ (NFWs) – receive nitrogen (N) loads predominantly as nitrate, facilitating N removal by denitrification. However, the conversion of agricultural soils into waterlogged wetland area is likely to increase climate gas emissions, particularly methane (CH4). There is thus a need to evaluate the benefits and risks of wetland creation at a large, watershed-scale. Here we investigate N retention and CH4 emission originating from watershed-scale wetland creation in South Sweden, the relation between both processes, and how CH4 emission depends on individual wetland parameters. We combine data from intensively studied reference wetlands with an extensive wetland survey to predict N retention and CH4 emission with simple models, to estimate the overall process rates (large-scale effects) as well as spatial variation among individual NFWs. We show that watershed-scale wetland creation serves targeted environmental objectives (N retention), and that CH4 emission is comparably low. Environmental benefit and risk of individual wetlands were not correlated, and may thus be managed independently. High cover of aquatic plants was the most important wetland property that suppressed CH4 net production, potentially facilitating N retention simultaneously. Further, differences between wetlands in water temperature and wetland age seemed to contribute to differences in CH4 net production. The nationally planned wetland creation (12,000 ha) could make a significant contribution to the targeted reduction of N fluxes (up to 27% of the Swedish environmental objective), at an environmental risk equaling 0.04% of the national anthropogenic climate gas emission.

  • 13.
    Thiere, Geraldine
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Weisner, Stefan
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Biodiversity and ecosystem functioning in created agricultural wetlands.: Key note presentation.2009Inngår i: 3rd Wetland Pollutant Dynamics and Control - WETPOL2009- Barcelona / [ed] Josep M. Bayona & Joan García, 2009, s. 29-30Konferansepaper (Fagfellevurdert)
  • 14.
    Weisner, Stefan E.B
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Bastviken Kallner, Sofia
    Department of Biology, Linköping University.
    Thiere, Geraldine
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Ehde, Per Magnus
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Tonderski, Karin S.
    Department of Biology, Linköping University.
    Influence of alternative states on nitrogen removal in experimental wetlands2007Inngår i: 2nd International Symposium on Wetland Pollutant Dynamics and Control - WETPOL 2007: extended abstracts / [ed] Mander Ülo, Koiv Margi, Vohla Chrisitna, Tartu: Institute of Geography, University of Tartu , 2007, s. 357-359Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Denitrification is the main process that remove nitrate from the water in wetlands. Plants can supply denitrifying bacteria with organic carbon and suitable attachment surfaces (Weisner et al. 1994). They also promote the development of anaerobic conditions through litter accumulation and decomposition, which would favour denitrification. The presence of plants has been shown to enhance nitrate removal in field studies (Bachand and Horne 2000). Toet et al. (2005) found a higher nitrogen removal in wetland compartments with emergent plants than with submersed plants. Results from microcosm studies have shown that the potential for denitrification is specific for different plant species (Bastviken et al. 2005).

    Wetlands may typically exist in alternative states, dominated by different kinds of vegetation. The purpose of this study was to investigate the effect of alternative state on nitrogen removal under controlled conditions in experimental wetlands.

  • 15.
    Weisner, Stefan E.B.
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Strand, John A.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Sahlén, Göran
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Thiere, Geraldine
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Ehde, Per Magnus
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Svensson, Jonas M.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Combating eutrophication and biodiversity loss in Sweden: importance of constructed wetlands in the agricultural landscape2007Inngår i: Multifunctions of wetland systems, Padua: PAN , 2007, s. 60-61Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The results of this evaluation show that constructed wetlands in the agricultural landscape are capable of a substantial reduction of the nutrient transport to downstream recipients, but only if properly located. These wetlands will also contribute to an increased biodiversity even if not planned primarily for this purpose. The use of wetlands for multiple functions needs to be developed to motivate large-scale wetland construction.

  • 16.
    Weisner, Stefan E.B.
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Thiere, Geraldine
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Effects of vegetation state on biodiversity and nitrogen retention in created wetlands: a test of the biodiversity–ecosystem functioning hypothesis2010Inngår i: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 55, nr 2, s. 387-396Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    1. Nitrogen retention in wetlands provides an example of an ecosystem function that is desired by human society, and is a rationale for the creation of wetlands to decrease nitrogen fluxes from nitrate-loaded river catchments to coastal waters.

    2. Here, we tested the impact of different vegetation states on species diversity and nitrogen retention during 4 years in surface-flow wetlands receiving nitrate-rich water. Tall emergent vegetation or submerged vegetation was introduced to six experimental wetlands each and six wetlands were left as unplanted controls for free development of vegetation. This resulted in three vegetation states dominated by emergent vegetation, by a mixture of submerged vegetation and filamentous green algae or by filamentous green algae.

    3. Species diversity (species richness and Shannon diversity) of plants was initially lowest in free development wetlands, but during the study became lower in the emergent vegetation wetlands than in the other wetlands. Diversity of macroinvertebrates was initially lower in the submerged vegetation wetlands than in the other wetlands, but this difference disappeared during the study. Nitrogen retention was consistently higher in emergent vegetation wetlands than in the other wetlands throughout the study.

    4. We conclude that plant diversity in wetlands dominated by tall emergent vegetation gradually became lower than in other wetlands, due to dominant species competitively excluding other plants. However, these wetlands were more efficient at removing nitrogen than those dominated by filamentous algae or submerged macrophytes.

    5. Management of wetlands often aims to decrease the dominance of tall emergent vegetation for the benefit of plant species diversity and habitat heterogeneity. Our results demonstrate a biodiversity benefit, but also show that this strategy may decrease the ability of wetlands to remove nitrogen. In this case, there is no support for the hypothesis that biodiversity enhances ecosystem function.

  • 17.
    Weisner, Stefan
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Johannesson, Karin
    IFM Biology, Linköping University, Linköping, Sweden.
    Thiere, Geraldine
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Svengren, Henrik
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Ehde, Per Magnus
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS).
    Tonderski, Karin S.
    IFM Biology, Linköping University, Linköping, Sweden.
    National Large-Scale Wetland Creation in Agricultural Areas—Potential versus Realized Effects on Nutrient Transports2016Inngår i: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 8, nr 11, artikkel-id 544Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During 2007–2013, the Swedish Board of Agriculture granted support within a national program to about 1000 wetlands, corresponding to a 5300-hectare wetland area, with the dual goal to remove nutrients from water and to improve biodiversity in agricultural landscapes. The aim of the present study was to compare the effects on nutrient transports that are realized within the national program to what could be obtained with the same area of wetlands if location and design of wetlands were optimized. In single, highly nutrient-loaded wetlands, a removal of around 1000 kg nitrogen and 100 kg phosphorus per hectare wetland area and year was estimated from monitoring data. Statistical models were developed to estimate the overall nutrient removal effects of wetlands created within the national program. Depending on model, the effect of the national program as a whole was estimated to between 27 and 38 kg nitrogen and between 2.7 and 4.5 kg phosphorus per hectare created wetland area and year. Comparison of what is achieved in individual wetlands to what was achieved in the national program indicates that nutrient removal effects could be increased substantially in future wetland programs by emphasising location and design of wetlands.

  • 18.
    Weisner, Stefan
    et al.
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Thiere, Geraldine
    Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), Bio- och miljösystemforskning (BLESS), Våtmarkscentrum.
    Mindre fosfor och kväve från jordbrukslandskapet: Utvärdering av anlagda våtmarker inom miljö- och landsbygdsprogrammet och det nya landsbygdsprogrammet2010Rapport (Annet vitenskapelig)
1 - 18 of 18
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