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Browsing by study line "Miljöförändring"

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  • Azam, Gausul (2020)
    Dog activities (urination and defecation) can be a source of nitrogen accumulation in the snowpack of urban parks. Urban parks are commonly visited by urban residents and excessive buildup of nitrogen in snowpack can be a health concern. This accumulation of nitrogen in snowpack may wash away during spring with the runoff of melting snow, which can cause the eutrophication and deterioration of lake ecosystems. In this study, I investigated the concentration of some nitrogen-related compounds along with a few physical parameters in the snowpack of urban parks and compared these between areas with high dog activities and areas with no dog activities. I hypothesized that, nitrogen concentrations will be higher in areas with high dog activities, like snowpack beside paths than in areas with no dog activities. The study was performed in 10 parks of two cities in Finland; Helsinki and Lahti. In these parks, samples were collected from snowpack immediately next to walking paths (path edge), and in control areas 8 m away from these paths, where dogs were unlikely to visit. Samples were collected from February to April of 2019. The concentration nitrogen from snow samples of both parts of parks were compared. The study showed that, the concentration of most nitrogen species, e.g. Total Nitrogen (TN), ammonium (NH4+), Total Organic Nitrogen (TON), and electrical conductivity followed a similar pattern of having higher values in snow from path edges where dog activities were the highest. However, the concentration of NO3 – and pH values were both slightly lower in the path edge samples compared to control areas undisturbed by dogs, but differences were not statistically significant. Information from this study can be useful for understanding the connection between dog activities and nitrogen build up in snowpack of urban parks, and can also be helpful for designing urban parks by considering environmental and health effects of nitrogen accumulation in the snow from dog activities. My findings can also be useful to urban waterbody related studies, e.g. eutrophication, and the accumulation of nutrients in lakes.
  • Korhonen, Henni (2021)
    The focus of this thesis is on environmental agency in two different video games, The Sims 4 Eco Lifestyle and Final Fantasy VII Remake. The research questions aim to answer how the player can act as an environmental agent in these two games and what are the key differences between these games. The study is executed in a form of qualitative two-case case study with the help of close reading. With close reading eight different types of agencies that form the typology of this study, will be analysed in order to answer the research questions. The data for this thesis was collected by playing both games and taking notes by following close reading. The notes were then analysed with the different types of agencies. The results showed clear overlapping of the types of agencies, and it could be said that environmental agency can be used better in the game when the overlapping is happening. The agencies complemented each other and made the possible learning process in the game more fulfilling. The main difference between the game seems to be that The Sims 4 Eco Lifestyle as a life simulation game offers more diverse possibilities for environmental player agency. The studies about environmental games are mainly focused on serious games and not so much on commercial games. Video games hold great potential to engage people in environmental things especially with the help of player agency. It offers the player the ability to make meaningful choices and if they are structure well, the player can see the consequences of their agency which serves as an effective feedback which could lead to positive learning. In this case, the environmental agency in the game could be transformed into real-life environmental agency. As video games have become more immersive and their environments more realistic, it could be worth considering that separating virtual environment from the real-life one might not be necessary anymore. Therefore, games like The Sims 4 Eco Lifestyle and Final Fantasy VII Remake could serve as an example of how environmental agency within them could be harnessed into wider use.
  • Kivilompolo, Sanna-Kaisa (2021)
    Aims of this study. Previous studies have shown cyanobacterial dominance and harmful cyanobacterial blooms to increase due to recent climate warming. The increase of aggressively blooming species and toxin-producing strains of cyanobacteria has been predicted to further increase in the future. However, information on the response of cyanobacteria communities to environmental forcing in the Arctic region – which is experiencing warming at over twice the rate compared to the global average – has been insufficient. Thus, it is crucial to study how algal and cyanobacterial communities have developed after industrialization to better understand and predict future trends of subarctic algal communities as well as changes within cyanobacteria communities experiencing environmental forcing. This study aims to provide information on the effect of recent climate warming and lake browning on algal communities in subarctic lakes, with a special focus on cyanobacteria and cyanotoxins. Materials and methods. Modern and historical primary producer group abundances of 23 subarctic lakes located on an ideal temperature and vegetation gradient were studied using sedimentary algal pigments as a proxy. The top-bottom method was used to study both changes within algal communities during the last ca. 150 years and the broader trends in algal communities of subarctic lakes. Pigment data was analyzed together with environmental data using ordination analyses (principal component analysis (PCA) and redundancy analysis (RDA)) as well as other statistical analyses in order to determine possible trends of change and to reveal the environmental variables that have the strongest impact on cyanobacterial abundance. Results and conclusions. Algal communities have changed during the last ca. 150 years and show a general trend of increased primary production as well as lake browning in the spruce, pine and birch (SPB) vegetation zone. Siliceous algae generally dominate modern algal communities, and relative abundances of cyanobacteria have declined throughout the vegetation gradient. Within the Barren (Ba)- and mountain birch woodland (MBW) vegetation zones, cyanobacteria communities show a marked decline in the abundance of assumed benthic species based on pigment data, and low abundances of planktic picocyanobacteria. However, due to climate warming and lake browning, abundances of cyanobacteria have increased in several sites within the SPB vegetation zone and are suspected to indicate an increase of harmful planktic species. The most significant environmental variables controlling the abundance of cyanobacteria were total phosphorus, temperature and the amount of organic matter. The results highlight the urgent need to mitigate climate warming in order to preserve the unique biota and characteristics of Arctic and subarctic lake ecosystems, and to prevent the possible harmful increase of cyanotoxins in these sensitive ecosystems.
  • Raubenheimer, Marie-Claire (2020)
    Oil spillages represent a serious environmental hazard for flora and fauna of marine and coastal ecosystems. Though marine oil spills have decreased since the 1970s, the increasing production of petroleum goods remains a potential source of pollution due to its use and transportation. When aquatic organisms, including fish, are exposed to toxic oil compounds, this can cause sublethal morphological changes and increase mortality. In this context, herring have been frequently studied, and results suggest that particularly herrings eggs and larvae are highly susceptible to oil toxicity. In this thesis, a Bayesian meta-analysis was conducted to investigate the effects of crude and fuel oil on the mortality of herring eggs from the genus Clupea. Observations from laboratory studies, collected during a literature review, served as input for the statistical analysis. To this end, Bayesian inference modeling was applied to generate posterior probability distributions for additional mortality caused by exposure to oil mixtures. Also, oil concentration, oil type, exposure time, and temperature were analyzed to study possible correlations with mortality impacts. The results of this study suggest that acute mortality of exposed herring eggs is similar to mortality observed for individuals exposed to only small concentrations or none at all. Of all evaluated oil types, medium grade crude oil caused the most significant change in instantaneous mortality with increasing oil concentration. Generally, distinct oil types had a greater influence on mortality outcomes than temperatures at the given concentrations. For the lowest temperatures, some correlations for increased mortality were found. Overall, the unexplained variability between the reviewed studies has a relatively small influence on mortality outcomes. In conclusion, the mortality of exposed herrings eggs is most likely delayed due to sublethal effects, rather than immediate, at the modeled concentrations. Altogether, uncertainty amongst the posterior probability distributions is high, indicating a wide possibility range for the monitored parameters' actual values. The reasons for elevated uncertainty likely stem from diverse experimental setups, biological differences between tested species, relatively small sample sizes, and model-related issues. Thus, future research could consider additional variables, information from observational studies and other fish species to reduce uncertainty in mortality outcomes.
  • Hanstén, Magnus (2019)
    An increasing number of fisheries utilize rights-based management approaches for achieving economic, social and environmental sustainability. It is widely accepted that fisheries management is to a large extent about managing human behaviour, hence social acceptance is prerequisite for a successful management regime. Based on stakeholder interviews, this study analyses the opinions related to the recently implemented individual transferable quota (ITQ) system for the Finnish herring and sprat fisheries. Similarly, opinions were collected in 2007 by Kulmala et al. related to a possible implementation of ITQs, thus creating a unique opportunity to compile results from both a pre and post individual quota management implementation scenario. In 2007, it was suggested that fishers would largely support an ITQ system in Finland. Accordingly, this study implies that most of the Finnish stakeholders are content with the properties of the new system, however inequalities were perceived among fishers targeting fish for human consumption. In general, the system is expected to achieve its primary goal of improved economic efficiency within the fishery industry.
  • Lahtela, Eero (2021)
    Municipal environmental authorities are required to conduct environmental monitoring. Unmanned aerial vehicles, UAVs, may be helpful in environmental monitoring but their applicability as a tool for municipal environmental monitoring has not been studied. In this thesis it was studied, how municipalities have been utilizing UAVs. Additionally, UAVs applicability for environmental monitoring and inspection work was tested using a litter monitoring experiment as an example. In the first part of the study, a questionnaire was sent to municipal environmental authorities in Finland, to municipalities in Sweden and to those participating in Eurocities WG Waste group (n = 512), covering the used applications, their utilization frequencies and successfulness, reasons for failures and future plans. The results were analyzed using descriptive statistics. In the second part of the study, a UAV was utilized in a litter monitoring experiment on four sites in Helsinki. Litter by category and leaves were counted based on visual observations from UAV imagery. The accuracy of UAV imagery detection was assessed by comparing its and ground assessment (GA) results. On one site, a control group also carried out UAV imagery detections in order to assess the magnitude of bias or offset occurring when both the GA and the litter detection from UAV imagery are conducted by a single individual. The Wilcoxon signed rank and Cronbach’s α reliability tests were used for statistical analysis of the results. Response rate of the questionnaire was low, 3.7% (n = 19). The pool of used applications was extensive and covered a variety of monitoring and inspecting targets with emphasis on the presumably manually piloted applications. Utilization was very successful. The most important reasons for failures were poor weather followed by lack of information and expertise. UAVs were included in the future plans of most participants for municipal environmental monitoring purposes. The UAV imagery detection accuracies of litter and leaves compared to the GA results were high, 90.5% for litter and 87.5% for litter and leaves, and no statistically significant differences existed between the assessment results. Especially leaves proved challenging to detect from UAV imagery. The control group’s detection accuracies were 67.9% without and 49.0% with leaves, and with leaves the results differed with statistical significance (p = 0.028). The internal reliability of the control group was relatively high, α = 0.776 without and α = 0.805 with leaves. UAVs are deemed sufficiently accurate and versatile as monitoring and inspecting tools for municipal environmental authorities. They have the capability to complement ground assessments or, with certain prerequisites, even function as an independent monitoring method. Further application and detection method development and research on municipal UAV utilization are needed.
  • Sihvonen, Ida (2023)
    Research has identified the importance of understanding the connection between heat wave risk perception of elderly and their adaptation actions. In addition, developing more tailormade risk communication to elderly has been emphasized. The aim of this study is to understand how elderly citizens in the district of Töölö, Helsinki perceive the risk and adapt to increasing heat waves in a central part of the city and what the role of early warning systems (EWS) could be by collecting information through interviews on heat wave adaptation and risk communication. The qualitative data (N=6) consisted of transcribed interview data collected during February- March 2023. The data was analyzed through a thematic analysis and through using both a deductive and an inductive process, main themes and subthemes were identified within the data. The theory used in the deductive process was the Protection Motivation Theory in order to test if the theory could be used in this context. The results show that the personal risk perception and general risk perception varies for elderly and adaptive actions are in general taken to protect oneself from heat waves. However, Töölö as a high exposure area does not clearly increase the amount of adaptation actions but can rather offer benefits through its geographical position by the sea. The elderly’s interest in improving heat wave risk communication through an early warning system in Finland is noticeable. However, the final role of the system still remains open, and skepticism was expressed about the real need of a system in Finland. The results highlight that the elderly’s personal risk perception is rather independent of their adaptation actions, and they still adapt to heat waves, even when they perceive the threat as low. The results also highlighted that the elderly use multiple information sources to follow updates on heat waves, but the ideal risk communication media needs to be determined to develop an early warning system according to the needs of vulnerable risk groups such as elderly.
  • Anna, Leppänen (2023)
    Climate change and temperature rise in the Arctic is resulting in a decrease in sea ice extent and changes in sea ice variability. The impact of climate change on sea ice variability can be better understood when studying past events of climate change and sea ice extent change. Past environmental change can be reconstructed using bioindicators such as chrysophyte cysts, siliceous resting stages of chrysophyte algae. Archaeomonas spp., a genus of chrysophyte cyst, is often found preserved in Marginal Ice Zone sediments in the Arctic and its relationship with sea ice extent is explored here, to further understand its potential as a sea ice proxy. Diatom slides from three cores in the North Atlantic (Melville Bay, the North Water Polynya and Placentia Bay) were used to evaluate relationships between Archaeomonas spp. and known sea ice diatom species like Fragilariopsis reginae-jahniae. The Melville Bay core spans the last 8000 years, the North Water Polynya core spans the last 4000 years, and the Placentia Bay core spans the last 5800 years, providing a broad account of Archaeomonas spp. and diatom species abundances over the Holocene. It was concluded that Archaeomonas spp. was not directly correlated with known sea ice diatom species like F. reginae-jahniae at any of the three study sites. Archaeomonas spp. did display some similar relationships with cold water species like Thalassiosira hyalina, Thalassiothrix longissima, Thalassiosira nordenskioeldii and Fragilariopsis oceanica, and pack ice species like Actinocyclus curvatulus and Melosira arctica. Archaeomonas spp. can form in a range of conditions but prefers colder conditions where sea ice may form or drift to, as opposed to warmer, open water conditions. However, it is not directly linked to sea ice. Further research should focus on understanding whether Archaeomonas spp. forms in sea ice or not. There were some suggestions made to identifying Archaeomonas spp. at species level, but further research should be conducted on Archaeomonas spp.’s morphology to advance identification.
  • Annala, Heidi (2023)
    Luontopohjaiset ratkaisut (NBS, Nature-based solutions) ovat tietoisesti suunniteltuja ratkaisuja komplekseihin haasteisiin, ja niiden ytimessä ovat ”luonnon” elementit, kuten valikoidut mikrobit ja kasvillisuus. Nämä elementit ovat luontopohjaisen ratkaisun ytimessä, ja näin tekevät NBS:stä usein ekologisesti kestävämmän vaihtoehdon perinteisille teknisille maisemaratkaisuille. Suuri osa olemassaolevasta kirjallisuudesta on siten keskittynyt NBS:n ekologiseen ulottuvuuteen huolimatta niiden sisäsyntyisestä moniulotteisuudesta. Sosiaaliset elementit ovat kuitenkin paitsi olennainen osa NBS:n suunnittelua ja toimintaa, myös niiden pitkän tähtäimen onnistumisen edellytys. Aiempi tutkimus on osoittanut, että luontopohjaisten ratkaisujen menestys riippuu ennen kaikkea niiden paikallisen yhteisön saavuttamasta yhteydestä ja omistajuudesta. Näiden suhteiden muodostuminen tapahtuu usealla tasolla, mukaan lukien psykologisella ja asuinaluetasolla. Siksi tämä tutkimus tarkastelee luontopohjaisiin ratkaisuihin yhdistettäviä merkityksiä ja näkemyksiä paikallisen, karttapohjaisen, audio-visuaalisen kyselyn kautta. Vastauksista nousee esiin kaksi primääristä huomiota: Ensiksi, aineistosta on mahdollista erottaa NBS- ja äänimaailmamieltymysten, sekä avointen paikan merkitysten pohdintojen kautta vähintään kaksi paikallista arkkityyppiä, jotka lähestyvät luontopohjaisia ratkaisuja uniikeilla tavoilla. Toiseksi, erot näiden arkkityyppien reaktioissa paikallisiin luontopohjaisiin ratkaisuihinsa voivat selittyä osin luontosuhteen ja paikallishistorian kautta. Nämä löydöt korostavat yhtäältä olemassaolevan henkilökohtaiseen psykologiseen ulottuvuuteen keskittyvän NBS-tutkimuksen merkitystä, ja toisaalta paikallisen ja yhteisötason ymmärrystä kokonaisen
  • Repetti, Sonja I. (2022)
    My master’s thesis aims to determine the effect of salinity on phytoplankton traits related to nutrient acquisition, and particularly how this interacts with resource availability. Salinity is an important driver structuring phytoplankton communities in the Baltic Sea. Salinity can also influence nutrient uptake by increasing metabolic rates required for osmotic adjustment. Thus, interaction between salinity and nutrient availability is expected to change community structure by altering phytoplankton traits determining resource competition. This is a particularly relevant area of study for the Baltic Sea due to predicted future freshening of the sea’s upper layer. We performed a microcosm experiment using artificial communities of 10 diverse phytoplankton species grown under different combinations of salinity (0, 5, 12 and 24), Nitrogen to Phosphorus molar ratio (N:P ratio = 2, 10, 16 and 80) and light (10 and 130 µmol photon m-2 s-1) conditions. A three-way interaction among these environmental parameters influenced phytoplankton traits associated with resource competition, as well as the presence and proportions of phytoplankton taxa. Light limitation inhibited community growth under all salinity conditions, but allowed diatom Phaeodactylum tricornutum to dominate. Community growth rate was higher under high light, but also more variable between salinity conditions. The strongest negative effects of nutrient limitation (N, P, and both nutrients together), both on growth rate and taxonomic diversity, were observed in the highest salinity treatment. In the freshwater treatment with the highest proportion of green algae Monoraphidium sp., N-limitation did not inhibit phytoplankton community growth and P-limitation had a more profound negative effect on community performance. Decreasing salinity appeared to decrease community C:N and C:P ratios. This shift is in opposition to the increasing C:N and C:P predicted as a consequence of other climate change-related drivers. Our results emphasise the importance of a trade-off between salinity and resource limitation in functioning of phytoplankton communities and suggest that future freshening of the Baltic Sea is likely to modify phytoplankton community composition and performance.
  • Vikkula, Sami (2021)
    Oil spills in aquatic environments are devastating disasters with both biological and economic impacts. Fish populations are among the many subjects of these impacts. In literature, there are numerous assessments of oil spill impacts on fish populations. From all applied research methods, the focus of this thesis is on Bayesian methods. In prior research, several Bayesian models have been developed for assessing oil spill impacts on fish populations. These models, however, have focused on the assessment of impacts from past spills. They have not been used for predicting impacts of possible future oil spills. Furthermore, the models have not utilized data from laboratory studies. Some examples can be found of models assessing economic impacts of oil spills on fish populations however, none of them assess the economic impacts that follow from decreases in biomass. The aim of this thesis is to develop a Bayesian bioeconomic prediction model, which would be able to predict oil spill impacts on Baltic Sea main basin herring population, and the consequential economic impacts on fishermen. The idea is to predict the impacts of several hypothetical oil spill scenarios. As a result of this thesis, a bioeconomic prediction model was developed, which can predict both biological and economic impacts of oil spills on Baltic Sea main basin herring through additional oil induced mortality of herring eggs. The model can be applied to other fish populations in other regions as well. The model utilizes laboratory studies for assessing population level impacts. The model can be used for both assessing risks of the impacts of possible future oil spills, and for decision analysis after a spill has already occurred. Furthermore, the model can be used for assessing unknown aspects of past oil spills. The economic predictions can be used, for example, to estimate the compensations that could possibly be paid to fishermen. In the future, the prediction model should be developed further, especially regarding its stock-recruitment relationship assumptions. In addition, the model’s assumptions regarding the calculation of oil induced additional mortality and the economic impacts, should be expanded.
  • Nurmesniemi, Miia (2023)
    The shallow bays and inlets of the coastal Baltic Sea consist of a patchy seafloor with different sediment types that are affected by anthropogenic pressure, such as organic matter loading. Benthic macrofauna affects the carbon and nutrient stock capacity of such coastal areas by storing these elements in their body tissues and thus working as a temporary carbon and nutrient pool. These nutrient stocks are especially stable when the animals are large and long-lived. Fluctuations in organic input have been suggested to modify the diversity, abundance, and biomass of the benthic communities and therefore affect the nutrient reserves bound within the fauna. However, there is little information on how stress, in form of increasing sediment organic matter content, change the stocks and stoichiometric ratios of benthic macrofaunal communities. This thesis investigates if the changes in sediment organic matter affect benthic community composition and organism size and its ability to function as a carbon (C), nitrogen (N) and phosphorous (P) pool by measuring: 1) how the benthic faunal diversity, abundance, and biomass composition and 2) the C:N:P content and ratios of the benthic fauna change between three different sediment categories. A significant difference was found between sandy and muddy sediments in terms of benthic biomass and abundance, as well as the carbon and phosphorus stocks. Large long-living bivalves were found in sandy sediments, but overall organism size was not significantly different between the sediment categories. In general, the results show that higher sediment organic matter content resulted in fewer individuals, biomass, and thus a smaller storage capacity of carbon and nutrients. No statistical differences were found between the C:N and N:P and C:P ratios along the three sediment types. However, somewhat more P was bound within the fauna at sites with more organic matter, compared to the sandy and mixed sediments. The results highlight the importance of macrofauna in the functional performance of the ecosystem function and their potential for shifts with increasing disturbance. In conclusion, the increase in sediment organic matter can significantly change the capacity of macrofaunal communities to bind carbon and nutrients and this might have implications for the coastal nutrient filter. More research regarding the fauna's ability to adapt to the changing environment is needed.
  • Pudas, Hannele Maria (2023)
    Tässä työssä tutkin, minkälaiset käyttäytymistä määrittävät tekijät koetaan esteiksi biojätteen lajittelulle sekä mitkä ihmisryhmät lajittelevat biojätteensä passiivisemmin kuin toiset HSY:n alueella. Analysoin tutkielmassani kyselytutkimusaineistoa klusterianalyysin avulla, jonka perusteella etsin mahdollisia lajittelua estäviä tekijöitä ja tarkastelen vastaajien demografisten tekijöiden jakaumaa passiivisten ja aktiivisten lajittelijoiden joukoissa. Lisäksi hyödynnän ympäristöpsykologian teorioita ja tutkimusta ympäristömyönteiseen käyttäytymiseen kannustamisesta. Tätä teoriataustaa ja tuloksiani soveltamalla ehdotan mahdollisia interventioita, joiden avulla voidaan tehostaa kotitalouksien biojätteen lajittelua pääkaupunkiseudulla ja Kirkkonummella. Biojätteen lajittelu kotitalouksissa on tärkeää, sillä lajitellulla voidaan lisätä jätteiden hyötykäyttöä, mikä edistää kiertotaloutta Suomessa. Biojäte on erityisen tärkeä jätelaji kierrättää, koska kompostoinnin ja mädätyksen avulla siitä saadaan lopputuotteina uusiutuvaa biokaasua, josta tuotetaan energiaa sähkönä yhteiskunnan tarpeeseen, sekä ravinnerikasta multaa, jota voidaan hyödyntää maanviljelyssä ja viherrakentamisessa keinolannoitteiden korvaajana. Kotitalouksissa syntyvä orgaaninen jäte sisältää runsaasti typpeä, joten biojätteen lajittelu edistää myös ekologisesti kestävää typen kiertoa. Analysoin työssäni HSY:n kuluttajakäyttäytymiskyselyn vastauksia monimenetelmällisesti hyödyntämällä kvantitatiivista klusterianalyysia sekä kvalitatiivista teema-analyysia. Tulosteni perusteella havaitaan, että passiivisten lajittelijoiden vastauksissa korostuu lajittelun vaivalloisuus, tiedonpuute sekä paikalliset deklaratiiviset normit käyttäytymistä rajoittavina tekijöinä. Lajitteluesteiden tunnistaminen ja kuvaileminen auttaa arvioimaan mahdollisia käyttäytymismuutostekniikoita, joilla kannustaa asukkaita lajittelemaan biojätteensä paremmin. Tuloksistani voidaan päätellä, että proseduraalisen tiedon saaminen, lajittelun ympäristövaikutuksista oppiminen sekä lajittelun helpottaminen voivat kannustaa asukkaita lajittelemaan biojätteensä huolellisemmin. Löydösten perusteella voidaan kohdentaa viestinnässä ja kampanjoinnissa käytettäviä tekniikoita, jolloin niillä voidaan tehokkaammin kannustaa ympäristömyönteiseen käyttäytymiseen ja saadaan HSY:n alueen lajitteluaste nousemaan biojätteen osalta.
  • Lardot, Sofia (2023)
    The anthropause following the beginning of the COVID-19 pandemic in 2020 was followed by a heavy decline in people’s mobility and outdoor activities, which has had differing effects on biodiversity in urban areas. In Finland, outdoor activities were allowed, and as a result, the use of greenspaces increased notably in relation to pre-pandemic times. My objective was to study how people’s outdoor activities developed during the pandemic in the form of recreational bird-watching in the Helsinki metropolitan area (including Espoo, Vantaa, and Kauniainen). To accomplish this, I retrieved data on the number of bird observers from Tiira (a Finnish bird information service focused on bird observations), and related this data to the pandemic periods, also taking into account variables such as daily temperature and the use of parks. I found the highest number of bird-watchers during both lockdowns in 2020 and 2021. I also found that the number of bird-watchers was significantly higher after all restrictions were lifted, in 2022, when contrasted with pre-pandemic times. It is notable that the lockdowns happened at the same time as the bird Spring migration, a naturally popular time among bird-watchers. Thus, I consider that this may have had a synergistic role in people taking the opportunity to dedicate more time for bird-watching since they had more time to go outside due to strict restrictions. After all the restrictions were lifted in 2022, some bird-watchers continued to spend more time in bird-watching due to habit or increased appreciation for the activity or outdoors. The findings highlight the importance and potential of citizen science in observing birds and enabling more efficient conservation efforts for them. The results showing the development of bird-watching activities during the pandemic could also potentially be used as a proxy for other outdoor activities, and combined with other studies on the relations of COVID-19 on humans and other species could help to better understand the complex socio-ecological relationships in cities and greenspaces.
  • Huttunen, Johanna (2022)
    Bumblebees are important pollinators globally and especially in Fennoscandia, yet they are declining. The amount of natural vegetation in cities is decreasing with urbanisation. Hence suitable habitats for urban bumblebees are diminishing. Brownfields can be important habitats for bumblebees in cities because they resemble natural habitats. I studied bumblebee communities in urban brownfields. My main aims were to evaluate how local and landscape scale environmental factors affect the suitability of a brownfield to be a habitat for bumblebees. I also evaluated whether certain bumblebee functional traits are filtered in the brownfields. I expected that especially local characteristics and primarily the amount of flowering plant cover and the size of a site would affect bumblebee richness and abundance. I also expected the bumblebee communities to be characterised by generalist feeders. I collected bumblebees using line tracking in 15 brownfield sites in the city of Lahti and sampled bumblebees six times during the summer of 2020. The share of ground cover types within each site was estimated, as well as the share of different habitat types within a 300 m buffer zone around the sites. The data were used to analyse which local and landscape characteristics affect bumblebee community composition, species richness, and abundance in a brownfield site. Trait analyses were used to test the relationship between bumblebee traits and environmental factors. I showed that bumblebee abundance and richness were affected by local site characteristics but not landscape-scale factors. However, community composition was associated with landscape characteristics, including forest and commercial or industrial areas. Unexpectedly, the size of a brownfield site did not affect community composition, richness, or abundance. Functional traits were filtered in brownfield sites, especially the prevalence of a short proboscis, which is linked to a generalist diet in these bees. Brownfield sites are rich in bumblebees. Brownfields are suitable habitats for bumblebees regardless of the scale of urbanisation, and even small sites can host a diversity of bumblebees. As the amount of natural habitat in urban areas is decreasing, brownfields should be considered important habitats for bumblebees and other pollinators in urban planning.
  • Liljebäck, Petra (2023)
    Climate change severely threatens ecosystem services and human well-being: vegetation and soils underneath it can be particularly vulnerable to climate warming. Soils hold the largest carbon stock in terrestrial ecosystems, and urban park soils, especially in cool climates, can hold remarkable carbon stocks and may be able to offset some atmospheric CO2 emissions. Land use changes, such as urbanization, influence soil organic carbon formation and soil carbon storages. In this study, I was interested whether three vegetation types (deciduous trees, conifers and lawn) differ in their capacity to store C in their rhizosphere, and whether this is affected by park size. I measured the proportion of tree canopy layer in class A park areas of the city of Helsinki, to estimate soil C storages of these areas and to examine C density (kg C m-2). Proportions of tree canopy layers in different park size groups were measured using QGIS and ortographs. Soil C storages were calculated using existing soil C data and average proportions of conifer and deciduous trees in parks of the city of Helsinki. Park size had a significant effect on proportion of the tree canopy coverage: canopy cover decreases with an increase in park size. Especially large parks are dominated by lawn. The average soil C densities in small, medium and large parks were 23.98 kg C m-2, 23.47 kg C m-2 and 23.15 kg C m-2, respectively. However, the overall proportion of conifer canopy in parks of the city of Helsinki is rather small, resulting in small differences in C densities between different park size categories, despite significant differences in tree canopy coverage between the three size groups. Most of the stored soil C in parks of the city of Helsinki are under lawn, even though it is the least efficient of the three studied vegetation types (deciduous trees, conifers, lawn) in soil C sequestration. Within a park size category and at park level, large parks store the highest amount of carbon per park. Even so, at the city level, the total amount of carbon is highest in the small parks due to their high number. Conifer trees associate with improved C sequestration to soils compared to deciduous trees and lawn. Increasing the amount of conifer trees in urban parks thus likely increase the important C storages of these soils. Results of this study highlight the importance of the contribution of urban parks and especially conifer trees in carbon sequestration. Future research related to urban soil C sequestration and the effects of vegetation type and climatic conditions is needed to better understand soil C accumulation and how the C sequestration of urban park soils could be enhanced.
  • Courroux, Maxime (2021)
    The changes in lake diatom assemblages as a response to climate warming over the past three decades were examined in 26 lakes across Northwestern Finnish Lapland using multivariate statistical techniques. The lakes are distributed along a steep climatic and vegetational gradient, covering three distinct vegetation zones spanning boreal coniferous forest, mountain birch woodland, and treeless tundra. Lakes were selected following a study realised by Weckström and Korhola in 2001, who had sampled the same lakes for surface-sediment diatom assemblages, physical, and chemical limnological variables. Climate data from the past 30 years was retrieved, showing a slow and steady yearly increase in temperature, with strong seasonal fluctuation and fall months experiencing the strongest warming. Surface sediment samples were taken from the lakes and their diatom communities analysed. A total of 185 diatom taxa representing 27 genera were recorded. Ordination techniques (DCA, CCA) at the genus and species level were performed to identify the main patterns of variation between diatom data from the original data set and the current study, and their relationship to environmental variables. Strong changes were recorded in four of the lakes with major shifts in dominant diatom species. Moderate changes were recorded in eight lakes, where dominance changes were recorded for a few species while the majority remained unchanged. The remaining 14 lakes did not show noticeable changes over the 30-year period. Changes observed in the studied lakes did not follow a widely observed pattern in northern Hemisphere lakes. The results indicate that while climate change is a driving factor behind changing lake dynamics with increasing temperatures and decreasing lake ice cover duration, it cannot be the only force responsible.
  • Pörsti, Saara Kyllikki (2022)
    Climate change have widespread increasing negative health impacts on urban residents. The impacts vary in different temporal and spatial dimensions and include health impacts such as increases in heat related illnesses, respiratory issues, and vector-borne diseases. Vulnerability and exposure to those impacts depend on different interacting factors from city level systems to individual characteristics. Papers that study how cities’ moderating factors impact on different climate change induced health impacts are an important part for setting adaptation policies. Little is known how city systems and system factors (social and physical environment and policy and planning) moderate climate change induced health impacts in cities and their role in different vulnerability and exposure outcomes. With an analytical framework that utilizes systems approach and follows conceptual framework that considers city systems as moderating factors to different vulnerability and exposure outcomes, this thesis answers the questions: How are the city systems and system factors, and climate risk elements (vulnerability, exposure) related? And what are the different types of interactions that lead to vulnerability and exposure outcomes? The main data of this qualitative case study is collected with 18 expert pair-interviews. The experts are selected from four residential areas that represent different municipalities in Helsinki and Turku. The interviews are transcribed and coded with Atlas.ti. The findings of this study emphasize that moderating factors have an impact on different vulnerability and exposure outcomes. The results also show that adaptation measures that would consider cities moderating factors, would have a significant impact on reduced exposure and vulnerability to begin with. Identification of different city system, climate risk and health impact pathway synergies doesn’t promote better adaptation policies as such. Better understanding of efficient adaptation policies require further studies of the consequences resulting from the policy decisions in physical and social environment in the long run.
  • Skogberg, Mikko (2020)
    Static floating chamber (FC) measurements of CH₄ and CO₂ fluxes from northern boreal river Kitinen were analyzed for this thesis. Measurements were carried out in summer 2018. Spatiotemporal variability was measured in the fluxes by comparing three chamber measuring locations: the opposite river banks and the middle of the river. Mean CO₂ flux estimate was 0.83±0.54 μmol CO₂ m⁻² s⁻¹ (mean ± SD, n = 73), consistent with other estimates for similar systems, with a corresponding k₆₀₀ CO₂ gas transfer velocity estimate of 17±9 cm h⁻¹ . Nonlinear modelling of CO₂ flux was found useful for analyzing floating chamber data from a river. The mean CH₄ flux was 0.0084±0.0047 μmol CH₄ m⁻² s⁻¹ , slightly lower than the median for different river systems in literature. The flux estimates were compared with eddy covariance measurements (EC). FC measurements are expected to give larger results, but additionally chambers are known to overestimate fluxes in flowing water. The comparison yielded chamber fluxes 3.3 and 2.9 times the EC median values for CO₂ and CH₄ respectively. Fluxes were similar between the three locations, and they peaked in late July for both gases in all loca- tions. Some differences over the river cross-section were observed. Discharge was significantly correlated to fluxes in the middle of the river, which could be explained by inhomogeneous flow. On two measuring days in early August, the mid-river CO₂ fluxes were three times those observed near the banks. The difference was also measured in methane. No clear cause was determined, but measuring spatial variation in surface water gas concentrations and flow could clarify the causes of similar observations in further studies.
  • Malkamäki, Henriikka (2023)
    Tropical coral reefs are amongst the most biodiverse and productive ecosystems on Earth. In recent decades, coral reefs have suffered an unprecedented decline in habitat-forming hard coral cover due to anthropogenic stressors, with severe impacts on ecosystem functioning and the provision of ecosystem services. Some of the pressing issues that coral reefs are facing can be mitigated through active reef restoration, such as coral transplantation, which aims to increase the hard coral cover, biodiversity, and structural complexity of a reef site. Studies on the passive benefits that increase the natural recovery potential and resilience of coral reefs following active restoration efforts remain scarce. In collaboration with Indo Ocean Project, this study aimed to compare benthic recruitment patterns between three coral sites located within the Nusa Penida Marine Protected Area, Indonesia. The reef sites included a restoration site with gardened Acropora corals, a natural site, and a rubble site that could serve as a restoration site. The experiment was conducted using standardized settlement tiles to measure and observe various response variables as indicators for the natural recovery potential and resilience capacity of the reef. The sites were also surveyed for their benthic reef cover, structural complexity, and fish abundance and community composition. The research objective was to find out how benthic recruitment patterns differ between restoration and natural reef sites, and why. The results confirm that active coral reef restoration efforts induce co-benefits in the benthic environment through enhanced structural complexity, leading to subsequent increases in overall fish abundance and particularly the number of herbivorous fish, and thus to a lower density of turf algae. These are promising findings for the later development of the reef site. The results do not imply that restoration efforts directly translate into enhanced coral recruitment or increases in crustose coralline algae abundance. However, the plentiful supply of spats observed at the restoration site indicates that local coral recruitment can improve over time after the transplanted corals have healed from transplantation stress and become fecund. Finally, the current rubble area can be expected to function as a restoration area in the future, as it appears to be within the reach of coral recruits. This study demonstrates that active coral reef restoration can yield benefits for the whole benthic ecosystem, and thereby aid recovery and strengthen resilience at localized scales. Given the accelerated rate of coral reef degradation, regular monitoring of restoration success is crucial to avoid loss of information regarding the benefits of active coral reef restoration for the fragile benthic ecosystem.