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  • 51.
    Andersson, Rina Argelia
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Meyers, Philip
    Department of Earth and Environmental Sciences, The University of Michigan, Ann Arbor, Michigan, U.S.A..
    Hornibrook, Edward
    Bristol Biogeochemistry Research Centre & Cabot Institute, School of Earth Sciences, University of Bristol, Queens Road, Bristol BS8 1RJ, United Kingdom.
    Kuhry, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Mörth, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Elemental and isotopic carbon and itrogen records of organic matter accumulation in a Holocene permafrots peat sequence in the East European Russian ArcticManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    A peat deposit from the East European Russian Arctic, spanning nearly 10,000 years, was investigated to reconstruct past environmental conditions and to study soil organic matter (SOM) degradation using analyses of bulk elemental and stable isotopic compositions and plant macrofossil remains. The peat accumulated initially in a wet fen that transformed into a peat plateau bog following aggradation of permafrost in the late Holocene (~2,500 cal a BP). Total organic carbon (TOC) and total nitrogen (N) concentrations are different in the bog peat compared to the fen peat, with lower values in the moss-dominated bog peat layers.  Lower concentrations of total hydrogen (H) are associated with degraded vascular plant residues.  The atomic ratios of bulk elemental parameters indicate better preservation of organic matter in peat deposits dominated by bryophytes relative to vascular plants.  The presence of permafrost in the peat plateau stage and water-saturated conditions at the bottom of the fen stage appear to be associated with better preservation of organic plant material.  δ15N values suggest N isotopic fractionation was driven primarily by microbial decomposition while differences in δ13C values appear to be associated mainly with changes in plant assemblages rather than diagenesis.  Positive shifts in both δ15N and δ13C values coincide with a local change to drier conditions as a result of the onset of permafrost and frost heave of the peat surface.  This pattern suggests that permafrost aggradation not only resulted in changes in vegetation but also aerated the underlying fen peat, which enhanced microbial denitrification, causing the observed 15N-enrichment.

  • 52.
    Andersson, Sofia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Late Holocene humidity variability in central Sweden2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The aim of this thesis was to reconstruct humidity variability in central Sweden during the late Holocene. A multi-proxy approach was used to infer humidity changes as recorded in a lake and a mire. Age-models were constructed based on radiocarbon dating and the Askja-1875 tephra. Stable isotopes (δ18O and δ13C) on Chara spp encrustations and Pisidium spp mollusc shells and carbon content were analysed in the lake record, whereas peat stratigraphy, humification, testate amoebae assemblages, C/N ratio and stable isotopes (δ13C and δ15N) were analysed in the mire record. Stable isotopes (δ2H and δ18O) on lake water showed that Lake Blektjärnen responded to changes in the balance between evaporation and input water (E/I ratio). A high E/I ratio results from a dry and probably warmer climate during which evaporation and atmospheric equilibration likely enrich lake water in 18O and 13C, respectively, and vice versa for a low E/I ratio. The relatively high Chara δ18O and δ13C values between ca 4400 and 4000 cal yr BP thus suggest relatively dry and likely warm conditions, whereas depleted values suggest wetter and probably cooler conditions between ca 4000 and 3000 cal yr BP. Again, drier and probably warmer conditions were inferred from the relatively enriched δ18O values between ca 2500 and 1000 cal yr BP, and depleted δ18O values were recorded between ca 1000 and 50 cal yr BP indicating wetter and likely cooler conditions. The results from the mire mainly indicated vegetation succession, however, the changes inferred at ca 2600 and 1000 cal yr BP could have been triggered by climate change. This study shows that the proxies responded sensitively to humidity changes in the investigated archives allowing for reconstruction of climate change in central Sweden during late Holocene.

  • 53.
    Andersson, Sofia
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Bergman, Jonas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Wastegård, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Schoning, Kristian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Synthesis of proxy response to climate change in central Sweden during the late HoloceneArtikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Biological and geochemical proxies from two lakes and two peat sites in central Sweden are used to test if the inferred climate change can be connected to previously reported temperature anomalies, inferred from stacked pollen mean annual and mean July temperatures mainly in Fennoscandia, during the late Holocene. We show that the reported temperature deviations (lower temperatures between 3800-3000, higher temperatures between 3000-500, and lower temperatures again between 500-50 cal yr BP), can be related to recorded changes in the investigated proxies. These periods correspond to changes inferred from two of the sites; in one of the lakes the reconstructed evaporation and input ratio (E/I) show a high ratio from a dry and likely warmer climate, with decreased importance of precipitation input, and vice versa for a low ratio, and, from one of the peat humification records. Beyween 600-300 cal yr BP magnetic susceptibility increased in a lacustrine sediment record and water table rose according to peat records. The proxies from central Sweden seem to support a late Holocene temperature maximum around ca 2000 cal yr BP, although this is speculative since it is represented by a few samples only.

  • 54.
    Andersson, Sofia
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Rosqvist, Gunhild
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Leng, Melanie J
    NERC Isotope Geosciences Laboratory, British Geological Survey, Nottingham NG12 5GG, UK.
    Wastegård, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Blaauw, Maarten
    School of Geography, Archaeology and Palaeoecology, Queen's University Belfast, BT7 1NN Belfast, UK.
    Late Holocene climate change in central Sweden inferred from lacustrine stable isotope dataInngår i: Journal of Quaternary Science, ISSN 0267-8179, E-ISSN 1099-1417Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Stable isotopes (18O and 13C) of lacustrine carbonates (Chara spp algae and Pisidium spp molluscs) from a lake sedimentary sequence in central Sweden were analysed to infer changes in lake hydrology and climate during the late Holocene. Results from analysis of lake water isotopes (18O and 2H) show that Lake Blektjärnen water isotope composition is responsive to the water balance between evaporation and input water (E/I ratio). A high E/I ratio results from a dry and probably warmer climate, decreasing the relative importance of precipitation input. Under such conditions evaporation and atmospheric equilibration enrich lake water in 18O and 13C, respectively, which is reflected in the isotopic composition of the carbonates in the lake. From the relatively positive Chara 18O values we infer that conditions were dry and warm between 4400-4000 cal yr BP whereas more negative values indicate that conditions were wetter and probably cooler between 4000-3000 cal yr BP. A drier climate is inferred from more positive values between 2500-1000 cal yr BP. However, a successive depletion after ca 1750 cal yr BP, also detected in several other 18O records (carbonate and diatom), suggest increasingly wetter conditions in Scandinavia after that time, which is probably related to increased zonal flow.

  • 55.
    Andersson, Sofia
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Rosqvist, Gunhild
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Leng, Melanie
    Wastegård, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Blaauw, Maarten
    Late Holocene humidity changes inferred from stable isotopes in Chara encrustations and Pisidium shells in a lacustrine sediment sequence from central Sweden2010Inngår i: Journal of Quaternary Science, ISSN 0267-8179, E-ISSN 1099-1417, Vol. 8, nr 25, s. 1305-1316Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Stable isotopes (δ18O and δ13C) of lacustrine carbonates (Chara spp. algae and Pisidium spp. molluscs) from a lake sedimentary sequence in central Sweden were analysed to infer changes in lake hydrology and climate during the late Holocene. Results from analysis of lake water isotopes (δ18O and δ2H) show that Lake Blektjärnen water isotope composition is responsive to the balance between evaporation and input water (E/I ratio). A high E/I ratio results from a dry and probably warmer climate, decreasing the relative importance of precipitation input. Under such conditions evaporation and atmospheric equilibration probably enrich lake water in 18O and 13C, respectively, which is reflected in the isotopic composition of the carbonates in the lake. From the relatively positive Chara δ18O values we infer that conditions were dry and warm between 4400 and 4000 cal. a BP, whereas more negative values indicate that conditions were wetter and probably cooler between 4000 and 3000 cal. a BP. A drier climate is inferred from more positive values between 2500 and 1000 cal. a BP. However, a successive depletion after ca. 1750 cal. a BP, also detected in several other δ18O records (carbonate and diatom), suggest increasingly wetter conditions in Scandinavia after that time, which is probably related to increased strength of the zonal flow.

  • 56.
    Andersson, Sofia
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Schoning, Kristian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Surface wetness and mire development during the late Holocene in central SwedenInngår i: Boreas, ISSN 0300-9483, E-ISSN 1502-3885Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Late Holocene mire development and surface wetness changes have been studied in a small mixed mire located in central Sweden. Today the mire is characterised by a mainly ombrotrophic centre dominated by Sphagnum mosses whereas Carex content increase towards the more minerotrophic mire margins. Two peat sequences extracted from the central ombrotrophic part were investigated for stratigraphy, humification, testate amoebae analysis, C/N ratio and 13C and 15N stable isotopes. Three main stages of mire development are identified with a first stage between ca 4200-2600 cal yr BP, characterised by water-logged conditions suggesting a minerotrophic fen stage. The second stage between ca 2600-1000 cal yr BP is characterised by more ombrotrophic conditions and Sphagnum dominated vegetation. The onset of the prominent change at ca 2600 cal yr BP could have been initiated by by climate change coincident with a change in solar activity. The last stage, between ca 1000-50 cal yr BP, is dominated by more ombrotrophic conditions suggesting increased precipitation. This study shows that the response of hydrological proxies in a mixed mire during its development towards more ombrotrophic conditions might result in conflicting results, which has to be considered in palaeoenvironmental reconstructions from mires that changes between ombrotrophic and minerotrophic settings.

  • 57.
    Andersson, Sofia
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Schoning, Kristian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Surface wetness and mire development during the late Holocene in central Sweden2010Inngår i: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 39, nr 4, s. 749-760Artikkel i tidsskrift (Fagfellevurdert)
  • 58.
    Andwinge, Maria
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    ’Paid pollination’ – en tjänst för odlade grödor och biodiversitet: Analys av den kommersiella pollineringens utbredning och utveckling i Taranaki-regionen, Nya Zeeland2011Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Pollinering är avgörande för ett antal kommersiella grödor samt för olika växtarter i inhemsk vegetation. Honungsbi (Apis mellifera) är en av de viktigaste pollinerarna. I regionen Taranaki i Nya Zeeland finns två aspekter av kommersiell pollinering, dels betalar många biodlare för tillgång till manuka för de antibakteriella egenskaperna honungen får av den, dels betalar frukt- och grönsaksodlare för pollinering av sina grödor. Markägare kan ha ett intresse av att spara manuka på sina marker och få en utkomst från biodlarna genom att dessa betalar för åtkomsten. Studien syftar till att klarlägga de effekter som kommersiell pollinering har i Taranaki-regionen idag och för framtida användning och har utgått från intervjuer med biodlare, frukt- och grönsaksodlare och personer som representerar myndigheterna. Resultaten visar att de ekonomiska effekterna av kommersiell pollinering i dag i Taranaki-regionen är relativt små. Även den kommersiella pollineringens roll för skydd och förvaltning av inhemsk natur undersöks. Kommersiell pollinering kan vara en viktig del inom naturskydd men är samtidigt beroende på om interaktionen med andra bin kan vara skadlig. Pollineringstjänster kan utvecklas dels genom information till markägare och jordbrukare, dels genom marknadsföring från biodlare.

  • 59.
    Andwinge, Maria
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Reading Pollen Records at Peloponnese, Greece2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The eastern Mediterranean area is a region of high archaeological importance, it is also a region where climate has been a force interacting with humans in shaping the landscape and vegetation history. Variations in pollen content and composition in various climate archives (e.g. lake sediments and peat sections) are widely used to reconstruct vegetation changes and human impact in the Quaternary environments. Pollen sampling has been conducted throughout the Peloponnese peninsula but there is a lack of regional synthesis of these locally based studies. The aims of the thesis are partly to show how pollen data may be used in a regional analysis on Late Pleistocene and Holocene vegetation changes, partly to assemble all published pollen data from Peloponnese peninsula in a database. The question formulations are; i) how may a database with pollen dataserve as a basis for interpretations of regional vegetation changes on Peloponnese?, ii) what are the possibilities of using classification of pollen and distinguish between driving factors behind the historic vegetation changes? The constructed database facilitates further research regarding pollen records at Peloponnese. Pollen recordsmay show important patterns in landscape changes during Late Pleistocene and Holocene but using pollen records at a regional scale need comparisons between coring sites which may be troublesome due to different approaches, different species investigated and varied calculation of pollen sum. In order to distinguish between driving forces and actors affecting the vegetation, pollen data may be used both in detail but also in using groups and classifications of the pollen included.

  • 60.
    Angelstam, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Urban green space for human well-being and biodiversity: Do people and birds favour the same?2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Urban green space has been proven by the field of environmental psychology to have high value for human well-being. Green space is also important for biodiversity. However, the management of urban green space is commonly focused on present aesthetic values and not on the level of naturalness and its consequences for humans and biodiversity. This study compares the green space situation in relation to human well-being and biodiversity in Lviv, Ukraine and Stockholm, Sweden. By sampling urban green space gradients, from unnatural to natural, as well as collecting data about visiting people and bird taxa in those areas, comparisons between these two response variables and the level of naturalness were made. The results show correlations between the level of naturalness and the social structure of human visitors as well as to the bird taxa present. The results thus indicate that both human well-being and biodiversity is positively related to the level of naturalness of green space. Since more and more people live in urban areas decision-makers should leave sufficient amounts of green space, for the inhabitants’ well-being, both people and other species, in physical planning. Given generally low levels of green space in urban settings, areas for recreation and rehabilitation should be enhanced further.

  • 61. Angelstam, Per
    et al.
    Andersson, Kjell
    Annerstedt, Matilda
    Axelsson, Robert
    Elbakidze, Marine
    Garrido, Pablo
    Grahn, Patrik
    Jonsson, K. Ingemar
    Pedersen, Simen
    Schlyter, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Skärbäck, Erik
    Smith, Mike
    Stjernquist, Ingrid
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Solving Problems in Social-Ecological Systems: Definition, Practice and Barriers of Transdisciplinary Research2013Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 42, nr 2, s. 254-265Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Translating policies about sustainable development as a social process and sustainability outcomes into the real world of social-ecological systems involves several challenges. Hence, research policies advocate improved innovative problem-solving capacity. One approach is transdisciplinary research that integrates research disciplines, as well as researchers and practitioners. Drawing upon 14 experiences of problem-solving, we used group modeling to map perceived barriers and bridges for researchers' and practitioners' joint knowledge production and learning towards transdisciplinary research. The analysis indicated that the transdisciplinary research process is influenced by (1) the amount of traditional disciplinary formal and informal control, (2) adaptation of project applications to fill the transdisciplinary research agenda, (3) stakeholder participation, and (4) functional team building/development based on self-reflection and experienced leadership. Focusing on implementation of green infrastructure policy as a common denominator for the delivery of ecosystem services and human well-being, we discuss how to diagnose social-ecological systems, and use knowledge production and collaborative learning as treatments.

  • 62. Ansmann, A.
    et al.
    Seifert, P.
    Tesche, Matthias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Wandinger, U.
    Profiling of fine and coarse particle mass: case studies of Saharan dust and Eyjafjallajokull/Grimsvotn volcanic plumes2012Inngår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 12, nr 20, s. 9399-9415Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The polarization lidar photometer networking (POLIPHON) method introduced to separate coarse-mode and fine-mode particle properties of Eyjafjallajokull volcanic aerosols in 2010 is extended to cover Saharan dust events as well. Furthermore, new volcanic dust observations performed after the Grimsvotn volcanic eruptions in 2011 are presented. The retrieval of particle mass concentrations requires mass-specific extinction coefficients. Therefore, a review of recently published mass-specific extinction coefficients for Saharan dust and volcanic dust is given. Case studies of four different scenarios corroborate the applicability of the profiling technique: (a) Saharan dust outbreak to central Europe, (b) Saharan dust plume mixed with biomass-burning smoke over Cape Verde, and volcanic aerosol layers originating from (c) the Eyjafjallajokull eruptions in 2010 and (d) the Grimsvotn eruptions in 2011. Strong differences in the vertical aerosol layering, aerosol mixing, and optical properties are observed for the different volcanic events.

  • 63.
    Applegate, Patrick
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Modeling the statistical distributions of cosmogenic exposure dates from moraines2010Inngår i: Geoscientific Model Development, Vol. 3, s. 293-307Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Geomorphic process modeling allows us to evalu-   calculating the mean does not improve this mismatch. Theate different methods for estimating moraine ages from cos-   extreme estimators (youngest date and oldest date) performmogenic exposure dates, and may provide a means to iden-      well under specific circumstances, but fail in other cases. Wetify the processes responsible for the excess scatter among   suggest a simple estimator that uses the skewnesses of in-exposure dates on individual moraines. Cosmogenic expo-       dividual data sets to determine whether the youngest date,sure dating is an elegant method for estimating the ages of   mean, or oldest date will provide the best estimate of morainemoraines, but individual exposure dates are sometimes bi-     age. Although this method is perhaps the most globally ro-ased by geomorphic processes. Because exposure dates may      bust of the estimators we tested, it sometimes fails spectac-be either “too young” or “too old,” there are a variety of    ularly. The failure of simple methods to provide accuratemethods for estimating the ages of moraines from exposure     estimates of moraine age points toward a need for more so-dates. In this paper, we present Monte Carlo-based models     phisticated statistical treatments.of moraine degradation and inheritance of cosmogenic nu-clides, and we use the models to examine the effectivenessof these methods. The models estimate the statistical dis-tributions of exposure dates that we would expect to obtainfrom single moraines, given reasonable geomorphic assump-tions. The model of moraine degradation is based on priorexamples, but the inheritance model is novel. The statisticaldistributions of exposure dates from the moraine degradationmodel are skewed toward young values; in contrast, the sta-tistical distributions of exposure dates from the inheritancemodel are skewed toward old values. Sensitivity analysisshows that this difference is robust for reasonable parame-ter choices. Thus, the skewness can help indicate whether aparticular data set has problems with inheritance or morainedegradation. Given representative distributions from thesetwo models, we can determine which methods of estimatingmoraine ages are most successful in recovering the correctage for test cases where this value is known. The mean isa poor estimator of moraine age for data sets drawn fromskewed parent distributions, and excluding outliers before calculating the mean does not improve this mismatch. Theextreme estimators (youngest date and oldest date) performwell under specific circumstances, but fail in other cases. Wesuggest a simple estimator that uses the skewnesses of in-dividual data sets to determine whether the youngest date,mean, or oldest date will provide the best estimate of moraineage. Although this method is perhaps the most globally ro-bust of the estimators we tested, it sometimes fails spectac-ularly. The failure of simple methods to provide accurateestimates of moraine age points toward a need for more so-phisticated statistical treatments.

  • 64.
    Applegate, Patrick
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Alley, Richard B.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Challenges in the Use of Cosmogenic Exposure Dating of Moraine Boulders to Trace the Geographic Extents of Abrupt Climate Changes: The Younger Dryas Example2011Inngår i: Abrupt Climate Change: Mechanisms, Patterns, and Impacts / [ed] Rashid, H; Polyak, L; MosleyThompson, E, Washington DC: American Geophysical Union (AGU), 2011, s. 111-122Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Cosmogenic exposure dating has sometimes been used to identify moraines associated with short-lived climatic events, such as the Younger Dryas (12.9-11.7 ka). Here we point out two remaining challenges in using exposure dating to identify moraines produced by abrupt climate changes. Specifically, (1) a commonly applied sampling criterion likely yields incorrect exposure dates at some sites, and (2) geomorphic processes may introduce bias into presently accepted nuclide production rate estimates. We tit a geomorphic process model that treats both moraine degradation and boulder erosion to collections of exposure dates from two moraines that were deposited within a few thousand years of the Younger Dryas. Subsampling of the modeled distributions shows that choosing boulders for exposure dating based on surface freshness yields exposure dates that underestimate the true age of the moraine by up to several thousand years. This conclusion applies only where boulders do not erode while buried but do erode after exhumation. Moreover, one of our fitted data sets is part of the global nuclide production rate database. Our fit of the moraine degradation model to this data set suggests that nuclide production rates at that site are several percent higher than previously thought. Potential errors associated with sampling strategies and production rate estimates are large enough to interfere with exposure dating of moraines, especially when the moraines are associated with abrupt climate changes. We suggest sampling strategies that may help minimize these problems, including a guide for determining the minimum number of samples that must be collected to answer particular paleoclimate questions.

  • 65.
    Applegate, Patrick
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Fisher, Tim
    University of Toledo.
    Ancient Perspectives on Arctic Climate Change and Ice Sheet Dynamics: Joint Meeting of the APEX Program and the MOCA Project2010Annet (Annet vitenskapelig)
    Abstract [en]

    none

  • 66.
    Applegate, Patrick J.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Kirchner, Nina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Stone, E. J.
    Keller, K.
    Greve, R.
    An assessment of key model parametric uncertainties in projections of Greenland ice sheet behavior2012Inngår i: The Cryosphere, ISSN 1994-0416, E-ISSN 1994-0424, Vol. 6, nr 3, s. 589-606Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lack of knowledge about the values of ice sheet model input parameters introduces substantial uncertainty into projections of Greenland Ice Sheet contributions to future sea level rise. Computer models of ice sheet behavior provide one of several means of estimating future sea level rise due to mass loss from ice sheets. Such models have many input parameters whose values are not well known. Recent studies have investigated the effects of these parameters on model output, but the range of potential future sea level increases due to model parametric uncertainty has not been characterized. Here, we demonstrate that this range is large, using a 100-member perturbed-physics ensemble with the SICOPOLIS ice sheet model. Each model run is spun up over 125 000 yr using geological forcings and subsequently driven into the future using an asymptotically increasing air temperature anomaly curve. All modeled ice sheets lose mass after 2005 AD. Parameters controlling surface melt dominate the model response to temperature change. After culling the ensemble to include only members that give reasonable ice volumes in 2005 AD, the range of projected sea level rise values in 2100 AD is similar to 40 % or more of the median. Data on past ice sheet behavior can help reduce this uncertainty, but none of our ensemble members produces a reasonable ice volume change during the mid-Holocene, relative to the present. This problem suggests that the model's exponential relation between temperature and precipitation does not hold during the Holocene, or that the central-Greenland temperature forcing curve used to drive the model is not representative of conditions around the ice margin at this time (among other possibilities). Our simulations also lack certain observed physical processes that may tend to enhance the real ice sheet's response. Regardless, this work has implications for other studies that use ice sheet models to project or hindcast the behavior of the Greenland Ice Sheet.

  • 67.
    Aroka, Nelly
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Rainwater Harvesting in Rural Kenya: Reliability in a Variable and Changing Climate2010Independent thesis Advanced level (degree of Master (Two Years)), 30 poäng / 45 hpOppgave
    Abstract [en]

    In many parts of the tropics irregular and erratic rainfall has great national economic as well as socio-economic effects. In Kenya, where a large part of the population live in rural areas and rainfed agriculture is the main livelihood, droughts and floods have farreaching impacts on communities. One form of mitigating the negative effects of drought is the implementation of simple, small-scale, low cost schemes called rainwater harvesting. This involves the capture, storing and redirection of rainfall, runoff, and groundwater. In Kenya, such schemes are being implemented in rural areas through different actors. Two Non-Governmental Organizations involved are the Kenya Rainwater Association and the German Agro Action that work in Tseikuru, a semi-arid area with water availability and sanitation issues. The main livelihood is agropastorialism and there is little experience with rainwater harvesting. Commonly, water is collected by digging shallow holes into dry river beds where groundwater tables are high. These areas are prone to contamination and could be situated many kilometres away, making water collection laborious. By implementing rainwater harvesting schemes water availability as well as water quality is expected to be improved. However, due to great rainfall variability and effects of climate change these schemes may fall short of their expectations. Also the potential change on water demand may affect communities’ response to prolonged dry spells. This study aims to examine whether the implemented rainwater harvesting schemes in rural Tseikuru are reliable in times of adverse rainfall and if increased water availability (and potentially also increased water demand) affects the communities’ vulnerability towards droughts. The study is based on interviews with local stakeholders and technicians during a Minor Field Study in Tseikuru, as well as statistical analysis on rainfall data over the area and literature studies. Results showed that rainwater harvesting schemes are generally successful in supplying readily available and safe water. However the rural population of Tseikuru have not completely abandoned their old habits of collecting water from dry riverbeds, choosing instead to treat the schemes as an alternative source to water, thereby avoiding dependency towards the schemes.

  • 68.
    Aronsson, Johanna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Saltvattenpåverkan i enskilda brunnar i kustnära områden: En undersökning av grundvattenförhållandena och riskerna för saltvattenpåverkan i S:t Annas skärgård, Östergötland2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Coastal areas are popular for housing, both for permanent living and holiday houses. At the same time, thin sediments and small storage capacity in the bedrock makes the ground water resources limited. The limited ground water resources combined with too large withdrawals of ground water makes salt water intrusion a problem in many coastal areas. This study examine the risk of salt water intrusion in drinking water supplying wells on the island Södra Finnö in S:t Anna archipelago, Östergötland, Sweden. A calculation of the relation between ground water recharge and withdrawal is obtained to analyze the ground water balance in the area. To investigate the thickness of the freshwater in the aquifer, the Ghyben-Herzberg principle is used, based on measurements of ground water levels in the area. The study also includes a GIS-analyze to investigate the risk of salt water intrusion for specific wells, and water samples analyzed for conductivity and sodium. The results show a positive ground water balance, which indicate the area is not to be seen as a risk area for salt water intrusion. However, the GIS-analyze and the water samples shows that some specific wells are in risk of, or has already been effected from, salt water intrusion. 

  • 69.
    Asokan, Shilpa M.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Appendix to Paper V: Climate model performance versus basin-scalehydro-climatic dataManuskript (preprint) (Annet vitenskapelig)
  • 70.
    Asokan, Shilpa M.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Irrigation effects on hydro-climatic change: Basin-wise water balance-constrained quantification and cross-regional comparison2014Inngår i: Surveys in geophysics, ISSN 0169-3298, E-ISSN 1573-0956, Vol. 35, nr 3, s. 879-895Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydro-climatic changes driven by human land and water use, including water use for irrigation, may be difficult to distinguish fromthe effects of global, natural and anthropogenic climate change. This paper quantifies and compares the hydro-climatic change effects ofirrigation using a data-driven, basin-wise quantification approach in two different irrigated world regions: the Aral Sea drainage basinin Central Asia, and the Indian Mahanadi River Basin draining into the Bay of Bengal. Results show that irrigation-driven changesin evapotranspiration and latent heat fluxes and associated temperature changes at the land surface may be greater in regions withsmall relative irrigation impacts on water availability in the landscape (here represented by the MRB) than in regions with severe suchimpacts (here represented by the Aral region). Different perspectives on the continental part of Earth’s hydrological cycle may thus implydifferent importance assessment of various drivers and impacts of hydro-climatic change. Regardless of perspective, however, actualbasin-wise water balance constraints should be accounted to realistically understand and accurately quantify continental water change.

  • 71.
    Asokan, Shilpa M.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Dutta, Dushmanta
    Analysis of water resources in the Mahanadi River Basin, India under projected climate conditions2008Inngår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 22, nr 18, s. 3589-3603Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The paper presents the outcomes of a study conducted to analyse water resources availability and demand in the Mahanadi River Basin in India under climate change conditions. Climate change impact analysis was carried out for the years 2000, 2025, 2050, 2075 and 2100, for the months of September and April (representing wet and dry months), at a sub-catchment level. A physically based distributed hydrologic model (DHM) was used for estimation of the present water availability. For future scenarios under climate change conditions, precipitation output of Canadian Centre for Climate Modelling and Analysis General Circulation Model (CGCM2) was used as the input data for the DHM. The model results show that the highest increase in peak runoff (38%) in the Mahanadi River outlet will occur during September, for the period 2075-2100 and the maximum decrease in average runoff (32·5%) will be in April, for the period 2050-2075. The outcomes indicate that the Mahanadi River Basin is expected to experience progressively increasing intensities of flood in September and drought in April over the considered years. The sectors of domestic, irrigation and industry were considered for water demand estimation. The outcomes of the analysis on present water use indicated a high water abstraction by the irrigation sector. Future water demand shows an increasing trend until 2050, beyond which the demand will decrease owing to the assumed regulation of population explosion. From the simulated future water availability and projected water demand, water stress was computed. Among the six sub-catchments, the sub-catchment six shows the peak water demand. This study hence emphasizes on the need for re-defining water management policies, by incorporating hydrological response of the basin to the long-term climate change, which will help in developing appropriate flood and drought mitigation measures at the basin level.

  • 72.
    Asokan, Shilpa M.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Jarsjö, Jerker
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Vapor flux by evapotranspiration: effects of changes in climate, land-use and water-use2010Inngår i: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 115, nr D24Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Enhanced evapotranspiration (ET) over irrigated land and associated latent heat flux change can modify the climate. Model studies of such climate change effects of irrigation are commonly based on land use parameterizations, in terms of irrigated land area, or land area equipped for irrigation. Actual ET change, however, may also be driven by water use change in addition to land use change. This study quantifies and compares ET changes due to changes in climate, land use, and water use from the preirrigation period 1901–1955 to the recent period 1990–2000 (with irrigation) for the example case of Mahanadi River Basin (MRB) in India. The results show that actual water use per unit area of irrigated land may vary greatly over a hydrological drainage basin. In MRB, much higher water use per irrigated land unit in the downstream humid basin parts leads to higher vapor flux by ET, and irrigation‐induced ET flux change, than in the upstream, water‐stressed basin parts. This is consistent with water supply limitations in water‐stressed basins. In contrast, the assumption in land use−based models that irrigation maintains high soil moisture contents can imply higher modeled water use and therefore also higher modeled ET fluxes under dry conditions than under humid conditions. The present results indicate water use as an important driver of regional climate change, in addition to land use and greenhouse gas‐driven changes.

  • 73.
    Auffret, Alistair
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    The role of past and present management in the seed dispersal of grassland plants in the rural landscape2010Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The destruction and fragmentation of semi-natural grasslands due toagricultural industrialisation during the past 150 years has had seriousconsequences for biodiversity in the rural landscape. Currently, plantcommunities are usually better explained by historical than by presentday landscape configurations, and the ability for plant species todisperse in space and in time, within and between remaining habitatfragments or to restoration sites will be an important factor in thefuture diversity in the landscape. Here, I present a landscape scaleseed bank and seed rain experiment covering semi-natural grasslands,pastures on former arable fields, abandoned grasslands and smallremnant habitats. The results suggest that in addition to grasslandspecialists remaining in the field layer of abandoned grasslands,remnant seed banks have the potential to be important contributors tothe future diversity of the rural landscape. However, unsuitablegrazing intensities in current pastures are limiting the potential fordispersal of target species across the landscape. Despite large changesin agricultural practice, there still exists the opportunity for human-mediated seed dispersal to increase functional connectivity infragmented landscapes, and I also present a review article in which Iassess past and present human-mediated seed dispersal vectors, andgive recommendations for management and further research.

  • 74.
    Auffret, Alistair
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Cousins, Sara
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Can motor vehicles substitute the movement of livestock for effective seed dispersal in the modern rural landscape?2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Before agricultural industrialisation, the dispersal of plant species through the rurallandscape was largely mediated by the movement of livestock. Today, species-rich,semi-natural grasslands exist as only small, isolated fragments, and livestock aregenerally kept within the same pasture throughout the grazing season. On the otherhand, the introduction of motor vehicles has provided a potential vector for seeddispersal through the landscape, and farming machinery, which is not confined toroads, can pick up and deposit a great deal of material. Our aim was to explore thepotential for motor vehicles to maintain the functional connectivity of the landscape inthe absence of free-ranging livestock. We collected manure samples from grazers onsemi-natural grassland pastures, and mud from the cars and tractors of five farmsduring the outdoor grazing season in a 10 km 2 landscape in southern Sweden, andgrew them in a greenhouse to assess their seed content. 31 713 seedlings of 109species emerged from 31 manure samples, while 12 675 seedlings of 111 speciesemerged from 49 samples of mud removed from motor vehicles. Both sets ofsamples were dominated by the genera Agrostis and Poa, which together stood for43% and 77% of the seedlings emerging from motor vehicle and manure samplesrespectively. Otherwise, manure samples contained several grassland specialists,whereas, despite the occasional grassland species, widespread ruderal speciesmade up the majority of the rest of the seeds dispersed by motor vehicles. Ourresults indicate that motor vehicles do not provide an effective link for the dispersal ofgrassland species through the rural landscape, and that the movement of grazersbetween fragmented grasslands should be encouraged to improve functionalconnectivity and biodiversity in the rural landscape.

  • 75.
    Auffret, Alistair
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Cousins, Sara
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Seed bank and seed rain in a rural landscape mosaic2010Inngår i: 40th Annual Conference - Geselschaft für Ökologie - Book of Abstracts: The future of biodiversity: genes, species, ecosystems / [ed] Volkmar Wolters, Janine Groh, Franziska Peter, Rainer Waldhardt, 2010Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Semi natural grasslands are among Europe's most species rich habitats, but modernagricultural change has placed them under threat. The potential for restoration mighthowever exist, thanks to remnant plant populations in abandoned grasslands and smallremnant habitats, and the reintroduction of grazing in former arable fields. This studyempirically investigated the potential contribution of seed banks and seed rain in therestoration and conservation of grassland plant populations in the rural landscape, and tosee if samples taken at the landscape scale could give a general and meaningful overview,despite the known small scale variability in seed distribution. We took 30 seed banksamples, and placed 30 seed traps in ten replicates of grazed semi-natural grasslands,grazed former arable fields, mid-field islets and abandoned semi-natural grasslands in a236km landscape in southern Sweden. Plant species occurrence at each site was alsoinvestigated. Seed bank and seed rain samples were planted in a greenhouse assess theirgerminable seed content, from which 54 376 seedlings of 188 species emerged. Aboveground vegetation was found to be a generally poor predictor of seed bank and seed rainin all habitats. The presence of grassland specialists in the bank and rain samples ofabandoned grasslands and grazed former arable fields where they were not present in thevegetation implies a recolonisation potential for grassland communities at large temporaland spatial scales.

  • 76.
    Auffret, Alistair G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Can seed dispersal by human activity play a useful role for the conservation of European grasslands?2011Inngår i: Applied Vegetation Science, ISSN 1402-2001, E-ISSN 1654-109X, Vol. 14, nr 3, s. 291-303Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective: To review the recent research into human-mediated dispersal (HMD) in the European rural landscape, and explore the potential positive aspect of HMD for grassland conservation, in contrast to it's common association with the spread of invasive species. Methods: A literature search was undertaken to identify HMD vectors in the rural landscape for discussion regarding dispersal potential past and present, implications for management, and the identification of future research needs. Results: Grazing animals are important propagule dispersers, but the reduced movement of livestock through the landscape has also meant a reduction in seeds dispersed in this way. Other, non-standard human-mediated dispersal vectors such as clothing and motor vehicles can also transport seeds of many species, and HMD vectors often transport seeds with a variety of dispersal specialisations. Recommendations: There should be a greater movement of grazing animals throughout the landscape, either within larger grazing areas or between existing grasslands. Where this is not possible, other, more directed dispersal of propagules from species-rich communities to target sites should be considered. The potential of non-standard HMD vectors to make a positive contribution to biodiversity should be considered, but more research into all types of HMD vectors is important if we are to fully understand their role in the dispersal of plant species in fragmented landscapes.

  • 77.
    Auffret, Alistair G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Seed mobility and connectivity in changing rural landscapes2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The success or failure of many organisms to respond to the challenges of habitat destruction and a warming climate lies in the ability of plant species to disperse between isolated habitats or to migrate to new ranges. European semi-natural grasslands represent one of the world's most species-rich habitats at small scales, but agricultural intensification during the 20th century has meant that many plant species are left only on small fragments of former habitat. It is important that these plants can disperse, both for the maintenance of existing populations, and for the colonisation of target species to restored grasslands. This thesis investigates the ecological, geographical and historical influences on seed dispersal and connectivity in semi-natural grasslands, and the mobility of plants through time and space. Seed dispersal by human activity has played a large role in the build-up of plant communities in rural landscapes, but patterns have shifted. Livestock are the most traditional, and probably the most capable seed dispersal vector in the landscape, but other dispersal methods may also be effective. Motor vehicles disperse seeds with similar traits to those dispersed by livestock, while 39% of valuable grasslands in southern Sweden are connected by the road network. Humans are found to disperse around one-third of available grassland species, including several protected and red-listed species, indicating that humans may have been valuable seed dispersers in the past when rural populations were larger. Past activities can also affect seed mobility in time through the seed bank, as seeds of grassland plant species are shown to remain in the soil even after the grassland had been abandoned. Today however, low seed rain in intensively grazed semi-natural grasslands indicates that seed production may be a limiting factor in allowing seeds to be dispersed in space through the landscape.

  • 78.
    Auffret, Alistair G.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Berg, Johan
    Stockholms universitet, Samhällsvetenskapliga fakulteten, Kulturgeografiska institutionen.
    Cousins, Sara
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Dispersal geography: a new concept for managing seed dispersal in rural landscapesManuskript (preprint) (Annet vitenskapelig)
  • 79.
    Auffret, Alistair G.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Cousins, Sara A. O.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Humans as Long-Distance Dispersers of Rural Plant Communities2013Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, nr 5, artikkel-id e62763Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Humans are known for their capacity to disperse organisms long distances. Long-distance dispersal can be important for species threatened by habitat destruction, but research into human-mediated dispersal is often focused upon few and/or invasive species. Here we use citizen science to identify the capacity for humans to disperse seeds on their clothes and footwear from a known species pool in a valuable habitat, allowing for an assessment of the fraction and types of species dispersed by humans in an alternative context. We collected material from volunteers cutting 48 species-rich meadows throughout Sweden. We counted 24 354 seeds of 197 species, representing 34% of the available species pool, including several rare and protected species. However, 71 species (36%) are considered invasive elsewhere in the world. Trait analysis showed that seeds with hooks or other appendages were more likely to be dispersed by humans, as well as those with a persistent seed bank. More activity in a meadow resulted in more dispersal, both in terms of species and representation of the source communities. Average potential dispersal distances were measured at 13 km. We consider humans capable seed dispersers, transporting a significant proportion of the plant communities in which they are active, just like more traditional vectors such as livestock. When rural populations were larger, people might have been regular and effective seed dispersers, and the net rural-urban migration resulting in a reduction in humans in the landscape may have exacerbated the dispersal failure evident in declining plant populations today. With the fragmentation of habitat and changes in land use resulting from agricultural change, and the increased mobility of humans worldwide, the dispersal role of humans may have shifted from providers of regular local and landscape dispersal to providers of much rarer long-distance and regional dispersal, and international invasion.

  • 80.
    Auffret, Alistair G.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Cousins, Sara A. O.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Past and present management influences the seed bank and seed rain in a rural landscape mosaic2011Inngår i: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 48, nr 5, s. 1278-1285Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    1. Seed bank and seed rain represent dispersal in time and space. They can be important sources of diversity in the rural landscape, where fragmented habitats are linked by their histories. 2. Seed bank, seed rain and above-ground vegetation were sampled in four habitat types (abandoned semi-natural grassland (ABA), grazed former arable field (FAF), mid-field islet (MFI) and grazed semi-natural grassland (SNG)) in a rural landscape in southern Sweden, to examine whether community patterns can be distinguished at large spatial scales and whether seed bank and seed rain are best explained by current, past or intended future vegetation communities. 3. We counted 54 357 seedlings of 188 species from 1190 seed bank and 797 seed rain samples. Seed bank, seed rain and above-ground vegetation communities differed according to habitat. Several species characteristic of managed grassland vegetation were present in the seed bank, seed rain and vegetation of the other habitats. 4. The seed banks of SNGs and the seed rain of the FAFs were generally better predicted by the surrounding above-ground vegetation than were the other habitat types. The seed rain of the grazed communities was most similar to the vegetation in the FAFs, while the seed banks of the abandoned grasslands most resembled the vegetation in SNGs. 5. Gap availability and seed input could be limiting the colonisation of target species in FAFs, while remnant populations in the seed bank and the presence of grassland specialists in the above-ground vegetation indicate that abandoned grasslands and mid-field islets could be valuable sources of future diversity in the landscape after restoration. 6. Synthesis and applications. SNG communities are able to form seed banks which survive land-use change, but their seed rain does not reflect their above-ground communities. It is important that grassland plants set seed. By connecting existing grasslands with restoration targets, increased disturbance in the target habitats would allow for colonisation via the seed bank or seed rain, while decreased grazing intensity would benefit seed production in the source grasslands. Otherwise, landscape-wide propagule availability might increase with a more varied timing and intensity of management.

  • 81.
    Auffret, Alistair G.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Cousins, Sara A.O.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Grassland connectivity by motor vehicles and grazing livestock2013Inngår i: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 36, nr 10, s. 1150-1157Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In addition to habitat loss and fragmentation, agricultural change has led to a change in seed dispersal processes in therural landscape through a loss of structural and functional connectivity. Here, human-mediated dispersal vectors areprevalent, and we explored whether the loss of connectivity via free-ranging livestock could be mitigated by the increasein roads and motor vehicles. We found that structurally, 39% of all valuable semi-natural grassland habitats in southernSweden are adjacent to public road verges, which in the rural landscape are often considered to be suitable habitat forgrassland species. Additionally, by collecting mud attached to cars and farming machinery and manure from livestock(cattle, horse, sheep) grazing semi-natural grassland pasture, we found that motor vehicles are also capable seed dispers-ers. A similar number of species were dispersed by both vectors, although the composition of samples was quite different.Motor vehicles dispersed more grassland specialists than invasive species, although in much lower abundances than didgrazing livestock. Despite these differences, motor vehicles were found to be able to disperse species with the same kindsof dispersal traits as livestock. A high number of seeds, species and specialists in manure samples means that greater move-ment of livestock is desirable to increase functional grassland connectivity. However, effective management could improvethe suitability of roadsides as grassland corridors and increase the availability of seeds for long-distance human-mediateddispersal via cars and tractors. Our results suggest that in many rural landscapes, connectivity by road networks couldhelp mediate habitat loss and fragmentation of grasslands. However, such effects can be context dependent, and the con-nectivity provided by roads could have serious negative consequences in other regions.

  • 82.
    Auffret, Alistair G.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Meineri, Eric
    Bruun, Hans Henrik
    Ejrnæs, Rasmus
    Graae, Bente J.
    Ontogenetic niche shifts in three Vaccinium species on a sub-alpine mountain side2010Inngår i: Plant Ecology & Diversity, ISSN 1755-0874, E-ISSN 1755-1668, Vol. 3, nr 2, s. 131-139Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Climate warming in arctic and alpine regions is expected to result in the altitudinal migration of plant species, but current predictions neglect differences between species' regeneration niche and established niche.

    Aims: To examine potential recruitment of Vaccinium myrtillus, V. uliginosum and V. vitis-idaea on a mountain slope in northern Sweden in relation to current adult occurrence.

    Methods: We combined a seed-sowing experiment in seven community types with adult occurrence observations and species distribution mapping.

    Results: Emergence of V. myrtillus and V. vitis-idaea seedlings was significantly related to community type, while V. uliginosum was indifferent, but exhibited the highest average emergence. Adult occurrence was related to community, and ontogenetic niche shifts were observed for all three study species. V. myrtillus was shown to have the highest potential recruitment in habitats at altitudes above its current populations.

    Conclusions: The potential for migration exists, but incongruence between regenerative and established niches presents a challenge for colonisers, as well as for plant migration modelling.

  • 83.
    Auffret, Alistair G.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Plue, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Scale-dependent diversity effects of seed dispersal by a wild herbivore in fragmented grasslands2014Inngår i: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 175, nr 1, s. 305-313Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dispersal limitation between habitat fragments is a known driver of landscape-scale biodiversity loss. In Europe, agricultural intensification during the twentieth century resulted in losses of both grassland habitat and traditional grassland seed dispersal vectors such as livestock. During the same period, populations of large wild herbivores have increased in the landscape. Usually studied in woodland ecosystems, these animals are found to disperse seeds from grasslands and other open habitats. We studied endozoochorous seed dispersal by roe deer (Capreolus capreolus) in fragmented grasslands and grassland remnants, comparing dispersed subcommunities of plant species to those in the established vegetation and the seed bank. A total of 652 seedlings of 67 species emerged from 219 samples of roe deer dung. This included many grassland species, and several local grassland specialists. Dispersal had potentially different effects on diversity at different spatial scales. Almost all sites received seeds of species not observed in the vegetation or seed bank at that site, suggesting that local diversity might not be dispersal limited. This pattern was less evident at the landscape scale, where fewer new species were introduced. Nonetheless, long-distance dispersal by large wild herbivores might still provide connectivity between fragmented habitats within a landscape in the areas in which they are active. Finally, as only a subset of the available species were found to disperse in space as well as time, the danger of future biodiversity loss might still exist in many isolated grassland habitats.

  • 84.
    Auffret, Alistair G.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Plue, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Cousins, Sara A. O.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    The spatial and temporal components of functional connectivity in fragmented landscapes2015Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, s. s51-S59Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Connectivity is key for understanding how ecological systems respond to the challenges of land-use change and habitat fragmentation. Structural and functional connectivity are both established concepts in ecology, but the temporal component of connectivity deserves more attention. Whereas functional connectivity is often associated with spatial patterns (spatial functional connectivity), temporal functional connectivity relates to the persistence of organisms in time, in the same place. Both temporal and spatial processes determine biodiversity responses to changes in landscape structure, and it is therefore necessary that all aspects of connectivity are considered together. In this perspective, we use a case study to outline why we believe that both the spatial and temporal components of functional connectivity are important for understanding biodiversity patterns in the present-day landscape, and how they can also help us to make better-informed decisions about conserving and restoring landscapes and improving resilience to future change.

  • 85.
    Auffret, Alistair G.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Schmucki, Reto
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Reimark, Josefin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Cousins, Sara A. O.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Grazing networks provide useful functional connectivity for plants in fragmented systems2012Inngår i: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 23, nr 5, s. 970-977Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Question To what extent does the movement of animals between fragmented habitat patches provide functional connectivity via endozoochorous seed dispersal? Location The Stockholm archipelago, Sweden. Methods We followed all movements of livestock between islands during one grazing season. After each movement, manure was collected and its seed content assessed through seedling emergence. Seedling data were then compared to vegetation surveys from the grazed islands with regard to functional traits. Results Light- and nitrogen-demanding locally abundant species, and those with relatively small and persistent seeds were more likely to be moved between islands. For quantitative traits, only a subset of the available trait ranges were dispersed, with extreme values left behind. Species apparently specialized to other means of dispersal emerged from the manure samples. Neither dispersed traits nor seed density changed with timing of movement, but seed richness and diversity both increased throughout the season. The subsets of endozoochorously-dispersed species in the established vegetation were more similar than non-dispersed subsets between islands linked by livestock. Conclusions Grazing networks contribute to the connectivity of the core species in the system, and could provide useful tools for grassland management in fragmented landscapes.

  • 86.
    Auffret, Alistair
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Schmucki, Reto
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Reimark, Josefin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Cousins, Sara
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    A trait-based analysis of the functional connectivity provided by mobile grazers in an island grazing system2011Inngår i: 8th IALE World Congress, Beijing 18-21 August 2011: Landscape Ecology for Sustainable Environment and Culture, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The area of species-rich semi-natural grassland in Europe has declined dramatically duringthe past two centuries. The Stockholm archipelago was once a vibrant agricultural landscape,with the movement of livestock between islands forming an extensive grazing network. Likein much of Europe, agricultural industrialisation led to most grasslands either beingabandoned to become scrub or woodland, or converted to arable fields and subsequentlyreverted to relatively species-poor pasture. The restoration of these habitats to species-richgrassland communities has been a major goal, but restoration success has often been found tobe seed or dispersal limited. In island systems, the hostility of the matrix exacerbates thisproblem, but also provides an ideal study system for investigating the dispersal of plantspecies between fragmented habitats. One management strategy has been to restart smallgrazing networks to improve connectivity in the landscape, and in the summer of 2009, wecollected fresh manure samples from grazing cattle and sheep after movement by boatbetween islands. These were then grown in a greenhouse, and 5915 seedlings of 74 speciesemerged from the 18 samples, corresponding to 18 movements within the grazing network.Comparing the species dispersed with the vegetation communities in the donor and receiverislands, we assess the subset of species and species traits which were transported. We can thusexamine the extent of the functional connectivity provided by these mobile grazers, and theeffect that timing of movement has on the range of species and traits dispersed.

  • 87. Austin, William E. N.
    et al.
    Abbott, Peter M.
    Davies, Siwan
    Pearce, Nicholas J. G.
    Wastegård, Stefan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Marine tephrochronology: an introduction to tracing time in the ocean2014Inngår i: Marine Tephrochronology / [ed] W. E. N. AUSTIN, P. M. ABBOTT, S. M. DAVIES, N. J. G. PEARCE, S. WASTEGÅRD, London: Geological Society of London, 2014, Vol. 398, s. 1-5Kapittel i bok, del av antologi (Fagfellevurdert)
  • 88. Azcárate, Juan
    et al.
    Balfors, Berit
    Bring, Arvid
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Strategic environmental assessment and monitoring: Arctic key gaps and bridging pathways2013Inngår i: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 8, nr 4, artikkel-id 044033Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Arctic region undergoes rapid and unprecedented environmental change. Environmental assessment and monitoring is needed to understand and decide how to mitigate and/or adapt to the changes and their impacts on society and ecosystems. This letter analyzes the application of strategic environmental assessment (SEA) and the monitoring, based on environmental observations, that should be part of SEA, elucidates main gaps in both, and proposes an overarching SEA framework to systematically link and improve both with focus on the rapidly changing Arctic region. Shortcomings in the monitoring of environmental change are concretized by examples of main gaps in the observations of Arctic hydroclimatic changes. For relevant identification and efficient reduction of such gaps and remaining uncertainties under typical conditions of limited monitoring resources, the proposed overarching framework for SEA application includes components for explicit gap/uncertainty handling and monitoring, systematically integrated within all steps of the SEA process. The framework further links to adaptive governance, which should explicitly consider key knowledge and information gaps that are identified through and must be handled in the SEA process, and accordingly (re)formulate and promote necessary new or modified monitoring objectives for bridging these gaps. 

  • 89.
    Azcárate, Juan
    et al.
    KTH Royal Institute of Technology.
    Balfors, Berit
    KTH Royal Institute of Technology.
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Bring, Arvid
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Scenario-based Transboundary Approach to Shape Arctic Futures2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Technological advances, climate change and increased strategic interest in the Arctic are causing rapid and long lasting transformations that challenge established governance and collaboration practices, and increase information demands to support regional decision making. In the rapidly transforming Arctic, however, scenarios of environmental change risk being insufficiently accounted for in adaptation planning, as monitoring of key environmental parameters has declined or is poorly optimized. Furthermore, application of support instruments for environmental planning, such as strategic environmental assessment, has been limited. This poster presents recent advancements in efforts to combine quantitative analysis of environmental monitoring in the Arctic with strategic governance research to develop instruments, such as scenarios, projections and assessment processes, that can facilitate relevant planning and decision making for change adaptation. that the research explores and aims to improve the preconditions for and links between environmental management, policy-relevant monitoring, and climate change adaptation strategies in the Arctic. Results include environmental monitoring assessment for the Arctic, and design of a transboundary strategic environmental assessment approach that includes scenarios as a main component for enabling strategic dialogues, information exchange and decision support. In this proposed approach, focus is placed on identifying conflicts of interest, gaps of knowledge and uncertainties, and on developing inclusive scenarios and future projections that could be used by different actors to facilitate improved understanding of climate change impacts on sensitive and unique Arctic ecosystems. The approach can be used to discuss and arrive at shared projections, visions and objectives for the Arctic, and its application and testing in research may aid in enabling Arctic actors to establish networks, interact, share information and develop their capacities to improve decisions on Arctic futures. 

  • 90. Azcárate, Juan
    et al.
    Balfors, Berit
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Bring, Arvid
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Transboundary approach proposal for sustainable and climate change adaptation strategies in the Arctic2012Konferansepaper (Annet vitenskapelig)
  • 91.
    Baheram, Elina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Nollalternativ i en miljökonsekvensbeskrivning2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Denna studie om nollalternativ i en miljökonsekvensbeskrivning utgör ett examensarbete inom masterprogrammet i Miljövård och fysisk planering på för naturgeografi och kvartärgeologi vid Stockholms universitet. Examensarbetet har även tagits fram i samarbete med WSP Samhällsbyggnad.

    I dagsläget tycks det saknas en entydig samsyn över hur nollalternativ i en MKB ska formuleras och hanteras. Med anledning av det har syftet med denna studie varit att utforska vilka förhållningssätt som finns till nollalternativet i en MKB samt att försöka ge en ökad förståelse för hur nollalternativet i en MKB bör hanteras. Därför redogör denna studie för vilket syfte och funktion nollalternativet fyller i en MKB tillsammans med de aspekter som bör beaktas vid hanteringen av nollalternativ i en MKB.

    Studien har genomförts med hjälp av fyra olika metoder som gemensamt bör kunna besvara studiens syfte och frågeställningar. För att bidra med en ökad förståelse kopplas den erhållna empirin till teorier om förutsägelse, osäkerhet och scenarier i en MKB.

    Resultatet i studien visar att syftet med nollalternativ i en MKB är att sätt den tänka planen eller projektet i en kontext och fyller därmed en betydelsefull funktion. I en MKB är det viktigt att belysa den osäkerhet som råder i de förutsägelser som görs om framtiden och ligger till grund för de bedömningar som görs. Detta gäller även för nollalternativet. Med anledning av osäkerheten är det även nödvändigt att överväga ifall det i alla lägen är lämpligt att nollalternativet utgör ett referensalternativ i relation till de övriga alternativen i MKB:n. I miljöbalken finns det även två definitioner av nollalternativet, beroende på ifall det är en plan eller projekt som ska miljökonsekvensbeskrivas. Denna skillnad är däremot inte alltid synlig i praktiken.

    Under studiens gång har det framkommit att det finns en efterfrågan om råd och rekommendationer för hantering av nollalternativ i en MKB. En förhoppning är därmed att denna studie ska generera en ökad kunskap om hanteringen av nollalternativ i en MKB.

  • 92. Baker, Paul A.
    et al.
    Fritz, Sherilyn C.
    Dick, Christopher W.
    Eckert, Andrew J.
    Horton, Brian K.
    Manzoni, Stefano
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Ribas, Camila C.
    Garzione, Carmala N.
    Battisti, David S.
    The emerging field of geogenomics: Constraining geological problems with genetic data2014Inngår i: Earth-Science Reviews, ISSN 0012-8252, E-ISSN 1872-6828, Vol. 135, s. 38-47Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development of a genomics-derived discipline within geology is timely, as a result of major advances in acquiring and processing geologically relevant genetic data. This paper articulates the emerging field of geogenomics, which involves the use of large-scale genetic data to constrain geological hypotheses. The paper introduces geogenomics and discusses how hypotheses can be addressed through collaboration between geologists and evolutionary biologists. As an example, geogenomic methods are applied to evaluate competing hypotheses regarding the timing of the Andean uplift, the closure of the Isthmus of Panama, the onset of trans-Amazon drainage, and Quaternary climate variation in the Neotropics.

  • 93.
    Ballarotta, Maxime
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Falahat, Saeed
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Brodeau, Laurent
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Döös, Kristofer
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    On the glacial and interglacial thermohaline circulation and the associated transports of heat and freshwater2014Inngår i: Ocean Science, ISSN 1812-0784, E-ISSN 1812-0792, Vol. 10, nr 6, s. 907-921Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The thermohaline circulation (THC) and the oceanic heat and freshwater transports are essential for understanding the global climate system. Streamfunctions are widely used in oceanography to represent the THC and estimate the transport of heat and freshwater. In the present study, the regional and global changes of the THC, the transports of heat and freshwater and the timescale of the circulation between the Last Glacial Maximum (LGM, ≈ 21 kyr ago) and the present-day climate are explored using an Ocean General Circulation Model and streamfunctions projected in various coordinate systems. We found that the LGM tropical circulation is about 10% stronger than under modern conditions due to stronger wind stress. Consequently, the maximum tropical transport of heat is about 20% larger during the LGM. In the North Atlantic basin, the large sea-ice extent during the LGM constrains the Gulf Stream to propagate in a more zonal direction, reducing the transport of heat towards high latitudes by almost 50% and reorganising the freshwater transport. The strength of the Atlantic Meridional Overturning Circulation depends strongly on the coordinate system. It varies between 9 and 16 Sv during the LGM, and between 12 to 19 Sv for the present day. Similar to paleo-proxy reconstructions, a large intrusion of saline Antarctic Bottom Water takes place into the Northern Hemisphere basins and squeezes most of the Conveyor Belt circulation into a shallower part of the ocean. These different haline regimes between the glacial and interglacial period are illustrated by the streamfunctions in latitude–salinity coordinates and thermohaline coordinates. From these diagnostics, we found that the LGM Conveyor Belt circulation is driven by an enhanced salinity contrast between the Atlantic and the Pacific basin. The LGM abyssal circulation lifts and makes the Conveyor Belt cell deviate from the abyssal region, resulting in a ventilated upper layer above a deep stagnant layer, and an Atlantic circulation more isolated from the Pacific. An estimate of the timescale of the circulation reveals a sluggish abyssal circulation during the LGM, and a Conveyor Belt circulation that is more vigorous due to the combination of a stronger wind stress and a shortened circulation route.

  • 94. Balouet, J-C
    et al.
    Oudijk, G
    Smith, K.T.
    Petrisor, I
    Grudd, H
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi.
    Stocklassa, B
    Applied Dendroecology and Environmental Forensics. Characterizing and Age Dating Environmental Releases:: Fundamentals and Case Studies.2007Inngår i: Environmental Forensics, ISSN 1527–5922, Vol. 8, nr 1-2, s. 1-17Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dendroecology, or the use of ring patterns to assess the age of trees and environmental factors controlling their growth, is a well-developed method in climatologic studies. This method holds great potential as a forensic tool for age dating, contamination assessment, and characterization of releases. Moreover, the method is independent of the physical presence of contamination at the time of sampling because it is focused on the effect rather than the cause. This review is one of the very few articles published to date exploring the forensic applicability of dendroecology. This article is organized in two parts: Part I describes the method principles and proposes a practical procedure for forensic applications; Part II exemplifies and validates the method through six case studies of successful forensic application (related to petroleum products and chlorinated solvent spills).

  • 95. Balouet, Jean Christophe
    et al.
    Burken, Joel G.
    Karg, Frank
    Vroblesky, Don
    Smith, Kevin T.
    Grudd, Håkan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Rindby, Anders
    Beaujard, Francois
    Chalot, Michel
    Dendrochemistry of Multiple Releases of Chlorinated Solvents at a Former Industrial Site2012Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, nr 17, s. 9541-9547Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Trees can take up and assimilate contaminants from the soil, subsurface, and groundwater. Contaminants in the transpiration stream can become bound or incorporated into the annual rings formed in trees of the temperate zones. The chemical analysis of precisely dated tree rings, called dendrochemistry, can be used to interpret past plant interactions with contaminants. This investigation demonstrates that dendrochemistry can be used to generate historical scenarios of past contamination of groundwater by chlorinated solvents at a site in Verl, Germany. Increment cores from trees at the Verl site were collected and analyzed by energy-dispersive X-ray fluorescence (EDXRF) line scanning. The EDXRF profiles showed four to six time periods where tree rings had anomalously high concentrations of chlorine (Cl) as an indicator of potential contamination by chlorinated solvents.

  • 96. Baresel, Christian
    et al.
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Diffuse subsurface zinc loads from mining areas in the Dalälven River Basin, Sweden2009Inngår i: Hydrology Research, ISSN 0029-1277, Vol. 40, nr 5, s. 445-453Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The zinc load from the Dalälven River to the Baltic Sea is greater than for any other watercourse in Sweden. This paper investigates zinc mass flows into and through the Dalälven River from major mining areas within its drainage basin. Reported zinc mass flow data for this river are re-analyzed using an input-output flow analysis approach. Results show major inconsistencies in previous data interpretations which totally neglected possible zinc mass load contributions from the groundwater system to the river. This paper quantifies significant subsurface zinc load contributions that are consistent with all independently available data. Furthermore, a possible explanation for why these subsurface contributions may have been missed in previous studies and by the prevailing Swedish environmental monitoring system is provided. The study indicates that the input-output flow analysis approach may be generally useful for identifying and quantifying diffuse, unmonitored and uncertain pollutant load contributions from ground- to surface water systems.

  • 97. Baresel, Christian
    et al.
    Destouni, Georgia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi.
    Uncertainty-Accounting Environmental Policy and Management of Water Systems2007Inngår i: Environmental Science & Technology, Vol. 41, nr 10, s. 3653–3659-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Environmental policies for water quality and ecosystem

    management do not commonly require explicit stochastic

    accounts of uncertainty and risk associated with the

    quantification and prediction of waterborne pollutant loads

    and abatement effects. In this study, we formulate and

    investigate a possible environmental policy that does require

    an explicit stochastic uncertainty account. We compare

    both the environmental and economic resource allocation

    performance of such an uncertainty-accounting environmental

    policy with that of deterministic, risk-prone and riskaverse

    environmental policies under a range of different

    hypothetical, yet still possible, scenarios. The comparison

    indicates that a stochastic uncertainty-accounting

    policy may perform better than deterministic policies over

    a range of different scenarios. Even in the absence of

    reliable site-specific data, reported literature values appear

    to be useful for such a stochastic account of uncertainty.

  • 98. Basu, N. B.
    et al.
    Destouni, G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Jawitz, J. W.
    Thompson, S. E.
    Loukinova, N. V.
    Darracq, A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Zanardo, S.
    Yaeger, M.
    Sivapalan, M.
    Rinaldo, A.
    Rao, P. S. C.
    Nutrient loads exported from managed catchments reveal emergent biogeochemical stationarity2010Inngår i: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 37, nr L23404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Complexity of heterogeneous catchments poses challenges in predicting biogeochemical responses to human alterations and stochastic hydro‐climatic drivers. Human interferences and climate change may have contributed to the demise of hydrologic stationarity, but our synthesis of a large body of observational data suggests that anthropogenic impacts have also resulted in the emergence of effective biogeochemical stationarity in managed catchments. Long‐term monitoring data from the Mississippi‐Atchafalaya River Basin (MARB) and the Baltic Sea Drainage Basin (BSDB) reveal that inter‐annual variations in loads (LT) for total‐N (TN) and total‐P (TP), exported from a catchment are dominantly controlled by discharge (QT) leading inevitably to temporal invariance of the annual, flow‐weighted concentration, = (LT/QT). Emergence of this consistent pattern across diverse managed catchments is attributed to the anthropogenic legacy of accumulated nutrient sources generating memory, similar to ubiquitously present sources for geogenic constituents that also exhibit a linear LTQT relationship. These responses are characteristic of transport‐limited systems. In contrast, in the absence of legacy sources in less‐managed catchments, values were highly variable and supply limited. We offer a theoretical explanation for the observed patterns at the event scale, and extend it to consider the stochastic nature of rainfall/flow patterns at annual scales. Our analysis suggests that: (1) expected inter‐annual variations in LT can be robustly predicted given discharge variations arising from hydro‐climatic or anthropogenic forcing, and (2) water‐quality problems in receiving inland and coastal waters would persist until the accumulated storages of nutrients have been substantially depleted. The finding has notable implications on catchment management to mitigate adverse water‐quality impacts, and on acceleration of global biogeochemical cycles.

  • 99. Basu, N. B.
    et al.
    Destouni, G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Jawitz, J. W.
    Thompson, S. E.
    Rinaldo, A.
    Sivapalan, M.
    Rao, P. C.
    Anthropogenic Signatures in Nutrient Loads Exported from Managed Catchments: Emergence of Effective Biogeochemical Stationarity2010Inngår i: Abstract H44C-03 presented at 2010 Fall Meeting, AGU, San Francisco, Calif., USA, 13–17 Dec, 2010Konferansepaper (Fagfellevurdert)
  • 100. Bayer-Raich, Martí
    et al.
    Jarsjö, Jerker
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för naturgeografi och kvartärgeologi (INK).
    Teutsch, Georg
    Breakthrough of attenuating contaminant plumes in pumping wells: Analytical model and implications for integral pumping tests.2009Inngår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 45, s. W02413-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Monitoring of contaminant plumes and predicting their future fate are essential for effective management of groundwater contaminants. Solute breakthrough curves from operating pumping wells can provide information on the water quality in relatively large aquifer regions, which may be unavailable to instrumentation and direct measurement for practical and/or economical reasons. Relations between spatially varying aquifer concentrations C0(x, y) initially surrounding a well and temporally varying concentrations of subsequently extracted well water, Cp(t), then need to be quantified. However, limited applicability of analytical expressions and numerical inaccuracies related to solving transport equations for converging flow fields hamper such quantifications even in homogeneous aquifers. We use a stream-tube approach and provide a general problem formulation that accounts for first-order degradation and linear, instantaneous, sorption/retardation in heterogeneous aquifers. An analytical expression is obtained for homogeneous aquifer conditions (in the well vicinity), relating any given initial C0(x, y) function and the subsequent contaminant breakthrough Cp(t) in the well. Results for wide plumes subject to first-order degradation show that concentrations at the extraction well will increase as a function of pumping time. This increase is despite the fact that late-time data reflect longer transport paths (to the well), along which mass is removed through degradation. We also derive unique solutions for the inverse problem, in particular considering how the average contaminant concentration Cav (averaged along a control plane through the well within its capture zone, perpendicular to the mean groundwater flow direction) depends on the measurable Cp(t). The solutions demonstrate that the longer the pumping time, the more sensitive the solutions for Cav become to degradation rate constants, which if needed can be determined in situ using multiple control planes.

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