Browsing Väitöskirjat by organization "Doctoral Programme in Interdisciplinary Environmental Sciences"

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  • Laaksoharju, Taina (Helsingin yliopisto, 2020)
    Nature contact has been acknowledged as beneficial for children’s development and wellbeing, as it is for all humans. At the same time, children’s free play in nature and independent mobility, ‘free-ranging,’ has been declining in Western societies in recent decades. One solution to this dilemma, nature clubs and camps with the aim of introducing and promoting children’s nature contact, are becoming increasingly common. Nature programmes aim to (re-)connect children and nature through educational goals. One example of such a place, the children's garden, is becoming increasingly recognized as a place where adults hope that children will learn various skills and subjects, while simultaneously hoping the children will improve their relationship with nature. Despite the known educational and health benefits of gardening, children's interactions with the actual physical elements of a place are less understood and examined. By recognizing more factors that affect children's process in forming a close, durable and meaningful relationship with natural places like the garden, adults become more capable of appropriately supporting children. The aim of this research was to unravel how children connect with such a natural space, the garden by looking at the place-specific affordances. The concept of affordances is the key to this study; it refers to the physical elements of the environment that reveal opportunities for interaction once they have been perceived. The research comprises two parts. The first phase of the study evaluated Finnish primary school children’s relationship with plants and nature, by comparing rural/suburban and boys’/girls’ attitudes and knowledge about plants and favourite places. The comparison was conducted through a survey of 76 children. Using mixed methods, the statistical analysis included paired cross tabulation, and chi-square-tests (χ2) to measure the significance of differences among the groups rural/suburban, and boys/girls. The second part of the study consisted of qualitative fieldwork with ethnographic participant and non-participant observations throughout summers 2008-2010 in the Kumpula School Garden in Helsinki. In order to study the phenomenon of how children make their connection to nature through place-based affordances, the study leans on an interpretivist ontology that views reality as understandable by observing actors within their social context. To assess the child-centred potential of a garden environment for building connection to nature, I examined the affordances in a garden camp context, focusing on 6- to 11-year-old, inexperienced children (~40 participants for each year of the study). The long-term fieldwork generated outstanding data: field reports and notes, videos, photographs and children’s drawings and interviews. Grounded theory method (GT) was applied in studies II and III. Analysis followed the GT analytical procedure of open coding, selective coding and theoretical coding. In GT, the initial basis for the study is to understand a particular social phenomenon in order to build a theory upon it. Inductive and repeated analysis focused on the children’s actions in combination with the actual natural affordances. In formulating the theory, the findings of garden affordances for children were evaluated relatively with these theoretical concepts: environmental child-friendliness (ECF), the zone of proximal development (ZPD), behavioural insideness, and connectedness to nature/place. Firstly, the results in study I showed that the relationship between nature and greenery differs according to residence and gender. The children living in a rural area (N= 34 in Paltamo, Kainuu) were more likely to mention natural places as their favourites than did their suburban counterparts (N=42 in Helsinki). Illustratively, rural children claimed to know the forest trees by name more often than the suburban children. In addition, the rural children understood mankind as part of nature, whereas suburban children were more likely to disagree with this claim. The group differences reported were statistically significant. The girls were, in general, more interested in plants than the boys. Alarmingly, 36% of the boys did not understand that plants are essential for human life. The girls understood better that plants are vital for human life. Second, results in the following studies II and III in the garden camp context showed that the versatility of affordances offered plenty of opportunities for building the nature-child relationship. The garden fostered social interactions by offering plentiful materials in a varied space. The variability and abundance of affordances boosted ZPD through scaffolding – learning together and from more experienced peers while using the affordances proved noteworthy in learning and passing on new skills. The essential factors that had a contributory role in the process of becoming empowered players within the setting were: sufficient time, the possibility of child-directed play and a space with a versatility of affordances available for use. With these factors, the garden affordances brought about 14 various play types. Trees were the most significant elements of the research site in fostering a relationship with nature. They answered children’s situational and individual needs by offering ideas, challenge, materials, and space for play. Wooden material affordances offered props and loose parts for different play needs. The trees possessed qualities equivalent to children’s needs for building self-confidence and emotion regulation, competence and belonging, creativity, excitement and affection. Climbing trees offered the children the challenge of handling risks autonomously. Consequently, trees serve well as indicator plants in assessing the children's connectedness to place. The children’s whole process of connecting with the place was captured, and the actual phases of this evolving connectedness are presented. Along with the concept of behavioural insideness that represents the behaviour of a child when she/he feels connected with a place, this study identifies the preceding phases: the initial phase as outsiders, then searchers, and finally the proactive insiders. In the first phase, as an outsider, the still insecure children looked for comfort around the vegetation. Tall trees were visibly inviting, offering an asylum or a shield before the children gained the confidence to start the searcher phase. The searchers, as the name implies, were constantly exploring their surroundings and the phase also involved showing off one's skills to make friends. For the searchers, the garden affordances offered versatility for choosing suitable materials and space. The biodiversity of the place was key to satisfying children’s needs by offering suitable affordances; it successfully fostered the development of behavioural insideness within two weeks, and this ultimately led to a strong connectedness to place. In the last phase as insiders, long-term play utilizing a wide variety of natural materials was typical, and the children behaved both spontaneously and imaginatively. The adults and peers had an effect on the children's connection process and to the actualization of garden's affordances, affecting the ECF. Impetus, which triggered the use of affordances, was either personal or situational. Some of the obstacles came from personal shortcomings, such as lack of interest or experience, or from fears and/or dislikes. Common obstacles from adults included a desire to move forward with the planned programme or an appeal to safety and rules. The development of a grounded theory, the IAO theory, outlines possible combinations of place-based impetuses, obstacles and affordances, all of which have an effect on the children’s process of connecting to place. The theory is an equation, which makes it user-friendly in assessing and planning children’s nature-based activities and environments. In addition, the theoretical framework of ‘Affordances channel connectedness to place’ opens up the external and internal preconditions necessary for children before they start utilizing the existing affordances, their three-phased process towards connectedness to place, and the manifestations of the final stage, behavioural insideness. Finally, a child-centred implication, PIT (Place-based, Intention and Time), provides guidelines to help adults to plan and conduct place-based, situational-sensitive nature activities for children. With these three GT outcomes, children’s connection to nature can be well supported.
  • Korpilo, Silviya (Helsingin yliopisto, 2018)
    Understanding use by and movement of people in urban green spaces is important to planning and management in order to balance between multiple user needs and the preservation of natural resources as ecologically and socially viable. Yet, in the current literature, little attention is paid to the intraspatial (i.e. within the area) behaviour of visitors and how this relates to the socio-ecological environment. In this thesis, I extend this knowledge by examining the links between spatial behaviour, characteristics, values and motivations of visitors, visitor use impacts and biodiversity in urban green spaces. I use a case study from Helsinki’s Central Park to answer four specific objectives. First, I aim to enhance the understanding of visitor spatial behaviour in terms of its distribution, intensity and related ecological impacts, as well as the social factors that affect it. Second, I examine the spatial relations between visitors’ movement, the values visitors assign to different landscapes and urban biodiversity, and how their integration can be used to inform spatial planning. Practically, I develop and demonstrate the use of participatory data collection methods for gathering citizen social-spatial information using smartphone GPS tracking and web-based public participation GIS. Finally, I provide recommendations for urban green space planning and management based on the findings. I identify several general and group-specific spatial and motivational patterns of visitors by comparing running, cycling, mountain biking, walking and dog walking in Central Park. I produce multi-scale spatial knowledge on the relationship between visitor use and impacts by examining dispersion trends at the stand and landscape level. At the landscape scale, the maps direct planning and managerial attention to threatened areas with spatial overlap between high ecological value and high density of visitor use. I go beyond visual analysis and investigate such ‘hotspots’ in-situ by mapping trampling impacts on paths and the forest floor vegetation. I provide ground evidence that the smartphone GPS tracking method effectively identifies areas of intensive use and heavy wear. In addition, my study identifies a ‘value-action’ gap in the public use of urban green spaces. The results show that visitors’ movement captures realized, everyday use that may spatially differ from the general values of people at the larger landscape scale. This highlights that both visitor spatial behaviour and perceived values provide important complementary information for urban green space planning and management. Participatory methodologies and related ethical considerations play an important role in this thesis. I demonstrate that integrating different participation modes for collecting volunteered information can help gather data that is heterogeneous, but rich and usable for various research and planning purposes. I discuss in detail the development and the benefits and limitations of these methods in order to support future transferability to different socio-ecological contexts. Overall, my thesis promotes collaboration and knowledge exchange between citizens, decision-makers, and researchers from different disciplines.
  • Mäntynen, Sanna (Helsingin yliopisto, 2018)
    Highly toxic polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) accumulate in the environment in sediments and soils. PCDD/Fs may pose considerable environmental and health risks because of their persistence in the environment. PCDD/Fs can be degraded slowly by microbial reductive dechlorination under anaerobic conditions which produces less chlorinated PCDD/Fs. Sediments of the Kymijoki River located in South-Eastern Finland are highly contaminated with PCDD/Fs and other chlorinated compounds. PCDD/Fs in sediments of the river mainly originate as unwanted byproducts from the production of the chlorophenol wood preservative Ky-5 between 1939 and 1984. The total volume of the most toxic 2,3,7,8-substituted PCDD/Fs contaminated sediments in the Kymijoki River, from Kuusankoski to the Baltic Sea, are estimated to be five million cubic meters of wet sediment. The Kymijoki River is the largest known source of PCDD/Fs to the Baltic Sea. The objective of this thesis was to gain knowledge on the sediment PCDD/Fs and the dechlorinating bacterial community at the Kymijoki River. We aimed to determine the potential for anaerobic microbial dechlorination of weathered PCDD/Fs in river sediments. Sediment samples were collected from the Kymijoki River located at 0, 20, 30, and 60 km downstream from the main source of contamination, and at a reference site. An anaerobic microcosm study was conducted to determine dechlorination potential and the effect of temperature on the reductive dechlorination process for spiked 1,2,3,4-tetrachlorodibenzofuran (1,2,3,4-TeCDF). Concentrations of weathered PCDD/Fs and activity of the indigenous dechlorinating microbial community were determined in sediment samples. The measured mean total concentrations for 2,3,7,8-PCDD/Fs were high in sediments at all study sites of the river. The predominant PCDD/F congeners were 1,2,3,4,6,7,8-HpCDF, 1,2,3,4,6,8,9-HpCDF, and OCDF at all sites. The sediment PCDD/F congener profiles were similar to that of the Ky-5 wood preservative. Dechlorination of spiked 1,2,3,4-TeCDF to less chlorinated dibenzofurans was detected after 10 and 29 months in sediment microcosms from the all studied sites. The pathway of 1,2,3,4-TeCDF dechlorination was mainly via 1,3,4-TrCDF to 1,3-DiCDF. The low temperature decreased the dechlorination rate of spiked TeCDF which suggests that dechlorination of weathered PCDD/Fs is limited at the in situ temperature of the river sediments. A native dechlorinating Dehalococcoides-like Chloroflexi community was present in sediment samples at all studied sites. The dechlorination pathway of 1,2,3,4-TeCDF suggests that dechlorination of aged PCDD/F congeners could generate non-2,3,7,8-substituted and hence less toxic PCDD/Fs. However, concentrations of 2,3,7,8-substituted PCDD/Fs have remained at approximately the same levels over the last few decades at each sampling location of the Kymijoki River. Furthermore, no substantial changes in the relative abundances of weathered PCDD/Fs were observed over 2.5 years in laboratory microcosm studies, indicating that anaerobic dechlorination of weathered PCDD/Fs was limited over the course of the experiment. Results of this study indicates that no or only minimal biodegradation of PCDD/F congeners has occurred in the river sediments over the last few decades since the contamination events. Therefore, concentrations of weathered PCDD/Fs in the sediments of the Kymijoki River are expected to remain at the same level for decades or centuries with further migration towards the Baltic Sea.
  • Roslund, Marja (Helsingin yliopisto, 2020)
    The incidence of immune-mediated diseases has increased rapidly in developed societies. According to the biodiversity hypothesis, the core reason is the evident biodiversity loss in urban areas. This biodiversity loss limits exposure to a diverse microbiota, which is associated with the human commensal microbiota and immune regulation. In addition, urban pollutants, such as polycyclic aromatic hydrocarbons (PAHs), may alter microbial communities and interfere with immune regulation. However, studies linking urban biodiversity loss, PAH pollution, environmental and human commensal microbiota and immune regulation are lacking. This study is one of the first to estimate the connections between environmental exposure, the commensal microbiota, and the immune response of urban children using both intervention trials and comparative studies. The aim of this study was also to develop practices to reduce the risk of non-communicable immune-mediated diseases that are globally recognized as emerging public health problems. These diseases comprise over 80 inflammatory disorders including allergies, type 1 diabetes, asthma and inflammatory bowel disease. The research focused on two aspects: the effect of biodiversity and pollution on the commensal microbiota of children and immune regulation. First, I estimated PAH induced bacterial shifts in polluted urban landscaping materials, and whether environmental exposure to PAHs can affect children’s commensal bacterial communities on the skin and in the gut. Secondly, we set up a human intervention trial in which urban environmental biodiversity was manipulated and examined its effects on environmental and commensal microbiota and immune regulation in children. The PAH pollution studies showed that PAHs may induce shifts in environmental and human commensal bacterial communities that are associated with human health and immune regulation. Bacterial shifts in urban landscaping materials depended on soil material type, indicating that in the future it is possible to design gardening and landscaping materials that are more resilient to bacterial shifts induced by PAH pollution. Soil PAH pollution in day-care center yards was associated with altered Actinobacteria, Bacteroidetes and Proteobacteria communities on children’s skin and in day-care yard soils. However, altered genera differed between skin and soil, excluding Mycobacterium, the abundance of which increased on skin and in soil with increasing surface soil PAH levels. Associations were not found between gut microbiota and PAH levels in day-care yard surface soils or ambient air. However, gaseous chrysene levels in the ambient air were associated with the endocrine signaling pathways predicted from the gut bacterial metagenome with the Kyoto Encyclopedia of Genes and Genomes. The peroxisome proliferator-activated receptor (PPAR) is a crucial signaling pathway in the regulation of inflammation, metabolism, and tumorigenesis. The PPAR signaling pathway together with the adipocytokine signaling pathway can regulate immune cells and affect hormonally-mediated diseases, including obesity, insulin sensitivity, puberty, and fertility. The PPAR and adipocytokine signaling pathways both decreased among children, with higher gaseous chrysene levels in the day-care center’s ambient outdoor air. These findings indicate that PAH concentrations that are below the risk assessment safety limits may alter the human commensal microbiota and interfere with endocrine signaling. The imbalance in human microbiota and the decrease in endocrine signaling pathways might contribute to inflammatory disorders. Therefore, optimal risk assessments should take into account the possibility of the disruption of endocrine signaling pathways and the microbiota–health nexus. The 28-day biodiversity intervention trial included 75 children in three different day-care environments (standard urban, biodiversity intervention, and nature-oriented). During this intervention, the environmental and intervention children’s commensal microbiota was diversified, which in turn promoted their immune regulation and eventually may have beneficial health consequences. Surface soil bacterial communities differed between intervention and standard day-care yards and, in particular, differences were seen within alpha-, beta-, and gammaproteobacterial classes. The relative abundance of bacteria typically found in the forests of Finland increased in intervention day-care yards. These environmental changes in day-care yards remained for 2 years. The diversity of proteobacterial communities in soil and on the skin of the day-care children increased during the 28-day intervention. Importantly, an increase in skin gammaproteobacterial diversity was associated with beneficial effects in immune regulation, promotion of the plasma transforming growth factor-β level and proportion of regulatory T cells, and a decline in pro-inflammatory interleukin 17A (IL-17A) levels. In addition, among intervention children the ratio between anti-inflammatory IL-10 and pro-inflammatory IL-17A increased, indicating that the biodiversity intervention promoted children’s immune regulation. In addition, among intervention children, I observed shifts within gut Ruminococcaceae and Lachnospiraceae communities that have earlier been associated with gut health. Interestingly, the microbiota on the skin and in the gut of intervention day-care children shifted toward those in nature-oriented day cares. I followed the environmental and commensal bacterial shifts on the skin, in the saliva, and in the gut for a 2-year period among children in the intervention group. This long-term study showed that the biodiversity intervention shifted the environmental and commensal bacterial communities at the intervention day cares, and these shifts include important primers for the immune system. In particular, environmental shifts were permanent based on the 2-year period. These results are proving valuable since now that we understand the effect of biodiversity in the living environment, we can shape children’s commensal bacteria and thus affect immune regulation. The challenge will be to design novel pathogen-free nature-based solutions for urban people that include a high diversity and richness of anti-inflammatory health-promoting bacteria. Future research should target this challenge. The results of this thesis support the biodiversity hypothesis: environmental biodiversity is associated with the commensal microbiota of humans and immune regulation. Indeed, both biodiversity loss and pollution in the urban environment may lead to an altered environmental microbiome. This in turn can lead to an imbalanced immune system and consequently increase the prevalence of emerging public health problems, including allergies, asthma, type 1 diabetes, and inflammatory bowel disease. Importantly, this study has demonstrated that modifying the living environment of children with microbiologically diverse natural materials might provide a feasible approach for decreasing the risk of immune-mediated diseases in urban populations.
  • Korkonen, Sanna (Helsingin yliopisto, 2020)
    The plankton of Finland’s vast amount of lakes are often dominated by diatoms and chrysophytes that, together with periphytic forms, end up in the sediment. All chrysophytes are known to produce siliceous resting stages called cysts that are endurable, considered species-specific, and well preserved in sediments. Thus far, the focus on utilizing these algal remains in palaeolimnology has been on diatoms, due to the ease of their identification compared to chrysophyte cysts. While cyst research in Finland has remained scarce, researchers elsewhere have successfully linked cyst morphotypes with several environmental variables. This has enabled the reconstruction of several environmental variables such as eutrophication, pH and temperature history, for several areas. In this thesis, cysts in lake sediments in Finland are studied for their distribution, seasonality and ecological preferences. The main aim is to create a cyst-based transfer function – a mathematical equation that formalizes the relationship between species and the environment – that could later be used in interpreting past environmental changes to simulate the impacts of future climate change. The reliability of the usage of sedimentary cysts in palaeolimnological environmental research was studied by comparing seasonal cyst assemblages accumulated during two hydrologically and weather-wise different years in sediment traps to the topmost surface sediment of a lake. In addition, previously unencountered cyst morphotypes are officially named and described, along with their ecological preferences. In total, 59 lakes in Finland, ranging from southern lakes to lakes above the treeline in Finnish Lapland, were sampled for their surface sediment for the cyst survey. In addition, sediment traps were employed and the surface sediment collected from Lake Nautajärvi to study cyst seasonality, sensitivity to hydrological and weather changes, and to verify that the surface sediment represents cyst production in the lake. All cyst identification was performed using a scanning electron microscope to enable the detection of minuscule ornamentation details. Altogether, 265 chrysophyte cyst morphotypes or collective categories were found among the 60 Finnish lakes. These cysts represent a variety of different cyst types, most of which are familiar from other cool, oligotrophic locations. However, 18 are new, previously undescribed morphotypes, currently exclusive to Finland. The most common cysts in Finland are unornamented types, most likely produced by several different species; there is also a variety of cysts that can be used in palaeolimnological investigations in the future. Temperature, pH, conductivity and total phosphorus were found to have a significant effect on cyst assemblages in Finland. Therefore, optima and tolerances for the most commonly occurring cyst types for these variables were calculated. Cysts in Finland show seasonality, with the majority of cysts being produced during spring and summer, while winter is essentially a standstill in cyst production. The most common cysts occur throughout the growing season, but there are also cysts that are linked to a specific season. Seasonal variation has a more profound effect on cyst occurrence than short-lived weather events between years. Surface sediment cyst assemblages comprised well with the sediment trap assemblages, supporting the assumption that produced cyst assemblages are well represented in lake sediment, and can hence be used in palaeolimnological investigations. This thesis sets the groundwork for chrysophyte cyst-related research in Finland, and fills a geographical void in cyst biogeography. Cysts in Finland show great potential, specifically in future pH and spring temperature reconstructions.
  • Leppänen, Jaakko (Helsingin yliopisto, 2019)
    The mining industry has a critical role in modern societies. However, the environmental harm induced by mining activities may be drastic. One of the most important aspects of mining pollution is water contamination due to accidental or controlled waste water release, or due to harmful leachate originating from waste areas. Whereas the water quality in receiving water systems is usually monitored, the ecological impacts of mine waters are assessed more rarely. One of the challenges when ecological impacts are studied is the lack of long-term data regarding the pre-mining conditions. Palaeolimnological methods allow the reconstruction of historical conditions of water bodies. Sedimentary geochemistry and subfossil remains of biological communities (e.g. cladoceran crustacea, diatom algae) can be used to assess the natural pre-disturbance variability, the impact of the disturbance and the post-disturbance dynamics. In this thesis, mining pollution is assessed within three projects, conducted on two boreal lakes in Finland. In Lake Kirkkojärvi, the impact of historical mining activity, namely, the direct release of mineral tailings was studied from a sediment core covering also the pre-mining environmental conditions. The impacts of the mine pollutants were reflected in cladoceran communities as declining species richness and diversity. The lake Kirkkojärvi bay was studied by using a palaeolimnological top-bottom approach. The bay has been receiving acid mine drainage for nearly 50 years. However, the cladoceran community change in the bay does not reflect any changes in acidity or metal pollution. In Lake Kivijärvi the Na2SO4- and metal-contaminated mine water has had a clear impact on cladoceran and diatom communities as both groups exhibit changes due to mining pollution. Based on the results, the most important contaminants in the studied systems are saline effluents and mineral tailings. Cladocera hold great potential in palaeolimnological mining pollution studies due to their sensitivity to changes in the water quality and due to their central location in food-webs. However, more research is still needed: Most importantly, some taxonomic issues must be clarified and in-situ toxicity studies should be conducted in order to find the most sensitive indicator species for different types of pollution. The results of this work present important information regarding pollution impact assessment. In particular, this study highlights the utility of Cladocera as early warning indicators, while supporting the use of multiple sediment proxies in palaeolimnological pollution research in order to provide information about the timing, direction, and magnitude of ecosystem impacts caused by pollution events. This is of essence for environmental management as globally the exploitation of poor-grade large mine deposits will drastically increase in the near future. Only by providing such crucial information on the short- and long-term impacts of mining on aquatic ecosystems and their resilience, a technologically, socially and environmentally sustainable management of mines can be guaranteed in the future.
  • Stjernberg, Mats (Helsingin yliopisto, 2019)
    This PhD study in urban geography focuses on a distinct neighborhood type in Finland, namely suburban housing estates (lähiö). Although suburban housing estates are currently topical in Finland, as they are often associated with various problems, there has been little research concerning their development in the country at large during the last few decades. The purpose of this study is to overcome this shortage by analyzing the socio-economic and demographic development of suburban housing estates within the whole of Finland and in different types of regions. The focus is on suburban housing estates dating from the 1960s and 1970s, which was the main period of housing estate construction in Finland. The study examines what was characteristic of such estates in 1990 and 2010, and what kind of changes can be seen in their socio-economic and demographic position during this time span. Furthermore, the research examines suburban housing estates in three different sub-regional types: growing, stable and shrinking sub-regions. For conducting the analysis, a GIS-based approach was developed for defining, identifying and locating housing estates dating from the 1960s and 1970s within the whole Finnish territory. The empirical analysis of the research is based on examining the development of suburban housing estates according to both individual variables as well as multivariate methods (principle components analysis and cluster analysis) with the intention of uncovering the relationships between different facets of change. The research findings show that Finnish suburban housing estates dating from the 1960s and 1970s were usually relatively average neighborhoods in 1990, but since then they have generally witnessed noticeable socio-economic decline along with profound demographic changes. Also the attractiveness of these types of neighborhoods has gradually decreased over time. The study suggests that the development of suburban housing estates is closely linked to broader societal changes and particularly to the development of their wider regions. Although decline is evident in most Finnish housing estates, it is notable that not all estates are socio-economically disadvantaged. This underlines that housing estates are far from homogenous and that their development paths have been highly diverse. Overall though, based on the changes identified in this study, the public concerns related to this distinct type of concrete suburbia are in many ways valid, and from the perspective of Finnish urban and housing policy, suburban housing estates appear to be one of the most central challenges during the years to come.
  • Chrysafi, Anna (Helsingin yliopisto, 2019)
    Stock assessment is a critical step in fisheries management, since it directly estimates reference points that help determine whether a population’s size is acceptable and subsequently, to set harvest levels. Therefore, many international agreements require that all exploited aquatic populations are assessed quantitatively. However, for the majority of the worlds’ harvested fish stocks, data is lacking. Such fisheries are often referred to as data-poor or data-limited and are a major challenge for stock assessment scientists and fisheries managers, since the traditional approaches to stock assessment cannot be implemented. The necessity to assess the status of all fisheries, led to the development of models tailored to data-limited situations. In this thesis, I first introduced the characteristics of data-limited fisheries, and then described the various quantitative indicators and models developed to assess them, some of which are widely used in real assessment schemes. I reviewed the approaches by their input requirements and their biological realism. Compared to the models used to assess data-rich stocks, models tailored to data-limited stock assessment contain a large degree of uncertainty and therefore, I recommended further exploration of the existing datalimited approaches. This thesis continued by focusing on a particular group of data-limited assessment methods, which are based on stock reduction analysis. Although such models can cope with low data availability, at the same time, they are particularly sensitive to the misspecification of relative stock status (expressed as the current biomass level relative to virgin biomass), a critical input requirement. However, stock status is unavailable for the majority of data-limited stocks. Therefore, I explored different sources of information used to estimate stock status under such circumstances. First, I considered the use of fisheries experts’ opinion and presented a method to elicit expert knowledge using a novel, user-friendly on-line application. To evaluate the experts’ ability to predict stock status, I compared the elicited distributions to stock statuses derived from data-rich models. In this work, I explored the performance of experts with different levels of experience in stock assessment, since scientific expertise is not evenly distributed throughout the world, and quantified how well they performed relative to each other. The results indicated that the true stock status is the most significant factor accounting for bias in expert opinions, followed by their experience level. Nevertheless, expert opinions are often used to inform management decisions and this thesis revealed that for data-limited stock assessment, expert elicited stock status priors potentially can be highly biased, leading to highly biased harvest recommendation levels. A way to overcome this issue is by calibrating expert judgment. To achieve this, my coauthors and I developed a hierarchical Bayesian model for expert calibration. The model’s main assumption is that experts’ biases vary as a function of the true value of the parameter, as identified in the expert elicitation experiment. Experts’ bias function was explicitly modeled, following the supra-Bayesian approach, using Gaussian processes to construct the prior, and the results of the expert elicitation experiment were used as calibration data to infer the posterior. The constructed models were tested both with simulated data and with the expert elicitation results. The tested models for expert judgment calibration, substantially improved stock status predictions compared to those that were uncalibrated and in comparison to vague uniform guesses, thereby demonstrating the value of calibration in minimizing expert bias. In the last article included in this thesis, uncalibrated and calibrated expert opinion derived stock status priors were compared to productivity and susceptibility (PSA) vulnerability scores and catch trend-derived (Boosted regression trees; BRTs) stock status priors. Furthermore, the performance of each of these methods was evaluated and compared to a commonly used prior that assumes a stock is at B40% (i.e. 40% of the virgin biomass). First, I evaluated the degree of bias in estimating true stock status and then, the effect of bias on the estimation procedure of overfishing limits (OFLs) in the specific assessment models for ten data-rich stocks. All, with the exception of fisheries experts with no experience in stock assessment, provided more accurate priors about stock status than the B40% rule. Experts with experience in stock assessment produced particularly informative and accurate priors, exemplifying their important role in the assessment procedure. Based on the performance evaluation and the data requirements for constructing a stock status prior, I recommended a procedure for selecting the most appropriate prior(s).
  • Virtanen, Elina (Helsingin yliopisto, 2020)
    Marine ecosystems are degrading around the world at an unprecedented rate. Loss of biodiversity, population declines, invasion of non-indigenous species, and change in community composition are apparent in all marine ecosystems. Various policies at multiple management levels address these challenges with specific targets for good ecological and environmental status of marine areas. While various policies, directives and strategies are applicable at global and regional levels, threats facing marine ecosystems in coastal areas are more localized. Thus, to achieve effective results, conservation and management actions should be designed and addressed locally, and carefully targeted to maximize cost-efficiency and benefits for the marine ecosystem. In this thesis, four case studies are developed which demonstrate how spatially explicit analyses can support seascape conservation, sustainable use of marine areas, as well as effective management actions: (1) locate key areas for conservation, (2) pinpoint areas for effective nutrient abatement, (3) identify locations for marine mineral extraction, and (4) estimate potential future changes in key communities with the projected declines in marine environment. This thesis aims to show how extensive data combined with appropriate spatial analysis paths together with cross-disciplinary marine science can support seascape conservation and ecosystem-based marine management. The role of management in sustaining marine biodiversity is investigated and the applicability of methods developed in terrestrial realm to marine environments is evaluated. The case studies are located in the northern Baltic Sea, where multiple stressors threaten marine biodiversity. The work relies on extensive species inventory data from 140,000 underwater sites, collected by the Finnish Inventory Programme for the Underwater Marine Environment (VELMU). Statistical modelling was used in case studies (1) and (4) to explain the distribution of species, and further in case studies (2) and (3) in describing hypoxia probabilities and the occurrence of ferromanganese concretions, respectively. Further, key areas for conservation were identified with spatial prioritization in case study (1). Based on the results, current marine protected areas (MPAs) leave almost three-quarters of ecologically important species occurrence areas unprotected. This highlights the need to further develop current MPA network, and the role of spatial planning in guiding the allocation of marine areas to human activities. Knowledge of unprotected key areas can be further utilized to promote private seascape conservation and sustainable use of marine areas. In case study (2), areas naturally prone to hypoxia development were identified with spatial analyses, borrowing concepts and methodologies from landscape ecology. The approach developed can be used to optimally target nutrient abatement measures to where they are most likely to be efficient, as well as explain why some areas are more or less immune to nutrient abatement actions already taken. Case study (4) further emphasizes that some areas would benefit more from nutrient abatement measures than others. Case study (3) demonstrated that marine minerals, namely ferromanganese concretions, are more widespread than previously anticipated. As concretions hold high quantities of minerals targeted by the emerging seabed mining industry, there may be economic opportunities for such extraction activities to take place also in the Baltic Sea. Results of the case studies (1) and (3) can guide detrimental mining activities to ecologically less valuable areas, where abundant concretions can be found. Spatially explicit analyses described in case studies (1)–(4) can provide valuable support for seascape conservation and ecosystem-based management and can give further guidance for sustainable use of marine areas. Finally, efficient management of marine areas requires the integration of local management actions into wider policy processes. Ecosystem-based marine spatial planning needs to adopt place-based management strategies and decisions that are actionable at various spatial scales and can be implemented locally.
  • Käyhkö, Janina (Helsingin yliopisto, 2020)
    This thesis is a study of climate change adaptation as a human adjustment process in the context of Northern European agriculture. It deals with the human decision-making entailing uncertainty, risks and opportunities brought about by climate change and climate policies. Agricultural production of food in Northern Europe is under pressure. There are constant changes in societal structures, such as policies and economic markets, as well as climatic stressors. The climate impacts pose direct risks to production, such as increasing floods and droughts, as well as indirect pressures through, for example, the global demand for arable lands. This constantly changing and complex socio-environmental context of food production is expected to drive processes of adjustment in the agricultural sector. Recent assessments suggest that in most parts of Europe adaptation measures in the agricultural sector will increase significantly in the coming years. Agricultural adaptation research is focused on the climate risks with respect to production and on the development of technical solutions. Agricultural and food production sciences are at the front line of technical development of adaptation measures, such as new plant varieties, production environments and cultivation measures. There is also a growing body of literature on the systemic complexity of adaptation needs and options focused on climate impacts. Farm-scale adaptation is mainly studied in the development and management research fields among other applied research focused on developing countries, farm economics and local case studies. The current literature suggests that farmers will implement the adaptation measures in order to secure their livelihoods and to sustain the productivity of agricultural soils and lands. The perspective of agri-food system practitioners, nevertheless, is less represented in adaptation literature. This is also true of research on the societal drivers and outcomes of adaptation. That said, there is research suggesting that although adaptation is aimed at decreasing risks and vulnerability, the farm-scale adaptation measures may have unintended harmful impacts to different actors and resources. These are identified in yet few empirical studies to involve economic losses at farm scale, local environmental damage and short-term productivity decreases. This presents a gap in the research that should provide background knowledge for governing the complex field of adaptation in agriculture and food production sectors. From the perspective of environmental and social sciences, the adaptation measures call for focused assessment in terms of their social drivers and socio-environmental outcomes in all regions globally. This thesis sets out to address this gap and increase understanding on adaptation measures as an issue of decision-making within complex socio-environmental contexts and trade-offs. This thesis applies a qualitative empirical study with an interdisciplinary epistemological stand and methodological approach that draws on agri-food system practitioner perceptions. The focus is on crop farmers and on farm-scale adaptation. Furthermore, attention is paid to other professionals of the sector who deal with various agri-food systems, development and management, and in governance. The research starts with an analysis of adaptation measures and the drivers for their implementation at farm scale and the agricultural sector, followed by an analysis of the potential unintended harmful outcomes of these measures. Finally, the transformative adaptation measures that concern the food systems in the Nordic context are analysed. Key findings of this thesis show that climate change adaptation measures in the Nordic agri-food systems are currently aimed at reducing risks and increasing long-term adaptive capacity when it serves the highly contextual and often subjective needs. These do not always reflect the public policy goals and often involve harmful outcomes with respect to other actors and the sustainable development goals. To advance sustainable implementation of adaptation measures in Nordic agriculture inevitably requires governance interventions that include actors from various fields of society.
  • Jokinen, Maarit (Helsingin yliopisto, 2019)
    Research and evaluation are crucial components of evidence-based policy, decision-making and effective conservation management. As research consumes the same limited resources that could be used for conservation, it should provide as valuable and useful information as possible. This requires framing research questions to be relevant to both researchers and users of the information. A general problem is that researchers may be detached from conservation policy and practice, and thus do not recognize information needs. Furthermore, measuring and predicting effects of conservation is not an easy task. The spatial scale considered, and whether the costs and side effects are taken into account, may affect the conclusions. Effective conservation has population-level effects, but accurately measuring population change requires adequate resources and both ecological and statistical expertise. In addition, as societal actions and change in human behaviour are needed to bring about the desired changes, interdisciplinary approaches are needed for finding solutions to conservation problems. In this thesis, I use the conservation of the Siberian flying squirrel (Pteromys volans) in Finland as a model case for developing more effective conservation research. As an arboreal species, the flying squirrel is threatened by forest habitat loss and degradation. I evaluate the ecological effectiveness of species protection regulation along with the side effects it has had on forest owner attitudes toward the species. I use species distribution modelling (SDM) to predict the occurrence probability of the species in Finland. I also evaluate the methods and results of the species monitoring scheme by using information from the SDM and modelled relationship between the species observed occurrence and abundance. I found that the effectiveness of the prior approval system for forest management on flying squirrel nest sites was low but made the species a symbol of broader socio-political disputes. Conservation ineffectiveness is partly due to insufficient restrictions for forest management, but also due to lacking occurrence information. I found that species occurrence probability is explained by several environmental variables, but the ability of SDM to predict occurrence at specific sites and years remains limited with available data. I also found that the design of the population monitoring scheme does not allow reliable inference of the change in population size from the collected occurrence data. To conclude, the effectiveness of both conservation measures and research related to the evaluation and monitoring of the effects of conservation − including the population monitoring scheme – have suffered from shortcomings. Certain relevant study questions have been ignored, the monitoring scheme suffers from methodological problems, available data are not analysed or synthetized, or results have not been provided in usable form. In addition, the connection between available information and conservation policy and practice is very weak: even the most usable and objectively relevant information may not have substantial instrumental value. Much stronger partnerships between policymakers, managers and researchers of various disciplines is needed to increase the effectiveness of conservation and conservation research.
  • Camarena Gómez, María Teresa (Helsingin yliopisto, 2019)
    Global warming is one of the most alarming pressures affecting marine ecosystems worldwide. One of the indirect effects of the increasing surface-water temperature is the change in phytoplankton community composition, shifting in some ecosystems from diatom predominance towards the dinoflagellate predominance or co-occurrence with diatoms during blooms. These distinct phytoplankton groups vary in the quality and/or quantity of the dissolved organic matter (DOM) they release, which may have contrasting effects on the associated bacterioplankton communities, in terms of structure and function, and also on the carbon flux passing through the microbial loop. The main objective of this thesis was to assess the effect of diatoms and dinoflagellates on shaping the bacterial community composition and dynamics in different ecosystems in which either one or both of these two groups dominate the phytoplankton bloom, such as the Baltic Sea and the Humboldt Current System (HCS) off Chile. This was achieved by conducting both experimental and field studies in these areas. Phytoplankton community composition and the stage of the bloom phase clearly affected to the bacterial community composition and dynamics in both ecosystems. Alphaproteobacteria, dominated by SAR11 and Rhodobacteraceae, was the most abundant bacterial class in all studies. The oligotrophic SAR11 dominated in pre-bloom conditions and was associated with dinoflagellates. In contrast, copiotrophic bacteria belonging to the classes Flavobacteriia, Gammaproteobacteria, Betaproteobacteria and the family Rhodobacteraceae (genera Loktanella, Planktotalea, Planktomarina and Amylibacter) were associated with diatom species such as Achnanthes taeniata, Chaetoceros spp., Skeletonema costatum and Thalassiosira levanderi in the Baltic Sea and with Thalassiosira spp. in the HCS. In addition, in the Baltic Sea, bacterial communities dominated by copiotrophs had higher bacterial production rates than in SAR11 dominated bacterial communities. Hence, the diatom-released DOM boosted the development of more productive bacterial communities during phytoplankton blooms. Further differences in the bacterial community composition were driven by the different salinities in these two ecosystems; Betaproteobacteria, Planctomycetes and Actinobacteria were more abundant in the brackish Baltic Sea than in the HCS. The results of this thesis highlight that the shift to the dinoflagellate dominance or co-occurrence with diatoms may affect the bacterial community composition and activity during bloom events. Certain diatom species promote the growth of copiotrophic bacteria, which contribute largely to high bacterial production rates and recycling of carbon. In contrast, the increase in dinoflagellate abundance associated with global warming may potentially change the pelagic remineralization of organic matter, which could reduce the carbon flux to higher trophic levels.
  • Fink, Christoph (Helsingin yliopisto, 2021)
    Data from digital media are increasingly used in conservation science. They help researchers and policymakers learn about the beliefs and values of people and their interactions with non-human nature, and observe relevant news and events on a global scale. In the ongoing global biodiversity crisis, this know­ledge becomes crucial. It is predominantly human activities that drive plant and animal species into extinction and destroy sensitive ecosystems (on which our wellbeing and survival depends). Knowing about people’s environmental perceptions is an important stepping stone in promoting a change away from unsustainable habits and a transition to more sustainable lifestyles. In this thesis, I explore, develop, and evaluate novel methods and approaches to unlock the new opportunities digital media offer to conservation science. The five individual publications that form chapters of the thesis build upon each other: first, I present a comprehensive review of relevant data sources and methods. In the second chapter, I discuss the data privacy implications of using digital media data in conservation science research. The third chapter presents a general framework to collect, filter, and identify social media data related to illegal wildlife trade. The fourth and fifth chapters, then, combine the findings of the first three: I demonstrate how to identify conservation-relevant events from the public opinion on social media and in online news, and investigate the online songbird trade in Indonesia, its price structure and the spatial characteristics of its supply chain. The concepts, the methods, and the openly-available tools presented in this thesis can guide conservation scientists and practitioners, as well as researchers in other fields, and inspire them to use digital media data in their own work.
  • Jerney, Jacqueline (Helsingin yliopisto, 2020)
    Phytoplankton plays a pivotal role for aquatic ecosystem functioning and global biogeochemistry. Climate change has affected phytoplankton community composition and distribution in the last decades, including a higher prevalence for harmful algal blooms in many areas. The globally distributed dinoflagellate Alexandrium ostenfeldii has for example started to form dense toxic blooms in the Baltic Sea and a new bloom location was recently discovered in western Japan. To survive unfavorable conditions this species forms resting stages, which may accumulate in sediments, forming a “seed bank”. The aim of this thesis was to investigate the relevance of the seed bank for the ecology and evolution of A. ostenfeldii and to understand the implications of these findings for persistence and possible expansion under ongoing global change. A combination of field surveys in Finland and Japan, experimental work and genotyping were carried out to address these aims. The results indicate that the seed bank stores a large clonal diversity, underlining its importance for stabilizing local populations against environmental fluctuations. No population structure was detected in temporal parts of a pelagic population, showing that differentiation does not happen during one season. The life cycle of A. ostenfeldii was found to be highly versatile, allowing overwintering of asexual resting stages without a pronounced dormancy period, and sexual reproduction throughout the season. Predicted future temperature and salinity did not affect germination of A. ostenfeldii, but affected growth rates, demonstrating their selective effect on the pelagic part of the population when detached from the seed bank. In addition, the importance of resting stages for colonizing new habitats, was stressed by the close relationship found between a recently discovered bloom population in Japan and geographically distant populations of similar habitats. Low genetic diversity indicated a recent introduction, potentially due to anthropogenic dispersal of resting stages. In conclusion, the seed bank plays a pivotal role for evolution and ecology of A. ostenfeldii. It ensures survival of a genetically diverse population, and slows down evolution, by linking contemporary populations to past populations via frequent re-seeding of resting stages. Although selection is buffered by phenotypic plasticity, future temperature and salinity may affect the pelagic part of the population, in the long run. A generalist life cycle of A. ostenfeldii and the presence of a seed bank support persistence and potential future temporal and spatial expansion under global change.
  • Assmuth, Aino (Helsingin yliopisto, 2020)
    Forests play a vital role in mitigating climate change, as they sequester and store large quantities of carbon. This dissertation examines how carbon storage may be increased by changing forest management at the stand level. To extend the economics of forest carbon storage beyond single-species even-aged stands, this dissertation develops a bioeconomic model framework that incorporates the size and species structure of the stand, and the optimal choice between continuous cover forestry and forestry based on clearcuts. The studies apply empirically estimated growth models for boreal conifer and broadleaf tree species. The dissertation consists of a summary section and three articles. The first article presents an analytically solvable economic model for timber production and carbon storage with optimized management regime choice between continuous cover and rotation forestry. Continuous-time optimal control theory is utilized to solve the thinning path and the potentially infinite rotation age: if no optimal finite rotation age exists, thinnings are performed indefinitely while maintaining continuous forest cover. The second article extends this model by applying a size-structured growth model for Norway spruce (Picea abies (L.) Karst.), road-side pricing of sawlog and pulpwood, variable and fixed harvesting costs, and several carbon pools. The timing and intensity of thinnings, the rotation age, and the management regime are optimized numerically. In the third article, the optimization approach of the second article is extended to mixed-species size-structured stands. Species mixtures include the commercially valuable Norway spruce and birch (Betula pendula Roth and B. pubescens Ehrh.), and other broadleaves (e.g. Eurasian aspen, Populus tremula L., and maple, Acer sp.) that have no market value. Optimal rotation age is shown to either increase or decrease with carbon price depending on interest rate and the speed of carbon release from harvested wood products. Given empirically realistic assumptions, carbon pricing increases the rotation period and eventually causes a regime shift from rotation management to continuous cover management. Hence, carbon pricing heightens the importance of determining the management regime – continuous cover or rotation forestry – through optimization. Optimal thinnings are invariably targeted to the largest size classes of each tree species. Carbon pricing postpones thinnings and increases the average size of harvested and standing trees, hence increasing mean stand volume. Without carbon pricing, commercially non-valuable other broadleaves are felled during each harvesting operation. When carbon storage is valued, some of the other broadleaves are retained standing until they are large, thus increasing tree species diversity and deadwood quantity. The results suggest that moderate carbon price levels increase timber yields, especially of sawlog that may be used for long-lived products. Increasing carbon storage through changes in forest management is shown to be relatively inexpensive, and the marginal abatement cost is the lower, the higher the number of tree species in the stand.
  • Salih, Enass Yousif Abdelkarim (Helsingin yliopisto, 2019)
    A variety of tree species, belonging to the genera Combretum, Anogeissus and Terminalia (Combretaceae) are well known for their uses in African traditional medicine for the treatment of infectious diseases and wounds. In this study, Anogeissus leiocarpus, Terminalia brownii and Terminalia laxiflora were selected based on ethnopharmacological information for in-depth studies on their antimicrobial effects and phytochemical constituents. The mentioned species were collected from the Blue Nile and Kordofan regions in Sudan. The main objectives of this research were (1) to perform ethnobotanical and ethnopharmacological documentation of the medicinal plants found in the study areas in Sudan, (2) to study the in vitro antibacterial and antifungal effects of extracts, obtained from A. leiocarpus, T. brownii and T. laxiflora, (3) to elucidate the chemical structures of compounds in extracts with promising antimicrobial activity and to (4) isolate fractions with antibacterial activity using preparative TLC and column chromatography. Ethnopharmacological and ethnobotanical information was collected from seven villages during three expeditions. According to this information species belonging to the family Combretaceae could be especially prospective as sources for antimicrobial extracts and compounds. Therefore various parts of the studied plants were subjected to antimicrobial testing using Staphylococcus aureus ATCC 25923, S. epidermidis ATCC 12228, Micrococcus luteus ATCC 4698 and Mycobacterium smegmatis ATCC 14468. In addition the plant pathogenic fungi, Aspergillus niger ATCC 9763, Aspergillus flavus ATCC 9763, Nattrassia mangiferae ATCC 96293 and Fusarium verticilloides (syn. F. moniliformis) ATCC 24378 were used. Compounds in the active extracts were characterised using HPLC-DAD, GC-MS, UHPLC/QTOF-MS and LC-MSn Tandem Mass Spectrometry. In studies I, II and III the ethnopharmacological data of the uses of Terminalia brownii, T. laxiflora and Anogeissus leiocarpus in traditional medicine in the villages in Sudan against diarrhoea and cough and for wound inflammation, could be verified. Our results demonstrate that especially extracts of the studied plants are active in vitro against the growth of human pathogenic bacteria, including a model bacterium for tuberculosis, with the lowest MIC values of 39 µg/ml. Pure compounds, such as punicalagin and corilagin, present in these active extracts, did not give as low MIC values and demonstrate that the antimicrobial compounds in the studied plants could act in concert. However, purification using Sephadex LH-20 of a root extract of T. brownii resulted in a significant reduction of the MIC against M. smegmatis from 5000 to 62,5 µg/ml. The chemical profiling of the most active extracts demonstrated the presence of a high variety of chemical classes, including ellagitannins, gallotannins, condensed tannins, flavonoids, stilbenes and fatty compounds. Methyl-(S)-flavogallonate was characterized for the first time from the roots of T. brownii and corilagin and its isomer, sanguiin H-4, and punicalagin have not been found before in the roots of T. laxiflora. Among the compounds in the studied species both antibiotic scaffolds and adjuvants could be found. Moreover, our in vitro results against phytopathogenic fungi demonstrate that T. brownii could be used for the protection of crop plants against fungal contamination.
  • Nurminen, Katariina (Suomen muinaismuistoyhdistys ry, 2021)
    ABSTRACT Burned fish bones are constantly being discovered in the excavations of Stone Age settlements in Finland. This abundance of fish bones, as well as the usual location of the settlements on the shore of lakes or the sea, illustrate the importance of fishing to the Stone Age economy. Added to this, examples of the fishing gear that was used, mostly made of stone, are also occasionally found in Stone Age contexts. Yet, despite the clear importance of fish and fishing in Stone Age Finland, the fish bones themselves have not been studied thoroughly before, although the diversity of the fishing culture at the time could be clarified by such analyses. I am interested in the everyday food acquisition strategies of the Stone Age forager communities. By studying the surviving bones and tracking the distribution of fish species, I have been able to create a picture of the fishing methods used at the time and the importance of fishing to the community. The availability of fish is highly dependent on the prevailing environmental conditions, and their behaviour directly influenced their potential as a food source. This empirically driven multidisciplinary study combines data from zooarchaeology, archaeology, ethnography, fisheries biology, environmental studies and, the most importantly, taphonomy. Research on burned bones is rare throughout the international research literature. The essential aspect of this research is to understand the nature of the bone material itself, because with burned bones many different factors can affect the results. Studying the effects of bone survival and the recovery methods used in excavations are thus an integral part of my research. For this study, I have selected ten sites with concentrated burned fish bone deposits, either on a hearth bottom or in a waste pit. In addition to these site-specific studies, I also address the specific issues of bone burning and excavation methods raised during the study. The archaeological bone fragments were analysed morphologically by comparing them with modern reference bones. However, due to the lack of reference bone material in Finland when I began this study, I started by preparing my own reference collection. There are several topics can now be more thoroughly and accurately discussed based on this study. According to results provided by the fish bone finds, it is argued that fishing was the most reliable source of daily food in Finland during the Stone Age. Fishing was a mostly opportunistic, low-level daily activity, and all types of fish were considered equally fit for consumption. Burning is a major taphonomical cause of bone loss. At the same time, it contributes to the preservation of compact skeletal parts. Based solely on the number of bone fragments preserved, no single species can be asserted to have been more important than another, as the bones' taphonomical stability varies between individual species. Fish bone finds from Finland are generally uniform throughout the Stone Age. All variation in the distribution patterns of fish species can be explained by the location of sites, environmental aspects, and excavation methods. The Stone Age fish bone finds support the theory postulating the use of historically known simple fishing gear. Based on the fish bone data, the fishing methods utilized remained the same throughout the Stone Age. Fishing was probably a year-round activity with some seasonal variations.
  • Jusufovski, Dunja (Helsingin yliopisto, 2020)
    Overexploitation is still a leading problem of many commercially targeted fish species. In addition to the high harvest rates and increasing biomass removals, harvested marine ecosystems have become a stage for the dynamic interplay of evolutionary and ecological processes. Removal through size selective fishing gear can cause negative pervasive effects on individual as well as population level. Observations of the individual phenotypic traits show a general trend of decreasing size and age at maturity that can have further negative effects on fecundity and population productivity. As these phenotypic changes become heritable (i.e., fisheries-induced evolution or FIE), this can further diminish the fish available to fisheries and render future fishing yields unsustainable. Current management requires additional measures to include avoidance and detection of evolutionary changes. In order to understand which fishing objectives precede evolutionary change in individual traits, in my thesis I explored how different fishing strategies of the European hake (Merluccius merluccius) fishery reflect on ecological and evolutionary processes. While management focusing on the protection of juvenile fish can minimise the negative ecological impact of fishing, it increases the potential for evolutionary change in fish phenotypic traits. In contrary to this, fishing mortality targeting a wider range of age–size classes avoids evolutionary shifts in individual traits, however such fishing strategy demonstrates higher biomass removals. In the wild, fisheries continuously interact with other predators, such as marine mammals, which can prey upon the same fish species or stock. The impact of these direct and indirect biological interactions between the marine mammals and fisheries is harder to detect and quantify, especially in synergy with other natural or anthropogenic stressors. In the context of fisheries-induced evolution, changes observed on an individual and population level caused by fisheries will also affect the prey size selectivity and prey availability to natural predators. My synthesis of recent research and findings on marine mammal–fisheries biological interactions demonstrates the need for improvement on data regarding marine mammal dietary and energetic requirements as well as their representation in model-based approaches. Moreover, combining different sources of knowledge about marine mammal–fisheries competition can aid to better quantify fish mortality caused by predation. Subsequently, this information would improve the fish stock assessments and provide insight on a sustainable window of opportunity to catch fish for fisheries and natural predators. Thus far, attempts to quantify predation and fish availability for fisheries and natural predators exist through studies using mainly ecosystem and fisheries models. To explore how predation and fisheries shape and direct individual as well as population parameters, I have used an individual-based model to simulate hake growth trajectories with regards to its own biological characteristics. As an individual grows, its life history is formed by ecological and evolutionary processes which also take into account the reproductive cost of survival and sexual size dimorphism (SSD). With co-evolved interactions between hake and the bottlenose dolphin (Tursiops truncatus) as the predator, fishing is introduced through a limited time period in order to observe prey recovery and resilience on an individual and population level. Although different types of predation give insight to discrepancies in the intensity of predation mortality, mere presence or absence of predation determines the projected values reached by prey individual and population parameters. Moreover, the joint effect of predation and fishing reveal contra-intuitive trends in hake individual traits and population parameters. The combination of duration and intensity of both size-selective removals, predation type and SSD determine the potential for persistent phenotypic and demographic changes after a period of overexploitation. Additionally, not all individual traits are equally susceptible to fisheries-induced evolution where the accountability of SSD and predation type can play a critical role. While fisheries remain the most detrimental source of mortality and size-selective removal for the harvested species, the indirect effects of fishing intensity diminish predator survival, thus having direct implications for top predator conservation. In conclusion, increasing the biological realism of the targeted species and incorporating different predation types with respect to evolutionary processes provide a more holistic approach to fisheries management: as it helps to avoid potential FIE and an overestimation of fish available to fisheries that can prevent top predator collapse. This will, ultimately, lead to a more ecosystem-based management with sustainable harvest rates and optimised fishing effort as well as the minimal cascading effects of size-selective removals.
  • Norppa, Miika (Helsingin yliopisto, 2019)
    This doctoral thesis examines the development of the inner city of Helsinki during a long timespan, from the birth of the city to the present day (1550‒2018). The study inspects 1. How the inner city of Helsinki has been developed in different times, especially from the viewpoint of the city spaces and physical structures, but also from the viewpoint of functions and for what reasons, 2. How various international, especially European trends, of city planning and architecture have influenced the planning of Helsinki inner city in different time periods? 3. What kind of influence the local context, more closely the history of inner city neighbourhoods, has had on the development the neighbourhoods? 4. How the recent neighbourhoods have been formed and what kind of needs for further development there are in the inner city of Helsinki? The research material can be divided into seven categories: research literature, professional magazine material, archive material, interviews, newspaper articles, statistics and observation material. The central theoretical framework of the research consists of the theory of city roles. By city roles I mean those livelihoods that are crucial for the existence of the city and through which the the role of the city in the hierarchies and networks of cities is determined. City roles and changes in them have historically had a tremendous significance in the development of the inner cities. In the history of Helsinki, this study recognises several city roles that have considerably determined what has been built in the inner city of Helsinki during different times. Architecture has generally reflected the heyday of a city role. Some of the city roles of Helsinki have ceded, and new city roles have replaced them, but many roles have had continuity, and several city roles have accumulated during the centuries. The second theoretical perspective of the study is offered by the concept of path dependency. According to the path dependency theory, historical events and choices have influence on how the city appears physically and functionally and on what possibilities and challenges the city will have ahead in the future. The present study examines path dependency especially in the city planning and architecture of the inner city of Helsinki. It describes closely the international influences in the planning of the inner city of Helsinki in different times. The decisions that other cities have made and the paths they have chosen have influenced the planning of Helsinki. International influences on the planning of the inner city of Helsinki have mostly come from the Baltic Sea region and European cities, but especially during the second half of the 20th century also from the United States. The local context has also, in one way or another, always influenced and has been taken into account in the planning of the inner city of Helsinki. During the last few decades, after the long period of emphasizing suburban planning, focus in the city planning of Helsinki has moved towards more compact urban development. In the planning of the inner city, there has been a slow comeback of traditional, urban city construction. This change has been associated with changes in the city roles, especially the weakening of the industrial role and the strengthening of city roles related to services. The revival of the traditional elements of inner city building has not, however, been complete. There are still pivotal differences between modern and traditional urban building in architecture, building practices and in the way local services are organized. Although there has been many well-meaning and successful efforts to regenerate the inner city, there are still things to do. During the 21st century, Helsinki has succeeded extremely well in different international comparisons of cities. The current study speculates whether Helsinki has during the beginning of the 21st century had a golden era during which the city would have acted as an international forerunner and what obstacles there are to achieving or retaining such a position. Keywords: Helsinki, inner city, city roles, path dependency, urban planning, architecture, history of urban planning, history of architecture, urban history, urban geography, history of Helsinki, planning influences, city centres, development of city centres
  • Saarela, Sanna-Riikka (Helsingin yliopisto, 2020)
    Environmental governance has a close relationship with scientific knowledge. Over decades, volumes of scientific knowledge have contributed to discovering, framing, understanding, monitoring and reconciling environmental problems. Quite recently, concerns about the use of scientific knowledge in decision-making and the ‘science-policy gap’ have emerged; and as a consequence, multi-way science-policy interaction (SPI) has been proposed. This thesis addresses SPI in Finnish public environmental governance by focusing on how SPI is constructed, managed and reflected upon by researchers and public authorities. I bring out challenges and successes that key actors have faced in their attempts to bridge the science-policy gap. I utilise key theoretical considerations from existing research on actors, knowledge-brokering processes, outcomes and context in SPI in analysing qualitatively four SPI cases. The results show that interaction between researchers and policymakers in Finnish environmental policy and planning cases has only recently started to evolve towards a more collaborative form. Although the actors still strongly subscribe to low-level interaction, they have also started to pay increasing attention to the various interaction means as well as to societal and personal benefits, constraints and driving forces associated with SPI. Path-dependency of an institutionalised SPI, competency and reward structures appear to be important in defining the nature of interaction. In addition, my results also demonstrate that strategic actions by researchers and policymakers may significantly affect SPI. The cases presented in this thesis show that careful and sensible co-development of concrete or abstract boundary objects have an important role in connecting people, issues and processes in SPI. Based on the results, it appears that the current structures and procedures do not yet adequately support mainstreaming SPI. For instance, institutionalised SPI may hinder the introduction of new interaction means, and researchers and policymakers appear not to have required competencies for taking on new roles as interactive actors in SPI. For those developing and advancing SPI in a national context, the practical lessons of this study emphasize careful design and preparation of SPI, a need to tailor interaction means according to the context and different phases of the SPI process, utilisation and co-development of a suitable boundary object in SPI. The inclusion of a knowledge broker in a multi-disciplinary SPI process, and ex post evaluation of outcomes of the SPI process. In the future, additional empirical research should be carried out on actualised SPI processes in order to achieve better understanding on what kind of interaction works in which policy and planning contexts.