Browsing by study line "Environmental Change"

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.

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.

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.

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.

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

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.

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.

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.

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.

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.