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  • 201. D'Orangeville, Loic
    et al.
    Maxwell, Justin
    Kneeshaw, Daniel
    Pederson, Neil
    Duchesne, Louis
    Logan, Travis
    Houle, Daniel
    Arseneault, Dominique
    Beier, Colin M.
    Bishop, Daniel A.
    Druckenbrod, Daniel
    Fraver, Shawn
    Girard, Francois
    Halman, Joshua
    Hansen, Chris
    Hart, Justin L.
    Hartmann, Henrik
    Kaye, Margot
    Leblanc, David
    Manzoni, Stefano
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Ouimet, Rock
    Rayback, Shelly
    Rollinson, Christine R.
    Phillips, Richard P.
    Drought timing and local climate determine the sensitivity of eastern temperate forests to drought2018In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 24, no 6, p. 2339-2351Article in journal (Refereed)
    Abstract [en]

    Projected changes in temperature and drought regime are likely to reduce carbon (C) storage in forests, thereby amplifying rates of climate change. While such reductions are often presumed to be greatest in semi-arid forests that experience widespread tree mortality, the consequences of drought may also be important in temperate mesic forests of Eastern North America (ENA) if tree growth is significantly curtailed by drought. Investigations of the environmental conditions that determine drought sensitivity are critically needed to accurately predict ecosystem feedbacks to climate change. We matched site factors with the growth responses to drought of 10,753 trees across mesic forests of ENA, representing 24 species and 346 stands, to determine the broad-scale drivers of drought sensitivity for the dominant trees in ENA. Here we show that two factors-the timing of drought, and the atmospheric demand for water (i.e., local potential evapotranspiration; PET)-are stronger drivers of drought sensitivity than soil and stand characteristics. Droughtinduced reductions in tree growth were greatest when the droughts occurred during early-season peaks in radial growth, especially for trees growing in the warmest, driest regions (i.e., highest PET). Further, mean species trait values (rooting depth and psi(50)) were poor predictors of drought sensitivity, as intraspecific variation in sensitivity was equal to or greater than interspecific variation in 17 of 24 species. From a general circulation model ensemble, we find that future increases in earlyseason PET may exacerbate these effects, and potentially offset gains in C uptake and storage in ENA owing to other global change factors.

  • 202. Douglas, P. M. J.
    et al.
    Stolper, D. A.
    Smith, D. A.
    Anthony, K. M. Walter
    Paull, C. K.
    Dallimore, S.
    Wik, Martin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Crill, Patrick M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Winterdahl, Mathias
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Eiler, J. M.
    Sessions, A. L.
    Diverse origins of Arctic and Subarctic methane point source emissions identified with multiply-substituted isotopologues2016In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 188, p. 163-188Article in journal (Refereed)
    Abstract [en]

    Methane is a potent greenhouse gas, and there are concerns that its natural emissions from the Arctic could act as a substantial positive feedback to anthropogenic global warming. Determining the sources of methane emissions and the biogeochemical processes controlling them is important for understanding present and future Arctic contributions to atmospheric methane budgets. Here we apply measurements of multiply-substituted isotopologues, or clumped isotopes, of methane as a new tool to identify the origins of ebullitive fluxes in Alaska, Sweden and the Arctic Ocean. When methane forms in isotopic equilibrium, clumped isotope measurements indicate the formation temperature. In some microbial methane, however, non-equilibrium isotope effects, probably related to the kinetics of methanogenesis, lead to low clumped isotope values. We identify four categories of emissions in the studied samples: thermogenic methane, deep subsurface or marine microbial methane formed in isotopic equilibrium, freshwater microbial methane with non-equilibrium clumped isotope values, and mixtures of deep and shallow methane (i.e., combinations of the first three end members). Mixing between deep and shallow methane sources produces a non-linear variation in clumped isotope values with mixing proportion that provides new constraints for the formation environment of the mixing end-members. Analyses of microbial methane emitted from lakes, as well as a methanol-consuming methanogen pure culture, support the hypothesis that non-equilibrium clumped isotope values are controlled, in part, by kinetic isotope effects induced during enzymatic reactions involved in methanogenesis. Our results indicate that these kinetic isotope effects vary widely in microbial methane produced in Arctic lake sediments, with non-equilibrium Delta(18) values spanning a range of more than 5 parts per thousand.

  • 203. Drobyshev, Igor
    et al.
    Bergeron, Yves
    de Vernal, Anne
    Moberg, Anders
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Ali, Adam A.
    Niklasson, Mats
    Atlantic SSTs control regime shifts in forest fire activity of Northern Scandinavia2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 22532Article in journal (Refereed)
    Abstract [en]

    Understanding the drivers of the boreal forest fire activity is challenging due to the complexity of the interactions driving fire regimes. We analyzed drivers of forest fire activity in Northern Scandinavia (above 60 N) by combining modern and proxy data over the Holocene. The results suggest that the cold climate in northern Scandinavia was generally characterized by dry conditions favourable to periods of regionally increased fire activity. We propose that the cold conditions over the northern North Atlantic, associated with low SSTs, expansion of sea ice cover, and the southward shift in the position of the subpolar gyre, redirect southward the precipitation over Scandinavia, associated with the westerlies. This dynamics strengthens high pressure systems over Scandinavia and results in increased regional fire activity. Our study reveals a previously undocumented teleconnection between large scale climate and ocean dynamics over the North Atlantic and regional boreal forest fire activity in Northern Scandinavia. Consistency of the pattern observed annually through millennium scales suggests that a strong link between Atlantic SST and fire activity on multiple temporal scales over the entire Holocene is relevant for understanding future fire activity across the European boreal zone.

  • 204. Dukpa, Dorji
    et al.
    Cook, Edward R.
    Krusic, Paul J.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Rai, P. B.
    Darabant, Andras
    Tshering, Ugyen
    Applied dendroecology informs the sustainable management of Blue Pine forests in Bhutan2018In: Dendrochronologia, ISSN 1125-7865, E-ISSN 1612-0051, Vol. 49, p. 89-93Article, review/survey (Refereed)
    Abstract [en]

    Tree ring science is a new discipline in Bhutan but has contributed substantially to our understanding of climate history and informed sustainable forest management practices in the country. This paper describes dendroecological contributions to the second aspect for Blue Pine using three case studies. i) The effects of livestock grazing impact on Blue Pine radial growth were quantified. Radial growth increment was tendentially higher after three years of livestock exclosure, as compared to continued grazing. However, differences remained statistically not significant, likely due to the brevity of the treatment period. ii) Radial growth rates of Blue Pine were characterized across a 400m elevation gradient. Cumulative radial growth over 40 years differed by a factor of more than three between the low and the high end of the gradient. However, below 2300 m, radial growth showed a continuous decline from 1990, likely as a results of drought due to climate change. iii) Effects of three levels of prescribed thinning of pole stage (DBH 30-50 cm) Blue Pine in central Bhutan showed distinct response to thinning. Heavy thinning lead to a thinning shock in the year after harvest and did not lead to significantly higher radial growth as compared to moderate thinning, which is thus recommended for the species. A positive thinning effect remained for seven years post operation. The case studies were incorporated into national guidelines on sustainable forest management in Bhutan and prove the demand for tree ring based research to inform policy and practice.

  • 205.
    Dymova, Taisiya
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Paleoglaciological study of the Ahlmannryggen, Borgmassivet and Kirwanveggen nunatak ranges, Dronning Maud Land, East Antarctica, using WorldView imagery2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Paleoglaciological reconstructions based on glacial geological and geomorphological traces are used to test and constrain numerical models of ice sheet extent and dynamics. MAGIC-DML (“Mapping, Measuring and Modelling Antarctic Geomorphology and Ice Change in Dronning Maud Land”) project is trying to reconstruct the timing and pattern of ice surface elevation changes since the mid-Pliocene across western Dronning Maud Land, East Antarctica. The study area has sparse pre-existing field data and considerable ice sheet model uncertainties. A remote sensing-based mapping of glacial geomorphology on nunataks and structures on the ice sheet surface is presented for a coastal-inland transect including Ahlmannryggen, Borgmassivet, and Kirwanveggen using high-resolution WorldView imagery. The primary aim of the study is to map traces of a thicker ice sheet on nunatak slopes that were formerly partly or entirely covered during ice surface highstands. Panchromatic and multispectral images were analysed in a multi-step procedure using ArcGIS, including image processing and mosaicking, visual feature recognition, and mapping. The identification of key landforms (such as till veneers and erratic boulders) required the adoption of some assumptions to differentiate, for example, till from regolith. Where patterned ground was mapped, we infer a presence of till rather than regolith because subglacial erosion is more likely to produce finer material than subaerial weathering. Very large boulders on plateau surfaces are mapped as erratics because they could not have been delivered by slope processes to local highpoints. However, the reliability of derived paleo-ice sheet reconstructions is limited by both the necessary assumptions and the absence of crosscutting relationships between landforms. At face value, the presence of till cover and erratics above the present ice surface on some nunataks indicate thicker ice in the past. According to the geomorphological mapping of the transect, in Kirwanveggen the former ice elevation was at least 100 m higher, in Borgmassivet the ice lowered more than 600 m and in Ahlmannryggen the ice was at least 300 m thicker. Additional mapping of structures on the ice sheet surface is used to yield target field routes for upcoming field season(s) to potential cosmogenic nuclide (CN) sampling locations. The chronology derived from CN dating will permit the delineation of ice sheet surface elevations as targets for ice sheet modeling.

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  • 206.
    Ebert, Karin
    Stockholm University, Faculty of Science, Department of Physical Geography.
    GIS analyses of ice-sheet erosional impacts on the exposed shield of Baffin Island, eastern Canadian Arctic2015In: Canadian journal of earth sciences (Print), ISSN 0008-4077, E-ISSN 1480-3313, Vol. 52, no 11, p. 966-979Article in journal (Refereed)
    Abstract [en]

    The erosional impacts of former ice sheets on the low-relief bedrock surfaces of Northern Hemisphere shields are not well understood. This paper assesses the variable impacts of glacial erosion on a portion of Baffin Island, eastern Canadian Arctic, between 68 degrees and 72 degrees N and 66 degrees and 80 degrees W. This tilted shield block was covered repeatedly by the Laurentide Ice Sheet during the late Cenozoic. The impact of ice-sheet erosion is examined with GIS analyses using two geomorphic parameters: lake density and terrain ruggedness. The resulting patterns generally conform to published data from other remote sensing studies, geological observations, cosmogenic exposure ages, and the distribution of the chemical index of alteration for tills. Lake density and terrain ruggedness are thereby demonstrated to be useful quantitative indicators of variable ice-sheet erosional impacts across Baffin Island. Ice-sheet erosion was most effective in the lower western parts of the lowlands, in a west-east-oriented band at around 350-400 m a.s.l., and in fjord-onset zones in the uplifted eastern region. Above the 350-400 m a.s.l. band and between the fjord-onset zones, ice-sheet erosion was not sufficient to create extensive ice-roughened or streamlined bedrock surfaces. The exception-where lake density and terrain ruggedness indicate that ice-sheet erosion had a scouring effect all across the study area-was in an area from Foxe Basin to Home Bay with elevations <400 m a.s.l. These morphological contrasts link to former ice-sheet basal thermal regimes during the Pleistocene. The zone of low glacial erosion surrounding the cold-based Barnes Ice Cap probably represents the ice cap's greater extent during successive Pleistocene cold stages. Inter-fjord plateaus with few ice-sheet bedforms remained cold-based throughout multiple Pleistocene glaciations. In contrast, zones of high lake density and high terrain ruggedness are a result of the repeated development of fast-flowing, erosive ice in warm-based zones beneath the Laurentide Ice Sheet. These zones are linked to greater ice thickness over western lowland Baffin Island. However, adjacent lowland surfaces with similar elevations of non-eroded, weakly eroded, and ice-scoured shield bedrock indicate that-even in areas of high lake density and terrain ruggedness-the total depth of ice sheet erosion did not exceed 50 m.

  • 207.
    Ebert, Karin
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Axelsson, Leona
    Harbor, Jon
    Stockholm University, Faculty of Science, Department of Physical Geography. Purdue University, USA.
    Opportunities and challenges for building alumni networks in Sweden: a case study of Stockholm University2015In: Journal of Higher Education Policy and Management, ISSN 1360-080X, E-ISSN 1469-9508, Vol. 37, no 2, p. 252-262Article in journal (Refereed)
    Abstract [en]

    Because of the potential value of alumni involvement for student success, for connections to society and as a base for future philanthropy, there is growing interest in developing university alumni relations programmes in countries that do not have a long tradition in this area. This case study of Stockholm University describes the goals, strategies, barriers and successes of building an alumni programme in an environment that lacks a tradition of alumni relations and aims to provide perspectives and ideas that can help other universities worldwide with their work towards building alumni programmes that fit their cultural contexts and goals.

  • 208.
    Ebert, Karin
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Ekstedt, Karin
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Jarsjö, Jerker
    Stockholm University, Faculty of Science, Department of Physical Geography.
    GIS analysis of effects of future Baltic sea level rise on the island of Gotland, Sweden2016In: Natural hazards and earth system sciences, ISSN 1561-8633, E-ISSN 1684-9981, Vol. 16, no 7, p. 1571-1582Article in journal (Refereed)
    Abstract [en]

    Future sea level rise as a consequence of global warming will affect the world's coastal regions. Even though the pace of sea level rise is not clear, the consequences will be severe and global. Commonly the effects of future sea level rise are investigated for relatively vulnerable development countries; however, a whole range of varying regions needs to be considered in order to improve the understanding of global consequences. In this paper we investigate consequences of future sea level rise along the coast of the Baltic Sea island of Gotland, Sweden, with the aim to fill knowledge gaps regarding comparatively well-suited areas in developed countries. We study both the quantity of the loss of features of infrastructure, cultural, and natural value in the case of a 2 m sea level rise of the Baltic Sea and the effects of climate change on seawater intrusion in coastal aquifers, which indirectly cause saltwater intrusion in wells. We conduct a multi-criteria risk analysis by using lidar data on land elevation and GIS-vulnerability mapping, which gives the application of distance and elevation parameters formerly unimaginable precision. We find that in case of a 2 m sea level rise, 3 % of the land area of Gotland, corresponding to 99 km(2), will be inundated. The features most strongly affected are items of touristic or nature value, including camping places, shore meadows, sea stack areas, and endangered plants and species habitats. In total, 231 out of 7354 wells will be directly inundated, and the number of wells in the high-risk zone for saltwater intrusion in wells will increase considerably. Some valuable features will be irreversibly lost due to, for example, inundation of sea stacks and the passing of tipping points for seawater intrusion into coastal aquifers; others might simply be moved further inland, but this requires considerable economic means and prioritization. With nature tourism being one of the main income sources of Gotland, monitoring and planning are required to meet the changes. Seeing Gotland in a global perspective, this island shows that holistic multi-feature studies of future consequences of sea level rise are required to identify overall consequences for individual regions.

  • 209.
    Eccleshall, Sarah V.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Hormes, Anne
    Hovland, Alexander
    Preusser, Frank
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Constraining the chronology of Pleistocene glaciations on Svalbard: Kapp Ekholm re-visited2016In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 45, no 4, p. 790-803Article in journal (Refereed)
    Abstract [en]

    The Kapp Ekholm site, in central Spitsbergen, shows alternating units of glaciomarine sandy silt and diamicton representing three glacial cycles and is key in reconstructing the Late Pleistocene glacial history of Svalbard. Part of the site is reinvestigated here by focusing on re-dating two units (B and F) interpreted as interglacial/interstadial glaciomarine deposits, in order to constrain the controversial chronology. A combination of Optical Stimulated Luminescence (OSL) on quartz, infrared stimulated luminescence with a 50 degrees C readout temperature (IRSL50) and post infrared-infrared stimulated luminescence (pIR), both on feldspar, was applied. While Formation B was beyond the dateable range of OSL, IRSL50 and pIR ages lead to the conclusion that this unit represents the Last Interglacial, Marine Isotope Stage (MIS) 5e, and the underlying diamicton the MIS 6 glacial. Formation F yielded ages implying that the formation represents the MIS 5a interstadial and the underlying diamicton is interpreted to represent the MIS 5b stadial. This agrees with conclusions drawn concerning the Pleistocene glaciations elsewhere on Svalbard.

  • 210.
    Edvinsson, Johan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Grundvattenmodellering och föroreningstransport av PFOS i Bredåkradeltat2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Perfluorerade alkylsyror (PFAS) är en grupp ämnen som de senaste åren har uppmärksammats för dess persistenta, bioackumulerande och toxiska egenskaper för människor och djur. Det är känt att brandövningsplatser där det filmbildande skummet AFFF har använts utgör betydande punktkällor för PFAS. Förutom att förorena marken vid brandövningsplatserna kan PFAS spridas med grundvattnet, vilket har orsakat förorenade dricksvattentäkter på ett flertal platser i Sverige. Hydrogeologiska modeller kan användas för att modellera grundvattnets flöden och medföljande föroreningar. Syftet med examensarbetet är att med en hydrogeologisk modell undersöka föroreningsspridning och transporttider av PFAS-ämnet perfluoroktansulfonat (PFOS) från en brandövningsplats till ytvatten och grundvattentäkter i Bredåkradeltat, väster om Kallinge i Blekinge.

    Den hydrogeologiska modellen skapades i Visual MODFLOW och transportmodelleringen gjordes med MT3D99 och MODPATH. Modellen kunde reproducera uppmätta grundvattennivåer, med en korrelationskoefficient (R) på 0,98 mellan modellerade och uppmätta nivåer. Med antagandet försumbar adsorption visade modellresultaten att en föroreningsplym med hög PFOS-koncentration (~90.000 ng/l) spreds från brandövningsplatsen till ett våtmarksområde väster om Klintabäcken, och vidare till dalen längs Klintabäcken med lägre koncentrationen (0–4.000 ng/l). Enligt modellen spreds dock inte föroreningen lika långt som uppmätta värden visar. När PFOS väl har nått Klintabäcken bedöms den kunna spridas snabbt med ytvattnet mot grundvattentäkterna, för att sedan infiltrera ned i isälvsmaterialet nära aktiva grundvattentäkter. Transporttiden av PFOS från brandövningsplatsen till Klintabäcken beräknades till sex år för den bäst kalibrerade modellen, vilket betyder att grundvattentäkterna kan ha varit förorenade sedan slutet av 1980-talet eller början av 1990-talet. Beräkningar av masstransport indikerar att runt 3,5 kg PFOS flödar genom Klintabäcken varje år, och att det mesta av den mängden kommer från området vid brandövningsplatsen.

    Trots förenklingar av Bredåkradeltats komplexa geologi och svårigheter att nå konvergens i modellen bedöms den kunna reproducera hydrogeologiska egenskaper inom deltat, samt föroreningsplymens spridning från brandövningsplatsen till Klintabäcken.

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  • 211.
    Edwards, Nathalie
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Telegrafberget & Ällmora träsk - ett potentiellt naturreservat på Brevikshalvön, Tyresö kommun2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Within the Regional Development Plan of the Stockholm area, certain lands are to be included and reserved for the sake of natural, cultural and recreational values. In Tyresö municipality, south of Stockholm, lies Telegrafberget and Ällmora träsk, an area located on the peninsula of Brevik. There is a proposition to establish this area as a nature reserve. This is mainly due to the recreational value as a leisure area, where people walk their dogs, pick mushrooms and berries, rock climb etc. But it also has ecological values of certain characters, such as an intact hydrographic basin, a pine forest with several 300 year old trees, including biotope typical fauna, and a landscape containing both a rather high hill and a fault line-formed lake. In addition, the area has an exciting history, where archaeological finds show that there has been people around the area since the Stone Age. This in turn can have a pedagogical value. There are already a number of nature reserves on the peninsula, each with its own specific character. To complement these with the proposed area would mean an additional width in the versatile network of protected nature in the relatively small area that forms the peninsula. It would thus be of great value, not only for the inhabitants of Tyresö, but also for other locals of Stockholm, and fully in line with the government mandate that declares the importance of closeness to nature.

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  • 212. Ehrmann, Steffen
    et al.
    Liira, Jaan
    Gärtner, Stefanie
    Hansen, Karin
    Brunet, Jörg
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Deconchat, Marc
    Decocq, Guillaume
    De Frenne, Pieter
    De Smedt, Pallieter
    Diekmann, Martin
    Gallet-Moron, Emilie
    Kolb, Annette
    Lenoir, Jonathan
    Lindgren, Jessica
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Naaf, Tobias
    Paal, Taavi
    Valdés, Alicia
    Verheyen, Kris
    Wulf, Monika
    Scherer-Lorenzen, Michael
    Environmental drivers of Ixodes ricinus abundance in forest fragments of rural European landscapes2017In: BMC Ecology, ISSN 1472-6785, E-ISSN 1472-6785, Vol. 17, article id 31Article in journal (Refereed)
    Abstract [en]

    Background: The castor bean tick (Ixodes ricinus) transmits infectious diseases such as Lyme borreliosis, which constitutes an important ecosystem disservice. Despite many local studies, a comprehensive understanding of the key drivers of tick abundance at the continental scale is still lacking. We analyze a large set of environmental factors as potential drivers of I. ricinus abundance. Our multi-scale study was carried out in deciduous forest fragments dispersed within two contrasting rural landscapes of eight regions, along a macroclimatic gradient stretching from southern France to central Sweden and Estonia. We surveyed the abundance of I. ricinus, plant community composition, forest structure and soil properties and compiled data on landscape structure, macroclimate and habitat properties. We used linear mixed models to analyze patterns and derived the relative importance of the significant drivers. Results: Many drivers had, on their own, either a moderate or small explanatory value for the abundance of I. ricinus, but combined they explained a substantial part of variation. This emphasizes the complex ecology of I. ricinus and the relevance of environmental factors for tick abundance. Macroclimate only explained a small fraction of variation, while properties of macro- and microhabitat, which buffer macroclimate, had a considerable impact on tick abundance. The amount of forest and the composition of the surrounding rural landscape were additionally important drivers of tick abundance. Functional (dispersules) and structural (density of tree and shrub layers) properties of the habitat patch played an important role. Various diversity metrics had only a small relative importance. Ontogenetic tick stages showed pronounced differences in their response. The abundance of nymphs and adults is explained by the preceding stage with a positive relationship, indicating a cumulative effect of drivers. Conclusions: Our findings suggest that the ecosystem disservices of tick-borne diseases, via the abundance of ticks, strongly depends on habitat properties and thus on how humans manage ecosystems from the scale of the microhabitat to the landscape. This study stresses the need to further evaluate the interaction between climate change and ecosystem management on I. ricinus abundance.

  • 213.
    Ek, Sandra
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Kan dioxiner och tributyltenn ha kontaminerat Gäddviken, NV Nacka kommun?: En förstudie om förekomsten av organiska föroreningar från tidigare industriverksamhet i Stockholmsområdet2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Stockholm area has been an industrial society for a long time resulting in thousands of polluted areas. These areas are characterized by high concentrations of heavy metals and organic toxins. The Swedish environmental goals include a specific paragraph assigned for polluted areas stating that in the year of 2020 there should be no areas that affects the environment or the health of the population.

    Gäddviken, which is one of these polluted areas, is situated in Nacka municipality approximately 3.5 km southeast of Stockholm inner city. The area has an attractive locality for building a new city district as it is situated by the sea and close to the city. Because of the polluted grounds, however it has to be decontaminated. Gäddviken has earlier been host to a pitch mill, oil depots both above ground and within the rock, a superphosphate plant, a sulfuric acid plant as well as a coffee roastery.

    The purpose of this study was to give a picture of the situation regarding organic toxins by studying if there are presumptions for enhance concentrations of dioxins or tributyltin (TBT) and, if so, where higher concentrations in should be situated. These two organic toxins have not been analyzed in earlier samples. The study, which has been based on literature, has an aspect of physical geography and quaternary geology including studying of maps to describe the natural settings in the area and how it has changed over time. A dataset of earlier analysis has been analyzed and partly illustrated in ArcMaps. Statistical correlations of the samples have also been done.

    The result of the study is that none of the industrial activities have polluted Gäddviken with dioxins or TBT. Higher concentrations of TBT, however, should be expected in other places around Svindersviken due to the high boats activities. If new samples where to be collected to confirm the results of this thesis the following is recommended. Samples for dioxins would be collected near the superphosphates old laboratory based on the experiments made there. Samples for TBT would be collected along the shoreline where many ships have been situated and also been sunken. Samples could also be collected in the sediments between Gäddviken and Hästholmssund to determine whether TBT have spread from boat activities north of the study area. Finally, a sample could be collected in the center of Gäddviken where high concentrations of zinc, copper, lead and arsenic overlaps. This would confirm whether it is the superphosphate plant that is the cause for the concentration of these metals or if these have been spread from the surrounding boat activities.

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  • 214.
    Ekenberg, Madeleine
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Using a lumped conceptual hydrological model for five different catchments in Sweden2016Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Hydrological models offer powerful tools for understanding and predicting. In this thesis we havereviewed the advantages and disadvantages of physically based distributed hydrological models andconceptually lumped hydrological models. Based on that review, we went into depth and developed aMATLAB code to test if a simple conceptual lumped hydrological model, namely GR2M, wouldperform satisfactory for five different catchments in different parts of Sweden. The model had ratherunsatisfactory results and underestimated runoff systematically throughout all the five catchments.Additions to the model structure, such as a buffer allowing an approximation for snowmelt delay, wereintroduced with varying degrees of success. Based on analytical exploration of the model theory, it canbe seen that the instability of the model is mainly caused by one of the two free parameters used inGR2M, namely the maximum soil storage capacity. The optimization method used showed lowsensitivity to changes in this parameter while the calculated soil storage had strong dependence on thisparameter. Based on these results, it is fair to say that a simple lumped model likely does not have theability to represent the full range of hydrological conditions found along the gradient of Sweden.

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  • 215.
    Ekholm, Tor
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Går det att bevara befintlig grönska vid förtätning av staden?: En fallstudie om hur grönytor och naturvärden prioriteras på privat mark i Malmö2019Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The ongoing trend with urban infill often implicates a conflict with urban green areas, which becomes a problem when green areas in cities are declining and when biodiversity is threatened on a global scale. This case study investigates how green areas and existing biological values are prioritized in an area in Malmö where infill is taking place (Översiktsplan för del av Kirseberg). Specifically, planning process and dialogue, on detailed comprehensive planning level, between the municipality and the landowner is analysed and compared with the policy plan for the area. The methods used are semi-structured interviews combining qualitative and quantitative data.The results show that many of the planning policies regarding green areas are prioritized and considered. However, when it comes to preserving existing vegetation and biological values, these policy goals are prioritized lower than the other policies, which leads to postponed conservation measures. Arguments for planning green areas are about structural concerns and attractivity. Municipal planners are concerned about the low amount of green areas and they find that policies and the planning and building act for green areas give a poor support in the planning process.Vague policy goals for green areas make it difficult for planners to balance between the many policy goals they need to consider. Although the actors have common interests and two-sided compromises are done, profit and a high exploitation level are the priorities of the landowner,which leads to fewer green areas. Landownership therefore limits municipal influence to planfor public interests like green areas. Furthermore, the political focus on high exploitation is another reason for this. Insufficient and outdated policies and planning material are also concerns that affects the planning of green areas.Green areas and biological values are not prioritized enough on the detailed comprehensive planning level neither in the policies of the plan, in the planning process nor in other policies. To change this, both planning laws, policies and political will need to prioritize green areas higher. Many studies state that the planning and building act is insufficient for planning green areas that support ecosystem services on private properties. This seems to apply to this case study as well.

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    Går det att bevara befintlig grönska vid förtätning av staden? Ekholm, T., 2019
  • 216.
    Eklund, Carl
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Ståndortsfaktorer och vegetation: En problematiserande litteraturstudie2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A site is an area where a population of a specific plant species has its habitat, often the connotation is forestry. The prerequisites for this, the site indices (also site variables or stand variables), can be found in the characteristics of the ground (edaphic factors) as well as the climatic impact. These elements affect the growth and production, which is of interest in forestry and forest sciences. Upon this the plants interact with each other as well as with other organisms, i.e. fungi, bacteria and animals, and there is also an anthropogenic impact where factors such as livestock grazing, atmospheric deposition and forest production strongly affects the vegetation.

    By studying some of the more prominent theories on vegetation societies/sociologies and plant strategies, as well as different aspects of the site concept, the hypothesis was that a problematizing picture of site indices can be found and some confounding variables that can give erroneous interpretation of results.

    A number of major works in vegetation classification was gone through, supplemented by supporting literature. An article search was conducted to find journal articles, using combinations of specific search terms related to site indices. To narrow down the results and give a more regional touch to the thesis, the filter was set only to show results from Scandinavia and Finland. The articles were grouped into themes and handled theme-wise.

    Even though there are few principal factors controlling the vegetation there are a number of variables which locally can have a large impact, such as snow, genetic traits and symbiosis. These variables can be hard to measure, and a lot of things at a detailed level are poorly investigated. Land use modifies the edaphic properties long after the usage have changed or been discontinued. The amounts and cycles of nitrogen and carbon are recurrent uncertainties in the articles, where deposits of nitrogen from the atmosphere plays an important but uneven role and measurements can be hard to compare due to differences in weather and climate. Added to this, organisms in the ground have a major role in the plants’ nutrient uptake, but the effects can be hard to study. A concluding remark is that even though all aspects of a site cannot always be included more confounding variables could be taken in account and models should be able to be calibrated to different theories on vegetation societies/sociologies and plant strategies. Many factors normally not counted as site indices, i.e. snow depth, soil biota symbiosis, and land use, could be valuable to include in e.g. modelling. 

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  • 217. Elbakidze, Marine
    et al.
    Hahn, Thomas
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Dawson, Lucas
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Zimmermann, N. E.,
    Cudlín, P.
    Friberg, N.
    Genovesi, P.
    Guarino, R.
    Helm, A.
    Jonsson, B.
    Lengyel, S.
    Leroy, B.
    Luzzati, T.
    Milbau, A.
    Pérez-Ruzafa, A.
    Roche, P.
    Roy, H.
    Sabyrbekov, R.
    Vanbergen, A.
    Vandvik, Vigdis
    Direct and indirect drivers of change in biodiversity and nature’s contributions to people2018In: The IPBES regional assessment report on biodiversity and ecosystem services for Europe and Central Asia / [ed] M. Rounsevell, M. Fischer, A. Torre-Marin Rando, A. Mader, Bonn, Germany: Secretariat of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services , 2018, p. 385-568Chapter in book (Refereed)
  • 218.
    Elmhagen, Bodil
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Borgström, Sara
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Boyd, Emily
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. University of Reading, England.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Dalen, Love
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ermold, Matti
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hedlund, Johanna
    Stockholm University, Faculty of Science, Department of Zoology.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Jaramillo, Fernando
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Lagerholm, Vendela K.
    Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Sweden.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Moor, Helen
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Nykvist, Björn
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Stockholm University, Stockholm Environment Institute.
    Pasanen-Mortensen, Marianne
    Stockholm University, Faculty of Science, Department of Zoology.
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Prieto, Carmen
    Stockholm University, Faculty of Science, Department of Physical Geography.
    van der Velde, Ype
    Stockholm University, Faculty of Science, Department of Physical Geography. Wageningen University & Research Center, Netherlands.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Interacting effects of change in climate, human population, land use, and water use on biodiversity and ecosystem services2015In: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 20, no 1, article id UNSP 23Article in journal (Refereed)
    Abstract [en]

    Human population growth and resource use, mediated by changes in climate, land use, and water use, increasingly impact biodiversity and ecosystem services provision. However, impacts of these drivers on biodiversity and ecosystem services are rarely analyzed simultaneously and remain largely unknown. An emerging question is how science can improve the understanding of change in biodiversity and ecosystem service delivery and of potential feedback mechanisms of adaptive governance. We analyzed past and future change in drivers in south-central Sweden. We used the analysis to identify main research challenges and outline important research tasks. Since the 19th century, our study area has experienced substantial and interlinked changes; a 1.6 degrees C temperature increase, rapid population growth, urbanization, and massive changes in land use and water use. Considerable future changes are also projected until the mid-21st century. However, little is known about the impacts on biodiversity and ecosystem services so far, and this in turn hampers future projections of such effects. Therefore, we urge scientists to explore interdisciplinary approaches designed to investigate change in multiple drivers, underlying mechanisms, and interactions over time, including assessment and analysis of matching-scale data from several disciplines. Such a perspective is needed for science to contribute to adaptive governance by constantly improving the understanding of linked change complexities and their impacts.

  • 219. Emmanouilidis, Alexandros
    et al.
    Katrantsiotis, Christos
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Norström, Elin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Risberg, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Kylander, Malin
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Sheik, Taariq Ali
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Iliopoulos, George
    Avramidis, Pavlos
    Middle to late Holocene palaeoenvironmental study of Gialova Lagoon, SW Peloponnese, Greece2018In: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 476, p. 46-62Article in journal (Refereed)
    Abstract [en]

    The coastal areas of Eastern Mediterranean have long been the subject of research, due to their rapid geomorphological changes, but also because of their archaeological interest. Our study is focused on a shallow coastal lagoon of Peloponnese, Gialova Lagoon, which for several years has attracted the scientific interest of archaeologists, geomorphologists as well as sedimentologists. Gialova lagoon is located near the ancient city of Pylos, the kingdom of king Nestor during the Mycenaean period (1600-1100 BC). The objectives of this study are: (a) to reconstruct the middle to late Holocene depositional environments of the lagoon and (b) to correlate our data to already existing publications, in order to shed new light on the Holocene evolution of the lagoon and the associated coastal palaeoenvironmental changes. An 8m deep vibracore was drilled and a multi proxy analysis was carried out on the sediment sequence, including sedimentological (grain size analysis and moment measures, total organic carbon - TOC, total nitrogen e TN and total phosphorus - TP), high resolution geochemical (XRF-scanning) and palaeontological (micro-and macro faunal) analysis. The chronological framework is based on five C-14 datings forming the basis for an age depth model, calculated using the OxCal software. The radiocarbon dates from previous studies (6 cores, similar to 20 dates) were also taken into account. The data synthesis and interpretation provided robust and coherent indications regarding the palaeoenvironment, shoreline changes and the rate of geomorphological changes of the coastal area of Gialova Lagoon, as well as useful information about the palaeonvironmental and palaeoclimatic conditions that prevailed during the Mycenaean period. The interpretation, reveal a transition from a shallow marine environment (65005800 yr B.P.) to a brackish/lagoonal (5800-3300 yr B.P.), followed by a shift towards a freshwater/marsh environment (3300 yr B.P. to present).

  • 220.
    Enarsson, Marie
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Minimera matsvinn: En studie om livsmedelsbutikers och kunders arbete och medvetenhet kring matsvinn2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden is a country that is good at taking care of the waste that arises. The amount of food waste is increasing continuously and if nothing happens soon there will be twice as much in 20 years. If sustainable development is to be achieved, the amount of thrown waste must be reduced. Naturvårdsverket (environmental protection agency) has suggested by commission of the government that food waste will decrease by 20 percent by 2020, unlike in 2010. Sweden throws 1.9 million tons of food waste every year. A large part of this is food that actually could have been eaten, if handled differently.

    Food loss is a global issue, which occurs in the whole world but also in the entire food chain. Various studies show that large quantities of food are discarded unnecessarily every day. It ́s different to reduce food loss in different steps in the food chain, depending on the food loss receiving in the various steps. The longer the products have been in the chain, the more energy and resources have been wasted.

    This study aims to find out how grocery stores handle food loss but also customers awareness around the topic. Semi-structured interviews with the responsible for the studied section, and "at-town interviews” with the costumers, have been conducted in three different grocery stores to obtain an image of how food loss is managed both at home and in stores. The results showed that food stores are conscious about the subject and have preventive measures in the routine to keep down losses, but they can always be better. At the same time stores will sell as much merchandise as possible which creating a complex world. Customers in the studied stores shows that most people thinking of food loss at home but that they don’t want to or can be interested for the grocery stores wastage. The study also shows that there is a difference between gender and ages, which is a rather interesting result. 

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  • 221. Engström, Rebecka
    et al.
    Howells, Mark
    Mörtberg, Ulla
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Multi-functionality of nature-based and other urban sustainability solutions: New York City study2018In: Land Degradation and Development, ISSN 1085-3278, E-ISSN 1099-145X, Vol. 29, no 10, p. 3653-3662Article in journal (Refereed)
    Abstract [en]

    In an increasingly urban world, developing sustainable cities is crucial for global sustainability. Urban nature-based solutions (NBS), such as green infrastructure, are often promoted for their potential to provide several urban services. These include stormwater mitigation, improving energy efficiency of buildings, and carbon emissions mitigation, but few studies have compared the multifunctionality of NBS to conventional urban solutions providing similar services. Fewer yet have acknowledged the indirect resource (specifically climate, land, energy, water [CLEW] nexus) impacts that these solutions may have. This paper analyzes these aspects, employing a simple CLEW nexus accounting framework, and attempts a consistent comparison across different resource systems. The comparison includes direct and indirect impacts of a set of stylizedand diversesolutions, each with different primary objectives: green roofs, representing a multifunctional urban NBS; permeable pavements targeting mitigation of stormwater flows; window retrofits targeting energy efficiency; and rooftop PV installations targeting CO2 emissions mitigation. The results highlight both the direct and total (CLEW nexus) impacts of green roofs on stormwater retention, energy use, and CO2 emissions. However, also for the studied conventional solutions with primarily a single direct function, CLEW nexus impacts spread across all measured dimensions (energy, water, and CO2) to varying degrees. Although the numerical results are indicative and uncertainty needs to be further assessed, we suggest that the development of this type of multifunctional, multisystem assessment can assist urban sustainability planning, with comprehensive and consistent comparison of diverse (NBS and conventional) solutions.

  • 222. Ericsdotter Engström, Rebecka
    et al.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Howells, Mark
    Ramaswamy, Vivek
    Rogner, Holger
    Bazilian, Morgan
    Cross-Scale Water and Land Impacts of Local Climate and Energy PolicyA Local Swedish Analysis of Selected SDG Interactions2019In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 11, no 7, article id 1847Article in journal (Refereed)
    Abstract [en]

    This paper analyses how local energy and climate actions can affect the use of water and land resources locally, nationally and globally. Each of these resource systems is linked to different Sustainable Development Goals (SDGs); we also explore related SDG interactions. A municipality in Sweden with the ambition of phasing out fossil fuels by year 2030 is used as illustrative case example. The local energy system is modelled in detail and indirect water and land requirements are quantified for three stylised decarbonisation scenarios of pathways to meeting climate and energy requirements (related to SDG13 and SDG7, respectively). Total local, national and global implications are addressed for the use of water and land resources, which relate to SDG6 for water, and SDG2 and SDG15 for land use. We find that the magnitude and location of water and land impacts are largely pathway-dependent. Some scenarios of low carbon energy may impede progress on SDG15, while others may compromise SDG6. Data for the studied resource uses are incoherently reported and have important gaps. As a consequence, the study results are indicative and subject to uncertainty. Still, they highlight the need to recognise that resource use changes targeting one SDG in one locality have local and non-local impacts that may compromise progress other SDGs locally and/or elsewhere in the world.

  • 223.
    Ericsdotter Engström, Rebecka
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. KTH Royal Institute of Technology, Sweden.
    Howells, Mark
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Bhatt, Vatsal
    Bazilian, Morgan
    Rogner, Hans-Holger
    Connecting the resource nexus to basic urban service provision – with a focus on water-energy interactions in New York City2017In: Sustainable cities and society, ISSN 2210-6707, Vol. 31, p. 83-94Article in journal (Refereed)
    Abstract [en]

    Urban water and energy systems are crucial for sustainably meeting basic service demands in cities. This paper proposes and applies a technology-independent “reference resource-to-service system” framework for concurrent evaluation of urban water and energy system interventions and their ‘nexus’ or ‘interlinkages’. In a concrete application, data that approximate New York City conditions are used to evaluate a limited set of interventions in the residential sector, spanning from low-flow toilet shifts to extensive green roof installations. Results indicate that interventions motivated primarily by water management goals can considerably reduce energy use and contribute to mitigation of greenhouse gas emissions. Similarly, energy efficiency interventions can considerably reduce water use in addition to lowering emissions. However, interventions yielding the greatest reductions in energy use and emissions are not necessarily the most water conserving ones, and vice versa. Useful further research, expanding the present analysis should consider a broader set of resource interactions, towards a full climate, land, energy and water (CLEW) nexus approach. Overall, assessing the impacts, trade-offs and co-benefits from interventions in one urban resource system on others also holds promise as support for increased resource efficiency through integrated decision making.

  • 224. Eriksson, Hampus
    et al.
    de la Torre-Castro, Maricela
    Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Purcell, Steven W.
    Olsson, Per
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Lessons for resource conservation from two contrasting small-scale fisheries2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, no 3, p. 204-213Article in journal (Refereed)
    Abstract [en]

    Small-scale fisheries present challenges to management due to fishers' dependency on resources and the adaptability of management systems. We compared social-ecological processes in the sea cucumber fisheries of Zanzibar and Mayotte, Western Indian Ocean, to better understand the reasons for resource conservation or collapse. Commercial value of wild stocks was at least 30 times higher in Mayotte than in Zanzibar owing to lower fishing pressure. Zanzibar fishers were financially reliant on the fishery and increased fishing effort as stocks declined. This behavioral response occurred without adaptive management and reinforced an unsustainable fishery. In contrast, resource managers in Mayotte adapted to changing fishing effort and stock abundance by implementing a precautionary fishery closure before crossing critical thresholds. Fishery closure may be a necessary measure in small-scale fisheries to preserve vulnerable resources until reliable management systems are devised. Our comparison highlighted four poignant lessons for managing small-scale fisheries: (1) diagnose the fishery regularly, (2) enable an adaptive management system, (3) constrain exploitation within ecological limits, and (4) share management responsibility.

  • 225.
    Eriksson, Johan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Naturen framför allt?: En studie om fritidsboendes påverkan och relation till landskapet i Stockholms skärgård2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    There are over 30 000 second homes, or holiday houses, in the archipelago outside Stockholm and they have become an integrated part of the landscape. Previous research has shown how the holiday houses affect the surrounding landscape i.e. through causing water shortage, loss of biodiversity and pollution. Also some positive aspects on biodiversity have been recorded due to holiday houses in the archipelago.

    This paper investigates the second home owners’ views towards the landscape in the Stockholm archipelago with the aim of highlighting underlying causes of the owner’s impacts on their surroundings. Through qualitative interviews it can be concluded that the participating respondents experience a strong connection to what they view as nature, and that the natural landscape is important for their comfort and wellbeing. Two different ways of using the surrounding landscape were identified; one more aesthetically and the other one more focused on utilization. The second home owners in the study seem to have a limited knowledge of their own impact, while at the same time possessing a wish to protect the nature. This concern for nature seems to spring from a view of the landscape as a resource that raises the value of the holiday house.

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  • 226.
    Eriksson, Marcus
    Stockholm University, Faculty of Science, Department of Physical Geography.
    A Risk Assessment Analysis: The risk of saltwater intrusion into freshwater wells and the effects of a futuresea level rise on the Baltic Sea island of Öland2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Freshwater is essential for a functional society and the human well-being. However, it should not be taken for granted. Freshwater aquifers in coastal are subject to current and future risk of becoming saltwater contaminated – reaching a tipping point. Freshwater security on islands is vulnerable. The aim of this empirical study is to identify the effects of a 2-meter sea level rise and the current risk of well salinization at the Baltic Sea island of Öland, Sweden. A Geographical Information System (GIS) was used to conduct a quantitative risk assessment analysis. Natural and physical parameters affect the risk of intrusion into wells including hydrology, geomorphology, and climatology. Anthropogenic causes and climate change also add to the risk of salinization. However, they are not included in the quantitative study. The spatial distribution of the current risk is mapped in this study and can be used as a tool to identify wells at risk. Moreover, a future sea level rise has been visualized and show that 3% of all wells on the island will get directly inundated along with 5% of the total land area. Important land such as urban areas, nature reserves, and animal protection areas will get inundated including the loss of environmental and socio-economic values. A precautionary approach needs to be implemented in future planning since many wells are already at risk of salinization. The complexity of the problem is vast, and this study aims to fill the gaps in literature and previous research in a more multi-criterion way. Nevertheless, the political discussion urgently needs to address the topic and a mitigation and adaptation strategy must be on the agenda.

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  • 227.
    Eriksson, Marcus
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Ebert, Karin
    Stockholm University, Faculty of Science, Department of Physical Geography. Södertörn University, Sweden; .
    Jarsjö, Jerker
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Well Salinization Risk and Effects of Baltic Sea Level Rise on the Groundwater-Dependent Island of Oland, Sweden2018In: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 10, no 2, article id 141Article in journal (Refereed)
    Abstract [en]

    In this study, we estimate baseline conditions in terms of the current risk of well salinization on the Baltic Sea island of Oland, Sweden, and assess the effects of future sea level rise on the land area, infrastructure and cultural values. We use a multicriterion geographical information systems (GIS) approach. Geomorphological and physical parameters affect the risk of saltwater intrusion into freshwater aquifers, including their hydrology, geomorphology, and climatology; the spatial distribution of the current risk of salinization is mapped in this study. In the event of a future 2 m sea level rise, a total land area of 67 km(2) will be inundated on Oland, corresponding to approximately 5% of the island's land surface. Inundation includes urban areas, nature reserves, and animal protection areas, implying the loss of environmental and socioeconomic values. A future 2 m sea level rise will also cause direct inundation of 3% of all wells on the island. Currently, 17.5% of all wells are at a high risk of becoming saltwater contaminated. More generally, the present results add evidence showing a relatively high vulnerability of major Baltic Sea islands and their infrastructure to future sea level rise. The approach used here and related results, including salinization risk maps, may prove useful for decision-makers in the planning of infrastructure. Drilling of new wells could for instance preferably be done in areas with identified lower risk-index values, which would facilitate an overall higher freshwater withdrawal in the interest of the entire island.

  • 228.
    Eriksson, Pia
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Meteorological differences between Rabots glaciär and Storglaciären and its impact on ablation2014Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    In the Kebnekaise Massif, Northern Sweden, the west facing glacier, Rabots glaciär, is loosing volume at a significantly higher rate than east facing, Storglaciären. By analyzing data from automatic weather stations situated on the ablation area on the glaciers we investigated the effect of meteorological differences on ablation. There was a difference in micro-climate between Rabots glaciär and Storglaciären. Generally Storglaciären had slightly warmer and drier air, had less or a thinner cloud layer but more precipitation. On both glaciers a glacier wind is dominant but high wind velocities were common especially on Storglaciären indicating a larger influence from the synoptic system. There was a good correlation for temperature and vapor pressure between the glaciers that indicate that both glaciers are strongly affected by the synoptic system. The meteorological parameters have similar effect on the ablation on the glaciers. Temperature, vapor pressure and the turbulent heat fluxes are the only meteorological parameters that suggest a linear affect on ablation. Net shortwave radiation contribute with the greatest amount of energy for ablation but decreased in relative importance as the temperature increased. Shortwave radiation, sensible and latent heat contributed with a total 184Wm-2 on Rabots glaciär and 222Wm-2 on Storglaciären. Rabots glaciär seem to have a significantly greater relative importance of the turbulent heat fluxes than Storglaciären. Although the differences in micro-climate were not great, using the ablation for Storglaciären to estimate ablation on Rabots glaciär would over estimate the ablation with 0.5m w.e..

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  • 229.
    Eriksson, Sandra
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Ekosystemtjänster vid dagvattenhantering: En jämförelse av öppna dagvattenlösningar i urban miljö2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Stormwater is a valuable resource but with climate change and changed precipitation it may cause problems in urban environments. With increasing urbanisation more land becomes exploited which can not naturally manage stormwater and solve the problems. The purpose with this study is to demonstrate the importance of green infrastructure to manage stormwater. The stormwater systems this study includes are different forms of green infrastructure; green areas, swales, ponds and wetlands. They manage stormwater, have different pros and cons and are various good at meeting the selected ecosystem services; balancing stormwater peaks, sewage treatment and groundwater recharge. Wetlands stand out as the best at meeting the ecosystem services balancing stormwater peaks and sewage treatment. Green areas are best with groundwater recharge. These areas can naturally manage stormwater and that is a strong reason to preserve and/or restore them during exploitation.

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  • 230.
    Erlandsson Lampa, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Lund University, Sweden.
    Belyazid, Salim
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Zanchi, Giuliana
    Akselsson, Cecilia
    Effects of whole-tree harvesting on soil, soil water and tree growth - A dynamic modelling exercise in four long-term experiments2019In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 414, article id 108832Article in journal (Refereed)
    Abstract [en]

    Whole tree harvesting (WTH) following final felling of productive forests is increasingly promoted as a method to extract biomass for energy purposes. Despite its importance, there is a limited number of experimental studies investigating the impacts of WTH on forest ecosystem sustainability. Modelling studies have previously been carried out to complement and explain empirical observations from four long-term WTH experiments in Sweden. The literature shows a significant discrepancy between these studies, and open questions remain as to the fate of the base cations that are not removed in the absence of WTH. This study uses the integrated ecosystem model ForSAFE, which simulate a forest ecosystem's biogeochemical processes and the feedbacks between these processes, to trace the fate of base cations for the said four long-term WTH experiments. The study shows that the model generally captures the observed effects of WTH on the stocks of base cations in the biomass and in the soil. The modelled results were also used to map how the base cations removed through WTH would otherwise (if left at the site) have been distributed in the ecosystem. The results indicate that the soil organic pool may be more important to the long-term base cation balance than the exchangeable pool, and should receive more attention in future research.

  • 231.
    Erlandsson, Rasmus
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Stoessel, Marianne
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Skånes, Helle
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Wennbom, Marika
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    An innovative use of orthophotos - possibilities to assess plant productivity from colour infrared aerial orthophotos2019In: Remote Sensing in Ecology and Conservation, ISSN 0034-429X, E-ISSN 2056-3485Article in journal (Refereed)
    Abstract [en]

    Studies of ecological processes should focus on a relevant spatial scale, as crude spatial resolution will fail to detect small scale variation which is of potentially critical importance. Remote sensing methods based on multispectral satellite images are used to assess primary productivity and aerial photos to map vegetation structure. Both methods are based on the principle that photosynthetically active vegetation has a characteristic spectral signature. Yet they are applied differently due to technical differences. Satellite images are suitable for calculations of vegetation indices, for example Normalized Difference Vegetation Index (NDVI). Colour infrared aerial photography was developed for visual interpretation and never regarded for calculation of indices since the spectrum recorded and post processing differ from satellite images. With digital cameras and improved techniques for generating colour infrared orthophotos, the implications of these differences are uncertain and should be explored. We tested if plant productivity can be assessed using colour infrared aerial orthophotos (0.5 m resolution) by applying the standard NDVI equation. With 112 vegetation samples as ground truth, we evaluated an index that we denote rel‐NDVIortho in two areas of the Fennoscandian mountain tundra. We compared the results with conventional SPOT5 satellite‐based NDVI (10 m resolution). rel‐NDVIortho was related to plant productivity (Northern area: P = <0.001, R2 = 0.73; Southern area: P = <0.001, R2 = 0.39), performed similar to SPOT5 satellite NDVI (Northern area: P = <0.001, R2 = 0.76; Southern area: P = <0.001, R2 = 0.40) and the two methods were highly correlated (cor = 0.95 and cor = 0.84). Despite different plant composition, the results were consistent between areas. Our results suggest that vegetation indices based on colour infrared aerial orthophotos can be a valuable tool in the remote sensing toolbox, offering a high‐spatial resolution proxy for plant productivity with less signal degradation due to atmospheric interference and clouds, compared to satellite images. Further research should aim to investigate if the method is applicable to other ecosystems.

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  • 232. Esper, Jan
    et al.
    Buntgen, Ulf
    Denzer, Sebastian
    Krusic, Paul J.
    Stockholm University, Faculty of Science, Department of Physical Geography. Navarino Environmental Observatory, Greece .
    Luterbacher, Juerg
    Schaefer, Regina
    Schreg, Rainer
    Werner, Johannes
    Environmental drivers of historical grain price variations in Europe2017In: Climate Research (CR), ISSN 0936-577X, E-ISSN 1616-1572, Vol. 72, no 1, p. 39-52Article in journal (Refereed)
    Abstract [en]

    Grain price (GP) volatility has been a central constituent of European commerce, with fluctuations in barley, rye and wheat prices having been carefully documented over centuries. However, a thorough understanding of the climatic and environmental drivers of long-term GP variations is still lacking. Here, we present a network of historical GP records from 19 cities in central and southern Europe for the 14th to 18th centuries. Spatial variability at interannual to multidecadal scales within this network was compared with reconstructed warm-season temperatures and hydro climatic conditions. We show that European GPs are tightly coupled with historical famines and that food shortages coincide with regional summer drought anomalies. Direct correlations between historical GP and reconstructed drought indices are low, hardly exceeding r = -0.2. Yet if the analysis is focused on extreme events, the climatic controls on high-frequency price variations become obvious: GPs were exceptionally high during dry periods and exceptionally low during wet periods. In addition, we find that GP variations were affected by temperature fluctuations at multidecadal timescales. The influence of summer temperatures is particularly strong over the 1650-1750 period, subsequent to the Thirty Years' War, reaching r = -0.40 at the European scale. This observation is supported by the lack of correlation among regional GP clusters during the period of hostilities and increased inter-regional correlation thereafter. These results demonstrate that the exchange of goods and spatial coherence of GP data in Europe were controlled both by socio-political and environmental factors, with environmental factors being more influential during peacetime.

  • 233. Esper, Jan
    et al.
    Holzkämper, Steffen
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Büntgen, Ulf
    Schöne, Bernd
    Keppler, Frank
    Hartl, Claudia
    St. George, Scott
    Riechelmann, Dana F. C.
    Treydte, Kerstin
    Site-specific climatic signals in stable isotope records from Swedish pine forests2018In: Trees, ISSN 0931-1890, E-ISSN 1432-2285, Vol. 32, no 3, p. 855-869Article in journal (Refereed)
    Abstract [en]

    Pinus sylvestris tree-ring delta C-13 and delta O-18 records from locally moist sites in central and northern Sweden contain consistently stronger climate signals than their dry site counterparts. We produced twentieth century stable isotope data from Pinus sylvestris trees near lakeshores and inland sites in northern Sweden (near Kiruna) and central Sweden (near Stockholm) to evaluate the influence of changing microsite conditions on the climate sensitivity of tree-ring delta C-13 and delta O-18. The data reveal a latitudinal trend towards lower C and O isotope values near the Arctic tree line (-0.8 parts per thousand for delta C-13 and - 2.4 parts per thousand for delta O-18 relative to central Sweden) reflecting widely recognized atmospheric changes. At the microsite scale, delta C-13 decreases from the dry inland to the moist lakeshore sites (- 0.7 parts per thousand in Kiruna and - 1.2 parts per thousand in Stockholm), evidence of the importance of groundwater access to this proxy. While all isotope records from northern and central Sweden correlate significantly against temperature, precipitation, cloud cover and/or drought data, climate signals in the records from moist microsites are consistently stronger, which emphasizes the importance of site selection when producing stable isotope chronologies. Overall strongest correlations are found with summer temperature, except for delta O-18 from Stockholm correlating best with instrumental drought indices. These findings are complemented by significant positive correlations with temperature-sensitive ring width data in Kiruna, and inverse (or absent) correlations with precipitation-sensitive ring width data in Stockholm. A conclusive differentiation between leading and co-varying forcings is challenging based on only the calibration against often defective instrumental climate data, and would require an improved understanding of the physiological processes that control isotope fractionation at varying microsites and joined application of forward modelling.

  • 234. Esper, Jan
    et al.
    Klippel, Lara
    Krusic, Paul J.
    Stockholm University, Faculty of Science, Department of Physical Geography. University of Cambridge, UK; Navarino Environmental Observatory, Greece.
    Konter, Oliver
    Raible, Christoph C.
    Xoplaki, Elena
    Luterbacher, Jürg
    Büntgen, Ulf
    Eastern Mediterranean summer temperatures since 730 CE from Mt. Smolikas tree-ring densities2020In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 54, no 3-4, p. 1367-1382Article in journal (Refereed)
    Abstract [en]

    The Mediterranean has been identified as particularly vulnerable to climate change, yet a high-resolution temperature reconstruction extending back into the Medieval Warm Period is still lacking. Here we present such a record from a high-elevation site on Mt. Smolikas in northern Greece, where some of Europe's oldest trees provide evidence of warm season temperature variability back to 730 CE. The reconstruction is derived from 192 annually resolved, latewood density series from ancient living and relict Pinus heldreichii trees calibrating at r(1911-2015) = 0.73 against regional July-September (JAS) temperatures. Although the recent 1985-2014 period was the warmest 30-year interval (JAS Twrt.1961-1990 = + 0.71 degrees C) since the eleventh century, temperatures during the ninth to tenth centuries were even warmer, including the warmest reconstructed 30-year period from 876-905 (+ 0.78 degrees C). These differences between warm periods are statistically insignificant though. Several distinct cold episodes punctuate the Little Ice Age, albeit the coldest 30-year period is centered during high medieval times from 997-1026 (- 1.63 degrees C). Comparison with reconstructions from the Alps and Scandinavia shows that a similar cold episode occurred in central Europe but was absent at northern latitudes. The reconstructions also reveal different millennial-scale temperature trends (NEur = - 0.73 degrees C/1000 years, CEur = - 0.13 degrees C, SEur = + 0.23 degrees C) potentially triggered by latitudinal changes in summer insolation due to orbital forcing. These features, the opposing millennial-scale temperature trends and the medieval multi-decadal cooling recorded in Central Europe and the Mediterranean, are not well captured in state-of-the-art climate model simulations.

  • 235. Esper, Jan
    et al.
    Krusic, Paul J.
    Stockholm University, Faculty of Science, Department of Physical Geography. Navarino Environmental Observatory, Greece.
    Charpentier Ljungqvist, Fredrik
    Stockholm University, Faculty of Humanities, Department of History.
    Luterbacher, Jürg
    Carrer, Marco
    Cook, Ed
    Davi, Nicole K.
    Hartl-Meier, Claudia
    Kirdyanov, Alexander
    Konter, Oliver
    Myglan, Vladimir
    Timonen, Mauri
    Treydte, Kerstin
    Trouet, Valerie
    Villalba, Ricardo
    Yang, Bao
    Büntgen, Ulf
    Ranking of tree-ring based temperature reconstructions of the past millennium2016In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 145, p. 134-151Article in journal (Refereed)
    Abstract [en]

    Tree-ring chronologies are widely used to reconstruct high-to low-frequency variations in growing season temperatures over centuries to millennia. The relevance of these timeseries in large-scale climate reconstructions is often determined by the strength of their correlation against instrumental temperature data. However, this single criterion ignores several important quantitative and qualitative characteristics of tree-ring chronologies. Those characteristics are (i) data homogeneity, (ii) sample replication, (iii) growth coherence, (iv) chronology development, and (v) climate signal including the correlation with instrumental data. Based on these 5 characteristics, a reconstruction-scoring scheme is proposed and applied to 39 published, millennial-length temperature reconstructions from Asia, Europe, North America, and the Southern Hemisphere. Results reveal no reconstruction scores highest in every category and each has their own strengths and weaknesses. Reconstructions that perform better overall include N-Scan and Finland from Europe, E-Canada from North America, Yamal and Dzhelo from Asia. Reconstructions performing less well include W-Himalaya and Karakorum from Asia, Tatra and S-Finland from Europe, and Great Basin from North America. By providing a comprehensive set of criteria to evaluate tree-ring chronologies we hope to improve the development of large-scale temperature reconstructions spanning the past millennium. All reconstructions and their corresponding scores are provided at www.blogs.uni-mainz.de/fb09climatology.

  • 236. Esper, Jan
    et al.
    Riechelmann, Dana F. C.
    Holzkämper, Steffen
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Circumferential and Longitudinal delta C-13 Variability in a Larix decidua Trunk from the Swiss Alps2020In: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 11, no 1, article id 117Article in journal (Refereed)
    Abstract [en]

    Tree-ring stable isotopes are insightful proxies providing information on pre-instrumental climate fluctuations, yet the variability of these data within a tree trunk has not been fully explored. Here, we analyze longitudinal and circumferential changes in tree-ring delta C-13 values from 1991-2010, considering seven height levels from 1 to 13 m above ground and six sampling directions (radii) separated by 60 degrees around the stem. The disk samples were taken from a 360-year old European larch (Larix decidua Mill.) that grew at 1675 m above sea level in the Simplon Valley, Switzerland. Results show that the circumferential delta C-13 variability, defined as the difference between the minimum and maximum isotope values within a single ring at a certain height, ranges from 0.5 to 2.8 parts per thousand. These differences appear substantial as they match the range of year-to-year variations retained in long tree-ring delta C-13 time series used for climate reconstruction. The assessment of longitudinal variability demonstrated a systematic change of similar to 0.1 parts per thousand m(-1) towards isotopically heavier (less negative) delta C-13 values with increasing tree height, likely reflecting a vertical gradient towards isotopically heavier needle tissue due to changing microclimatic conditions and CO2 stratification within the canopy. Calibration against regional climate data indicates no substantial signal changes in delta C-13 values within the trunk. We conclude that the longitudinal isotope gradient adds uncertainty to long delta C-13 chronologies derived from subfossil material of unknown (and changing) sampling heights. The large circumferential variability recorded in the sub-alpine larch suggests that more than two cores are needed to analyze absolute delta C-13 values representative for each tree.

  • 237. Everett, A.
    et al.
    Murray, T.
    Selmes, N.
    Rutt, I. C.
    Luckman, A.
    James, T. D.
    Clason, Caroline
    Stockholm University, Faculty of Science, Department of Physical Geography. University of Plymouth, UK.
    O'Leary, M.
    Karunarathna, H.
    Moloney, V.
    Reeve, D. E.
    Annual down-glacier drainage of lakes and water-filled crevasses at Helheim Glacier, southeast Greenland2016In: Journal of Geophysical Research - Earth Surface, ISSN 2169-9003, E-ISSN 2169-9011, Vol. 121, no 10, p. 1819-1833Article in journal (Refereed)
    Abstract [en]

    Supraglacial lake drainage events are common on the Greenland ice sheet. Observations on the west coast typically show an up-glacier progression of drainage as the annual melt extent spreads inland. We use a suite of remote sensing and modeling techniques in order to study a series of lakes and water-filled crevasses within 20 km of the terminus of Helheim Glacier, southeast Greenland. Automatic classification of surface water areas shows a down-glacier progression of drainage, which occurs in the majority of years between 2007 and 2014. We demonstrate that a linear elastic fracture mechanics model can reliably predict the drainage of the uppermost supraglacial lake in the system but cannot explain the pattern of filling and draining observed in areas of surface water downstream. We propose that the water levels in crevasses downstream of the supraglacial lake can be explained by a transient high-pressure wave passing through the subglacial system following the lake drainage. We support this hypothesis with analysis of the subglacial hydrological conditions, which can explain both the position and interannual variation in filling order of these crevasses. Similar behavior has been observed in association with jokulhaups, surging glaciers, and Antarctic subglacial lakes but has not previously been observed on major outlets of the Greenland ice sheet. Our results suggest that the behavior of near-terminus surface water may differ considerably from that of inland supraglacial lakes, with the potential for basal water pressures to influence the presence of surface water in crevasses close to the terminus of tidewater glaciers.

  • 238.
    Falk, Simon
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Åre kommun och klimatförändringar: En studie kring hotet mot Åre kommuns vinterturism och dess anpassning till framtida klimatförändringar2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today’s climate research shows that the climate may increase its temperature. One sector that is being threatened by global warming is the winter tourism of the Swedish municipality Åre. Tourism is an important economical source of income in Åre and is now threatened by a shortened winter season. The aim of this study is to investigate future climate scenarios and to assess how prepared Åre is for a changing climate and if the decision makers in the municipality are working on adapting to these future changes.

    This study contains a literary study where scientific reports and articles about similar cases to Åre are being analysed. This part of the study gives an insight in how other ski resorts have adapted to climate change. Interviews with people working within Åre municipality have been conducted in order to find out how they adapt to the changes in the climate and how their awareness on future climate changes are. An interview with a meteorologist/climatologist on the Swedish institute of Meteorology and Hydrology (SMHI) has also been conducted to try and understand the reliability of the climate change scenarios.

    Some of the climate scenarios studied in this study and that have formed the basis of the report have been the once from the UNs Intergovernmental panel on climate change (IPCC). These scenarios give a perception on the potential climate of northern Europe from 2071 to 2100. The scenarios from the UN show that the average winter temperatures around Åre will increase gradually during this time interval. The precipitation is also expected to increase which could lead to more snow in the area. In a short term Åre may favour the climate changes while ski resorts in the Alps and southern Sweden may be affected more by climate changes. Åre is, unlike many other ski resorts, working hard to adapt the climate changes by for instance focusing more and more on the summer tourism. They are also making changes in the transportation services where they try to use so-called “green power”. Åre seems to be able to maintain their winter tourism for many years to come and will probably become a famous place for summer tourism as well. 

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  • 239. Farahat, Emad
    et al.
    Zhang, Peng
    Gunnarson, Björn E.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Fuentes, Mauricio
    Stridbeck, Petter
    Linderholm, Hans W.
    Are standing dead trees (snags) suitable as climate proxies? A case study from the central Scandinavian Mountains2018In: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 33, no 2, p. 114-124Article in journal (Refereed)
    Abstract [en]

    Standing dead trees (snags) play important roles in forest ecology by storing carbon as well as providing habitats for many species. Moreover, snags preserved for hundreds of years can provide useful data to extend tree-ring chronologies used for climatological and ecological studies beyond the lifespans of living trees. Here we examined the growth patterns of Scots pine snags from the central Scandinavian Mountains, in relation to still living trees. Using changes point analyses, we showed that a majority (74%) of the snags displayed significant negative growth changes prior (on average 17 years) to death. Change points around the same years were also seen in living trees, but they recovered their growth. The average growth reduction of snags showing negative growth changes before death was 46%. In most cases the final growth change points coincided with very cold summers, or to a lesser degree to period of cool summers. It was suggested that pines ending up as snags were less resilient than the trees which continued living, and thus not able to recover after cold summer events. Since the snag growth reductions prior to death were partly unrelated to climate, care should be taken when using such data in dendroclimatological studies.

  • 240.
    Farineau, Anne
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Diamonds in the Rough: Remote predictive mapping using multispectral satellite imagery for kimberlite exploration on northeast Banks Island, NT2015Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    This study demonstrates the use and limitations of Remote Predictive Mapping (RPM) as an aid to kimberlite exploration on northeast Banks Island, Northwest Territories, Canada. It focuses on the effectiveness of ASTER and Landsat 8 optical multi-spectral satellite imagery for discerning the spectral properties of different bedrock and surficial materials that outcrop or blanket the regional terrain. Statistical algorithms and digital image enhancement techniques were used to highlight patterns and anomalies within each scene in order to determine the range of materials and specific deposits (e.g., till, glaciofluvial) that could be the source of recovered kimberlite indicator minerals (KIMs) from stream sediment samples. Field inspection and sampling were in part guided by these patterns and anomalies. During the course of fieldwork, numerous outliers of the Pliocene Beaufort Formation fluvial sand and gravel deposits were discovered on upland surfaces in northeastern Banks Island. These outcrops sit well beyond (east) of any previous mapped Beaufort Fm. extents, and it is hypothesized that as they exist within catchments where Industry has recovered KIMs, they could be a source of bedrock-inherited KIMs. Field observations and spectral sampling using a portable spectroradiometer were integrated with ASTER and Landsat data to predict the spatial extents of Beaufort Fm. deposits. Using test and field-validated Beaufort Fm. sites, Spectral Angle Mapper (SAM) whole pixel spectral target detection was compared with Matched Filtering (MF), Mixture-Tuned Matched Filtering (MTMF) sub-pixel spectral target detection methods and Parallelepiped classification for ASTER scenes 1228 and 0686.  Each method was also performed on ASTER scene 0541 to assess the potential for Quaternary sediment discrimination, using pixel ROIs from a field-validated glaciolacustrine deposit. The sub-pixel sensitivity of the MF/MTMF methods was determined to have the best potential for the discrimination of surficial materials on NE Banks Island.  MF/MTMF also had the best results for discriminating Beaufort Fm. in scene 1228, but Parallelepiped classification was the most effective prediction method for scene 0686. These inconsistent results indicate spectral variability between Beaufort Fm. sites, a consideration for any further study in the region.  

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  • 241. Fatichi, Simone
    et al.
    Manzoni, Stefano
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Or, Dani
    Paschalis, Athanasios
    A Mechanistic Model of Microbially Mediated Soil Biogeochemical Processes: A Reality Check2019In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 33, no 6, p. 620-648Article in journal (Refereed)
    Abstract [en]

    Present gaps in the representation of key soil biogeochemical processes such as the partitioning of soil organic carbon among functional components, microbial biomass and diversity, and the coupling of carbon and nutrient cycles present a challenge to improving the reliability of projected soil carbon dynamics. We introduce a new soil biogeochemistry module linked with a well-tested terrestrial biosphere model T&C. The module explicitly distinguishes functional soil organic carbon components. Extracellular enzymes and microbial pools are differentiated based on the functional roles of bacteria, saprotrophic, and mycorrhizal fungi. Soil macrofauna is also represented. The model resolves the cycles of nitrogen, phosphorus, and potassium. Model simulations for 20 sites compared favorably with global patterns of litter and soil stoichiometry, microbial and macrofaunal biomass relations with soil organic carbon, soil respiration, and nutrient mineralization rates. Long-term responses to bare fallow and nitrogen addition experiments were also in agreement with observations. Some discrepancies between predictions and observations are appreciable in the response to litter manipulation. Upon successful model reproduction of observed general trends, we assessed patterns associated with the carbon cycle that were challenging to address empirically. Despite large site-to-site variability, fine root, fungal, bacteria, and macrofaunal respiration account for 33%, 40%, 24%, and 3% on average of total belowground respiration, respectively. Simulated root exudation and carbon export to mycorrhizal fungi represent on average about 13% of plant net primary productivity. These results offer mechanistic and general estimates of microbial biomass and its contribution to respiration fluxes and to soil organic matter dynamics.

  • 242. Faucherre, Samuel
    et al.
    Juncher Jørgensen, Christian
    Blok, Daan
    Weiss, Niels
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Siewert, Matthias Benjamin
    Stockholm University, Faculty of Science, Department of Physical Geography. Umeå University, Sweden.
    Bang-Andreasen, Toke
    Hugelius, Gustaf
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Kuhry, Peter
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Elberling, Bo
    Short and Long-Term Controls on Active Layer and Permafrost Carbon Turnover Across the Arctic2018In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 123, no 2, p. 372-390Article in journal (Refereed)
    Abstract [en]

    Decomposition of soil organic matter (SOM) in permafrost terrain and the production of greenhouse gases is a key factor for understanding climate change-carbon feedbacks. Previous studies have shown that SOM decomposition is mostly controlled by soil temperature, soil moisture, and carbon-nitrogen ratio (C:N). However, focus has generally been on site-specific processes and little is known about variations in the controls on SOM decomposition across Arctic sites. For assessing SOM decomposition, we retrieved 241 samples from 101 soil profiles across three contrasting Arctic regions and incubated them in the laboratory under aerobic conditions. We assessed soil carbon losses (C-loss) five times during a 1year incubation. The incubated material consisted of near-surface active layer (AL(NS)), subsurface active layer (AL(SS)), peat, and permafrost samples. Samples were analyzed for carbon, nitrogen, water content, C-13, N-15, and dry bulk density (DBD). While no significant differences were observed between total AL(SS) and permafrost C-loss over 1year incubation (2.32.4% and 2.51.5% C-loss, respectively), AL(NS) samples showed higher C-loss (7.94.2%). DBD was the best explanatory parameter for active layer C-loss across sites. Additionally, results of permafrost samples show that C:N ratio can be used to characterize initial C-loss between sites. This data set on the influence of abiotic parameter on microbial SOM decomposition can improve model simulations of Arctic soil CO2 production by providing representative mean values of CO2 production rates and identifying standard parameters or proxies for upscaling potential CO2 production from site to regional scales.

  • 243. Fazel, Nasim
    et al.
    Berndtsson, Ronny
    Uvo, Cintia Bertacchi
    Madani, Kaveh
    Stockholm University, Faculty of Science, Department of Physical Geography. Imperial College London, UK.
    Kløve, Bjørn
    Regionalization of precipitation characteristics in Iran's Lake Urmia basin2018In: Journal of Theoretical and Applied Climatology, ISSN 0177-798X, E-ISSN 1434-4483, Vol. 132, no 1-2, p. 363-373Article in journal (Refereed)
    Abstract [en]

    Lake Urmia in northwest Iran, once one of the largest hypersaline lakes in the world, has shrunk by almost 90% in area and 80% in volume during the last four decades. To improve the understanding of regional differences in water availability throughout the region and to refine the existing information on precipitation variability, this study investigated the spatial pattern of precipitation for the Lake Urmia basin. Daily rainfall time series from 122 precipitation stations with different record lengths were used to extract 15 statistical descriptors comprising 25th percentile, 75th percentile, and coefficient of variation for annual and seasonal total precipitation. Principal component analysis in association with cluster analysis identified three main homogeneous precipitation groups in the lake basin. The first sub-region (group 1) includes stations located in the center and southeast; the second sub-region (group 2) covers mostly northern and northeastern part of the basin, and the third sub-region (group 3) covers the western and southern edges of the basin. Results of principal component (PC) and clustering analyses showed that seasonal precipitation variation is the most important feature controlling the spatial pattern of precipitation in the lake basin. The 25th and 75th percentiles of winter and autumn are the most important variables controlling the spatial pattern of the first rotated principal component explaining about 32% of the total variance. Summer and spring precipitation variations are the most important variables in the second and third rotated principal components, respectively. Seasonal variation in precipitation amount and seasonality are explained by topography and influenced by the lake and westerly winds that are related to the strength of the North Atlantic Oscillation. Despite using incomplete time series with different lengths, the identified sub-regions are physically meaningful.

  • 244. Felde, Vivian A.
    et al.
    Flantua, Suzette G. A.
    Jenks, Cathy R.
    Benito, Blas M.
    De Beaulieu, Jacques-Louis
    Kuneš, Petr
    Magri, Donatella
    Nalepka, Dorota
    Risebrobakken, Bjørg
    ter Braale, Cajo J. F.
    Allen, Judy R. M.
    Granoszewski, Wojciech
    Helmens, Karin F.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Huntley, Brian
    Kondratienė, Ona
    Kalnina, Laimdota
    Kupryjanowicz, Mirosława
    Malkiewicz, Małgorzata
    Milner, Alice M.
    Nita, Małgorzata
    Noryśkiewicz, Bożena
    Pidek, Irena A.
    Reille, Maurice
    Salonen, J. Sakari
    Šeirienė, Vaida
    Winter, Hanna
    Tzedakis, Polychronis C.
    Birks, H. John B.
    Compositional turnover and variation in Eemian pollen sequences in Europe2020In: Vegetation History and Archaeobotany, ISSN 0939-6314, E-ISSN 1617-6278, Vol. 29, no 1, p. 101-109Article in journal (Refereed)
    Abstract [en]

    The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes compared to the Holocene. Here, we assemble 47 carefully selected Eemian pollen sequences from Europe to explore geographical patterns of (1) total compositional turnover and total variation for each sequence and (2) stratigraphical turnover between samples within each sequence using detrended canonical correspondence analysis, multivariate regression trees, and principal curves. Our synthesis shows that turnover and variation are highest in central Europe (47-55 degrees N), low in southern Europe (south of 45 degrees N), and lowest in the north (above 60 degrees N). These results provide a basis for developing hypotheses about causes of vegetation change during the Eemian and their possible drivers.

  • 245. Feng, Xue
    et al.
    Ackerly, David D.
    Dawson, Todd E.
    Manzoni, Stefano
    Stockholm University, Faculty of Science, Department of Physical Geography.
    McLaughlin, Blair
    Skelton, Robert P.
    Vico, Giulia
    Weitz, Andrew P.
    Thompson, Sally E.
    Beyond isohydricity: The role of environmental variability in determining plant drought responses2019In: Plant, Cell and Environment, ISSN 0140-7791, E-ISSN 1365-3040, Vol. 42, no 4, p. 1104-1111Article in journal (Refereed)
    Abstract [en]

    Despite the appeal of the iso/anisohydric framework for classifying plant drought responses, recent studies have shown that such classifications can be strongly affected by a plant's environment. Here, we present measured in situ drought responses to demonstrate that apparent isohydricity can be conflated with environmental conditions that vary over space and time. In particular, we (a) use data from an oak species (Quercus douglasii) during the 2012-2015 extreme drought in California to demonstrate how temporal and spatial variability in the environment can influence plant water potential dynamics, masking the role of traits; (b) explain how these environmental variations might arise from climatic, topographic, and edaphic variability; (c) illustrate, through a common garden thought experiment, how existing trait-based or response-based isohydricity metrics can be confounded by these environmental variations, leading to Type-1 (false positive) and Type-2 (false negative) errors; and (d) advocate for the use of model-based approaches for formulating alternate classification schemes. Building on recent insights from greenhouse and vineyard studies, we offer additional evidence across multiple field sites to demonstrate the importance of spatial and temporal drivers of plants' apparent isohydricity. This evidence challenges the use of isohydricity indices, per se, to characterize plant water relations at the global scale.

  • 246. Feng, Xue
    et al.
    Ackerly, David D.
    Dawson, Todd E.
    Manzoni, Stefano
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Skelton, Rob P.
    Vico, Giulia
    Thompson, Sally E.
    The ecohydrological context of drought and classification of plant responses2018In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 21, no 11, p. 1723-1736Article, review/survey (Refereed)
    Abstract [en]

    Many recent studies on drought‐induced vegetation mortality have explored how plant functional traits, and classifications of such traits along axes of, for example, isohydry–anisohydry, might contribute to predicting drought survival and recovery. As these studies proliferate, the consistency and predictive value of such classifications need to be carefully examined. Here, we outline the basis for a systematic classification of plant drought responses that accounts for both environmental conditions and functional traits. We use non‐dimensional analysis to integrate plant traits and metrics of environmental variation into groups that can be associated with alternative drought stress pathways (hydraulic failure and carbon limitation), and demonstrate that these groupings predict physiological drought outcomes using both synthetic and measured data. In doing so, we aim to untangle some confounding effects of environment and trait variations that undermine current classification schemes, advocate for more careful treatment of the environmental context within which plants experience and respond to drought, and outline a pathway towards a general classification of drought vulnerability.

  • 247. Ferreira, C. S. S.
    et al.
    Walsh, R. P. D.
    Kalantari, Zahra
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Ferreira, A. J. D.
    Impact of Land-Use Changes on Spatiotemporal Suspended Sediment Dynamics within a Peri-Urban Catchment2020In: Water, E-ISSN 2073-4441, Vol. 12, no 3Article in journal (Refereed)
    Abstract [en]

    Understanding sediment dynamics in peri-urban catchments constitutes a research challenge because of the spatiotemporal complexity and variability of land-uses involved. This study investigates differences in the concentration of total sediments (TSC) and suspended sediments (SSC) in the small peri-urban Mediterranean Ribeira dos Covoes catchment (40% urban area) in central Portugal. Suspended sediment responses at the catchment outlet (E) and in three upstream sub-catchments, during periods of urbanization (2011-2013) and stabilizing land-use (2017-2018) are compared for storm-event datasets encompassing similar ranges of rainstorm sizes and antecedent rainfall condition. The Quinta sub-catchment, with the lowest urban area (22%) but subject to major construction activities affecting 17% of its area, led to highest TSC and SSC during urbanization (attaining 4320 mg/L and 4184 mg/L, respectively), and a median reduction of 38% and 69%, respectively, during stabilization. Espirito Santo sub-catchment, with highest urban area (49%) and minor construction activities, displayed similar median TSC in both periods (258-240 mg/L) but highest SSC reduction (76%), highlighting the impact of the anthropogenic disturbance mainly on fine-particle sediments and a good connectivity with the stream. Porto Bordalo sub-catchment, with 39% urban area and subject to the construction of a four-line road covering 1.5% of its area, showed the lowest TSC and SSC concentrations and the lowest median reductions in both periods (31% and 64%, correspondingly), mainly because of the impact of an unplanned retention basin established with soil from the construction site. Overall, median TSC and SSC reduced 14% and 59% at E, from urbanization to stabilization. Information about sediment dynamics should guide stakeholders in establishing strategies to reduce sediment loads and mitigate the impacts on urban aquatic ecosystems.

  • 248.
    Fetisova, Ekaterina
    et al.
    Stockholm University, Faculty of Science, Department of Mathematics.
    Brattström, Gudrun
    Stockholm University, Faculty of Science, Department of Mathematics.
    Moberg, Anders
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Sundberg, Rolf
    Stockholm University, Faculty of Science, Department of Mathematics.
    Towards a flexible statistical modelling by latent factors for evaluation of simulated responses to climate forcings: Part IManuscript (preprint) (Other academic)
    Abstract [en]

    Evaluation of climate model simulations is a crucial task in climate research. In a work consisting of three parts, we propose a new statistical framework for evaluation of simulated responses to climate forcings, based on the concept of latent (unobservable) factors. Here, in Part I, we suggest several latent factor models of different complexity that can be used for evaluation of temperature data from climate model simulations against climate proxy data from the last millennium. Each factor model is developed for use with data from a single region, which can be of any size. To be able to test the hypotheses of interest, we have applied the technique of confirmatory factor analysis. We also elucidate the link between our factor models and the statistical methods used in Detection and Attribution (D\&A) studies. In particular, we demonstrate that our factor models can be used as an alternative approach to the methods used in D\&A studies. An additional advantage of their use is that they, in contrast to the commonly used D\&A methods, make it, in principle, possible to investigate whether the forcings of interest act additively or if any interaction effects exist.In Part II we investigate and illustrate the expansion of factor models to structural equation models, which permits the statistical modelling of more complicated climatological relationships. The performance of some of our statistical models suggested in Part I and Part is evaluated and compared in a numerical experiment, whose results are presented in Part III.

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  • 249.
    Fetisova, Ekaterina
    et al.
    Stockholm University, Faculty of Science, Department of Mathematics.
    Moberg, Anders
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Brattström, Gudrun
    Stockholm University, Faculty of Science, Department of Mathematics.
    Towards a flexible statistical modelling by latent factors for evaluation of simulated responses to climate forcings: Part IIManuscript (preprint) (Other academic)
    Abstract [en]

    Evaluation of climate model simulations is a crucial task in climate research. In a work consisting of three parts, we propose a new statistical framework for evaluation of simulated responses to climate forcings, based on the concept of latent (unobservable) variables. In Part I, several latent factor models were suggested for evaluation of temperature data from climate model simulations, forced by a varying number of forcings, against climate proxy data from the last millennium. Here, in Part II, focusing on climatological characteristics of forcings, we deepen the discussion by suggesting two alternative latent variable models that can be used for evaluation of temperature simulations forced by five specific forcings of natural and anthropogenic origin. The first statistical model is formulated in line with confirmatory factor analysis (CFA), accompanied by a more detailed discussion about the interpretation of latent temperature responses and their mutual relationships. Introducing further\emph{causal links} between some latent variables, the CFA model is extended to a structural equation model (SEM), which allows us to reflect more complicated climatological relationships with respect to all SEM's variables. Each statistical model is developed for use with data from a single region, which can be of any size. Associated with different hypotheses, the CFA and SEM models can, as a beginning, be fitted to observable simulated data only, which allows us to investigate the underlying latent structure associated with the simulated climate system. Then, the best-fitting model can be fitted to the data with real climate proxy data included, to test the consistency between the latent simulated temperature responses and their real-world counterparts embedded in observations. The performance of both these statistical models and some models suggested in Part I is evaluated and compared in a numerical experiment, whose results are presented in Part III.

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  • 250.
    Fetisova, Ekaterina
    et al.
    Stockholm University, Faculty of Science, Department of Mathematics.
    Moberg, Anders
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Brattström, Gudrun
    Stockholm University, Faculty of Science, Department of Mathematics.
    Towards a flexible statistical modelling by latent factors for evaluation of simulated responses to climate forcings: Part IIIManuscript (preprint) (Other academic)
    Abstract [en]

    Evaluation of climate model simulations is a crucial task in climate research. In a work consisting of three parts, we propose a new statistical framework for evaluation of simulated responses to climate forcings, based on the concept of latent (unobservable) variables. In Part I, several latent factor models were suggested for evaluation of temperature data from climate model simulations, forced by a varying number of forcings, against climate proxy data from the last millennium. In Part II, focusing on climatological characteristics of forcings, we deepen the discussion by suggesting two alternative latent variable models that can be used for evaluation of temperature simulations forced by five specific forcings of natural and anthropogenic origin. The first statistical model is formulated in line with confirmatory factor analysis (CFA), accompanied by a more detailed discussion about the interpretation of latent temperature responses and their mutual relationships. Introducing further causal links between some latent variables, the CFA model is extended to a structural equation model (SEM), which allows us to reflect more complicated climatological relationships with respect to all SEM's variables. Each statistical model is developed for use with data from a single region, which can be of any size. Here, in Part III, the performance of both these statistical models and some models suggested in Part I is evaluated and compared in a pseudo-proxy experiment, in which the true unobservable temperature is replaced by temperature data from a selected climate model simulation. The present analysis involves seven regional data sets. Focusing first on the ability of the models to provide an adequate and climatologically defensible description of the unknown underlying structure, we may conclude that given the climate model under consideration, the SEM model in general performed best. As for the factor model, its assumptions turned out to be too restrictive to describe the observed relationships in all but one region. The performance of another factor model, reflecting the assumptions typically made in many D\&A studies, can be characterised as unacceptable due to its high sensitivity to insignificant coefficient estimates. Regarding the fourth statistical model analysed - a factor model with two indicators and one latent factor - it can be recommended to apply it with caution due to its sensitivity to departures from the independence assumptions among the model variables, which can make the interpretation of the latent factor unclear. The conclusions above have been confirmed in some form of a cross-validation study, presuming the availability of several data sets within each region of interest. Importantly, the present pseudo-proxy experiment is performed only for zero noise level, implying that the five SEM models and one factor model await further investigation to fully test their performance for realistic levels of added noise.

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