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  • 1. Abiven, Samuel
    et al.
    Hund, Andreas
    Martinsen, Vegard
    Cornelissen, Gerard
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM). Norwegian University of Life Sciences (NMBU), Norway; Norwegian Geotechnical Institute (NGI), Norway .
    Biochar amendment increases maize root surface areas and branching: a shovelomics study in Zambia2015In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 395, no 1-2, p. 45-55Article in journal (Refereed)
    Abstract [en]

    Positive crop yield effects from biochar are likely explained by chemical, physical and/or biological factors. However, studies describing plant allometric changes are scarcer, but may be crucial to understand the biochar effect. The main aim of the present study is to investigate the effect of biochar on root architecture under field conditions in a tropical setting. The presented work describes a shovelomics (i.e., description of root traits in the field) study on the effect of biochar on maize root architecture. Four field experiments we carried out at two different locations in Zambia, exhibiting non-fertile to relatively fertile soils. Roots of maize crop (Zea mays L.) were sampled from treatments with fertilizer (control) and with a combination of fertilizer and 4 t.ha(-1) maize biochar application incorporated in the soil. For the four sites, the average grain yield increase upon biochar addition was 45 +/- 14 % relative to the fertilized control (from 2.1-6.0 to 3.1-9.1 ton ha(-1)). The root biomass was approximately twice as large for biochar-amended plots. More extensive root systems (especially characterized by a larger root opening angle (+14 +/- 11 %) and wider root systems (+20 +/- 15 %)) were observed at all biochar-amended sites. Root systems exhibited significantly higher specific surface areas (+54 +/- 14 %), branching and fine roots: +70 +/- 56 %) in the presence of biochar. Biochar amendment resulted in more developed root systems and larger yields. The more extensive root systems may have contributed to the observed yield increases, e.g., by improving immobile nutrients uptake in soils that are unfertile or in areas with prolonged dry spells.

  • 2.
    Abramsson-Zetterberg, Lilianne
    et al.
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Ilback, Nils-Gunnar
    The synthetic food colouring agent Allura Red AC (E129) is not genotoxic in a flow cytometry-based micronucleus assay in vivo2013In: Food and Chemical Toxicology, ISSN 0278-6915, E-ISSN 1873-6351, Vol. 59, p. 86-89Article in journal (Refereed)
    Abstract [en]

    The safety of several azo colouring agents, used as food additives, has during the years been questioned. Allura Red AC (E129) has in some publications been classified as genotoxic. In fact, in the European Union, Allura Red is permitted as a food additive in human food, but, surprisingly, it was not acceptable as an additive for use in animal feed. In this study we have evaluated whether Allura Red is genotoxic using a flow cytometer-based micronucleus assay in peripheral blood of mice. Male FVB mice were given a single intra-peritoneal injection of various doses of Allura Red and sacrificed at 46 h after treatment. The tested doses were 0, 100, 200, 400, 600, 800, 1000, 1500, and 2000 mg/kg body weight (b.w.). Each dose group constituted three mice, except for in the dose group of 1000 mg/kg b.w., which constituted four mice. Blood samples were collected and the frequency of micronucleated polychromatic erythrocytes (fMNPCE) and the cell proliferation (%PCE) was determined. The analyses did not show any significant difference in the %PCE or in the fMNPCE. Consequently, under the testing circumstances one can conclude that Allura Red is not genotoxic.

  • 3.
    Ahlbeck, Ida
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hansson, Sture
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Hjerne, Olle
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Evaluating fish diet analysis methods by individual-based modelling2012In: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 69, no 7, p. 1184-1201Article in journal (Refereed)
    Abstract [en]

    Knowledge of diet compositions is important in ecological research. There are many methods available and numerous aspects of diet composition. Here we used modelling to evaluate how well different diet analysis methods describe the true diet of fish, expressed in mass percentages. The methods studied were both basic methods (frequency of occurrence, dominance, numeric, mass, points) and composite indices (Index of Relative Importance, Comparative Feeding Index). Analyses were based on both averaged stomach content of individual fish and on pooled content from several fish. Prey preference, prey size, and evacuation rate influenced the performance of the diet analysis methods. The basic methods performed better than composite indices. Mass and points methods produced diet compositions most similar to the true diet and were also most robust, indicating that these methods should be used to describe energetic-nutritional sources of fish.

  • 4. Akselsson, Cecilia
    et al.
    Belyazid, Salim
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Critical biomass harvesting - Applying a new concept for Swedish forest soils2018In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 409, p. 67-73Article in journal (Refereed)
    Abstract [en]

    The contribution of forest harvesting to base cation losses and soil acidification has increased in recent years in Sweden, as the demand for bioenergy has increased and the sulphur deposition has decreased. Thus, new policy tools are required to evaluate the progress of the recovery from acidification, and as a basis for forest management recommendations. In this study we introduce and test a concept, Critical biomass harvesting. The concept builds on the concept Critical loads, which has been used world-wide for several decades as a bridge between science and policies related to transboundary air pollution and acidification. The basis for the concept is an acidity mass balance, with sources and sinks of acidity. A critical limit defines the highest acceptable acidification status of the water leaving the root zone. Based on the critical limit, the highest allowed biomass harvesting can be calculated, keeping the other parameters constant. In this study the critical limit was set to ANC (Acid Neutralizing Capacity) = 0. Nitrogen was assumed to be affecting acidity only if it leaches from the root zone. The critical biomass harvesting was calculated for almost 12000 National Forest Inventory sites with spruce and pine forest, using the best available data on deposition, weathering and nitrogen leaching. The exceedance of critical biomass harvesting was calculated as the difference between the estimated harvest losses and the critical biomass harvesting. The results were presented as median values in merged catchments in a catchment database, with totally 2079 merged catchments in Sweden. According to the calculations, critical biomass harvesting was exceeded in the southern half of Sweden already at stem harvesting in spruce forests. Whole-tree harvesting expanded the exceedance area, and increased the exceedance levels in southern Sweden. The exceedance in pine forest was lower and affected smaller areas. It was concluded that the concept of critical biomass harvesting can be successfully applied on the same database that has been used for critical load calculations in Sweden, using basically the same approach as has been extensively applied, evaluated and discussed in a critical load context. The results from the calculations in Sweden indicate that whole-tree harvesting, without wood ash recycling, can be expected to further slow down recovery, especially in the most acidified parts of the country, in the southwest.

  • 5.
    al Rawaf, Rawaf
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Social-Ecological Urbanism: Lessons in Design from the Albano Resilient Campus2017Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Currently there is a demand for practical ways to integrate ecological insights into practices of design, which previously have lacked a substantive empirical basis. In the process of developing the Albano Resilient Campus, a transdisciplinary group of ecologists, design scholars, and architects pioneered a conceptual innovation, and a new paradigm of urban sustainability and development: Social-Ecological Urbanism.  Social-Ecological Urbanism is based on the frameworks of Ecosystem Services and Resilience thinking. This approach has created novel ideas with interesting repercussions for the international debate on sustainable urban development. From a discourse point of view, the concept of SEU can be seen as a next evolutionary step for sustainable urbanism paradigms, since it develops synergies between ecological and socio-technical systems. This case study collects ‘best practices’ that can lay a foundational platform for learning, innovation, partnership and trust building within the field of urban sustainability. It also bridges gaps in existing design approaches, such as Projective Ecologies and Design Thinking, with respect to a design methodology with its basis firmly rooted in Ecology.

  • 6.
    Alexander, Steven M.
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. National Socio-Environmental Synthesis Center, USA.
    Bodin, Örjan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Barnes, Michele L.
    Untangling the drivers of community cohesion in small-scale fisheries2018In: International Journal of the Commons, ISSN 1875-0281, E-ISSN 1875-0281, Vol. 12, no 1, p. 519-547Article in journal (Refereed)
    Abstract [en]

    Sustainable fisheries require strong management and effective governance. However, small-scale fisheries (SSF) often lack formal institutions, leaving management in the hands of local users in the form of various governance approaches (e.g. local, traditional, or co-management). The effectiveness of these approaches inherently relies upon some level of cohesion among resource users to facilitate agreement on common policies and practices regarding common pool fishery resources. Understanding the factors driving the formation and maintenance of community cohesion in SSF is therefore critical if we are to devise more effective participatory governance approaches and encourage and empower decentralized, localized, and community-based resource management approaches. Here, we adopt a social relational network perspective to propose a suite of hypothesized drivers that lead to the establishment of social ties among fishers that build the foundation for community cohesion. We then draw on detailed data from Jamaica's small-scale fishery to empirically test these drivers by employing a set of nested exponential random graph models (ERGMs) based on specific structural building blocks (i.e. network configurations) theorized to influence the establishment of social ties. Our results demonstrate that multiple drivers are at play, but that collectively, gear-based homophily, geographic proximity, and leadership play particularly important roles. We discuss the extent to which these drivers help explain previous experiences, as well as their implications for future and sustained collective action in SSF in Jamaica and elsewhere.

  • 7.
    Allard, Anna
    et al.
    Institutionen för Skoglig Resurshushållning .
    Skånes, Helle
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
    Miljöövervakning via infraröda flygbilder, ett väl använt verktyg med goda framtidsutsikter i Sverige2010In: Kart- och bildteknik (Mapping and Image Science), Vol. 4, p. 20-23Article in journal (Other (popular science, discussion, etc.))
  • 8.
    Andersson, Anastasia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Johansson, Frank
    Sundbom, Marcus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology.
    Laikre, Linda
    Stockholm University, Faculty of Science, Department of Zoology.
    Lack of trophic polymorphism despite substantial genetic differentiation in sympatric brown trout (Salmo trutta) populations2017In: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633, Vol. 26, no 4, p. 643-652Article in journal (Refereed)
    Abstract [en]

    Sympatric populations occur in many freshwater fish species; such populations are typically detected through morphological distinctions that are often coupled to food niche and genetic separations. In salmonids, trophic and genetically separate sympatric populations have been reported in landlocked Arctic char, whitefish and brown trout. In Arctic char and brown trout rare cases of sympatric, genetically distinct populations have been detected based on genetic data alone, with no apparent morphological differences, that is cryptic structuring. It remains unknown whether such cryptic, sympatric structuring can be coupled to food niche separation. Here, we perform an extensive screening for trophic divergence of two genetically divergent, seemingly cryptic, sympatric brown trout populations documented to remain in stable sympatry over several decades in two interconnected, tiny mountain lakes in a nature reserve in central Sweden. We investigate body shape, body length, gill raker metrics, breeding status and diet (stomach content analysis and stable isotopes) in these populations. We find small significant differences for body shape, body size and breeding status, and no evidence of food niche separation between these two populations. In contrast, fish in the two lakes differed in body shape, diet, and nitrogen and carbon isotope signatures despite no genetic difference between lakes. These genetically divergent populations apparently coexist using the same food resources and showing the same adaptive plasticity to the local food niches of the two separate lakes. Such observations have not been reported previously but may be more common than recognised as genetic screenings are necessary to detect the structures.

  • 9. Andrade, Carlos A. P.
    et al.
    Nascimento, Francisco
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Conceicao, Luis E. C.
    Linares, Fatima
    Lacuisse, Marc
    Dinis, Maria T.
    Red Porgy, Pagrus pagrus, Larvae Performance and Nutritional Condition in Response to Different Weaning Regimes2012In: Journal of the World Aquaculture Society, ISSN 0893-8849, E-ISSN 1749-7345, Vol. 43, no 3, p. 321-334Article in journal (Refereed)
    Abstract [en]

    Red porgy, Pagrus pagrus, is a candidate species for aquaculture diversification. The aim of this work was to assess whether an early supply of enriched Artemia (D1) or a direct step to dry diets (D3) would be advantageous weaning strategies for red porgy larvae, compared to a later supply of Artemia followed by dry diets (D2). Direct weaning to dry diet resulted in significantly lower growth, survival, pancreatic (trypsin and lipase), and intestinal (alkaline phosphatase) enzyme-specific activity, with the exception of leucine-alanine peptidase. The direct weaning strategy presented severe nutritional restrictions from early weaning stages with an associated delay of the maturation of digestive system. The two-step strategy presented in D1 and D2 resulted in comparable results in most parameters, including survival. Weaning using enriched Artemia as an intermediate step is confirmed as the most adequate strategy for red porgy larvae. Digestive enzymes and selected fatty acids correlated well with performance responses to dietary regimes, thereby supporting the use of these parameters as sensitive and reliable indicators of red porgy nutritional or physiological status during larval stages.

  • 10. Andrade, Carlos A. P.
    et al.
    Nascimento, Francisco J. A.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Nogueira, Natacha
    Pimenta, Filomena
    Dinis, Maria T.
    Narciso, Luis
    Allometric Growth in Red Porgy Larvae: Developing Morphological Indices for Mesocosm Semi-Intensive Culture2013In: North American Journal of Aquaculture, ISSN 1522-2055, E-ISSN 1548-8454, Vol. 75, no 1, p. 42-49Article in journal (Refereed)
    Abstract [en]

    We studied the morphological development, allometric growth, and cannibalistic behavior of Red Porgy Pagrus pagrus reared in mesocosm semi-intensive culture. The study was conducted from hatching to 32 d after hatching (DAH). Red porgy ontogeny was characterized by strong positive allometric growth of body depth at anus (BDA) to 6.7mm total length (TL) at about 2122 DAH. The BDA combined with standard length (SL) in a morphometric index was found to be better correlated with dry weight than TL and provided an improved method to estimate larval growth. Mouth size also exhibited strong positive allometric growth at early larval stages that, together with inflation of the swim bladder, may have contributed to improve feeding ability, in preparation for the high energy demands of metamorphosis. A predictive regression model developed for cannibalism underestimated prey size. Cannibalism coincided with the development of acidic digestion and was first evident at 27 DAH as larvae reached about 23% of their maximum size variation. We hypothesize that cannibalism is associated with larval size and condition, but is prompted by physiological and energetic factors. The bivariate morphometric index developed in this study can be used to mitigate cannibalism by controlling larval size variation and improving feed supply. The morphological measurements and morphometric indices that result from this study provide important tools for improving red porgy larvae culture. Received December 13, 2011; accepted July 12, 2012

  • 11.
    Axelsson, Roger
    Stockholm University, Faculty of Humanities, Department of History.
    Det medeltida Sverige: 4, Småland. 5, Tjust2008Book (Other (popular science, discussion, etc.))
  • 12.
    Bauer, Barbara
    et al.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Meier, H. E. Markus
    Casini, Michele
    Hoff, Ayoe
    Margoński, Piotr
    Orio, Alessandro
    Saraiva, Sofia
    Steenbeek, Jeroen
    Tomczak, Maciej T.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Reducing eutrophication increases spatial extent of communities supporting commercial fisheries: a model case study2018In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 75, no 4, p. 1306-1317Article in journal (Refereed)
    Abstract [en]

    In this study we investigate if eutrophication management has the potential to substantially affect which areas are going to be most suitable for commercial fishing in the future. We use a spatial ecosystem model, forced by a coupled physical-biogeochemical model, to simulate the spatial distribution of functional groups within a marine ecosystem, which depends on their respective tolerances to abiotic factors, trophic interactions, and fishing. We simulate the future long-term spatial developments of the community composition and their potential implications for fisheries under three different nutrient management scenarios and changing climate. The three nutrient management scenarios result in contrasting developments of bottom oxygen concentrations and phytoplankton abundance, with substantial effects on fish production. Nutrient load reduction increases the spatial extent of the areas suitable for the commercially most valuable demersal fish predator and all types of fisheries. This suggests that strategic planning of fishery management strategies could benefit from considering future changes in species distributions due to changes in eutrophication. We show that combining approaches from climate research, physical oceanography, biogeochemistry, biogeography, and trophic ecology with economical information provides a strong foundation to produce scientific knowledge that can support a multisectoral management of ecosystems.

  • 13.
    Bergendahl, I. Ahlbeck
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Holliland, Per Benjamin
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hansson, Sture
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Karlöf, Oliver
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Feeding range of age 1+year Eurasian perch Perca fluviatilis in the Baltic Sea2017In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 90, no 5, p. 2060-2072Article in journal (Refereed)
    Abstract [en]

    Using the widespread Eurasian perch Perca fluviatilis as a model organism, feeding ranges were investigated using stable-isotope ratios (N-15 and C-13) and body condition. Differences were found between closely located sampling sites in a littoral area without obvious migration barriers, indicating that individual fish had small feeding ranges. Body condition differences between sampled stations were consistent over 4 years. Such sedentary behaviour is important to consider in, e.g. fisheries management and environmental monitoring, as local catch regulations may be meaningful or geographic stability in sampling locations may reduce noise in data.

  • 14. Bermudez, Rafael
    et al.
    Feng, Yuanyuan
    Roleda, Michael Y.
    Tatters, Avery O.
    Hutchins, David A.
    Larsen, Thomas
    Boyd, Philip W.
    Hurd, Catriona L.
    Riebesell, Ulf
    Winder, Monika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Long-Term Conditioning to Elevated pCO(2) and Warming Influences the Fatty and Amino Acid Composition of the Diatom Cylindrotheca fusiformis2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 5, article id e0123945Article in journal (Refereed)
    Abstract [en]

    The unabated rise in anthropogenic CO2 emissions is predicted to strongly influence the ocean's environment, increasing the mean sea-surface temperature by 4 degrees C and causing a pH decline of 0.3 units by the year 2100. These changes are likely to affect the nutritional value of marine food sources since temperature and CO2 can influence the fatty (FA) and amino acid (AA) composition of marine primary producers. Here, essential amino (EA) and polyunsaturated fatty (PUFA) acids are of particular importance due to their nutritional value to higher trophic levels. In order to determine the interactive effects of CO2 and temperature on the nutritional quality of a primary producer, we analyzed the relative PUFA and EA composition of the diatom Cylindrotheca fusiformis cultured under a factorial matrix of 2 temperatures (14 and 19 degrees C) and 3 partial pressures of CO2 (180, 380, 750 mu atm) for >250 generations. Our results show a decay of similar to 3% and similar to 6% in PUFA and EA content in algae kept at a pCO(2) of 750 mu atm (high) compared to the 380 mu atm (intermediate) CO2 treatments at 14 degrees C. Cultures kept at 19 degrees C displayed a similar to 3% lower PUFA content under high compared to intermediate pCO(2), while EA did not show differences between treatments. Algae grown at a pCO(2) of 180 mu atm (low) had a lower PUFA and AA content in relation to those at intermediate and high CO2 levels at 14 degrees C, but there were no differences in EA at 19 degrees C for any CO2 treatment. This study is the first to report adverse effects of warming and acidification on the EA of a primary producer, and corroborates previous observations of negative effects of these stressors on PUFA. Considering that only similar to 20% of essential biomolecules such as PUFA (and possibly EA) are incorporated into new biomass at the next trophic level, the potential impacts of adverse effects of ocean warming and acidification at the base of the food web may be amplified towards higher trophic levels, which rely on them as source of essential biomolecules.

  • 15.
    Bildtgård, Torbjörn
    Stockholm University, Faculty of Social Sciences, Department of Social Work.
    Alimentalities - Food for Sociology2015In: Mat är mer än mat: samhällsvetenskapliga perspektiv på mat och måltider / [ed] Kerstin Bergström, Inger M. Jonsson, Hillevi Prell, Inga Wernersson, Helena Åberg, Göteborg: Göteborgs universitet, 2015, p. 247-254Chapter in book (Refereed)
  • 16. Björkman, Maria
    et al.
    Hambäck, Peter
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Rämert, Birgitta
    Neighboring monocultures enhance the effect of intercropping in turnip root flies (Delia floralis).2007In: Entomologia Experimentalis et Applicata, Vol. 124, p. 319-326Article in journal (Refereed)
    Abstract [en]

    Knowledge of insect behaviour is essential for accurately interpreting studies of diversification and to develop diversified agroecosystems that have a reliable pest-suppressive effect. In this study, we investigated the egg-laying behaviour of the turnip root fly, Delia floralis (Fall.) (Diptera: Anthomyiidae), in an intercrop-monoculture system. We examined both the main effect of intercropping and the effect on oviposition in the border zone between a cabbage monoculture [Brassica oleracea L. var. capitata (Brassicaceae)] and a cabbage-red clover intercropping system [Trifolium pratense L. (Fabaceae)]. To investigate the border-effect, oviposition was measured along a transect from the border between the treatments to the centre of experimental plots. Intercropping reduced the total egg-laying of D. floralis with 42% in 2003 and 55% in 2004. In 2004, it was also found that the spatial distribution of eggs within the experimental plots was affected by distance from the adjoining treatment. The difference in egg-laying between monoculture and intercropping was most pronounced close to the border, where egg-laying was 68% lower on intercropped plants. This difference in egg numbers decreased gradually up to a distance of 3.5 m from the border, where intercropped plants had 43% fewer eggs than the corresponding monocultured plants. The reason behind this oviposition pattern is most likely that flies in intercropped plots have a higher probability of entering the monoculture if they are close to the border than if they are in the centre of a plot. When entering the monoculture, flies can pursue their egg-laying behaviour without being disrupted by the clover. As the final decision to land is visually stimulated, flies could also be attracted to fly from the intercropped plots into the monoculture, where host plants are more visually apparent. Visual cues could also hinder flies in a monoculture from entering an intercropped plot. Other possible patterns of insect attack due to differences in insect behaviour are discussed, as well as the practical application of the results of this study.

  • 17. Björkman, Maria
    et al.
    Hopkins, Richard
    Hambäck, Peter
    Stockholm University, Faculty of Science, Department of Botany.
    Rämert, Birgitta
    Effects of plant competition and herbivore density on the development of the turnip root fly (Delia floralis) in an intercropping system2009In: Arthropod-plant interactions, ISSN 1872-8855, Vol. 3, p. 55-62Article in journal (Refereed)
    Abstract [en]

    In this study, interactive effects of plant competition and herbivory on plant quality and herbivore development were examined in a greenhouse experiment where cabbage plants [Brassica oleracea L. var. capitata (Brassicaceae)] were intercropped with red clover [Trifolium pratense L. (Fabaceae)]. Cabbages were grown with two red clover densities and attack rates by the root feeding herbivore the turnip root fly, Delia floralis Fall. (Diptera: Anthomyiidae). Above ground and below ground cabbage biomass was reduced through intercropping and larval damage. Intercropping also resulted in lower nitrogen and higher carbon root levels compared with levels in the roots of monocultured cabbage. Furthermore, both root nitrogen and carbon levels increased with herbivory. Root neutral detergent fibre (NDF) and lignin content increased in response to both increased plant competition and higher egg densities. For lignin, an interaction effect was observed in the form of elevated levels in intercropped plants subjected to larval damage, while levels in roots of monocultured cabbage remained unchanged. The quality changes brought about by clover competition affected D. floralis development negatively, which resulted in reduced pupal weight. In addition, increased egg density also decreased larval growth. The effects on the development of D. floralis in relation to host plant quality are discussed.

  • 18.
    Blasiak, Robert
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The University of Tokyo, Japan; United Nations University Institute for the Advanced Study of Sustainability, Japan.
    Spijkers, Jessica
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. James Cook University, Australia.
    Tokunaga, Kanae
    Pittman, Jeremy
    Yagi, Nobuyuki
    Österblom, Henrik
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Climate change and marine fisheries: Least developed countries top global index of vulnerability2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 6, article id e0179632Article in journal (Refereed)
    Abstract [en]

    Future impacts of climate change on marine fisheries have the potential to negatively influence a wide range of socio-economic factors, including food security, livelihoods and public health, and even to reshape development trajectories and spark transboundary conflict. Yet there is considerable variability in the vulnerability of countries around the world to these effects. We calculate a vulnerability index of 147 countries by drawing on the most recent data related to the impacts of climate change on marine fisheries. Building on the Intergovernmental Panel on Climate Change framework for vulnerability, we first construct aggregate indices for exposure, sensitivity and adaptive capacity using 12 primary variables. Seven out of the ten most vulnerable countries on the resulting index are Small Island Developing States, and the top quartile of the index includes countries located in Africa (17), Asia (7), North America and the Caribbean (4) and Oceania (8). More than 87% of least developed countries are found within the top half of the vulnerability index, while the bottom half includes all but one of the Organization for Economic Co-operation and Development member states. This is primarily due to the tremendous variation in countries' adaptive capacity, as no such trends are evident from the exposure or sensitivity indices. A negative correlation exists between vulnerability and per capita carbon emissions, and the clustering of states at different levels of development across the vulnerability index suggests growing barriers to meeting global commitments to reducing inequality, promoting human well-being and ensuring sustainable cities and communities. The index provides a useful tool for prioritizing the allocation of climate finance, as well as activities aimed at capacity building and the transfer of marine technology.

  • 19.
    Boonstra, Wiebren J.
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. University of Oslo, Norway.
    Birnbaum, Simon
    Stockholm University, Faculty of Social Sciences, Department of Political Science. Institute for Futures Studies, Stockholm.
    Björkvik, Emma
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    The quality of compliance: investigating fishers' responses towards regulation and authorities2017In: Fish and Fisheries, ISSN 1467-2960, E-ISSN 1467-2979, Vol. 18, no 4, p. 682-697Article in journal (Refereed)
    Abstract [en]

    A substantial amount of scientific effort goes into understanding and measuring compliance in fisheries. Understanding why, how and when fishers follow or violate rules is crucial for designing effective fishery policies that can halt overfishing. Non-compliance was initially explained almost exclusively with reference to economic and self-interested motivations. More recently, however, most explanations involve a combination of economic, social, political and environmental factors. Despite this recent development towards more holistic explanations, many scientists continue to frame the issue in binary terms: fishers either follow rules, or they don't. In this article we challenge this binary interpretation and focus attention on the diversity of fishers' dispositions and perceptions that underpin compliant behaviour. To this aim we construct a typology of fishers' responses towards regulation and authorities, thereby developing conceptual tools to understand different motivations and attitudes that underlie compliance outcomes. For this purpose, we identify the motivational postures of 'creativity' and 'reluctance', and then highlight their empirical relevance with an interview study of Swedish fishers. Reasons for studying the quality and diversity of fishers' motivations and responses are not purely academic. Conceptualizing and observing the quality of compliance can help policymakers and managers gauge and anticipate the potentiality of non-compliant fishing practices that may threaten the resilience of marine ecosystems.

  • 20.
    Boonstra, Wiebren J.
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. University of Oslo, Norway.
    Hentati-Sundberg, Jonas
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Classifying fishers' behaviour. An invitation to fishing styles2016In: Fish and Fisheries, ISSN 1467-2960, E-ISSN 1467-2979, Vol. 17, no 1, p. 78-100Article in journal (Refereed)
    Abstract [en]

    The study and classification of fishers’ behaviour remains a much debated topic. There is a tension between detailed empirical studies, which highlight the variety and diversity of fisheries, and the parsimony and generalization required to satisfy science and policy demands. This study contributes to this debate. The first sec- tion reviews quantitative methods currently used for classifying fishing practices. The review uncovers significant weaknesses in quantitative classification methods, which, we argue, can be improved through the complementary use of qualitative methods. To this purpose, we introduce the concept of ‘fishing style’, which integrates quantitative classification methods with qualitative analysis. We explain the scientific premises of the fishing-style concept, outline a general methodological framework and present a fishing-style analysis of Swedish Baltic Sea fisheries. Based on these results, we conclude that it is possible to classify fishing practices in a rel- atively uniform and limited number of styles that can highlight the rich, empirical diversity of fishers’ behaviour. We therefore propose that fishing-style analysis, based on an integration of quantitative and qualitative methods, can be an impor- tant step towards more effective and sustainable fisheries management.

  • 21. Borg, Saskia
    et al.
    Seubert, Janina
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI). Karolinska Institutet, Sweden.
    Lipids in Eating and Appetite Regulation - A Neuro-Cognitive Perspective2017In: European Journal of Lipid Science and Technology, ISSN 1438-7697, E-ISSN 1438-9312, Vol. 119, no 12, article id 1700106Article in journal (Refereed)
    Abstract [en]

    Foods high in dietary fat provide a particularly energy-rich source of nutrition. A preferred food choice in humans, their intake is thought to contribute substantially to the current obesity epidemic. Fat has recently been proposed to constitute a basic taste; yet, its diverse sensory properties in the olfactory and somatosensory domain, as well as its postingestive effects have made the exact attributes that make its consumption so appealing difficult to disentangle. Recent scientific advances have shed light on the different molecular mechanisms underlying the sensory detection of fat in the periphery, and described their relevance for perceptual experience and eating behavior. However, these different analysis levels are to date poorly integrated, both within each sensory modality, and from a multisensory perspective.

  • 22.
    Brown, Ian
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
    Polarimetric scattering from shallow firn and forests with snow cover2010In: Proceedings of the ESA Living Planet SymposiumBergen, Norway: (ESA SP-686, December 2010) / [ed] H. Lacoste-Francis, Noordwijk, Netherlands: European Space Agency , 2010Conference paper (Other academic)
    Abstract [en]

    In this paper the potential for inferring shallow firn depth from polarimetric SAR (PolSAR) data at L- and C-band is investigated. Using ALOS PALSAR and Radarsat-2 SAR imagery, and field data including Ground Penetrating Radar profiles and shallow cores, we investigate the spatial distribution of backscatter and decompose backscatter using polarimetric methods to analyse how polarimetric scattering is affected by firn depth near the firn line. The investigation is aimed at a more refined delineation of glacier firn lines and a better understanding of scattering from firn, superimposed ice and the bare ice facies. We found that PolSAR can be used to infer shallow firn thicknesses up to depths of at least 2 m water equivalent (m w.e.) and that old and contemporary firn surfaces can be differentiated using PolSAR. Contrary to many previous investigations the importance of surface scattering in the firn area is also emphasised in the scattering decompositions. Volume scattering was found to have a secondary or tertiary importance. This has important implications for the analysis of backscatter using semi-empirical models.The effect of snow depth on backscatter in pro-glacial a sub-Arctic forest and its potential for improving forest mapping is also discussed. Snow depth data were acquired by manual probing and snowpit measurements. In addition forest stand densities were assessed in situ and NDVI and tasseled cap transformations were made in optical remote sensing data (SPOT-4) to parameterise the forest. Scatterer decomposition and pedestal height products were found to be related to snowpack depth. It was not possible to separate the influences of snow cover and forest structure due to the partial dependence of the former on the latter. Nevertheless it can be concluded that PolSAR improves our ability to map the forest margins of low density, sub-Arctic forests. Our findings have implications for the implementation of algorithms for the exploitation of future SAR missions including Sentinel-1.

  • 23.
    Brüchert, Volker
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Bonaglia, Stefano
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Raymond, Caroline
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Sediment med nyckelroll i näringsväven2014In: HavsUtsikt, ISSN 1104-0513, Vol. 1, p. 20-21Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    I sedimenten sker processer som kan vara helt avgörande för näringsbalansen i havsvattnet. Omvandlingen av fosfor till olika former är relativt väl känd, medan detaljerna i kvävets kretslopp är betydligt mindre kända. Mer än hälften av den årliga tillförseln av kväve till Östersjön beräknas omsättas till kvävgas i sedimentet, vilket sedan går förlorat för de flesta marina organismer.

  • 24.
    Byerley, Andrew
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    'The Frightened Land: Land,Landscape and Politics in South Africa in the twentieth Century': Book Review2009In: Urban Studies, Vol. 46, no 1, p. 235-238Article in journal (Refereed)
  • 25.
    Caretta, Martina Angela
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Managing variability and scarcity. An analysis of Engaruka: A Maasai smallholder irrigation farming community2015In: Agricultural Water Management, ISSN 0378-3774, E-ISSN 1873-2283, Vol. 159, p. 318-330Article in journal (Refereed)
    Abstract [en]

    This article examines the common-pool regime of Engaruka, a smallholder irrigation farming community in northern Tanzania. Irrigation is a complex issue due to water asymmetry. Water use is regulated in Engaruka through boundary, allocation, input and penalty rules by a users’ association that controls and negotiates water allocation to avoid conflicts among headenders and tailenders. As different crops – maize and beans, bananas and vegetables – are cultivated, different watering schemes are applied depending on the water requirements of every single crop. Farmers benefit from different irrigation schedules and from different soil characteristics through having their plots both downstream and upstream. In fact, depending on water supply, cultivation is resourcefully extended and retracted. Engaruka is an ethnically homogeneous and interdependent community where headenders and tailenders are often the same people and are hence inhibited to carry out unilateral action. Drawing on common-pool resource literature, this study argues that in a context of population pressure alongside limited and fluctuating water availability, non-equilibrium behavior, consisting in negotiating water rights and modifying irrigation area continuously through demand management, is crucial for the satisfaction of basic and productive needs and for the avoidance of water conflicts.

  • 26. Caron, Patrick
    et al.
    Ferrero y de Loma-Osorio, Gabriel
    Nabarro, David
    Hainzelin, Etienne
    Guillou, Marion
    Andersen, Inger
    Arnold, Tom
    Astralaga, Margarita
    Beukeboom, Marcel
    Bickersteth, Sam
    Bwalya, Martin
    Caballero, Paula
    Campbell, Bruce M.
    Divine, Ntiokam
    Fan, Shenggen
    Frick, Martin
    Friis, Anette
    Gallagher, Martin
    Halkin, Jean-Pierre
    Hanson, Craig
    Lasbennes, Florence
    Ribera, Teresa
    Rockström, Johan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Schuepbach, Marlen
    Steer, Andrew
    Tutwiler, Ann
    Verburg, Gerda
    Food systems for sustainable development: proposals for a profound four-part transformation2018In: Agronomy for Sustainable Development, ISSN 1774-0746, E-ISSN 1773-0155, Vol. 38, no 4, article id 41Article, review/survey (Refereed)
    Abstract [en]

    Evidence shows the importance of food systems for sustainable development: they are at the nexus that links food security, nutrition, and human health, the viability of ecosystems, climate change, and social justice. However, agricultural policies tend to focus on food supply, and sometimes, on mechanisms to address negative externalities. We propose an alternative. Our starting point is that agriculture and food systems' policies should be aligned to the 2030 Agenda for Sustainable Development. This calls for deep changes in comparison with the paradigms that prevailed when steering the agricultural change in the XXth century. We identify the comprehensive food systems transformation that is needed. It has four parts: first, food systems should enable all people to benefit from nutritious and healthy food. Second, they should reflect sustainable agricultural production and food value chains. Third, they should mitigate climate change and build resilience. Fourth, they should encourage a renaissance of rural territories. The implementation of the transformation relies on (i) suitable metrics to aid decision-making, (ii) synergy of policies through convergence of local and global priorities, and (iii) enhancement of development approaches that focus on territories. We build on the work of the Milano Group, an informal group of experts convened by the UN Secretary General in Milan in 2015. Backed by a literature review, what emerges is a strategic narrative linking climate, agriculture and food, and calling for a deep transformation of food systems at scale. This is critical for achieving the Sustainable Development Goals and the Paris Agreement. The narrative highlights the needed consistency between global actions for sustainable development and numerous local-level innovations. It emphasizes the challenge of designing differentiated paths for food systems transformation responding to local and national expectations. Scientific and operational challenges are associated with the alignment and arbitration of local action within the context of global priorities.

  • 27.
    Celorio-Mancera, Maria de la Paz
    et al.
    Max Planck Society.
    Heckel, David G.
    Vogel, Heiko
    Transcriptional analysis of physiological pathways in a generalist herbivore: responses to different host plants and plant structures by the cotton bollworm, Helicoverpa armigera2012In: Entomologia Experimentalis et Applicata, ISSN 0013-8703, E-ISSN 1570-7458, Vol. 144, no 1, p. 123-133Article in journal (Refereed)
    Abstract [en]

    The generalist cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), can consume host plants in more than 40 families, and often utilizes several tissues of a single plant. It is believed that generalists owe their success to the deployment of various members of multigene families of detoxification and digestive enzymes, a strategy that may also be responsible for rapid evolution of insecticide resistance. However, studies of generalist adaptations have been limited to specific genes or gene families, and an overview of how these adaptations are orchestrated at the transcriptional level is lacking. We used Drosophila melanogaster Meigen gene homology to H. armigera-expressed sequence tags to identify key groups of genes and pathways differentially regulated in the gut of fifth instars after 2 days of feeding on a variety of food sources. A series of microarray hybridizations was performed following two alternating loop designs, one comparing the gut gene expression upon feeding on various hosts (cotton, bean, tobacco, and chickpea) and two artificial diets (pinto bean and wheat germ-based), whereas the second design compared the gut expression toward feeding on various plant structures within cotton (leaf, square, and boll). The transcriptional responses toward bean and tobacco feeding treatments were more closely related in comparison with the rest of the diets, whereas the gene expression profiles toward cotton leaf and square-feeding were highly similar. We furthermore found significant changes in several pathways not directly responsible for detoxification mechanisms. Genes involved in primary and secondary metabolism, environmental information processing, and cellular processes were found to be differentially expressed. In addition, regulation of xenobiotic metabolism and the extracellular matrix-receptor pathways appeared differentially regulated across feeding treatments. Three cytochrome P450 genes – CYP6AE17, CYP6B6, and CYP9A17 – grouped as part of a xenobiotic metabolism pathway, were up-regulated in the bean-feeding treatment, and down-regulated in both tobacco and cotton-feeding treatments. CYP4L11, CYP4L5, and CYP4S13 were differentially expressed upon feeding on different cotton plant structures. The present work provides host plant and plant structure-specific transcriptional responses in a lepidopteran herbivore, including pathways and gene candidates for future studies of H. armigera physiology under a more integrative ecologically meaningful framework.

  • 28.
    Charpentier Ljungqvist, Fredrik
    Stockholm University, Faculty of Humanities, Department of History. Stockholm University, Faculty of Humanities, Centre for Medieval Studies.
    1600-talet – det kallaste århundradet2011In: Sveriges historia : 1600–1721 / [ed] Nils Erik Villstrand, Stockholm: Norstedts , 2011, p. 441-445Chapter in book (Other (popular science, discussion, etc.))
  • 29.
    Charpentier Ljungqvist, Fredrik
    Stockholm University, Faculty of Humanities, Department of History.
    Global nedkylning: klimatet och människan under 10 000 år2009Book (Other (popular science, discussion, etc.))
    Abstract [sv]

    Klimatet har förändrats både regionalt och globalt sedan senaste istiden tog slut, ofta med dramatiska konsekvenser för naturen och människan. Fastän det talas så mycket om klimatförändringar idag är det få som vet särskilt mycket om hur klimatet har varierat förr.

    Det är först under de senaste åren som forskningen börjat kunna beskriva vad som faktiskt hänt med klimatet under olika tider, på olika platser. Historikern Fredrik Charpentier Ljungqvist har tagit ett samlat grepp på den senaste forskningen och resultatet är en resa i vått och torrt, i hetta och kyla, jorden runt under 10 000 år. Vi får stifta bekantskap med många olika folk och kulturer – babylonier, romare, mayaindianer och vikingar – som alla under historiens gång varit utsatta för klimatförändringar.

  • 30.
    Charpentier Ljungqvist, Fredrik
    Stockholm University, Faculty of Humanities, Department of History. Stockholm University, Faculty of Humanities, Centre for Medieval Studies.
    Klimatkris på medeltiden2009In: Populär Historia, ISSN 1102-0822, no 12, p. 48-52Article in journal (Other (popular science, discussion, etc.))
  • 31. Cheung, William W. L.
    et al.
    Frolicher, Thomas L.
    Asch, Rebecca G.
    Jones, Miranda C.
    Pinsky, Malin L.
    Reygondeau, Gabriel
    Rodgers, Keith B.
    Rykaczewski, Ryan R.
    Sarmiento, Jorge L.
    Stock, Charles
    Watson, James R.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Princeton University, USA.
    Building confidence in projections of the responses of living marine resources to climate change2016In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 73, no 5, p. 1283-1296Article in journal (Refereed)
    Abstract [en]

    The Fifth Assessment Report of the Intergovernmental Panel on Climate Change highlights that climate change and ocean acidification are challenging the sustainable management of living marine resources (LMRs). Formal and systematic treatment of uncertainty in existing LMR projections, however, is lacking. We synthesize knowledge of how to address different sources of uncertainty by drawing from climate model intercomparison efforts. We suggest an ensemble of available models and projections, informed by observations, as a starting point to quantify uncertainties. Such an ensemble must be paired with analysis of the dominant uncertainties over different spatial scales, time horizons, and metrics. We use two examples: (i) global and regional projections of Sea Surface Temperature and (ii) projection of changes in potential catch of sablefish (Anoplopoma fimbria) in the 21st century, to illustrate this ensemble model approach to explore different types of uncertainties. Further effort should prioritize understanding dominant, undersampled dimensions of uncertainty, as well as the strategic collection of observations to quantify, and ultimately reduce, uncertainties. Our proposed framework will improve our understanding of future changes in LMR and the resulting risk of impacts to ecosystems and the societies under changing ocean conditions.

  • 32.
    Crona, Beatrice I.
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The Royal Swedish Academy of Sciences, Sweden.
    Daw, Tim M.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. University of East Anglia, UK.
    Swartz, Wilf
    Norström, Albert V.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Nyström, Magnus
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Thyresson, Matilda
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Folke, Carl
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The Royal Swedish Academy of Sciences, Sweden.
    Hentati-Sundberg, Jonas
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Österblom, Henrik
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Deutsch, Lisa
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Troell, Max
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Royal Swedish Academy of Sciences, Sweden.
    Masked, diluted and drowned out: how global seafood trade weakens signals from marine ecosystems2016In: Fish and Fisheries, ISSN 1467-2960, E-ISSN 1467-2979, Vol. 17, no 4, p. 1175-1182Article in journal (Refereed)
    Abstract [en]

    Nearly 40% of seafood is traded internationally and an even bigger proportion is affected by international trade, yet scholarship on marine fisheries has focused on global trends in stocks and catches, or on dynamics of individual fisheries, with limited attention to the link between individual fisheries, global trade and distant consumers. This paper examines the usefulness of fish price as a feedback signal to consumers about the state of fisheries and marine ecosystems. We suggest that the current nature of fisheries systems and global markets prevent transmission of such price signals from source fisheries to consumers. We propose several mechanisms that combine to weaken price signals, and present one example - the North Sea cod - to show how these mechanisms can be tested. The lack of a reliable price feedback to consumers represents a challenge for sustainable fisheries governance. We therefore propose three complimentary approaches to address the missing feedback: (i) strengthening information flow through improved traceability and visibility of individual fishers to consumers, (ii) capitalizing on the changing seafood trade structures and (iii) bypassing and complementing market mechanisms by directly targeting citizens and political actors regarding marine environmental issues through publicity and information campaigns. These strategies each havelimitations and thus need to be pursued together to address the challenge of sustainability in global marine fisheries.

  • 33.
    Cullhed, Anders
    Stockholm University, Faculty of Humanities, Department of History of Literature and History of Ideas, History of Literature.
    The Garden against History: Reflections on the Hortus Conclusus Theme in Premodern Literature2010In: Bulletin för trädgårdshistorisk forskning, ISSN 1652-2362, no 23, p. 6-8Article in journal (Other academic)
  • 34. Daewel, Ute
    et al.
    Hjøllo, Solfrid Saetre
    Huret, Martin
    Ji, Rubao
    Maar, Marie
    Niiranen, Susa
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Travers-Trolet, Morgane
    Peck, Myron A.
    van de Wolfshaar, Karen E.
    Predation control of zooplankton dynamics: a review of observations and models2014In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 71, no 2, p. 254-271Article, review/survey (Refereed)
    Abstract [en]

    We performed a literature review to examine to what degree the zooplankton dynamics in different regional marine ecosystems across the Atlantic Ocean is driven by predation mortality and how the latter is addressed in available modelling approaches. In general, we found that predation on zooplankton plays an important role in all the six considered ecosystems, but the impacts are differently strong and occur at different spatial and temporal scales. In ecosystems with extreme environmental conditions (e.g. low temperature, ice cover, large seasonal amplitudes) and low species diversity, the overall impact of top-down processes on zooplankton dynamics is stronger than for ecosystems having moderate environmental conditions and high species diversity. In those ecosystems, predation mortality was found to structure the zooplankton mainly on local spatial and seasonal time scales. Modelling methods used to parameterize zooplankton mortality range from simplified approaches with fixed mortality rates to complex coupled multispecies models. The applicability of a specific method depends on both the observed state of the ecosystem and the spatial and temporal scales considered. Modelling constraints such as parameter uncertainties and computational costs need to be balanced with the ecosystem-specific demand for a consistent, spatial-temporal dynamic implementation of predation mortality on the zooplankton compartment.

  • 35. Dahlström, Anna
    et al.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    The History (1620-2003) of Land Use, People and Livestock, and the Relationship to Present Plant Species Diversity in a Rural Landscape in Sweden2006In: Environment and History, ISSN 0967-3407, E-ISSN 1752-7023, Vol. 12, p. 191-212Article in journal (Refereed)
    Abstract [en]

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

  • 36. Daniel, Terry C.
    et al.
    Muhar, Andreas
    Arnberger, Arne
    Aznar, Olivier
    Boyd, James W.
    Chan, Kai M. A.
    Costanza, Robert
    Elmqvist, Thomas
    Stockholm University, Stockholm Resilience Centre.
    Flint, Courtney G.
    Gobster, Paul H.
    Gret-Regamey, Adrienne
    Lave, Rebecca
    Muhar, Susanne
    Penker, Marianne
    Ribe, Robert G.
    Schauppenlehner, Thomas
    Sikor, Thomas
    Soloviy, Ihor
    Spierenburg, Marja
    Taczanowska, Karolina
    Tam, Jordan
    von der Dunk, Andreas
    Contributions of cultural services to the ecosystem services agenda2012In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 109, no 23, p. 8812-8819Article in journal (Refereed)
    Abstract [en]

    Cultural ecosystem services (ES) are consistently recognized but not yet adequately defined or integrated within the ES framework. A substantial body of models, methods, and data relevant to cultural services has been developed within the social and behavioral sciences before and outside of the ES approach. A selective review of work in landscape aesthetics, cultural heritage, outdoor recreation, and spiritual significance demonstrates opportunities for operationally defining cultural services in terms of socioecological models, consistent with the larger set of ES. Such models explicitly link ecological structures and functions with cultural values and benefits, facilitating communication between scientists and stakeholders and enabling economic, multicriterion, deliberative evaluation and other methods that can clarify tradeoffs and synergies involving cultural ES. Based on this approach, a common representation is offered that frames cultural services, along with all ES, by the relative contribution of relevant ecological structures and functions and by applicable social evaluation approaches. This perspective provides a foundation for merging ecological and social science epistemologies to define and integrate cultural services better within the broader ES framework.

  • 37.
    Daume, Stefan
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Fueldner, Kai
    Forest Tweets - Informal Digital Coverage of the Oak Processionary Moth or Why Foresters should care about Social Media2016In: Allgemeine Forst und Jagdzeitung, ISSN 0002-5852, Vol. 187, no 9-10, p. 185-197Article in journal (Refereed)
    Abstract [en]

    Changing climate conditions and new forest threats such as invasive alien species present new challenges for forest practitioners and demand effective responses that may exceed the traditional information and data needs, served by the available forest monitoring resources and regimes. Motivated by examples in other domains, it has thus been proposed to make use of informal online information sources, so-called social media such as blogs, the micro-blogging service Twitter or the social network Facebook, to supplement traditional environmental information sources. Here we present an example of such an information source using 5074 English and German Twitter messages posted between May 2012 and December 2015 and directly referencing the Oak processionary moth. We focus on different analytical approaches which can facilitate an efficient automatic analysis of large social media data sets in order to extract trends on the public discourse on this exemplary forest threat. Specifically, we present temporal and geographical messaging patterns, a content analysis of the messages including shared web links as well as a network analysis of the users contributing the information. We find that messaging patterns generally show a good alignment with the lifecycle of the sample species, but that distinct differences in the content emphasis and messaging patterns for the Twitter messages attributed to the UK and Germany can be observed. We conclude that, while the chosen example is unlikely to contribute novel primary observations of Oak processionary infestations, the presented methods are an efficient approach to monitor public discussions on this sample forest threat and can directly inform public outreach and engagement strategies, which could in turn support the gathering of primary observations and is furthermore applicable to a broad range of other forest threats such as invasive alien species. Our results suggest that forest practitioners should thus consider social online media as a supplemental information source worthy of further exploration.

  • 38.
    Daw, Tim M.
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. University of East Anglia, United Kingdom.
    Coulthard, Sarah
    Cheung, William W. L.
    Brown, Katrina
    Abunge, Caroline
    Galafassi, Diego
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Peterson, Garry D.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    McClanahan, Tim R.
    Omukoto, Johnstone O.
    Munyi, Lydiah
    Evaluating taboo trade-offs in ecosystems services and human well-being2015In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, no 22, p. 6949-6954Article in journal (Refereed)
    Abstract [en]

    Managing ecosystems for multiple ecosystem services and balancing the well-being of diverse stakeholders involves different kinds of trade-offs. Often trade-offs involve noneconomic and difficult-to-evaluate values, such as cultural identity, employment, the well-being of poor people, or particular species or ecosystem structures. Although trade-offs need to be considered for successful environmental management, they are often overlooked in favor of win-wins. Management and policy decisions demand approaches that can explicitly acknowledge and evaluate diverse trade-offs. We identified a diversity of apparent trade-offs in a small-scale tropical fishery when ecological simulations were integrated with participatory assessments of social-ecological system structure and stakeholders' well-being. Despite an apparent win-win between conservation and profitability at the aggregate scale, food production, employment, and well-being of marginalized stakeholders were differentially influenced by management decisions leading to trade-offs. Some of these trade-offs were suggested to be taboo trade-offs between morally incommensurable values, such as between profits and the well-being of marginalized women. These were not previously recognized as management issues. Stakeholders explored and deliberated over trade-offs supported by an interactive toy model representing key system trade-offs, alongside qualitative narrative scenarios of the future. The concept of taboo trade-offs suggests that psychological bias and social sensitivity may exclude key issues from decision making, which can result in policies that are difficult to implement. Our participatory modeling and scenarios approach has the potential to increase awareness of such trade-offs, promote discussion of what is acceptable, and potentially identify and reduce obstacles to management compliance.

  • 39. de Fraiture, Charlotte
    et al.
    Wichelns, Dennis
    Rockström, Johan
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Kemp-Benedict, Eric
    Eriyagama, Nishadi
    Gordon, Line J.
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Hanjra, Munir A.
    Hoogeveen, Jippe
    Huber-Lee, Annette
    Karlberg, Louise
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Looking ahead to 2050: scenarios of alternative investment approaches2007In: Water for Food, Water for Life: A Comprehensive Assessment of Water Management in Agriculture / [ed] David Molden, London: Earthscan , 2007, p. 91-145Chapter in book (Refereed)
  • 40. De Frenne, Pieter
    et al.
    Rodriguez-Sanchez, Francisco
    Coomes, David Anthony
    Baeten, Lander
    Verstraeten, Gorik
    Vellend, Mark
    Bernhardt-Roemermann, Markus
    Brown, Carissa D.
    Brunet, Jorg
    Cornelis, Johnny
    Decocq, Guillaume M.
    Dierschke, Hartmut
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Gilliam, Frank S.
    Hedl, Radim
    Heinken, Thilo
    Hermy, Martin
    Hommel, Patrick
    Jenkins, Michael A.
    Kelly, Daniel L.
    Kirby, Keith J.
    Mitchell, Fraser J. G.
    Naaf, Tobias
    Newman, Miles
    Peterken, George
    Petrik, Petr
    Schultz, Jan
    Sonnier, Gregory
    Van Calster, Hans
    Waller, Donald M.
    Walther, Gian-Reto
    White, Peter S.
    Woods, Kerry D.
    Wulf, Monika
    Graae, Bente Jessen
    Verheyen, Kris
    Microclimate moderates plant responses to macroclimate warming2013In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 110, no 46, p. 18561-18565Article in journal (Refereed)
    Abstract [en]

    Recent global warming is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., thermophilization of communities). Lack of community responses to increased temperature, however, has also been reported for several taxa and regions, suggesting that climatic lags may be frequent. Here we show that microclimatic effects brought about by forest canopy closure can buffer biotic responses to macroclimate warming, thus explaining an apparent climatic lag. Using data from 1,409 vegetation plots in European and North American temperate forests, each surveyed at least twice over an interval of 12-67 y, we document significant thermophilization of ground-layer plant communities. These changes reflect concurrent declines in species adapted to cooler conditions and increases in species adapted to warmer conditions. However, thermophilization, particularly the increase of warm-adapted species, is attenuated in forests whose canopies have become denser, probably reflecting cooler growing-season ground temperatures via increased shading. As standing stocks of trees have increased in many temperate forests in recent decades, local microclimatic effects may commonly be moderating the impacts of macroclimate warming on forest understories. Conversely, increases in harvesting woody biomass-e.g., for bioenergy-may open forest canopies and accelerate thermophilization of temperate forest biodiversity.

  • 41. De Smedt, Pallieter
    et al.
    Baeten, Lander
    Berg, Matty P.
    Gallet-Moron, Emilie
    Brunet, Jorg
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Decocq, Guillaume
    Diekmann, Martin
    Giffard, Brice
    De Frenne, Pieter
    Hermy, Martin
    Bonte, Dries
    Verheyen, Kris
    Desiccation resistance determines distribution of woodlice along forest edge-to-interior gradients2018In: European journal of soil biology, ISSN 1164-5563, E-ISSN 1778-3615, Vol. 85, p. 1-3Article in journal (Refereed)
    Abstract [en]

    Forest edges show strong abiotic and biotic gradients potentially altering community composition and ecosystem processes such as nutrient cycling. While abiotic gradients are well studied, short-scale biotic gradients, like detritivore species composition and their associated trait distribution remains a poorly explored research-field. We sampled woodlice in 160 forest patches across Europe at varying distances from the forest edge and discovered that species desiccation resistance determines distribution along forest edge-to-interior gradients. Forest edges are warmer and dryer compared to interiors and favour drought-tolerant species, while abundance and activity of drought-sensitive species is reduced at the edge. Key ecological factors for litter-dwelling detritivores (i.e. humidity) act as environmental filter, because of species-specific differences in desiccation resistance. Future research should focus on quantifying the consequences of a changing detritivore community and their associated functional traits for nutrient cycling.

  • 42. Defeo, Omar
    et al.
    Castrejon, Mauricio
    Perez-Castaneda, Roberto
    Castilla, Juan C.
    Gutierrez, Nicolas L.
    Essington, Timothy E.
    Folke, Carl
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Beijer Institute, Royal Swedish Academy of Sciences, Sweden.
    Co-management in Latin American small-scale shellfisheries: assessment from long-term case studies2016In: Fish and Fisheries, ISSN 1467-2960, E-ISSN 1467-2979, Vol. 17, no 1, p. 176-192Article in journal (Refereed)
    Abstract [en]

    Co-management (Co-M), defined as the sharing of management tasks and responsibilities between governments and local users, is emerging as a powerful institutional arrangement to redress fisheries paradigm failures, yet long-term assessments of its performance are lacking. A comparative analysis of five small-scale Latin American shellfisheries was conducted to identify factors suggesting success and failure. In Chile, Uruguay and Mexico Co-M produced positive effects, including stabilization of landings at low levels, increase in abundance, CPUE, unit prices and revenues per unit of effort, and reduced interannual variability in several fishery indicators, particularly in landings. Co-M was successful because it was mainly bottom-up implemented and accompanied by-catch shares (spatial property rights and community quotas). By contrast, Co-M implementation was unable to prevent the collapse of the Galapagos sea cucumber fishery, as reflected by a decrease in abundance and CPUE. Negative effects were also observed in the Galapagos spiny lobster fishery during Co-M implementation. However, recovery was observed in recent years, reflected in a stabilization of fishing effort and the highest CPUE and economic revenues observed since the beginning of the Co-M implementation phase. The combined effects of market forces, climate variability and a moratorium on fishing effort were critical in fishery recovery. We conclude that Co-M is not a blueprint that can be applied to all shellfisheries to enhance their governability. These social-ecological systems need to be managed by jointly addressing problems related to the resources, their marine environment and the people targeting them, accounting for their socioeconomic and cultural contexts.

  • 43.
    Drury O'Neill, Elizabeth
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Small-Scale Fisheries Governance: Broadening Perspectives on Markets, Relationships and Benefits in Seafood Trade2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This licentiate adresses the relative ambiguity surounding benefit flows from small-scale fisheries seafood trade with a specific focus on how they may be impacted by market and social stuctures. Small-scale fishery governenace has previously taken a narrowly approach to sustainability. Focused on managing fishing activities, economic-led market interventions and overlooking the embededness of the fishers within a broader social structure. Also failing to address fisheries as interlinked social-ecological systems where feedbacks between the two can impact future sustainability. The larger PhD project takes a step towards combining these two out-of-focus areas by taking a systems perspective, through a Value Chain approach, to fisheries governance, associated market influences and the consequent benefit flows from marine ecosystem services. This licentiate begins by unpacking dynamics within the social realm that may impact benefit flows and ultimately resource extraction decisions, potentially contributing to feedbacks from the marine ecosystem. Research uses mixed-methods and is case-orientated with sites across two tropical marine small-scale fisheries in Zanzibar and the Philippines. Results present two market environments with distinct structures, conduct, reciprocity systems and notably, gender roles. However both systems experience economic transactions underlain by broader social relations and binds. These various features manifest themselves in different, yet often unexpected, ways through income equalities, distributions and reciprocal networks of fishers and trading actors. Once a broadened and diversified view of the SSF trading environment is appropriated, it is clear that benefit flows are impacted by various contextual features (e.g. gender, transaction forms and buyer types). Governance-related research or interventions should incorporate undervalued local attributes such as cultural characteristics, social relationships and market participation as they play a role in who benefits from seafood trade. Thus If governance is to be improved for sustainably increasing food and livelihood security it is necessary to unpack these benefit flow mechanisms and, in particular, the local social dynamics that mediate fishers’ everyday interplay with the marine ecosystem. Future steps include the aim to identify potential social-ecological feedbacks between the disentangled market environments and the local marine ecosystems as a result of interactions in SSF trade. 

  • 44.
    Drury O'Neill, Elizabeth
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Crona, Beatrice
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The Royal Swedish Academy of Sciences, Sweden.
    Assistance networks in seafood trade - A means to assess benefit distribution in small-scale fisheries2017In: Marine Policy, ISSN 0308-597X, E-ISSN 1872-9460, Vol. 78, p. 196-205Article in journal (Refereed)
    Abstract [en]

    This article addresses the connections between value chain actors in the tropical-marine small-scale fisheries of Zanzibar, Tanzania, to contribute to a better understanding of the fisher-trader link and how connections in general might feed into livelihood security. A sample of 168 fishers and 130 traders was taken across 8 sites through questionnaires and observations. The small-scale fishery system is mapped using a value chain framework both traditionally and from a less economic point of view where the assistance-exchange networks between fishery actors add another layer of complexity. Auxiliary actors previously disregarded emerge from the latter method thus shedding light on the poorly understood distribution of benefits from seafood trade. Female actors participate quite differently, relative to males in the market system, detached from high-value links such as the tourist industry, and access to predetermined or secured sales deals. Data shows that the fisher-trader link is not as one-sided as previously presented. In fact it has a more symbiotic exchange deeply nested in a broader trading and social system. Expanding the analysis from this link by taking a further step downstream highlights traders' own sales arrangements and the social pressures they are under in realizing them. A complex picture, inclusive of diversified perspectives, on interactions in the market place is presented, as well as a. reflection on the remaining critical question: how to integrate this type of data into decisions about future fisheries governance.

  • 45. 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.

  • 46. Duro, Nuno
    et al.
    Batista-Santos, Paula
    da Costa, Mario
    Maia, Rodrigo
    Castro, Isabel V.
    Ramos, Margarida
    Ramalho, Jose C.
    Pawlowski, Katharina
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Maguas, Cristina
    Ribeiro-Barros, Ana
    The impact of salinity on the symbiosis between Casuarina glauca Sieb. ex Spreng. and N-2-fixing Frankia bacteria based on the analysis of Nitrogen and Carbon metabolism2016In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 398, no 1-2, p. 327-337Article in journal (Refereed)
    Abstract [en]

    Casuarina glauca is an actinorhizal plant that establishes root-nodule symbiosis with N-2-fixing bacteria of the genus Frankia. This plant is highly recalcitrant to extreme environmental conditions such as salinity and drought. The aim of this study was to evaluate the impact of salt stress on the symbiotic relationship between C. glauca and Frankia Thr, focusing on N and C metabolism. Symbiotic and non-symbiotic plants were exposed to 0, 200, 400 and 600 mM NaCl. The following analyses were performed: stable carbon (delta C-13) and nitrogen (delta N-15) isotope signature; nitrogenase activity in nodules (acetylene reduction assay); and gene expression of a set of genes involved in nodule infection and N/C metabolism (qRT-PCR). Data were analysed using two-way ANOVA. Salt stress induced an enrichment in delta C-13 and delta N-15, reflecting a negative impact of salt in the relative water content and N-2 fixation, respectively. Furthermore, nitrogenase activity in nodules was insignificant already at 200 mM NaCl, consistent with the expression patterns of nifH as well as of plant genes involved in nodule induction and metabolism. The ability of C. glauca to thrive under highly saline environments is not dependent on the symbiosis with Frankia.

  • 47.
    Edvinsson, Rodney
    Stockholm University, Faculty of Social Sciences, Department of Economic History.
    Harvests and grain prices in Sweden 1665-18702012In: Agricultural History Review, ISSN 0002-1490, Vol. 60, p. 1-18Article in journal (Refereed)
    Abstract [en]

    This paper investigates the impact of harvests and international markets on Swedish grain prices, 1665-1870. The paper finds that harvests at a national level had a greater impact on domestic grain prices than international grain prices. However, at a regional level, grain prices tended to be affected more by harvests outside the region. Furthermore, in the long term, foreign prices became a more important determinant of national grain prices. The conclusion is that, under certain circumstances, grain prices can be used as an indicator of harvest fluctuations and to construct historical national accounts, at least at a sufficiently aggregated level. Such an endeavour needs to be combined with a careful analysis of the impact of prices in the surrounding area.

  • 48. Eero, Margit
    et al.
    Hjelm, Joakim
    Behrens, Jane
    Buchmann, Kurt
    Cardinale, Massimiliano
    Casini, Michele
    Gasyukov, Pavel
    Holmgren, Noel
    Horbowy, Jan
    Hussy, Karin
    Kirkegaard, Eskild
    Kornilovs, Georgs
    Krumme, Uwe
    Koster, Friedrich W.
    Oeberst, Rainer
    Plikshs, Maris
    Radtke, Krzysztof
    Raid, Tiit
    Schmidt, Joern
    Tomczak, Maciej T.
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Vinther, Morten
    Zimmermann, Christopher
    Storr-Paulsen, Marie
    Food for Thought Eastern Baltic cod in distress: biological changes and challenges for stock assessment2015In: ICES Journal of Marine Science, ISSN 1054-3139, E-ISSN 1095-9289, Vol. 72, no 8, p. 2180-2186Article in journal (Refereed)
    Abstract [en]

    The eastern Baltic (EB) cod (Gadus morhua) stock was depleted and overexploited for decades until the mid-2000s, when fishing mortality rapidly declined and biomass started to increase, as shown by stock assessments. These positive developments were partly assigned to effective management measures, and the EB cod was considered one of the most successful stock recoveries in recent times. In contrast to this optimistic view, the analytical stock assessment failed in 2014, leaving the present stock status unclear. Deteriorated quality of some basic input data for stock assessment in combination with changes in environmental and ecological conditions has led to an unusual situation for cod in the Baltic Sea, which poses new challenges for stock assessment and management advice. A number of adverse developments such as low nutritional condition and disappearance of larger individuals indicate that the stock is in distress. In this study, we (i) summarize the knowledge of recent changes in cod biology and ecosystem conditions, (ii) describe the subsequent challenges for stock assessment, and (iii) highlight the key questions where answers are urgently needed to understand the present stock status and provide scientifically solid support for cod management in the Baltic Sea.

  • 49. Eklöf, Karin
    et al.
    Meili, Markus
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Åkerblom, Staffan
    von Bromssen, Claudia
    Bishop, Kevin
    Impact of stump harvest on run-off concentrations of total mercury and methylmercury2013In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 290, p. 83-94Article in journal (Refereed)
    Abstract [en]

    Forest harvesting operations have been reported to increase the levels of both total mercury (THg) and methylmercury (MeHg) in runoff water and downstream biota. Mobilization of such harmful substances by logging may pose ecological risks that may be influenced further by site preparation and stump harvest. Stump harvest is currently being explored as a method to increase the supply of biofuels. In this catchment study we investigated the effects of stump harvest, in comparison with ordinary site-preparation, on the runoff concentrations of THg and MeHg as well as several other chemistry parameters. Both treatments were also compared with unharvested reference catchments. Water samples from watercourses draining these catchments were analyzed for various variables including THg, MeHg, total organic carbon, absorbance and total suspended solids. One year of pre-treatment data, starting when the treated areas were just logged, and 2 years of post-treatment data, after stump harvest or site-preparation, were collected with a sample frequency of twice a month. The concentrations of THg and MeHg in the treated areas were decreasing after both stump harvest and site preparation relative to the reference catchment. Further, our results indicate that stump harvest has not caused increased concentrations of any of the studied parameters in relation to traditional site preparation. Two factors are proposed to be responsible for the lack of response to stump harvest and site preparation; (1) the areas are still undergoing recovery from the former logging which may have led to greater Hg export and/or (2) there is variability among sites in how they respond to forestry operations, depending on the biogeochemical and hydrological status of the area. Although no forestry response caused by stump harvest or site preparation was found, we noted that the concentrations of both THg and especially MeHg were high (median THg: 4.5-10.4 ng L-1, median MeHg: 0.7-2.1 ng L-1) in all catchments both before and after treatment, compared to other studies. Variables indicating the organic carbon content were the ones most strongly correlated to the variation of both THg and MeHg in the PLS models based on the dataset from the whole sampling period and all catchments. The relatively high concentrations of THg and MeHg during the study period appeared to be more influenced by organic carbon, but also hydrology and temperature as well as possibly the initial logging rather than by the soil disturbance caused by either stump harvest or site preparation.

  • 50.
    Enfors, Elin
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology. Stockholm University, Stockholm Resilience Centre.
    Barron, Jennie
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Makurira, Hodson
    University of Zimbabwe.
    Rockström, Johan
    Stockholm University, Stockholm Resilience Centre, Stockholm Environment Institute.
    Tumbo, Siza
    Sokoine University of Agriuclture.
    Yield and soil system changes from conservation tillage in dryland farming: A case study from North Eastern Tanzania2011In: Agricultural Water Management, ISSN 0378-3774, E-ISSN 1873-2283, Vol. 98, no 11, p. 1687-1695Article in journal (Refereed)
    Abstract [en]

    Yield levels in smallholder farming systems in semi-arid sub-Saharan Africa are generally low. Water shortage in the root zone during critical crop development stages is a fundamental constraining factor. While there is ample evidence to show that conservation tillage can promote soil health, it has recently been suggested that the main benefit in semi-arid farming systems may in fact be an in situ water harvesting effect. In this paper we present the result from an on-farm conservation tillage experiment (combining ripping with mulch and manure application) that was carried out in northeastern Tanzania from 2005 to 2008, testing this hypothesis. Special attention was given to the effects on the water retention properties of the soil. The tested conservation treatment only had a clear yield increasing effect during one of the six experimental seasons (maize grain yields increased by 41%, and biomass by 65%), and this was a season that received exceptional amounts of rainfall (549 mm). While the other seasons provided mixed results, there seemed to be an increasing yield gap between the conservation tillage treatment and the control towards the end of the experiment. Regarding soil system changes, small but significant effects on chemical and microbiological properties, but not on physical properties, were observed. This raises questions about the suggested water harvesting effect and its potential to contribute to stabilized yield levels under semi-arid conditions. We conclude that, at least in a shorter time perspective, the tested type of conservation tillage seems to boost productivity during already good seasons, rather than stabilize harvests during poor rainfall seasons. Highlighting the challenges involved in upgrading these farming systems, we discuss the potential contribution of conservation tillage towards improved water availability in the crop root zone in a longer-term perspective.

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