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  • 251.
    Cousins, Sara A. O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen. växtekologi.
    Aggemyr, Elsa
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen. växtekologi.
    The influence of field shape, area and surrounding landscape on plant species richness in grazed ex-fields2008Inngår i: BIOLOGICAL CONSERVATION, Vol. 141, s. 126-135Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Over the past 100 years species-rich semi-natural grasslands have decreased dramatically in Western Europe, where former arable fields (ex-fields) are used instead as pasture. The disappearance of semi-natural grasslands have caused a threat to the biodiversity in agricultural landscapes. Many typical grassland plants are dispersal limited, thus grazed ex-fields can be used to investigate if species spontaneously colonise these new grassland habitats. We examined the relationship between surrounding landscape, field area, shape, distance between edge and centre, and plant species diversity in ex-fields that had been grazed for 15-18 years. The results showed that there were 35% more plant species in fields surrounded by commercial forestry production compared to those surrounded by open agricultural landscape. Area and shape did not influence species richness, although there was increasing number of species in the centre with decreasing distance from the edge. 25% of the species where typical grassland species, and ex-fields surrounded by forest had 91% more grassland species compared to those in the open landscape. It is possible to increase grassland plant occurrences by grazing ex-fields surrounded by forest or other grassland remnant habitats, particularly in landscapes where grazed semi-natural grasslands are scarce.

  • 252.
    Cousins, Sara A. O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Eriksson, Ove
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    The influence of management history and habitat on plant species richness in a rural hemiboreal landscape, Sweden2002Inngår i: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 17, nr 6, s. 517-529Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We explored patterns of plant species richness at different spatial scales in 14 habitats in a Swedish rural landscape. Effects of physical conditions, and relationships between species richness and management history reaching back to the 17 (th) century were examined, using old cadastral maps and aerial photographs. The most species-rich habitats were dry open semi- natural grasslands, midfield islets and road verges. Alpha diversity (species richness within sites) was highest in habitats on dry substrates (excluding bedrock with sparse pines) and beta diversity (species richness among sites) was highest in moist to wet habitats. Alpha and beta components of species richness tended to be inversely related among habitats with similar species richness. Management history influenced diversity patterns. Areas managed as grasslands in the 17 th and 18 th century harboured more species than areas outside the villages. We also found significant relationships between species richness and soil type. Silt proved to be the most species- rich topsoil (10- 20 cm) in addition to thin soils top of on green- or limestone bedrock. The variation in species richness due to local relief or form of the site also showed significant relationships, where flat surfaces had the highest number of species. In contrast, no significant relationship was found between species richness and aspect. Our study suggests that present- day diversity patterns are much influenced by management history, and that small habitat, e. g., road verges and midfield islets, are important for maintaining species richness.

  • 253.
    Cousins, Sara A. O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Eriksson, Åsa
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    Franzen, Daniel
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    Reconstructing past land use and vegetation patterns using palaeogeographical and archaeological data: A focus on grasslands in Nynas by the Baltic Sea in south-eastern Sweden2002Inngår i: Landscape and Urban Planning, ISSN 0169-2046, E-ISSN 1872-6062, Vol. 61, nr 1, s. 1-18Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Past landscape characteristics were reconstructed in Nynas, south-eastern Sweden, using geographical and archaeological data together with pollen stratigraphy and an existing shore displacement model, with the aim to explore the development of semi-natural grasslands in the area. A 2.3 m peat core was analysed and radiocarbon dated at three levels. The pollen stratigraphy was estimated to start at approximately 3800 C-14 years before present (BP), at the end of Late Neolithic. Human activities are evident, from both archaeological findings and pollen analysis, for more than 4000 years. Grazing is apparent, possibly more intense around 3200 C-14 years BP, 2500-2600 C-14 years BP, 2100-2200 C-14 years BP, and 1300/1400 C-14 years BP to present day. From 1900+/-80 C-14 years BP and onwards cultivation is intensified at the same time as spruce (Picea abies) expands. Maps on land-cover distribution in the late 17th century was used as a model for the utilisation of the landscape during the Iron Age. Land-covers on very thin soils were grazed and sometimes mown within the village boundaries, but they were also used for cultivation in narrow strips where bedrock is adjacent to clays. Till and varved glacial clays would have been used for cultivation. A reasonable estimation is that 10% of the study area could have been used for cultivation 1900 C-14 years BP, compared to 28% in the end of the 17th century. During the last century there has been a shift towards more arable fields and more forestry. There are 10% open or semi-open grassland left today, and 6% wooded grassland, compared with 47% open or semi-open grassland in the 17th century. Little more than half of the open grasslands are managed today, all by grazing. It is argued that encroachment of trees and shrubs on open or semi-open grasslands will not only reduce species richness in the landscape but also threaten parts of our cultural heritage.

  • 254.
    Cousins, Sara A. O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Ihse, Margareta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    A methodological study for biotope and landscape mapping based on CIR aerial photographs1998Inngår i: Landscape and Urban Planning, ISSN 0169-2046, E-ISSN 1872-6062, Vol. 41, nr 3-4, s. 183-192Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we present a method for base-line mapping of biotope and landscape elements in the rural Swedish agricultural landscape. The overall goal is to elaborate a classification system for a national landscape monitoring program, based on interpretation of existing colour infrared (CIR) aerial photographs at the scale 1:30000, and including a field control. The classification system developed was tested by mapping landscape elements in strategically selected test areas, and it is assessed with respect to interpretation accuracy. The landscape elements, mapped separately as patches, lines and points, are significant for the biodiversity on landscape level, and are susceptible to change. The classification system is based on a hierarchical approach in five levels, with regard to land use and management, nature type and succession stage, moisture, physiognomy, vegetation cover and plant species. By using the method and the suggested classification system, a base-line mapping can be done very quickly and accurately. The mapping rate is 1.4-2.8 km(2)/h and the interpretation accuracy is 95-99%.

  • 255.
    Cousins, Sara A. O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Kaligaric, Mitja
    Bakan, Branko
    Lindborg, Regina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Political Systems Affect Mobile and Sessile Species Diversity - A Legacy from the Post-WWII Period2014Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, nr 8, s. e103367-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Political ideologies, policies and economy affect land use which in turn may affect biodiversity patterns and future conservation targets. However, few studies have investigated biodiversity in landscapes with similar physical properties but governed by different political systems. Here we investigate land use and biodiversity patterns, and number and composition of birds and plants, in the borderland of Austria, Slovenia and Hungary. It is a physically uniform landscape but managed differently during the last 70 years as a consequence of the political map of Europe after World War I and II. We used a historical map from 1910 and satellite data to delineate land use within three 10-kilometre transects starting from the point where the three countries meet. There was a clear difference between countries detectable in current biodiversity patterns, which relates to land use history. Mobile species richness was associated with current land use whereas diversity of sessile species was more associated with past land use. Heterogeneous landscapes were positively and forest cover was negatively correlated to bird species richness. Our results provide insights into why landscape history is important to understand present and future biodiversity patterns, which is crucial for designing policies and conservation strategies across the world.

  • 256.
    Cousins, Sara A. O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Lavorel, Sandra
    Centre d’Ecologie Fonctionnelle et Ev olutive, CNRS, Montpellier, France.
    Davies, Ian
    Ecosystem Dynamics Group, Research School of Biological Sciences, Australian National University, Australia.
    Modelling the effects of landscape pattern and grazing regimes on the persistence of plant species with high conservation value in grasslands in south-eastern Sweden2003Inngår i: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 18, nr 3, s. 315-332Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Semi-natural grasslands in Sweden are threatened by land-use change and lack of management with attendant risk to their biodiversity. We present a model to explore the effects of grazing frequency and intensity on plant species persistence, and the relative effects of grassland size and pattern. We used a landscape modelling platform, LAMOS (LAndscape MOdelling Shell), to design a landscape model of vegetation dynamics incorporating the effects of local succession, dispersal and grazing disturbance. Five plant functional groups (PFG), representing various combinations of persistence and dispersal character, light requirements and disturbance responses, were defined to model species dynamics. Based on old cadastral maps three different landscapes were designed representing specific time-layers, i.e., a historical (17th to 18th century), a pre-modern (1940s) and a present-day landscape. Simulations showed that a threshold was crossed when grasslands decreased in area to about 10 - 30% of the modelled area, and as a consequence the biomass of grassland-specific PFGs was strongly reduced. These competition sensitive groups did not persist in the model even with intense grazing in the present-day landscape, where grasslands occupy 11% of the total area. However, all grassland species would have been able to persist in the historical landscape, where grasslands occupied 59% of the total area, even without grazing. Our results suggest that continuous but low-intensity grazing is more positive for grassland PFGs than discontinuous but highly intensive grazing. This effect was particularly strong when the frequency and/or intensity of grazing dropped below a threshold of 20%. Simulations using three landscape maps designed to explore effects of further fragmentation and habitat loss showed that the spatial pattern of remaining grasslands is important for the persistence of grassland-specific PFG. The model presented here is an advance towards more realistic grazing models to explore the effects of prescribed grazing and landscape fragmentation on the persistence species or plant functional groups.

  • 257.
    Cousins, Sara A. O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Lindborg, Regina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Assessing changes in plant distribution patterns - indicator species versus plant functional types2004Inngår i: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 4, nr 1, s. 17-27Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To meet conservation goals it is necessary to assess vegetation status and to be able to monitor effects of management and environmental change. In northern Europe grazed grasslands are one of the most threatened habitat in the rural landscape and thus in focus for conservation plans. At present managers use species indicator list to assess past and present management status of grassland and succession stages in particular, as well as effects of the environment. However, these indicators have rarely been scientifically tested. In this study we discuss if plant functional traits may be a key to select suitable indicator species for monitoring land-use change in Swedish rural landscape. The suitability of two possible monitoring tools: (i) plant species selected from functional traits (PFTs) and (ii) indicator species commonly used today to assess grassland management status, were tested along two gradients, a succession gradient and a wetness gradient. We found no association between successional change and plant functional traits, but a response in plant functional traits was found along the wetness gradient. However, the more common non-scientific indicator species responded fairly well to the varying gradient categories along both gradients. We believe that there is a need to further validate the ecological mechanisms behind the present-day indicators and to place them in a geographical context.

  • 258.
    Cousins, Sara A. O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen. växtekologi.
    Lindborg, Regina
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Remnant grassland habitats as source communities for plant diversification in agricultural landscapes2008Inngår i: BIOLOGICAL CONSERVATION, Vol. 141, s. 233-240Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lately there has been a shift in Sweden from grazing species-rich semi-natural grasslands towards grazing ex-arable fields in the modern agricultural landscape. These fields normally contain a fraction of the plant species richness compared to semi-natural grasslands. However, small remnant habitats have been suggested as important for plant species diversity and conservation as they may function as refugia for grassland specialists in fragmented and highly modified agricultural landscapes. In this study, we examined whether plant communities on small remnant habitats, i.e. midfield islets, can function as sources for grassland species to disperse out into surrounding grazed ex-fields (former arable fields). We examined species richness and grassland specialists (species favoured by grazing) and their ability to colonize fields after 5 and 11 years of grazing. The fields that had been grazed for a shorter time were fairly species-poor with few grassland specialists. A longer period of grazing had a positive effect on total and small-scale species diversity in both islets and fields. Species composition became more similar with time, and the number of grassland specialists in both habitats increased. We found that grassland specialists dispersed step-wise into the fields, and the number of grassland specialists decreased with distance from the source. Our study suggests that remnant habitats, such as midfield islets, do function as a source community for grassland specialists and enhance diversification of grassland species when grazing is introduced. For long-term conservation of plant species, incorporating small refugia into larger grazing complexes may thus enhance species richness.

  • 259.
    Cousins, Sara A. O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Lindborg, Regina
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Mattsson, Sofia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Land use history and site location are more important for grassland species richness than local soil properties2009Inngår i: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 27, s. 483-489Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lately there has been a shift in Sweden from grazing species-rich semi-natural grasslands towards grazing ex-arable fields in the modern agricultural landscape. Grazing ex-arable fields contain a fraction of the plant species richness confined to semi-natural grasslands. Still, they have been suggested as potential target sites for re-creation of semi-natural grasslands. We asked to what extent does fine-scale variation in soil conditions, management history and site location effect local plant diversity in grazed ex-arable fields. We examined local soil conditions such as texture, pH, organic carbon, nitrogen (N) and extractable phosphate (P) and effects on plant richness in ten pairs of grazed ex-fields and neighbouring semi-natural grasslands in different rural landscapes. Each grassland pair where in the same paddock. A multivariate test showed that site location and land use history explained more of differences in species richness than local soil property variables. Plant species richness was positively associated to grazed ex-fields with low pH, low N and P levels. Sites with high plant richness in semi-natural grasslands also had more species in the adjacent grazed ex-fields, compared to sites neighbouring less species-rich semi-natural grasslands. Although both soil properties and species richness were different in grazed ex-fields compared to semi-natural grassland, the site location within a landscape, and vicinity to species-rich grasslands, can override effects of soil properties. In conclusion, if properly located, ex-arable fields may be an important habitat to maintain plant diversity at larger spatio-temporal scales and should considered as potential sites for grassland restoration.

  • 260.
    Cousins, Sara A. O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). Växtekologi.
    Ohlson, Helena
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen. Växtekologi.
    Eriksson, Ove
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen. Växtekologi.
    Effects of historical and present fragmentation on plant species diversity in semi-natural grasslands in Swedish rural landscapes.2007Inngår i: Landscape Ecology, ISSN 0921-2973, Vol. 22, nr 5, s. 723-730Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Habitat loss and fragmentation of natural and semi-natural habitats are considered as major threats to plant species richness. Recently several studies have pinpointed the need to analyse past landscape patterns to understand effects of fragmentation, as the response to landscape change may be slow in many organisms, plants in particular. We compared species richness in continuously grazed and abandoned grasslands in different commonplace rural landscapes in Sweden, and analysed effects of isolation and area in three time-steps (100 and 50 years ago and today). Old cadastral maps and aerial photographs were used to analyse past and present landscape patterns in 25 sites. Two plant diversity measures were investigated; total species richness and species density. During the last 100 years grassland area and connectivity have been reduced by about 90%. Present-day habitat area was positively related to total species richness in both habitats. There was also a relationship to habitat area 50 years ago for continuously grazed grasslands. Only present management was related to species density: continuously grazed grasslands had the highest species density. There were no relationships between grassland connectivity, present or past, and any diversity measure. We conclude that landscape history is not directly important for present-day plant diversity patterns in ordinary landscapes, although past grassland management is a prerequisite for the grassland habitats that can be found there today. It is important that studies are conducted, not only in very diverse landscapes, but also in managed landscapes in order to assess the effects of fragmentation on species.

  • 261.
    Cousins, Sara A. O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Vanhoenacker, Didrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    Detection of extinction debt depends on scale and specialisation2011Inngår i: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 144, nr 2, s. 782-787Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many plants can persist in landscapes for a long time after focal habitats have disappeared or become fragmented, which might contribute to an extinction debt. Delayed responses of plant occurrence have recently received great attention, particularly in conservation, although evidence for extinction debts is incongruent. Here we asked if we could detect an extinction debt for plant species after 100 years of fragmentation, depending on regional or local (gamma or alpha respectively) diversity measure used, and if all plant species or only habitat specialists were investigated. Historical and contemporary grassland patterns were analysed in 33 rural landscapes (each 1 km(2) in diameter) in south-eastern Sweden. Results show that managed semi-natural grassland had declined from 39% to 3% in 100 years. Diversity measured at regional scale was best explained by grassland extent 100 years ago, for both all species and grassland specialists. Present-day management, but neither present nor past grassland extent, was important for grassland specialists' occurrence at the local scale, although present-day grassland proportion had a positive influence on species richness at the local scale. We found evidence of an extinction debt at both local and regional scale when all species were included in the analysis, but not for grassland specialist species at the local scale. However, the extinction debt is still to be settled for grassland specialists at the regional scale, and therefore the estimation of extinction debts in fragmented habitats presents one of the greatest challenges for conservation today and in the future.

  • 262. Cunningham, Laura
    et al.
    Bigler, Christian
    Rydberg, C
    Rosqvist, Gunhild
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Leng, Melanie
    Goslar, Tomas
    Berntsson, Annika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Wastegård, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Preliminary Results for Stuor Guossásjavri, Northern Sweden2009Inngår i: European Climate of the Last Millennium, Millennium Milestone meeting 3, Cala Millor, Mallorca, 3rd-15th March 2009, 2009, s. 58-59Konferansepaper (Fagfellevurdert)
  • 263. Cunningham, Laura
    et al.
    Bigler, Christian
    Rydberg, Cecilia
    Rosqvist, Gunhild
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Berntsson, Annika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Kaislahti Tillman, Päivi
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Jonsson, Christina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Leng, Melanie
    Wastegård, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Goslar, Tomasz
    Preliminary Sampling Report from Stuor Guossásjavri, Northern Sweden2008Inngår i: European Climate of the Last Millennium, Millennium Milestone meeting 2, Cala Millor, Mallorca, 13th-15th March 2008, 2008, s. 80-81Konferansepaper (Annet vitenskapelig)
  • 264.
    Cunningham, Laura
    et al.
    School of Geography & Geosciences, University of St Andrews.
    Bishop, Kevin
    Department of Environmental Assessment, Swedish University of Agricultural Sciences.
    Mettävainio, Ewa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Rosén, Peter
    Climate Impacts Research Centre, Umeå University.
    Paleoecological evidence of major declines in total organic carbon concentrations since the nineteenth century in four nemoboreal lakes2011Inngår i: Journal of Paleolimnology, ISSN 0921-2728, E-ISSN 1573-0417, Vol. 45, nr 4, s. 507-518Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A decade of widespread increases in surface water concentrations of total organic carbon (TOC) in some regions has raised questions about longer term patterns in this important constituent of water chemistry. This study uses near-infrared spectroscopy (NIRS) to infer lake water TOC far beyond the decade or two of observational data generally available. An expanded calibration dataset of 140 lakes across Sweden covering a TOC gradient from 0.7 to 24.7 mg L-1 was used to establish a relationship between the NIRS signal from surface sediments (0-0.5 cm) and the TOC concentration of the water mass. Internal cross-validation of the model resulted in an R (2) of 0.72 with a root mean squared error of calibration (RMSECV) of 2.6 mg L-1. The TOC concentrations reconstructed from surface sediments in four Swedish lakes were typically within the range of concentrations observed in the monitoring data during the period represented by each sediment layer. TOC reconstructions from the full sediment cores of four lakes indicated that TOC concentrations were approximately twice as high a century ago.

  • 265. Cunningham, Laura K.
    et al.
    Austin, William E. N.
    Knudsen, Karen Luise
    Eiriksson, Jon
    Scourse, James D.
    Wanamaker, Alan D., Jr.
    Butler, Paul G.
    Cage, Alix G.
    Richter, Thomas
    Husum, Katrine
    Hald, Morten
    Andersson, Carin
    Zorita, Eduardo
    Linderholm, Hans W.
    Gunnarson, Björn E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). Swedish University of Agricultural Sciences, Sweden.
    Sicre, Marie-Alexandrine
    Sejrup, Hans Petter
    Jiang, Hui
    Wilson, Rob J. S.
    Reconstructions of surface ocean conditions from the northeast Atlantic and Nordic seas during the last millennium2013Inngår i: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 23, nr 7, s. 921-935Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We undertake the first comprehensive effort to integrate North Atlantic marine climate records for the last millennium, highlighting some key components common within this system at a range of temporal and spatial scales. In such an approach, careful consideration needs to be given to the complexities inherent to the marine system. Composites therefore need to be hydrographically constrained and sensitive to both surface water mass variability and three-dimensional ocean dynamics. This study focuses on the northeast (NE) North Atlantic Ocean, particularly sites influenced by the North Atlantic Current. A composite plus regression approach is used to create an inter-regional NE North Atlantic reconstruction of sea surface temperature (SST) for the last 1000 years. We highlight the loss of spatial information associated with large-scale composite reconstructions of the marine environment. Regional reconstructions of SSTs off the Norwegian and Icelandic margins are presented, along with a larger-scale reconstruction spanning the NE North Atlantic. The latter indicates that the Medieval Climate Anomaly' warming was most pronounced before ad 1200, with a long-term cooling trend apparent after ad 1250. This trend persisted until the early 20th century, while in recent decades temperatures have been similar to those inferred for the Medieval Climate Anomaly'. The reconstructions are consistent with other independent records of sea-surface and surface air temperatures from the region, indicating that they are adequately capturing the climate dynamics of the last millennium. Consequently, this method could potentially be used to develop large-scale reconstructions of SSTs for other hydrographically constrained regions.

  • 266. Curry, B. Brandon
    et al.
    Konen, Michael E.
    Larson, Timothy H.
    Yansa, Catherine H.
    Hackley, Keith C.
    Alexanderson, Helena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Lowell, Thomas V.
    The DeKalb mounds of northeastern Illinois as archives of deglacial history and postglacial environments2010Inngår i: Quaternary Research, ISSN 0033-5894, E-ISSN 1096-0287, Vol. 74, nr 1, s. 82-90Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The ""type"" DeKalb mounds of northeastern Illinois, USA (42.0 degrees N, -88.7 degrees W), are formed of basal sand and gravel overlain by rhythmically bedded fines, and weathered sand and gravel. Generally from 2 to 7 m thick, the fines include abundant fossils of ostracodes and uncommon leaves and stems of tundra plants. Rare chironomid head capsules, pillclam shells, and aquatic plant macrofossils also have been observed. Radiocarbon ages on the tundra plant fossils from the ""type"" region range from 20,420 to 18,560 cal yr BP. Comparison of radiocarbon ages of terrestrial plants from type area ice-walled lake plains and adjacent kettle basins indicate that the topographic inversion to ice-free conditions occurred from 18,560 and 16,650 cal yr BP. Outside the ""type"" area, the oldest reliable age of tundra plant fossils in DeKalb mound sediment is 21,680 cal yr BP; the mound occurs on the northern arm of the Ransom Moraine (-88.5436 degrees W, 41.5028 degrees N). The youngest age, 16,250 cal yr BP, is associated with a mound on the Deerfield Moraine (-87.9102 degrees W, 42.4260 degrees N) located about 9 km east of Lake Michigan. The chronology of individual successions indicates the lakes persisted on the periglacial landscape for about 300 to 1500 yr.

  • 267. Cvetkovic, V.
    et al.
    Carstens, C.
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Lagrangian modeling of advective solute transport along hydrological pathways2012Konferansepaper (Fagfellevurdert)
  • 268. Cvetkovic, V.
    et al.
    Carstens, C.
    Selroos, J.-O.
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Water and solute transport along hydrological pathways2012Inngår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 48, nr 6, s. W06537-(15 pp)Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A Lagrangian framework for material transport along hydrological pathways is presented and consequences of statistically stationary space-time flow velocity variations on advective transport are investigated. The two specific questions addressed in this work are: How do temporal fluctuations affect forward and backward water travel time distributions when combined with spatial variability? and Can mass transfer processes be quantified using conditional probabilities in spatially and temporally variable flow? Space-time trajectories are studied for generic conditions of flow, with fully ergodic or only spatially ergodic velocity. It is shown that forward and backward distributions of advective water travel time coincide for statistically stationary space-time variations. Temporal variability alters the statistical structure of the Lagrangian velocity fluctuations. Once this is accounted for, integration of the memory function with the travel time distribution is applicable for quantifying retention. Further work is needed to better understand the statistical structure of space-time velocity variability in hydrological transport, as well as its impact on tracer retention and attenuation.

  • 269. Cvetkovic, Vladimir
    et al.
    Frampton, Andrew
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Solute transport and retention in three-dimensional fracture networks2012Inngår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 48, s. W02509-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Resolving the hydrodynamic control of retention is an important step in predictive modeling of transport of sorbing tracers in fractured rock. The statistics of the transport resistance parameter beta [T/L] and the related effective active specific surface area s(f) [1/L] are studied in a crystalline rock volume on a 100 m scale. Groundwater flow and advective transport are based on generic boundary conditions and realistic discrete fracture networks inferred from the Laxemar site, southeast Sweden. The overall statistics of beta are consistent with statistics of the water residence time tau; the moments of beta vary linearly with distance, at least up to 100 m. The correlation between log tau and log beta is predominantly linear, however, there is significant dispersion; the parameter s(f) strongly depends on the assumed hydraulic law (theoretical cubic or empirical quadratic). Fast and slow trajectories/segments in the network determine the shape of the beta distribution that cannot be reproduced by infinitely divisible model over the entire range; the low value range and median can be reproduced reasonably well with the tempered one-sided stable density using the exponent in the range 0.35-0.7. The low percentiles of the beta distribution seems to converge to a Fickian type of behavior from a 50 to 100 m scale.

  • 270.
    Cárdenas, Pulgar, Camila, Natalia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Riskfyllda aktivitetsutrymmen?: En studie av två barn med utländsk bakgrund bosatta i miljöer med skilda socioekonomiska förutsättningar2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This study has as an objective to compare and evaluate the living conditions of two immigrant children residing in different places in Sweden. Given that immigrants often are looked upon as a social and physical vulnerable group in relation to disadvantageous socioeconomic conditions the children's lives were analyzed in relation to four public health objects. By using Runkeeper, GIS, Equipop data, time geographic material, telephone conversations and a web survey the children lives are analyzed within their activity spaces. The children formed their lives in different socioeconomic environments and adapted their lives after their conditions. The perspective on individual level can be put in contrast with studies based on society level. In relation to this the lives of these two children are observed as deviant because they showed a good health status in social and physical aspects. Some theories and hypothesis could be verified and some of these could be falsified.

    Keywords: Activity spaces, immigrant, socioeconomic conditions, health status.

  • 271. Da, Chau Thi
    et al.
    Phuoc, Le Huu
    Duc, Huynh Ngoc
    Troell, Max
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre. The Royal Swedish Academy of Sciences, Sweden.
    Berg, Håkan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Use of Wastewater from Striped Catfish (Pangasianodon hypophthalmus) Pond Culture for Integrated Rice-Fish-Vegetable Farming Systems in the Mekong Delta, Vietnam2015Inngår i: Agroecology and Sustainable Food Systems, ISSN 2168-3565, E-ISSN 2168-3573, Vol. 39, nr 5, s. 580-597Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article investigates the feasibility of reusing wastewater from striped catfish (Pangasianodon hypophthalmus) pond culture as nutrient input for integrated rice-Nile tilapia-green bean farming systems, and to what extent this could contribute to decreasing the environmental impacts on water quality from the striped catfish industry in the Mekong Delta. Four treatments in triplicates were used to investigate the growth of rice and green bean varieties under different combinations of inorganic fertilizer and water from the river and a striped catfish pond culture. The Nile tilapia (Oreochromis niloticus) was cultured at low density without feeding in a canal adjacent to the rice field. Rice yields ranged from 3,514 to 4,023 kg ha(-1) with no significant differences between treatments (p > 0.05). The yield of green bean ranged from 2,671 to 3,282 kg ha(-1) (p < 0.05), with the highest yields for beans only receiving water from the striped catfish pond. The water quality concentrations decreased significantly when passing through the rice plots for almost all treatments (p < 0.05). Total phosphorus and nitrogen levels in the outflowing water were reduced by almost 50% compared to the inflowing water from the striped catfish pond. Overall, the results indicated that an integrated system generates both economic and environmental benefits as compared to monocultures.

  • 272.
    Dahlberg, Annika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Reservat, jordbruk, aktörer och värden. Flexibla kategorier för en hållbar landskapsvård2014Inngår i: Begagnade landskap – använt, vårdat och värderat / [ed] Anders Wästfelt, Stockholm: Riksantikvarieämbetet, 2014, 1, s. 41-63Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 273.
    Dahlberg, Annika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). Stockholms universitet, Samhällsvetenskapliga fakulteten, Kulturgeografiska institutionen.
    The importance and complexity of access rights in times of change2009Inngår i: What belongs in a changing nature? Northern and Southern perspectives on nature and everyday landscapes / [ed] Stenseke, M, & Saltzman, K., 2009, s. 14-15Konferansepaper (Annet vitenskapelig)
  • 274.
    Dahlberg, Annika
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Burlando, Catie
    Natural Resource Institute, University of Manitoba.
    Addressing trade-offs: Experiences from conservation and development initiatives in the Mkuze Wetlands, South Africa2009Inngår i: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 14, nr 2, s. online-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Present-day conservation policies generally include the aim to integrate biodiversity conservation and local development, and describe this as a win–win solution that can satisfy all interests. This is challenged by research claiming that many efforts fail to match practice to rhetoric. South Africa has made strong commitments to fulfill the dual goals of conservation and development, and the iSimangaliso Wetland Park is promoted as an example of this. We explore present and potential outcomes of conservation and development interventions in a community bordering the Wetland Park through the perspective of different stakeholders, with the aim of uncovering opportunities and risks. In terms of improving local livelihoods as well as involvement in conservation, the success of the studied interventions varied. Local communities may accept restrictions on resource use as a result of realistic and fairly negotiated trade-offs, but if perceived as unjust and imposed from above, then mistrust and resistance will increase. In this area, collaboration between conservation organizations and the local community had improved, but still faced problems associated with unequal power relations, unrealistic expectations, and a lack of trust, transparency, and communication. As unsustainable efforts are a waste of funds and engagement, and may even become counterproductive, policy visions need to be matched by realistic allocations of staff, time, funds, and training. At the national and international level, the true cost of conservation has to be recognized and budgeted for if efforts at integrating conservation and development are to succeed.

  • 275.
    Dahlberg, Annika
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). Stockholms universitet, Samhällsvetenskapliga fakulteten, Kulturgeografiska institutionen.
    Rohde, Rick
    Centre of African Studies, University of Edinburgh.
    Sandell, Klas
    Department of Geography and Tourism, Karlstad university.
    Public access, conservation and environmental justice: A comparison of national park policy in three countries (South Africa, Sweden, Scotland)2009Inngår i: The multifunctional commons of the world landscapes: Between private property and public use, 2009Konferansepaper (Annet vitenskapelig)
  • 276.
    Dahlberg, Annika
    et al.
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Kulturgeografiska institutionen.
    Trygger, Sophie
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Indigenous medicine and primary health care: The importance of lay knowledge and use of medicinal plants in rural South Africa2009Inngår i: Human Ecology, ISSN 0300-7839, E-ISSN 1572-9915, Vol. 37, nr 1, s. 79-94Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Indigenous medicine is important to rural livelihoods, but lay knowledge and use ofmedicinal plants has not been extensively studied. Research in KwaZulu-Natal, South Africa, showed that medicinal plants were frequently used by villagers and contributed to their ability to cope with health problems. Knowledge of plants and household remedies was extensive and varied in that households often held different knowledge. Villagers mainly relied on common species, and were generally aware of alternative species for a certain ailment. People were flexible in their use of indigenous and western health care, which were both perceived as beneficial. Improved cooperation between health care systems could improve health standards. Extraction of medicinal plants has been described as unsustainable in the region found in the study area. It is argued that conservation policies aimed to restrict access should be differential and potentially not include local consumption, since this may be ecologically unnecessary and entail local hardships.

  • 277.
    Dahlin, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Västra Järvafältets grod- och kräldjursfauna2011Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Syftet med studien var att öka kunskapen om grod- och kräldjursfaunans utbredning ochförekomst inom västra Järvafältets naturreservat och Barkarbyfältets norra delar, samt attundersöka om det föreligger en hotbild mot grod- och kräldjursfaunan i och med utbyggnadenav Barkarbystaden.

    En grod- och kräldjursinventering gjordes under våren och sommaren 2010 med enkompletterande inventering under våren 2011. Tidigare fynd gjorda under 2003-2009 harockså tagits med i denna uppsats med avsikten att försöka ge en så riktig bild av grod- ochkräldjursfaunans förekomst som möjligt.

    Under perioden 2003-2011 hittades samtliga grod- och kräldjur som förväntades finnas, dockmed undantag för den relikta och sällsynta arten, hasselsnoken (Coronella austriaca). Inomundersökningsområdet finns goda och varierande livsmiljöer för såväl reptiler som föramfibier. Dock bör det finnas förutsättningar för att skapa bättre miljöer för groddjur genomatt anlägga småvatten samt att stärka förbindelser mellan lokala populationer inom ochutanför undersökningsområdet.

    Barkarbystaden och dess pågående utbyggnad kan komma att påverka reptilernas habitatkring Barkarbystadens norra delar och södra Säbysjön. Dock kan Barkarbystaden med sinagröna förbindelser och anlagda parkmiljöer generellt ha en positiv inverkan på grod- ochkräldjursfaunan om utförandet sker med hänsyn och med viss anpassning till dennaorganismgrupp.

  • 278. Dahl-Jensen, D.
    et al.
    Albert, M. R.
    Aldahan, A.
    Azuma, N.
    Balslev-Clausen, D.
    Baumgartner, M.
    Berggren, A. -M
    Bigler, M.
    Binder, T.
    Blunier, T.
    Bourgeois, J. C.
    Brook, E. J.
    Buchardt, S. L.
    Buizert, C.
    Capron, E.
    Chappellaz, J.
    Chung, J.
    Clausen, H. B.
    Cvijanovic, I.
    Davies, S. M.
    Ditlevsen, P.
    Eicher, O.
    Fischer, H.
    Fisher, D. A.
    Fleet, L. G.
    Gfeller, G.
    Gkinis, V.
    Gogineni, S.
    Goto-Azuma, K.
    Grinsted, A.
    Gudlaugsdottir, H.
    Guillevic, M.
    Hansen, S. B.
    Hansson, Margareta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Hirabayashi, M.
    Hong, S.
    Hur, S. D.
    Huybrechts, P.
    Hvidberg, C. S.
    Iizuka, Yoshinori
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). Hokkaido University, Japan.
    Jenk, T.
    Johnsen, S. J.
    Jones, T. R.
    Jouzel, J.
    Karlsson, N. B.
    Kawamura, K.
    Keegan, K.
    Kettner, E.
    Kipfstuhl, S.
    Kjaer, H. A.
    Koutnik, M.
    Kuramoto, T.
    Koehler, P.
    Laepple, T.
    Landais, A.
    Langen, P. L.
    Larsen, L. B.
    Leuenberger, D.
    Leuenberger, M.
    Leuschen, C.
    Li, J.
    Lipenkov, V.
    Martinerie, P.
    Maselli, O. J.
    Masson-Delmotte, V.
    McConnell, J. R.
    Miller, H.
    Mini, O.
    Miyamoto, A.
    Montagnat-Rentier, M.
    Mulvaney, R.
    Muscheler, R.
    Orsi, A. J.
    Paden, J.
    Panton, C.
    Pattyn, F.
    Petit, J. -R
    Pol, K.
    Popp, T.
    Possnert, G.
    Prie, F.
    Prokopiou, M.
    Quiquet, A.
    Rasmussen, S. O.
    Raynaud, D.
    Ren, J.
    Reutenauer, C.
    Ritz, C.
    Rockmann, T.
    Rosen, J. L.
    Rubino, M.
    Rybak, O.
    Samyn, D.
    Sapart, C. J.
    Schilt, A.
    Schmidt, A. M. Z.
    Schwander, J.
    Schuepbach, S.
    Seierstad, I.
    Severinghaus, J. P.
    Sheldon, S.
    Simonsen, S. B.
    Sjolte, J.
    Solgaard, A. M.
    Sowers, T.
    Sperlich, P.
    Steen-Larsen, H. C.
    Steffen, K.
    Steffensen, J. P.
    Steinhage, D.
    Stocker, T. F.
    Stowasser, C.
    Sturevik, A. S.
    Sturges, W. T.
    Sveinbjornsdottir, A.
    Svensson, A.
    Tison, J. -L
    Uetake, J.
    Vallelonga, P.
    van de Wal, R. S. W.
    van der Wel, G.
    Vaughn, B. H.
    Vinther, B.
    Waddington, E.
    Wegner, A.
    Weikusat, I.
    White, J. W. C.
    Wilhelms, F.
    Winstrup, M.
    Witrant, E.
    Wolff, E. W.
    Xiao, C.
    Zheng, J.
    Eemian interglacial reconstructed from a Greenland folded ice core2013Inngår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 493, nr 7433, s. 489-494Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Efforts to extract a Greenland ice core with a complete record of the Eemian interglacial (130,000 to 115,000 years ago) have until now been unsuccessful. The response of the Greenland ice sheet to the warmer-than-present climate of the Eemian has thus remained unclear. Here we present the new North Greenland Eemian Ice Drilling ('NEEM') ice core and show only a modest ice-sheet response to the strong warming in the early Eemian. We reconstructed the Eemian record from folded ice using globally homogeneous parameters known from dated Greenland and Antarctic ice-core records. On the basis of water stable isotopes, NEEM surface temperatures after the onset of the Eemian (126,000 years ago) peaked at 8 +/- 4 degrees Celsius above the mean of the past millennium, followed by a gradual cooling that was probably driven by the decreasing summer insolation. Between 128,000 and 122,000 years ago, the thickness of the northwest Greenland ice sheet decreased by 400 +/- 250 metres, reaching surface elevations 122,000 years ago of 130 +/- 300 metres lower than the present. Extensive surface melt occurred at the NEEM site during the Eemian, a phenomenon witnessed when melt layers formed again at NEEM during the exceptional heat of July 2012. With additional warming, surface melt might become more common in the future.

  • 279. Dahlke, H. E.
    et al.
    Behrens, T.
    Seibert, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Andersson, L.
    Test of statistical means for the extrapolation of soil depth point information using overlays of spatial environmental data and bootstrapping techniques2009Inngår i: Hydrological Processes, Vol. 23, nr 21, s. 3017-3029Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydrological modelling depends highly on the accuracy and uncertainty of model input parameters such as soil properties. Since most of these data are field Surveyed, geostatistical techniques Such as kriging, classification and regression trees or more sophisticated soil-landscape models need to be applied to interpolate point information to the area. Most of the existing interpolation techniques require a random or regular distribution of points Within the study area but are not adequate to satisfactorily interpolate soil catena or transect data. The soil landscape model presented in this study is predicting soil information from transect or catena point data using a statistical mean (arithmetic, geometric and harmonic mean) to calculate the soil information based on class means of merged spatial explanatory variables. A data set of 226 soil depth measurements covering a range of 0-6.5 m was used to test the model. The point data were sampled along four transects in the Stubbetorp catchment, SE-Sweden. We overlaid a geomorphology map (8 classes) with digital elevation model-derived topographic index maps (2-9 classes) to estimate the range of error the model produces with changing sample size and input maps. The accuracy of the soil depth predictions was estimated with the root mean square error (RMSE) based oil a testing and training data set. RMSE ranged generally between 0.73 and 0.83 m +/- 0.013 m depending on the amount of classes the merged layers had, but were smallest for a map combination with a low number of classes predicted with the harmonic mean (RMSE = 0.46 m). The results show that the prediction accuracy of this method depends oil the number of point values in the sample, the value range of the measured attribute and the initial correlations between point values and explanatory variables, but suggests that the model approach is in general scale invariant. Copyright (C) 2009 John Wiley & Sons, Ltd.

  • 280. Dahlke, Helen E.
    et al.
    Easton, Zachary M.
    Fuka, Daniel R.
    Lyon, Steve W.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Steenhuis, Tammo S.
    Modelling variable source area dynamics in a CEAP watershed2009Inngår i: Ecohydrology, ISSN 1936-0584, Vol. 2, nr 3, s. 337-349Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the Northeast US, saturation excess is the most dominant runoff process and locations of runoff areas, typically called variable source areas (VSAs), are determined by the available soil water storage and the landscape topographic position. To predict runoff generated from VSAs some water quality models use the Soil Conservation Service Curve Number equation (SCS-CN), which assumes a constant initial abstraction of rainfall is retained by the watershed prior to the beginning of runoff. We apply a VSA interpretation of the SCS-CN runoff equation that allows the initial abstraction to vary with antecedent Moisture conditions. We couple this modified SCS-CN approach with a semi-distributed water balance model to predict runoff, and distribute predictions using a soil topographic index for the Town Brook watershed in the Catskill Mountains of New York State. The accuracy of predicted VSA extents using both the original and the modified SCS-CN equation were evaluated for 14 rainfall-runoff events through a comparison with average water table depths measured at 33 locations in Town Brook from March-September 2004. The modified SCS-CN equation captured VSA dynamics more accurately than the original equation. However, during events with high antecedent rainfall VSA dynamics were still under-predicted suggesting that VSA runoff is not captured solely by knowledge of the soil water deficit. Considering the importance of correctly predicting runoff generation and pollutant source areas in the landscape, the results of this study demonstrate the feasibility of integrating VSA hydrology into water quality models to reduce non-point source pollution.

  • 281.
    Dahlke, Helen E.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). University of California System .
    Easton, Zachary M.
    Fuka, Daniel R.
    Walter, M. Todd
    Steenhuis, Tammo S.
    Real-Time Forecast of Hydrologically Sensitive Areas in the Salmon Creek Watershed, New York State, Using an Online Prediction Tool2013Inngår i: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 5, nr 3, s. 917-944Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the northeastern United States (U.S.), watersheds and ecosystems are impacted by nonpoint source pollution (NPS) from agricultural activity. Where agricultural fields coincide with runoff-producing areas-so called hydrologically sensitive areas (HSA)-there is a potential risk of NPS contaminant transport to streams during rainfall events. Although improvements have been made, water management practices implemented to reduce NPS pollution generally do not account for the highly variable, spatiotemporal dynamics of HSAs and the associated dynamics in NPS pollution risks. This paper presents a prototype for a web-based HSA prediction tool developed for the Salmon Creek watershed in upstate New York to assist producers and planners in quickly identifying areas at high risk of generating storm runoff. These predictions can be used to prioritize potentially polluting activities to parts of the landscape with low risks of generating storm runoff. The tool uses real-time measured data and 24-48 h weather forecasts so that locations and the timing of storm runoff generation are accurately predicted based on present-day and future moisture conditions. Analysis of HSA predictions in Salmon Creek show that 71% of the largest storm events between 2006 and 2009 were correctly predicted based on 48 h forecasted weather data. Real-time forecast of HSAs represents an important paradigm shift for the management of NPS in the northeastern U.S.

  • 282.
    Dahlke, Helen E.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Easton, Zachary M.
    Lyon, Steve W.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Walter, M. Todd
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Steenhuis, Tammo S.
    Dissecting the variable source area concept - Subsurface flow pathways and water mixing processes in a hillslope2012Inngår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 420, s. 125-141Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study uses an instrumented (trenched) 0.5 ha hillslope in the southern tier of New York State, USA, to provide new data and insights on how variable source areas and associated flow pathways form and combine to connect rainfall with downstream water flows across a hillslope. Measurements of water fluxes in the trench, upslope water table dynamics, surface and bedrock topography, and isotopic and geochemical tracers have been combined for a four-dimensional (space-time) characterization of subsurface storm flow responses. During events with dry antecedent conditions infiltrating rainwater was found to percolate through a prevailing fragipan layer to deeper soil layers, with much (33-71%) of the total discharge of the hillslope originating from deeper water flow below the fragipan. During storm events with wet antecedent conditions and large rainfall amounts, shallow lateral flow of event and pre-event water above the fragipan occurred and was one magnitude greater than the deeper water flow contribution. Spatial surface and subsurface water quality observations indicate that water from a distance of up to 56 m contributed runoff from the hillslope during storm events. In addition, mobilization of total dissolved phosphorus (TDP) with subsurface flow played a greater role than with overland or near-surface flow. During all events TDP loads were highest in the total discharge during peak flows (8-11.5 kg ha(-1) d(-1)), except during the largest storm event, when TDP concentrations were highly diluted. These results have implications for strategies to protect streams and other downstream water recipients from waterborne nutrient and pollutant loading.

  • 283.
    Dahlke, Helen E.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Easton, Zachary M.
    Walter, M. Todd
    Steenhuis, Tammo S.
    Field test of the variable source area interpretation of the curve number rainfall runoff equation2012Inngår i: Journal of irrigation and drainage engineering, ISSN 0733-9437, E-ISSN 1943-4774, Vol. 138, nr 3, s. 235-244Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Soil Conservation Service Curve Number (SCS-CN) method is a widely used empirical rainfall-runoff equation. Although the physical basis of the method has been debated, several researchers have suggested that it can be used to predict the watershed fraction that is saturated and generating runoff by saturation excess from variable source areas (VSAs). In this paper, we compare saturated runoff-contributing areas predicted with the VSA interpretation of the SCS-CN method with field-measured VSAs in a 0.5 ha hillslope in central New York State. We installed a trench below a VSA and simultaneously recorded water flux from different soil layers at the trench face and water table dynamics upslope of the trench. This setup allowed us to monitor runoff initiation and saturation-excess overland flow in response to rainfall and different water table depths in the hillslope during 16 storm events. We found that the SCS-CN method accurately predicted the observed VSA and showed best agreement if the VSA was defined as the area where the water table was within 10 cm of the soil surface. These results not only demonstrate that the VSA interpretation of the SCS-CN method accurately predicts VSA extents in small watersheds but also that the transient water table does not necessarily need to intersect the land surface to cause a storm runoff response. DOI:10.1061/(ASCE)IR.1943-4774.0000380.

  • 284.
    Dahlke, Helen E.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Lyon, Steve W.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Early melt season snowpack isotopic evolution in the Tarfala valley, northern Sweden2013Inngår i: Annals of Glaciology, ISSN 0260-3055, E-ISSN 1727-5644, Vol. 54, nr 62, s. 149-156Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigated the stable water isotopic (delta O-18 and delta D) evolution of two snowpacks located at the same elevation on a north-facing (Nf) and a south-facing (Sf) slope within the Tarfala research catchment, northern Sweden, and the potential impact of pre-freshet snowpack melt on streamflow. Our results indicate that over the study period the Sf snowpack showed a more enriched isotopic composition, especially in the top of the profile, and contributed more snowmelt to streamflow than the Nf slope. The Sf snowpack also showed a significantly higher variability in snowpack delta O-18 levels and snowpack snow water equivalent (SWE) over time. Comparing snowpack and snowmelt isotopic values it was seen that the Sf slope experienced earlier snowmelt from upslope positions due to greater insolation that subsequently enhanced the meltwater flux at the base of downslope snowpacks. In contrast, the Nf slope primarily underwent changes within the snowpack and experienced relatively minimal melt. Detailed field-based isotopic snowmelt studies such as this highlight the potential importance of incorporating spatio-temporal runoff generation concepts into distributed energy-balance models, which could allow for more accurate prediction with regard to the spatio-temporal dynamics associated with the snowmelt ion pulse.

  • 285.
    Dahlke, Helen E.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Lyon, Steve W.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Jansson, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Karlin, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Rosqvist, Gunhild
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Isotopic investigation of runoff generation in a glacierized catchment in northern Sweden2014Inngår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 28, nr 3, s. 1383-1398Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, summer rainfall contributions to streamflow were quantified in the sub-arctic, 30% glacierized Tarfala (21.7km(2)) catchment in northern Sweden for two non-consecutive summer sampling seasons (2004 and 2011). We used two-component hydrograph separation along with isotope ratios (O-18 and D) of rainwater and daily streamwater samplings to estimate relative fraction and uncertainties (because of laboratory instrumentation, temporal variability and spatial gradients) of source water contributions. We hypothesized that the glacier influence on how rainfall becomes runoff is temporally variable and largely dependent on a combination of the timing of decreasing snow cover on glaciers and the relative moisture storage condition within the catchment. The results indicate that the majority of storm runoff was dominated by pre-event water. However, the average event water contribution during storm events differed slightly between both years with 11% reached in 2004 and 22% in 2011. Event water contributions to runoff generally increased over 2011 the sampling season in both the main stream of Tarfala catchment and in the two pro-glacial streams that drain Storglaciaren (the largest glacier in Tarfala catchment covering 2.9km(2)). We credit both the inter-annual and intra-annual differences in event water contributions to large rainfall events late in the summer melt season, low glacier snow cover and elevated soil moisture due to large antecedent precipitation. Together amplification of these two mechanisms under a warming climate might influence the timing and magnitude of floods, the sediment budget and nutrient cycling in glacierized catchments.

  • 286.
    Dahlke, Helen E.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Lyon, Steve W.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Stedinger, J. R.
    Rosqvist, Gunhild
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Jansson, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Contrasting trends in floods for two sub-arctic catchments in northern Sweden - does glacier presence matter?2012Inngår i: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 16, nr 7, s. 2123-2141Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Our understanding is limited to how transient changes in glacier response to climate warming will influence the catchment hydrology in the Arctic and Sub-Arctic. This understanding is particularly incomplete for flooding extremes because understanding the frequency of such unusual events requires long records of observation not often available for the Arctic and Sub-Arctic. This study presents a statistical analysis of trends in the magnitude and timing of flood extremes and the mean summer discharge in two sub-arctic catchments, Tarfala and Abisko, in northern Sweden. The catchments have different glacier covers (30% and 1%, respectively). Statistically significant trends (at the 5% level) were identified for both catchments on an annual and on a seasonal scale (3-months averages) using the Mann-Kendall trend test. Stationarity of flood records was tested by analyzing trends in the flood quantiles, using generalized least squares regression. Hydrologic trends were related to observed changes in the precipitation and air temperature, and were correlated with 3-months averaged climate pattern indices (e.g. North Atlantic oscillation). Both catchments showed a statistically significant increase in the annual mean air temperature over the comparison time period of 1985-2009 (Tarfala and Abisko p < 0.01), but did not show significant trends in the total precipitation (Tarfala p = 0.91, Abisko p = 0.44). Despite the similar climate evolution over the studied period in the two catchments, data showed contrasting trends in the magnitude and timing of flood peaks and the mean summer discharge. Hydrologic trends indicated an amplification of the streamflow and flood response in the highly glacierized catchment and a dampening of the response in the non-glacierized catchment. The glacierized mountain catchment showed a statistically significant increasing trend in the flood magnitudes (p = 0.04) that is clearly correlated to the occurrence of extreme precipitation events. It also showed a significant increase in mean summer discharge (p = 0.0002), which is significantly correlated to the decrease in glacier mass balance and the increase in air temperature (p = 0.08). Conversely, the non-glacierized catchment showed a significant decrease in the mean summer discharge (p = 0.01), the flood magnitudes (p = 0.07) and an insignificant trend towards earlier flood occurrences (p = 0.53). These trends are explained by a reduction of the winter snow pack due to higher temperatures in the winter and spring and an increasing soil water storage capacity or catchment storage due to progressively thawing permafrost.

  • 287. Dahlström, Anna
    et al.
    Cousins, Sara A. O.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Eriksson, Ove
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    The History (1620-2003) of Land Use, People and Livestock, and the Relationship to Present Plant Species Diversity in a Rural Landscape in Sweden2006Inngår i: Environment and History, ISSN 0967-3407, E-ISSN 1752-7023, Vol. 12, s. 191-212Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The traditional agriculture in Europe favoured numerous plant and animal species that are presently declining. Integrated studies based on various sources are needed in order to unravel the complex relationships between changing landscapes and biological diversity. The objectives of this study were to describe changes in land use during c. 350 years in a Swedish agricultural landscape in relation to changes in human population and livestock, and to analyse relationships between historical land use and present-day plant species diversity. There were only minor long-term changes in land use, population and livestock between 1640 and 1854 in the two studied hamlets, but detailed data 1620-41 showed a large short-term fluctuation in livestock numbers. After 1854 larger changes took place. Grasslands were cultivated and livestock composition changed. After 1932, livestock number decreased and most of the former grazed outland (areas located outside the fenced infields) turned into forest by natural succession. 7 per cent of the study area is still grazed semi-natural grassland. The highest plant species richness is today found on semi-natural grassland with a long continuity of grazing. The distribution of five target species suggests that previous land use still has an important effect today. The majority of their occurrences are remnant populations located in previous outland pastures which are today forests.

  • 288.
    Dahlén, Ewa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Ekonomi eller politiska beslut: Vad styr fristående gymnasieskolors lokalisering?2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    In the beginning of the 1990s the responsibility for the schools shifted from the government to the local authorities. This started an era with a freedom of choice for students where they themselves could choose which school to go to. The new system also opened up the possibility for independent private schools to exist side by side with local authority held schools. The overall aim of this study is to determine the factors that affect the location of these independent schools and the geographical pattern these independent schools create. The study in this paper is based on materials from statistics and interviews. The statistics is from SCB (Statistics Sweden), Skolverket (a government agency that work for the Ministry of Education) and Skolinspektionen (a government agency that supervises that schools follow laws and regulations) and the interviews are with principals and owners of independent schools and representatives from Skolverket, Skolinspektionen and Friskolornas riksförbund (The national association for independent schools). Since the 1990s the independent schools have become nearly as many as the local authority held schools, but are concentrated to 41 percent of Sweden’s municipalities. When comparing this to the local authority held schools that are in 96 percent of Sweden’s municipalities means that the independent schools are in high numbers in a few municipalities. The study shows a geographical pattern of independent schools mainly in large cities. In this paper I examine if the concentration of independent schools in a small part of Sweden’s municipalities is due to political reasons or economical reasons. In conclusion the study indicates that economical factors is the main reasons for their geographical location. The main reasons for locating in urban areas are based on the number of students, diversity, opportunity, and the closeness to universities but also the closeness to entertainment as cafés.

  • 289. Dahms, Henriette
    et al.
    Lenoir, Lisette
    Lindborg, Regina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Wolters, Volkmar
    Dauber, Jens
    Restoration of Seminatural Grasslands: What is the Impact on Ants?2010Inngår i: Restoration Ecology, ISSN 1061-2971, E-ISSN 1526-100X, Vol. 18, nr 3, s. 330-337Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The number of species-rich seminatural grasslands in Northern Europe has decreased significantly due to the abandonment of traditional land use practices. To preserve these habitats, an increasing number of abandoned and overgrown grasslands have been restored by cutting down trees and shrubs and reintroducing grazing. These practices are considered a useful tool to recover the species richness of vascular plants, but their impact on other taxa is hardly known. Here we studied ants as one important group of grassland insects. We investigated (1) the effects of restoration of nongrazed and afforested seminatural grasslands, compared to continuously managed reference sites; and (2) the modulating impacts of habitat characteristics and time elapsed since restoration. We found a total of 27 ant species, 11 of these were characteristic of open habitats and seven characteristic of forests. Neither species richness per site nor the number of open-habitat species, nor the number of forest species differed between restored and reference sites. Yet, within the restored sites, the total species richness and the number of open-habitat species was positively related to the time since restoration and the percentage of bare rock. High frequencies of most open-habitat species were associated with low vegetation, older restored sites, and reference sites. Most forest species showed their highest frequencies in tree- and shrub-dominated habitat. We conclude that restoration efforts have been successful in terms of retrieving species richness. A regular and moderate grazing regime subsequent to the restoration is suggested in order to support a high abundance of open-habitat species.

  • 290.
    Dalberg, Annika
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Rohde, Rick
    Sandell, Klas
    National parks and environmental justice: comparing access rights and ideological legacies in three countries2010Inngår i: Conservation and Society, ISSN 0972-4923, E-ISSN 0975-3133, Vol. 8, nr 3, s. 209-224Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    National parks are often places where people have previously lived and worked—they have been formed by a combination of natural and human processes that embody an identifiable history of cultural and political values. Conservation of protected areas is primarily about how we perceive such landscapes, how we place differential values on different landscape components, and who gets to decide on these values. Thus, conservation has been and still is very much about issues of power and environmental justice. This paper analyses the social, political and nvironmental histories of three national park regimes (South Africa, Sweden and Scotland) through the lens of public access rights. We examine the evolving status of access rights—in a broad sense that includes access to land, resources and institutions of governance—as a critical indicator of the extent to which conservation policies and legislation realise the aims of environmental justice in practice. Our case studies illustrate how access rights are contingent on the historical settings and ideological contexts in which the institutions controlling national park management have evolved. Dominant cultural, political and scientific ideologies have given rise to historical precedents and institutional structures that affect the promotion of environmental justice in and around national parks today. In countries where national parks were initially created to preserve perceived ‘wilderness’, with decisions taken by powerful elites and central authorities, this historical legacy has prevented profound change in line with new policy directives. The comparative analysis of national park regimes, where historical trajectories both converge and diverge, was useful in improving our understanding of contemporary issues involving conservation, people and politics.

  • 291. Daniau, A. -L
    et al.
    Bartlein, P. J.
    Harrison, S. P.
    Prentice, I. C.
    Brewer, S.
    Friedlingstein, P.
    Harrison-Prentice, T. I.
    Inoue, J.
    Izumi, K.
    Marlon, J. R.
    Mooney, S.
    Power, M. J.
    Stevenson, J.
    Tinner, W.
    Andric, M.
    Atanassova, J.
    Behling, H.
    Black, M.
    Blarquez, O.
    Brown, K. J.
    Carcaillet, C.
    Colhoun, E. A.
    Colombaroli, D.
    Davis, B. A. S.
    D'Costa, D.
    Dodson, J.
    Dupont, L.
    Eshetu, Z.
    Gavin, D. G.
    Genries, A.
    Haberle, S.
    Hallett, D. J.
    Hope, G.
    Horn, S. P.
    Kassa, T. G.
    Katamura, F.
    Kennedy, L. M.
    Kershaw, P.
    Krivonogov, S.
    Long, C.
    Magri, D.
    Marinova, E.
    McKenzie, G. M.
    Moreno, P. I.
    Moss, P.
    Neumann, F. H.
    Norström, Elin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Paitre, C.
    Rius, D.
    Roberts, N.
    Robinson, G. S.
    Sasaki, N.
    Scott, L.
    Takahara, H.
    Terwilliger, V.
    Thevenon, F.
    Turner, R.
    Valsecchi, V. G.
    Vanniere, B.
    Walsh, M.
    Williams, N.
    Zhang, Y.
    predictability of biomass burning in response to climate changes2012Inngår i: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 26, s. GB4007-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Climate is an important control on biomass burning, but the sensitivity of fire to changes in temperature and moisture balance has not been quantified. We analyze sedimentary charcoal records to show that the changes in fire regime over the past 21,000 yrs are predictable from changes in regional climates. Analyses of paleo-fire data show that fire increases monotonically with changes in temperature and peaks at intermediate moisture levels, and that temperature is quantitatively the most important driver of changes in biomass burning over the past 21,000 yrs. Given that a similar relationship between climate drivers and fire emerges from analyses of the interannual variability in biomass burning shown by remote-sensing observations of month-by-month burnt area between 1996 and 2008, our results signal a serious cause for concern in the face of continuing global warming.

  • 292.
    Darracq, A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, G.
    In-stream nitrogen attenuation: model-aggregation effects and implications for coastal nitrogen impacts2005Inngår i: Environmental Science & Technology, ISSN 0013-936X, Vol. 39, nr 10, s. 3716-3722Artikkel i tidsskrift (Fagfellevurdert)
  • 293.
    Darracq, A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, G.
    Physical versus biogeochemical interpretations of Nitrogen and Phosphorus attenuation in streams and its dependence on stream characteristics2007Inngår i: Global Biogeochemical Cycles, Vol. 21, nr GB3003Artikkel i tidsskrift (Fagfellevurdert)
  • 294.
    Darracq, A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Greffe, F.
    Hannerz, F.
    Destouni, G.
    Cvetkovic, V.
    Nutrient transport scenarios in a changing Stockholm and Mälaren valley region2005Inngår i: Water Science and Technology, ISSN 0273-1223, Vol. 51, nr 3-4, s. 31-38Artikkel i tidsskrift (Fagfellevurdert)
  • 295.
    Darracq, A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Lindgren, G.A.
    Destouni, G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Long-term development of Phosphorus and Nitrogen loads through the subsurface and surface water systems of drainage basins2008Inngår i: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 22, nr 3, s. GB3022-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We analyze and compare simulations and controlling processes of the past 60 years and possible future short-and long-term development of phosphorus and nitrogen loading from the Swedish Norrstrom drainage basin to the Baltic Sea under different inland source management scenarios. Results indicate that both point and agricultural source inputs may need to be decreased by at least 40% in order to reach a long-term sustainable 30% reduction of anthropogenic coastal nitrogen loading, as required by national environmental goals. A corresponding 20% anthropogenic phosphorus load reduction goal may be reached in the short term by analogous combined 40% source input reduction, but appears impossible to maintain as a long-term achievement by inland source abatement only. In general, realistic quantification of the slow subsurface nutrient transport and accumulation-release dynamics may be essential for accurately predicting and managing nutrient loading to surface and coastal waters.

  • 296.
    Darracq, Amelie
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK). Land and Water Resources.
    Long-term development, modeling and management of nutrient loading to inland and coastal waters2007Doktoravhandling, monografi (Annet vitenskapelig)
  • 297.
    Darracq, Amelie
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi.
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi.
    Physical versus biogeochemical interpretations of nitrogen and phosphorus attenuation in streams and its dependence on stream characteristics2007Inngår i: Global Biogeochemical Cycles, Vol. 21, nr GB3003Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate the influence of biogeochemical nutrient attenuation rates versus physical solute travel times on nutrient transport and attenuation in streams with different characteristics. Comparative results indicate smaller biogeochemical in-stream attenuation rate and greater decrease of this rate with stream depth for phosphorus than for nitrogen. Because physical solute travel times also decrease with stream depth, equally for both nutrients, the resulting relative nutrient mass attenuation becomes essentially independent of stream depth for phosphorus but decreases with stream depth for nitrogen. Coarse interpretation models, without relevant representation of subgrid physical transport variability may lead to systematic misinterpretation of relative nitrogen mass attenuation behavior as a predominantly biogeochemical attenuation rate effect instead of a physical transport time effect. Incorrect understanding and distinction between

    physical and biogeochemical processes and effects may generally induce misleading cause-effect conclusions on environmental loads and prevent us from reaching environmental goals of worldwide importance.

  • 298.
    Darracq, Amelie
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Water resource informatics, management and adaptation under a warming climate2008Konferansepaper (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    International Workshop on The Sustainable City - Technologies and Systems for Sustainable Development, School of Environmental Studies, CUSAT-Cochin University of Science and Technology, Kerala State, India, December 10-12, 2008

  • 299.
    Darracq, Amelie
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Persson, Klas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Prieto, Carmen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Jarsjö, Jerker
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Quantification of advective solute travel times and mass transport through hydrological catchments2010Inngår i: Environmental Fluid Mechanics, ISSN 1567-7419, E-ISSN 1573-1510, Vol. 10, nr 1-2, s. 103-120Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study has investigated and outlined the possible quantification and mapping of the distributions of advective solute travel times through hydrological catchments. These distributions are essential for understanding how local water flow and solute transport and attenuation processes affect the catchment-scale transport of solute, for instance with regard to biogeochemical cycling, contamination persistence and water quality. The spatial and statistical distributions of advective travel times have been quantified based on reported hydrological flow and mass-transport modeling results for two coastal Swedish catchments. The results show that the combined travel time distributions for the groundwater-stream network continuum in these catchments depend largely on the groundwater system and model representation, in particular regarding the spatial variability of groundwater hydraulic parameters (conductivity, porosity and gradient), and the possible contributions of slower/deeper groundwater flow components. Model assumptions about the spatial variability of groundwater hydraulic properties can thus greatly affect model results of catchment-scale solute spreading. The importance of advective travel time variability for the total mass delivery of naturally attenuated solute (tracer, nutrient, pollutant) from a catchment to its downstream water recipient depends on the product of catchment-average physical travel time and attenuation rate.

  • 300.
    Darracq, Amelie
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Persson, Klas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Prieto, Carmen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Jarsjö, Jerker
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Scale and model resolution effects on the distributions of advective solute travel times in catchments2010Inngår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 24, nr 12, s. 1697-1710Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Advective solute travel times and their distributions in hydrological catchments are useful descriptors of the dynamics and variation of the physical mass transport among and along the different source-to-recipient pathways of solute transport through the catchments. This article investigates the scale dependence and the effects of model and data resolution on the quantification of advective travel times and their distributions in the Swedish catchment areas of Norrström and Forsmark. In the surface water networks of the investigated (sub)catchments, the mean advective travel time increases with (sub)catchment scale, whereas the relative travel time variability around the mean value (coefficient of variation, CV) is scale-invariant and insensitive to model resolution. In the groundwater and for the whole (sub)catchments, both the mean value and the CV of travel times are scale-invariant, but sensitive to model resolution and accuracy. Such quantifications and results of advective travel times constitute important steps in the development of improved understanding and modelling of nutrient, pollutant and tracer transport through catchments.

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