| 1. |
- Axelsson Linkowski, Weronika
(författare)
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Managing mountains, past and present conditions for traditional summer farming and Sami reindeer husbandry in northern Scandinavia
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traditional land use and conditions for maintenance of biodiversity are often interlinked. When land use changes and ecosystems change as a result, there is a risk to loose both the traditional ecological knowledge and the biodiversity connected to this land use. This thesis focuses on traditional land use, summer farming and Sami reindeer husbandry, in the mountain areas of northern Scandinavia (mainly Sweden), in a historical and contemporary perspective. The overall aim is to contribute to the understanding of the conditions for the traditional land use in the Scandinavian (mainly Swedish) mountains, using the concepts of traditional ecological knowledge (TEK) and a historical-ecological perspective. Both summer farming and reindeer husbandry are under strong external pressure and face large challenges today. Some of these challenges are shared and some differ between the two types of northern pastoralism. Scandinavian summer farmers experience that different views on their land use from different authorities affect them negatively. The increasing populations of large carnivores also worry the summer farmers. Recent depredation rates are in fact of the same level as historically (around 1900). Interviews showed that traditional knowledge about protective measures had eroded during years without carnivores, but also that farming practices have changed recently and that new knowledge developed. Sami plant use has been studied historically, but information about Sami plant management of Angelica archangelica was not documented. We argue that Sami ecological knowledge should be used to ensure sustainable harvest methods. Today traditional reindeer husbandry faces severe problems due to the reduction of winter grazing land by different encroachments, most importantly from modern forestry. The negative effects are even larger since increasingly difficult winter conditions create a need for a wider range of good grazing areas. Traditional knowledge is essential in the herders´ daily work, but the usability of the knowledge is severely constrained by recent changes. In the future planning of an ecologically and socially sustainable mountain management it is necessary to work with traditional land users and integrate their traditional knowledge.
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| 2. |
- Miller, Andrea
(författare)
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The role of rodents in the transmission of Echinococcus multilocularis and other tapeworms in a low endemic area
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Echinococcus multilocularis is zoonotic tapeworm in the Taeniidae family with a two part lifecycle involving a canid definitive host and a rodent intermediate host. The work of this thesis followed the first identification E. multilocularis in Sweden in 2011 in a red fox (Vulpes vulpes). The main purpose was to describe the importance of the rodents for E. multilocularis transmission in Sweden. Echinococcus multilocularis was identified in both the water vole (Arvicola amphibius) and the field vole (Microtus agrestis), but not the bank vole (Myodes glareolus) or mice (Apodemus spp). As the number of E. multilocularis positive rodents was low (n=9), the examination of other taeniid parasites was used to investigate overall parasite transmission patterns. Rodents caught in field habitat (field voles and water voles) were ten times more likely to be parasitized than rodents caught in forest habitat (bank voles and mice). These results provide further support for the importance of field- and water voles found in field habitat for cestode transmission. Still, these rodent species differ from the most common rodent intermediate hosts in central Europe, and metacestode development within these species may be limited. Thus, the presence of E. multilocularis in Sweden could be constrained by the lack of an ideal intermediate host. The distribution E. multilocularis was found to be highly aggregated with localized areas of high parasite egg contamination. Despite an extremely low national prevalence, multiple positive rodents and feces were identified in areas with known and unknown E. multilocularis status. This success is credited to the targeted sampling strategy, which was designed to focus collection efforts in areas where risk for parasite presence was estimated to be highest. This sampling strategy could be used as a basis for future risk-based sampling to detect E. multilocularis in areas where parasite prevalence is low or unknown.
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| 3. |
- Giusti, Matteo, 1982-
(författare)
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Home for future Earth lovers : Foundations of nature-connecting habitats for children
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modern childhood is increasingly segregated from nature. Yet, children’s nature experiences are first steps for sustainable futures. In this thesis, I research the foundations of habitats that can connect children to nature. I call them nature-connecting habitats.Five papers in this thesis answer: (RQ1) what is children’s human-nature connection (HNC)?; and (RQ2) what are the requirements of nature-connecting habitats for children? The preschools paper shows that five-year-olds with nature-rich routines have higher HNC than children with nature-poor routines, but it cannot understand which nature experiences are most influential. Hence, the salamanders paper assesses children’s participation in a nature conservation project. Discrepancies between the qualitative and quantitative results reveal an assessment gap with theoretical roots, which impedes the assessment of nature experiences in practical time-frames. To close this gap, the review paper surveys the literature and shows that attributes of the mind, qualities of nature experiences, and attachment to places are all aspects of HNC. The embody paper conceptualizes an embodied approach to HNC to overcome the barriers identified previously, and the toolbox paper operationalises it to develop a toolbox to assess children’s HNC and nature-connecting habitats.Answering RQ1, results show that children’s HNC is a complex set of embodied abilities. Human-nature relationships that could enable, promote, or assist sustainable development are a set of abilities that children can learn. These abilities are relationships between mind, body, culture, and environment, and progress following non-linear dynamics. This thesis identifies 10 of these abilities of HNC and finds that children learn them in three consecutive phases. Phase one – being in nature – includes feeling comfortable in natural spaces, and being curious about nature. Phase two – being with nature – includes reading natural spaces, acting in natural spaces, feeling attached to natural spaces, knowing about nature, and recalling memories with nature. Phase three – being for nature – includes taking care of nature, caring about nature, and being one with nature.Answering RQ2, two requirements of nature-connecting habitats are found: significant nature situations and various nature routines. Nature situations that can connect children to nature are characterised by configurations of 16 qualities – qualities of significant nature situations. These qualities are: entertainment, thought-provocation, awe, surprise, intimacy, mindfulness, self-restoration, creative expression, physical activity, challenge, engagement of senses, child-driven, involvement of mentors, structure/instructions, social/cultural endorsement, and involvement of animals. This set of qualities delineates the kinds of nature situations that nature-connecting habitats have to provide. These qualities should be various and recurring to allow children’s HNC to progress – hence, various nature routines. These lists of abilities and qualities form a toolbox capable of assessing where and how children connect to nature, named ACHUNAS.This thesis sets the stage to develop nature-connecting habitats. Children’s HNC and nature-connecting habitats are not the only intervention to promote sustainable futures, but they might be necessary conditions to meet the ever-shifting target of sustainable civilizations.
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| 4. |
- Lindkvist, Emilie, 1973-
(författare)
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Learning-by-modeling : Novel Computational Approaches for Exploring the Dynamics of Learning and Self-governance in Social-ecological Systems
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As a consequence of global environmental change, sustainable management and governance of natural resources face critical challenges, such as dealing with non-linear dynamics, increased resource variability, and uncertainty. This thesis seeks to address some of these challenges by using simulation models. The first line of research focuses on the use of learning-by-doing (LBD) for managing a renewable resource, exemplified by a fish stock, and explores LBD in a theoretical model using artificial intelligence (Paper I and II). The second line of research focuses on the emergence of different forms of self-governance and their interrelation with the dynamics of trust among fishers when harvesting a shared resource, using an agent-based model. This model is informed by qualitative data based on small-scale fisheries in Mexico (Paper III and IV). Paper I and II find that the most sustainable harvesting strategy requires that the actor values current and future yields equally, cautiously experiments around what is perceived as the best harvest action, and rapidly updates its ‘mental model’ to any perceived change in catch. More specifically, Paper II reveals that understanding these aspects in relation to the type of change can yield not only increased performance, but also, and more importantly, increased robustness to both fast and slow changes in resource dynamics. However, when resource dynamics include the possibility of a more fundamental shift in system characteristics (a regime shift), LBD is problematic due to the potential for crossing a threshold, resulting in possible persistent reductions in harvests (Paper I). In Paper III, results indicate that cooperative forms of self-governance are more likely to establish and persist in communities where fishers’ have prior cooperative experience, fishers’ trustworthiness is more or less equal, and that this likelihood increases when resource availability fluctuates seasonally. Finally, to achieve a transformation toward more cooperative forms of self-governance, interventions are required that can strengthen both financial capital and trust among the members of the cooperatives (Paper IV). The unique contribution of this thesis lies in the method for ‘quantitatively’ studying LBD, the stylized model of a small-scale fishery, and the analysis of the two models to advance our understanding of processes of learning and self-governance in uncertain and variable social-ecological environments. Together, the results shed light on how social and ecological factors and processes co-evolve to shape social-ecological outcomes, as well as contributing to the development of novel methods within the emerging field of sustainability science.
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| 5. |
- Abadikhah, Marie, 1992
(författare)
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Microbial communities in biological electrochemical systems
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Biological electrochemical systems (BES) can be used as biosensors and for recovery of resources from waste streams. BES utilizes microbial communities that grow on the surface of electrodes in the form of biofilms. Electrogenic bacteria residing in the anode biofilm initiate oxidation reactions, resulting in the release of electrons and subsequent electrical current generation. The electrons flow to the cathode where reduction reactions take place. Microbial biofilms may also be involved in the catalysis of cathode reactions. Many factors are involved in shaping the composition and performance of the microbial communities in BES, most of which remain poorly understood. In this thesis, the impact of electrode material and biotic interactions on performance and microbial community assembly was investigated in microbial electrolysis cells (MECs) oxidizing volatile fatty acids at the anode. MECs are a type of BES that require an applied electric potential to generate products such as H2, CH4, and acetate at the cathode. MECs with mixed-culture biofilms on both the anode and the cathode were studied. Two experiments were conducted. The first was a comparison of MECs with three different cathode materials: carbon nanoparticles, titanium, and steel. The second was a comparison of MECs with three different anode materials: carbon cloth, graphene, and nickel. Furthermore, the effect of dispersal limitation as well as the presence of viruses and their associations with microorganisms was investigated. MECs with carbon cloth anodes had the highest current density and shortest lag time during startup. In contrast, no significant impact of cathode material on MEC performance was seen. The anode communities were dominated by electrogens from the Desulfobacterota phylum, while the cathodes were dominated by methanogens from the Methanobacteriaceae family. Stochastic initial attachment by competing electrogens on the anode explained variations in the startup time between replicate MECs. In each experiment at least two different Desulfobacterota species competed for dominance on the anode. MECs that enabled dispersal between the system tended to have the same dominating taxa. Biotic interactions also affected the microbial communities in the system. Network analysis showed that the anode communities had a greater number of negative interactions between taxa compared to the cathode. Due to the need for direct contact by electrogens to transfer electrons to the anode, there is a higher competitive element to the colonization of the anode biofilm. Viral infection is another type of biotic interaction. Analysis of the prokaryotic and viral communities resulted in the identification of CRISPR-based and prophage virus-host associations, indicating previous infections and prophage inductions of electrochemically active microorganisms. These findings suggest that while there is selective pressure for electrogenic bacteria on the anode, stochastic factors, and biotic interactions play a larger role compared to electrode material in shaping the anode community.
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| 6. |
- Abbott, Jessica
(författare)
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Ontogeny and Population Biology of a Sex-Limited Colour Polymorphism
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study has involved investigation of number of populations of the damselfly Ischnura elegans over several years, looking at frequency changes over time, morphological differences between the sexes and the morphs, differences in growth rate and development time, differences in fecundity between the morphs, and genetic differentiation between populations. I. elegans is a small annual damselfly with three female colour morphs (Androchrome, Infuscans, and Infuscans-obsoleta), one of which (the Androchrome) is considered a male mimic; males are monomorphic. Empirically estimated selection coefficients were used in a population genetic and dynamic model with environmental variation which predicted coexistence of the three morphs. This suggests that negative frequency-dependence on fecundity mediated by male mating harassment is sufficient to explain coexistence of the morphs. Field data also showed that fecundity decreased with increasing frequency in the population for all three morphs. Investigation of sexual dimorphism revealed that the sexes differed in development time, growth rates, and adult size and shape and that sexual size dimorphism is produced in I. elegans by a combination of development time and development rate acting in concert. The female morphs also differed in development time, growth rates, and adult size and shape, although in this case effects of development time and development rate cancelled each other out. In addition, male-like body shape had a negative effect on fecundity in Infuscans-obsoleta females but not in Androchrome or Infuscans females. Quantitative genetic parameters for morphological traits showed that an evolutionary response to selection on body shape is possible. Comparisons of Fst-values and the lack of isolation by distance both suggest that this is a highly dynamic non-equilibrium system, and genetic diversity appears to be influenced by wind direction. The results in this study indicate that the morphs are subject to negative frequency-dependent selection via male mating harassment, and that the differences between the morphs are part of their identity as alternative adaptive strategies.
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| 7. |
- Abdelgadir, Mohanad
(författare)
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Aquatic ecosystem function and environmental change across spatial scales
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Microbial communities comprise immense diversity, mediating numerous ecosystem functions such as nitrogen transformation in aquatic ecosystems. Yet, how microbial communities and ecosystem functions respond to changes in environmental conditions at different spatial scales in aquatic habitats is not fully understood. This thesis investigates the effect of changes in environmental conditions at different spatial scales on Baltic Sea microbial diversity and nitrogen transformation, specifically denitrification, with a focus on biodiversity-ecosystem function relationship. Two spatial scale settings were examined. A small spatial scale setting was examined with experimental mesocosms of benthic sediment of different salinity and dissolved oxygen levels and at different spatial arrangements, and an incubation experiment conducted with benthic sediments from two different aquatic habitats enriched with 15N nitrate isotope. Microbial diversity, denitrification gene transcript abundances, and potential denitrification rate were analyzed. At a large spatial scale of the Baltic Sea benthic and coastal seascape, a metadata-based modeling approach was employed to investigate how current environmental conditions and future climatic change scenarios affect the predicted spatial distribution of key taxa of denitrifiers and nitrogen-fixing filamentous cyanobacteria. Results showed that salinity and dissolved oxygen levels significantly influenced denitrification capacity, according to analyses of transcript abundances of nirS and nosZ genes, which was mainly driven by habitat environmental conditions rather than habitat spatial arrangement. Bacterial community composition in experimental mesocosms was significantly affected by salinity. Findings from the small scale mesocosms experiments indicate that salinity can be an important driver of microbial denitrification capacity and affect microbial diversity in studied mesocosms. At large coastal and seascape scales, multi-realm environmental variables from both marine and terrestrial domains had significant impacts on the predicted distribution of the studied microbial taxa. The predicted distribution under different global warming trajectories indicated that rising temperatures in year2050 and 2100 risk reducing the current bio-climatically suitable areas of the studied denitrifiers and filamentous cyanobacteria across the Baltic Sea. The studies with experimental mesocosms and modeling approaches presented in this thesis contribute knowledge and novel predictions on the spatial response of ecosystem function and microbial communities to ongoing and future environmental changes in the Baltic Sea.
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| 8. |
- Abraham, David
(författare)
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Molecular aspects of pheromone evolution in moths
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Moths rely on the sense of smell (olfaction) as the main sensory input system in search for potential food sources and in selection of suitable females by males. Specific pheromones are fundamental to the reproductive isolation of species and consequently the olfactory system of moths has evolved to a high level of sensitivity and specificity. This thesis investigates differences between two pheromone types found in geometrid and noctuid moths. These two pheromone types are based on olefinic acetate and polyenic hydrocarbon pheromone components that differ in biosynthesis. Olefinic acetates are biosynthesised from palmitic acid while the polyenic hydrocarbon pheromone components are biosynthesised from linoleic or linolenic acid. To examine the evolution of these pheromone types within the geometrid moth family I constructed a phylogenetic tree based on 'neutral' genes. The combination of the phylogenetic tree with current knowledge about the two pheromone types, revealed that subfamilies within the geometrids have changed at least twice from one pheromone type to another. In addition, I examined if species that use different pheromone components also differ in their pheromone binding proteins (PBPs). Pheromone-binding proteins are soluble proteins, which increase the capture and the solubilization of pheromone molecules in the lymph surrounding the olfactory receptors. PBPs have been identified for several species of moths, among which also noctuid species. The Noctuid PBPs that identified so far, are divided into two groups, a conserved and a more variable group. These different PBP groups originate from gene duplication; the genes encoding PBPs in Agrotis ipsilon and Agrotis segetum all comprise three exons and two introns but differ in length, mostly in intron 2. It has been hypothesised that the differences between PBPs from the two groups and between PBPs from different species were related to their pheromone system. Species using the same main pheromone components could have similar PBPs. Phylogenetic analysis of all known PBPs supported this hypothesis for the noctuid PBPs that use olefinic acetate pheromone components. For this reason, I therefore attempted to identify PBPs for the geometrids Idaea aversata and Bupalus piniaria, and the closely related drepanid Cilix glaucata, which represent both the olefinic acetate and the polyenic hydrocarbon pheromone types. From partial sequences I found that these PBPs belong to the non-noctuid group of PBPs that show high similarity when the species are closely related, regardless of the pheromone types they represent.
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| 9. |
- Agostinelli, Marta
(författare)
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Fungal assemblages in forest trees : influence of internal and external conditions
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Forest trees host a plethora of microorganisms (bacteria, viruses, fungi) whose roles and diversity are still poorly understood despite the increased scientific interest for the past decades. The thesis focuses on the diversity of endophytic and epiphytic fungi in the aerial tissues of broadleaved trees. It tests a basic hypothesis that the diversity and frequency of endophytic and epiphytic fungi vary depending on the vitality and disease susceptibility of the host. Additionally the thesis explores if the chemical variation in trees may relate to differences in fungal community. Particularly, the aim was to describe how the fungal communities of three broadleaved species relate to the general vitality or specific pathogen resistance of the trees, and if herbivory or fertilization influence the fungi through altered levels of potentially antimicrobial metabolites, condensed tannins. Culture-based and culture-independent (NGS) techniques were used to capture the fungal community in the twigs of pedunculate oak (Quercus robur L), in the leaves of aspen (Populus tremula L), and in the leaves and twigs of European ash (Fraxinus excelsior L). The secondary metabolites were studied with HPLC, LC-MS, and GC-MS analyses. The results showed that the fungal assemblages are influenced by a complex network of factors related to the status of the host (internal factors: health, chemotype) and its environment (season, site, nitrogen, herbivory). Trees with different vitality or different phenotypic response to pathogen hosted quantitatively and qualitatively diverse fungal communities. Tissue type and seasonal variation were confirmed to be highly selective factors in shaping fungal communities of forest trees. The endophytic communities associated with xylem seemed to be shaped by the tree vitality more readily than the fungi associated with leaf or bark. Condensed tannins, nitrogen fertilization, and herbivory did not explain the structure of fungal communities in aspen leaves. Leaf phenolic metabolites reflected well the general vitality phenotype of the trees, but the relationship between fungi and phenolics may not be straightforward. The technological advances and the use of different methods to survey fungal communities may help disclosing the unknown fungal biodiversity hosted by forest trees. Further studies on fungal communities are needed to reveal the ecological relevance that fungal assemblages have in the regulation of major ecological cycles. Understanding the mechanisms regulating the establishment of fungal communities may contribute to the possibility of using fungal assemblages in forest practices to help forest coping with sudden changes and be able to provide different ecosystem services.
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| 10. |
- Agrell, Cecilia
(författare)
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Atmospheric transport of persistent organic pollutants to aquatic ecosystems
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The load of persistent organic pollutants (POPs) is considered high in the Baltic ecosystem. The Baltic Sea spans over 12 latitudes and the regional differences in climate affect the behavior of POPs. Therefore spatial and temporal variability of the concentrations of POPs in air and precipitation within this area has been investgated at 16 (mostly rural) stations around the Baltic Sea between 1990-1993. In addition, the deposition of gaseous and particulate associated POPs to the Baltic Sea is estimated from empirical data. This atmospheric input of POPs is compared with the input from rivers. Additionally, data from Ross Island, Antarctica and Lake Kariba, Zimbabwe, Africa is presented, and all results are discussed and explained using the ”global fractionation hypothesis” as a framework. In the Baltic Sea, concentrations of individual POPs in air were found to be influenced by their physical-chemical properties, ambient air temperature and location. A latitudinal gradient, with higher levels in the south was found for PCBs and the gradient was more pronounced for the low volatility congeners. As a result, the high volatility congeners in air increased in relative importance with latitude. Generally, PCB concentrations increased with temperature, but slopes of the partial pressure in air versus reciprocal temperature were different between congeners and between stations. In general, the low volatility congeners were more temperature dependent than the high volatility PCB congeners. Steep slopes at a sampling location indicate that the concentration in air is largely determined by diffusive exchange with soils. Lack of a temperature dependence may be due to the influence of long-range transported air masses at remote sites and due to the episodic, or random nature of PCB sources at urban sites. The concentrations of individual congeners in precipitation were found to be influenced by atmospheric concentrations of PCBs, ambient temperature, precipitation volume and the compounds physical-chemical properties. Concentrations of PCBs in precipitation decreased with temperature, and the slopes of this relationship were the same for all stations but differed between congeners. High volatility congeners showed steeper slopes for the temperature relationship than did low volatility PCB congeners. Annual wash out ratios were calculated and found to decrease with congener volatility. Wash out ratios generally decreased with temperature. At snow scavenging events the wash out ratio of PCBs increased with a factor of 2. Latitudinal trends for PCB concentrations in precipitation and for deposition were not statistically significant, but tended to be higher in the south for low volatility congeners. For high volatility congeners the latitudinal trend was reversed. Deposition of PCB congeners varied seasonally, with a factor between 2.0-3.2, and was generally highest during fall. The calculated yearly deposition of PCBs to the Baltic Sea was 387 kg and 5-18 kg for individual congeners, with PCB-138 having the highest flux.
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