Maatalous- metsätieteellinen tiedekunta

 

Recent Submissions

  • Hautakangas, Sami (Helsingin yliopisto, 2020)
    The main theme in this dissertation is to determine the means of achieving the Baltic Sea Action Plan targets, with an emphasis on municipal wastewaters. Thus, the nitrogen and phosphorus reduction potentials of wastewater treatment plants and costs of nutrient reductions are calculated. The nutrient reduction potential is huge for municipal wastewater. Furthermore, abating nutrients in wastewater treatment plants is cheaper than previously thought. In particular, phosphorus abatement costs are much lower than those in agriculture. A numerical model is built to demonstrate that a considerable share of the targets of the Baltic Sea Action Plan can be met by nutrient abatement in wastewater treatment plants. Moreover, it is shown that with properly designed initial allocations, a nutrient trading scheme can even out the cost burden between wastewater treatment plants. However, transaction costs may play a significant role in nutrient trading in the Baltic Sea region. With an analytical model, it is demonstrated that if a water utility has market power, a tightening nutrient policy may decrease the price of potable water but increase the wastewater tariff. Based on the analytical model, a numerical model is built to illustrate that households connected to small water utilities face higher prices and higher price increases associated with environmental protection measures than do households connected to large water utilities. Finally, it is shown when the level of nutrient abatement reaches the upper limit, the costs water utilities face no longer depend on the instrument applied.
  • Deng, Biar (Helsingin yliopisto, 2020)
    Rainfed agriculture is a vital land use practice for food security and economic development in most of drylands, but particularly in sub-Saharan Africa (SSA). However, it is becoming an increasingly uncertain and inefficient practice in SSA because of climate change and extremes (i.e. low and erratic rainfall, high temperatures, floods, and drought occurrence), and low soil fertility and water supply. For example, yields of sorghum, which is the main staple food crop in South Sudan, are dwindling under rainfed cultivation in its main production areas in the north of the country due to the previously mentioned factors. Nevertheless, soil amendment materials, such as biochars, along with integration of sorghum production into agroforestry systems, which can improve soil fertility and water storage capacity, could assist in improving the crop yields. In this dissertation, the effects of Acacia seyal-based agroforestry and addition of biochar on soil water retention and supply and on sorghum yields were examined. The research focused on 1) the potential of using biochar as a soil amendment combined with A. seyal-based agroforestry in a field experiment, 2) the effect of biochar on alleviating water stress on sorghum yield in greenhouse conditions, and 3) simulation of the potential effect of biochar amendments on improving sorghum biomass and grain yield, especially as indicated by differences in yield between wet and dry years. The two-year agroforestry field experiment (Paper I) was carried out at Magara Village north of Renk in South Sudan, during the growing seasons of 2011 and 2012. The split block experiment included three A. seyal tree density treatments: no trees; scattered trees (100 trees ha-1) and dense trees (400 trees ha-1) and two biochar amendment treatments (0 t ha-1 and 10 t ha-1). The soil consisted of silty loam underlain by clay, and the biochar source was A. seyal trees. A soil analysis showed that agroforestry resulted in lower soil pH, N, and total and exchangeable Ca2+ contents and higher C/N ratios compared to sole sorghum cultivation. The application of biochar significantly increased the soil C and exchangeable K+ contents as well as the pedotransfer-derived field capacity and plant available water contents, but significantly decreased the content of exchangeable Ca2+ and cation exchange capacity. The inclusion of A. seyal trees significantly decreased the sorghum grain yields, and the effect of biochar on grain yield compared to sole sorghum cultivation without amendment was not significant. The Land Equivalent Ratio (LER, the sum of the fractions of the intercropped yields divided by the sole-crop yields) value was 0.3 for dense A. seyal intercropping combined with biochar in both 2011 and 2012 and with scattered A. seyal intercropping in 2011, but it was twofold greater (0.6) in 2012 with biochar amendment. The greenhouse experiment (Paper II) was carried out at the Viikki Campus, Helsinki, Finland, during May–December 2011. The main factor was drought stress with three levels of soil moisture content: 60% of field capacity (well-watered), 40% (medium drought) and 20% (severe drought). The same type A. seyal biochar, in the same amounts as applied in the field experiment (0 t ha-1 and 10 t ha-1), was used. Drought stress had a significant effect on sorghum gas exchange but not on sorghum stomatal traits. The stomatal conductance and photosynthesis and transpiration rates were all significantly reduced under severe drought compared to values found in plants that were under medium drought or well-watered. The photosynthetic water use efficiency (WUE) increased with the level of drought stress. Drought stress significantly reduced the sorghum biomass and grain yields compared to those observed in well-watered plants. Biochar addition did not have a significant effect on any of sorghum stomatal traits, gas exchange or grain yield. The biochar/sorghum simulation study (Paper III) was carried out using the water-driven crop-growth model AquaCrop (version 6.1). The model was parameterized for the field experiment site and soil conditions. Soil fertility stress parameters were adjusted so that simulated biomass and grain yield values best matched the levels recorded in the field experiment. Climate data for 2011 and 2012, both wet years, and for 1990, an extremely dry year, were extracted from the Climate Forecast System Reanalysis (CFRS) online dataset. The effects of biochar were simulated using the changes in soil hydraulic properties (increases in field capacity, available water capacity and saturated conductivity) reported in a published meta-analysis study. Generally, the simulated biochar amendments having the greatest effect on soil hydraulic properties increased the water content of the rooting depth in all three years, but an increase in sorghum production was only discernible for 1990. The results from paper I showed that sorghum yields are lowered when the crop is grown in agroforestry systems. As sorghum is not tolerant of shade, the reduction in sorghum production with increasing tree density was probably due to canopy cover and shading. This effect thus overrode any benefit of having the trees in the cultivation system. The results from paper II indicated that biochar has no significant effect on alleviating drought stress on sorghum production and grain yields, while the results from paper III showed biochar, while improving soil hydraulic properties, only resulted in increased sorghum biomass production and grain yield in very dry years. Overall, the results from this study showed that the propounded benefits of agroforestry and biochar need further study and critical assessment, particularly in semi-arid environments where the water supply through rainfall is low and erratic but the water demand is constantly high. The results may well vary with different crops and agroforestry systems, as well as with different soil types and the type and dose of biochar. Furthermore, the results may only become apparent with sufficient time and therefore long-term studies are needed.
  • Lehto, Reetta (Helsingin yliopisto, 2020)
    Food eaten at preschool forms a significant part of preschoolers’ diets. In addition to foods served at preschool, other factors in the mealtime environment may also impact children’s dietary intake. Such factors include mealtime practices, such as the serving style of the food, the personnels’ role in modelling healthy eating, and encouraging children to try new/less-favourite foods. Additionally, more distal factors in the mealtime environment, such as written food policies and cooperation with catering service, can associate with dietary intake. The use of mealtime practices vary greatly between preschools, so determinants of preschool mealtime practices, such as neighbourhood socioeconomic status (SES), are also of interest. This study aimed to examine how the preschool mealtime environment, including mealtime practices used by early educators and preschool-level facilitators of and barriers to healthy nutrition, is associated with children’s dietary intake at preschool. The examined dietary factors were vegetable consumption, fresh and frozen fruits and berries consumption, fibre intake, energy intake (proportion of daily energy intake at preschool) and added sugar intake. Another aim of the thesis was to assess whether preschool neighbourhood SES associates with mealtime practices in preschool groups. The thesis applies data from the Increased Health and Wellbeing in Preschools (DAGIS) project. The study data consist of the cross-sectional DAGIS survey conducted in 2015-2016 in eight municipalities in Southern and Western Finland. Of the preschool managers in the participating 66 municipal preschools, 58 (88% of all) reported preschool-level facilitators of and barriers to healthy eating, including food policies, cooking onsite or not, lack of resources, cooperation challenges with catering services, etc. A total of 379 (79%) early educators filled in a questionnaire on their mealtime practices and opinions about preschool food. Lunch situations of preschool groups were observed by research personnel to assess serving style. Early educators kept food records for the participating children on 2 preschool days. In total, 586 children fulfilled the inclusion criteria of having food consumption data of three meals at preschool on at least one day. Map grid data on preschool neighbourhood SES were received from Statistics Finland. Sub-study I associated the personnels’ positive opinions about preschool food with higher consumption of vegetables among children. In contrast, role modelling by the personnel and personnels’ positive opinion about the preschool food associated with a smaller proportion of daily energy intake at preschool among children. Lastly, encouragement to eat fruits and vegetables was associated with higher fibre intake. Serving style was not associated with any of the studied dietary intake variables. Sub-study II found that children consumed more vegetables and had a higher fibre intake in preschools belonging to the highest tertile of the number of food policies compared to the lowest tertile. Additionally, manager-reported cooperation challenges with catering service was associated with both higher fibre intake and lower odds of children eating fruits and berries at preschool. Lack of resources (personnel, materials, planning time) was also associated with lower odds of children eating fruits and berries. Other preschool-level factors, such as cooking site, were not associated with children’s dietary intake. Sub-study III examined associations between preschool neighbourhood SES and mealtime practices in preschool groups. In the unadjusted model, high preschool neighbourhood SES associated with higher odds of role modelling by the personnel and rewarding with food, and lower odds of birthday treats available at birthdays. However, in the adjusted model, only rewarding with food remained associated with preschool neighbourhood SES. To conclude, several factors in the preschool mealtime environment were associated with children’s dietary intake at preschool. Regarding previous studies, some of the found associations were controversial. New associations were found not only between the personnels’ opinions about the food and children’s dietary intake but also between cooperation challenges with catering service and children’s dietary intake. These findings, especially cooperation between preschool and catering personnel, should be studied further and more thoroughly. All in all, the preschool mealtime environment can partly determine children’s dietary intake at preschool, and these factors should be acknowledged when promoting healthy food intake at preschool.
  • Mehtiö, Terhi (Helsingin yliopisto, 2020)
    Improving the feed efficiency of dairy cows improves both the economic and environmental sustainability of milk production. However, feed efficiency is a complex trait affected by several factors. It is influenced by the genetic ability and physiological state of the cow, along with diet, management and other environmental factors. This complexity is a challenge when defining and measuring feed efficiency traits. In addition, easy, cheap and accurate techniques for on-farm measuring of feed intake, body weight and energy status of cows have been lacking. The overall aim of this thesis was to develop new recording methods for feed efficiency traits and explore the genetic background of feed efficiency in dairy cows. In particular, the main goals were to develop simple, practical and novel methods for measuring both cow-specific diet digestibility and energy status on farms, develop models for overall and partial metabolisable energy efficiency, and assess the genetic background in all these traits. The data used were collected from research farms in Finland and Norway. In addition, fertility, milk recording and infrared spectral data from Finland were used. The results indicated that near-infrared reflectance spectroscopy can be used to assess cow-specific diet digestibility from faecal samples. The coefficient of genetic variation for diet digestibility was rather small but could be utilised if improving diet digestibility pays off the costs of sample collection and processing. Nonetheless, every unit improvement in diet digestibility corresponds to proportionally the same amount of savings in feed requirements and thus may become of significant interest in the future. In this thesis two new feed efficiency traits were explored. These traits allowed more accurate modelling, and may be utilised in the prediction of breeding values in the future. The results indicated that some genetic variation may exist in the efficiency of using metabolisable energy for milk production, maintenance and growth in dairy cows. The concentration of non-esterified fatty acid (NEFA) in blood increases, when a cow is in negative energy status, and thus NEFA can be used as an indicator for energy status. In this thesis prediction equations for blood NEFA concentration were developed. Predicted NEFA was based on the mid-infrared reflectance spectroscopy of milk samples. The results indicated that predicted NEFA and four other energy status indicator traits were moderately heritable during the first three months of lactation. Moderate genetic correlations were found between energy status indicators and the fertility trait, the interval from calving to first insemination, in the first month of lactation, indicating an unfavourable relationship between energy status indicators and fertility. The results of this thesis provide information needed for genetic improvement of feed efficiency in dairy cows and may be utilised on farms in dairy cow nutrition and management.
  • Aaltonen, Heidi (Helsingin yliopisto, 2020)
    Northern Hemisphere permafrost soils store approximately 50% of the global soil carbon (C), a quarter of which could thaw by the end of the century. Thawing exposes previously frozen soil organic matter (SOM) to decomposition, resulting in release of greenhouse gases (GHG) from the soils. Vast areas of permafrost soils are covered by boreal forests currently acting as sinks of C. As global warming is strongest at northern latitudes, the occurrence of boreal forest fires may increase. Forest fires further advance permafrost thaw and forest soils may turn from sinks to sources. This thesis examines how forest fires affect the quality of SOM and GHG emissions from permafrost soils in boreal forests by conducting chemical fractionation of SOM and soil incubations, as well as manual chamber measurements of GHGs. Forest fires increased the active layer depth on top of permafrost, altered species composition of vegetation and affected the organic layer depth and the SOM pools. Fires decreased the quality of SOM, observed as reduction in the proportional amount of labile SOM fraction and increased SOM temperature sensitivity, as well as enrichment with heavier isotopes of 13C and 15N. GHG measurements showed that fire initially decreased carbon dioxide flux from the soil and it returned to its pre-fire status approximately 50 years after the fire. The effects of fires on methane and nitrous oxide fluxes were not significant. Forest fires have significant effects on the release of GHGs from permafrost soils. In the future, the fate of permafrost stored SOM is dependent on its degradability, the frequency of fire events and the ability of forests to regenerate, allowing permafrost recovery, in the changing climate. There is a demand for further studies investigating the specifics of different permafrost ecosystems and building a complete picture to estimate total emissions from permafrost regions.
  • Lankia, Tuija (Helsingin yliopisto, 2020)
    The benefits of outdoor recreation are numerous. By the everyman’s right there is an abundant supply of outdoor recreation opportunities in Finland, and outdoor recreation is a popular way for Finns to spend free time. In this thesis the importance of the recreational use of nature in Finland was studied in economic terms. First, the value of recreational use of nature in Finland was mapped. The number of recreation visits was estimated regionally and by three different area types 1) areas used under everyman’s right, 2) state owned recreation and nature conservation are-as, and 3) leisure homes. The monetary value of the visits is estimated using the travel cost method. The results of the mapping demonstrated the recreational value of eco-systems in monetary terms. In terms of the total number of visits and the value of visits the results emphasized the relative importance of close-to-home recreation compared to longer nature trips including overnight stays. Second, the extent of the recreation benefits obtained from visits to leisure homes was estimated with the travel cost method. The results showed how location by a shoreline and an electricity supply of a leisure home increased the recreational value of a visit but presence of harmful algal bloom that prevents water recreation decreased it. The recreation value per visit was estimated to be €170–250 per trip. According to the results, the presence of algae that prevent aquatic recreation decreases the value per trip by 40 per cent, and the lack of a beach reduces it by 45 per cent; electricity supply in a leisure home increases the value by 3–5 per cent. Third, the effect of hypothetical future changes in water quality on recreational benefits of swimming in Finland was assessed. Based on population level recreation demand survey and combined travel-cost contingent behavior model, the recreational value of swimming in natural waters in Finland in current state were estimated to be 16 euros per visit. A hypothetical decline in water quality to a level at which the water visibility would be less than 1 m and abundant slime would exist decreased the value to 9 euros. A water quality improvement to a level at which the perceived water visibility would be over 2 m and no slime would exist increased the value per trip to 22 euros. Fourth, individual recreationists’ willingness to pay to land owners for management practices that influence recreational quality was investigated. About 10 per cent of the recreationists who participated in the survey were willing to pay to direct the management of their typical recreation site on privately owned lands and about half were willing spend their own time on the practical work of the nature management. The mean willingness to pay was estimated to be 92 euros per year and the mean willingness to spend own time 3.5 days per year
  • Pynnönen, Sari (Finnish Society of Forest Science, 2020)
    This dissertation examines forest owners’ views of forest-related decision support services and knowledge use in them in private forests in Finland. Decision support services provide information through forest management planning and advice. The decision-making about and implementation of forest management take place in a multi-actor network that produces, distributes, and utilises knowledge in technical and social knowledge systems. The thesis is based on two surveys, extensive focus group data and field notes from workshops. It adopts a mixed methods approach. The results show that forest owners with timber production objectives considered the current decision support services most useful. Those who emphasised nature values or had multiple objectives were less satisfied. Forest management preferences are more versatile than what they appear based on overall ownership objectives. The majority of owners are interested in diversifying their forest management to increase other forest functions along-side timber production. Two knowledge systems, technical and social, influence knowledge use in forest management. Several points of discontinuity were identified in knowledge flows within and between forest-related actors and organisations. The codified, technical knowledge system dominates knowledge production and use. The importance of the social knowledge system has not been fully recognised. Independence from time and place, gratuitousness and ease-of-use make forest-related e-service more inviting. Lack of forest inventory data or its perceived low quality and discordance with forest owner objectives deter owners from using e-service. Forest owners expect decision support services to acknowledge their diverse and multiple forest use objectives. Information services on the management of nature values and integration of various objectives are needed. Knowledge flows are weakened by the domination of codified, forest resource-related knowledge, social structures and practices that inhibit the diffusion of knowledge within an organisation, and emphasis on the economic targets. Organisations on the forest sector are in key positions for changing the prevailing decision support practices, but so far the development of new practices has been slow.
  • Kytö, Elina (Helsingin yliopisto, 2020)
    Purchase behavior is a frequent but highly complicated human behavior affected by numerous factors. In the food industry, several sensory and consumer research responses are generally used to predict future sales to maximize market success. However, the failure rate is estimated to be extremely high, and new methods and measurements for prediction are needed. This thesis investigates the role of different consumer and sensory research measurements – especially the measure of purchase intention – in food purchase behavior prediction. The aim is to examine the ability of purchase intention, and other explicit and implicit responses, to predict food purchases with varying amounts of product information. The focus is on factors related to the consumer (perception, previous usage, emotions, habits, and beliefs) and the product (expectations, product type, and sensory quality as internal factors, and brand and package design as external factors). The association between the amount of product information, the different measurements, and the actual purchase behavior regarding two types of dairy snack products (a flavored protein quark and a natural yogurt) is studied. The product information phases were 1) expectation based on the brand and packaging pictures that simulated an in-store experience (before trying the product), 2) sensory quality perception based on blind tasting, and 3) actual perception based on tasting with brand and packaging pictures that simulated an in-home experience (after tasting the product). The responses were measured using explicit responses (purchase intention, pleasantness, emotions, recommendation, brand relationship, and willingness to eat again) and implicit responses (event-related potential, reaction time, and pupil size). In addition, various consumer-related factors, such as previous use of and familiarity with the studied products by brand, change seeking, purchase drivers, purchase moment, and purchase decision level, were measured. Finally, purchase behavior was measured using self-reported surveys within a one-month period after the evaluations. Purchase intention and recommendation responses measured in the actual perception condition were found to be the most accurate predictors of food purchases. Overall, explicit responses were associated with purchase behavior more strongly than implicit responses. Furthermore, measurements after only sensory quality perception were poor predictors of purchases. In conclusion, purchase behavior was predicted better when more product information was available.
  • Liu, Chang (Helsingin yliopisto, 2020)
    Faba bean is a legume that is not only rich in proteins but also is well adapted to the short growing seasons in the Nordic and Baltic countries. Considering the economic cost and sustainability issues, growing interests are focused on plant proteins. In this study, the potential applications of modified faba bean protein isolate (FBPI) in oil-in-water (O/W) emulsions were investigated. The overall aim of the research was to study how different modifications of FBPI affected the physical and oxidative stability of O/W emulsions. Modification of FBPI by microbial transglutaminase (MTG) induced protein cross-linking. MTG treatments for longer time (120 and 240 min) induced excessive surface hydrophobicity, resulting in decreased emulsifying activity and physical stability of emulsions. On the other hand, a short time (60 min) MTG treatment improved FBPI’s potential to maintain the physical stability while improving lipid oxidative stability of the emulsion. This might be attributed to thicker interfacial layer, larger droplet size, and protective effect of protein. Alcalase hydrolysis of FBPI to a degree of hydrolysis (DH) of 4% produced an emulsion with improved physical stability and least of lipid oxidation while maintaining protein oxidative stability as compared to emulsions prepared with native and extensively hydrolyzed (DHs of 9 and 15%) FBPI. FBPI hydrolysates with DH of 4% exhibited molecular weight better applicable to interfacial layer stability, increased surface net charge for more repulsive electrostatic force, and increased hydrophobicity. Considering the important role of interfacial layer thickness in emulsion stability, FBPI and chitosan (CH) were associated in different ways to construct different types of interfacial layer. Emulsions with layer-by-layer (LBL) interfacial structure not only showed better physical stability, but also had superior oxidative stability. This might be attributed to that CH assisted in forming LBL interface, which increased the interfacial layer thickness/compactness and maintained the interfacial protein adsorption. In conclusion, the emulsifying functionality of FBPI, and thereby the stability of FBPI containing O/W emulsions can be improved by different ways of modifications via several mechanisms.
  • Heikkilä, Maria (Helsingin yliopisto, 2020)
    Nutrition plays an important role in athletic performance. Its full potential is rarely realized due to limited nutrition knowledge among athletes and their coaches. Misunderstandings and gaps in knowledge can lead to food choices that do not support athletic development. This thesis study was undertaken to gain further insight into the nutrition knowledge of young Finnish endurance athletes. Another aim was to evaluate how athletes’ knowledge and nutritional skills can be improved. Study I created and validated a questionnaire measuring knowledge in different areas of sports nutrition. This questionnaire was then used in Study II, which aimed to measure the nutrition knowledge of young Finnish endurance athletes and their coaches. The results of Study II were used to develop an education intervention, aiming to improve athletes’ nutrition knowledge and dietary intake, in Study III. The intervention compared the effects of participatory nutrition sessions alone to those enhanced by a mobile app. In Study II, a total of 312 athletes and 94 coaches completed the questionnaire. The athletes were 17.9±1.2 and the coaches 44.3±12.3 years old. Half of the athletes were women and half men; of the coaches 27% were women. Of the athletes 36% were cross country skiers, 35% orienteers and the rest other endurance athletes. Seventy-nine athletes took part in the intervention in Study III. Their mean age was 18.0±1.4 years, 56% of them were men and 44% were women, and 42% were cross-country skiers. The education in the intervention was based on the Self-Determination Theory and the concept of meaningful learning processes. The education sessions included discussions, tasks and goal setting, which were all intended to increase the athletes’ intrinsic motivation. This motivation in turn is a prerequisite for effective learning. The three sessions lasted 90 minutes each and were held fortnightly. The athletes filled in the questionnaire at baseline and a week and three months after the last session. The athletes in the mobile app group used the app for four days after each session and took photos of everything they ate or drank. Both groups completed a three-day food diary at baseline and three months after the last session and received personal feedback on it. On average, the athletes in Study II answered 73% and the coaches 81% of the items correctly. However, over a half of the athletes and 44% of the coaches scored below the mean knowledge score, at worst answering only 47% of the items correctly. The coaches scored better in all sections of the questionnaire. The questions in the ‘Dietary supplements’ section proved to be the most difficult for the athletes, and those in the ‘Nutrition recommendations for endurance athletes’ section for the coaches. The older the athletes were, the higher was their mean nutrition knowledge score. Among the coaches, the situation was the opposite. On average, the female athletes and coaches scored better than the men. The athletes who were part of a national team had higher knowledge scores than those who were not. The athletes’ nutrition knowledge improved significantly during the intervention. At baseline, their knowledge score was 78%. A week after the education sessions, the athletes in the mobile app group answered on average 87% of the questions correctly and three months later, 86%. In the group without the mobile app, the scores were 85% and 84%, respectively. There was no significant difference between the groups in any sections of the questionnaire. The mean energy intake of the athletes was below the estimated energy expenditure during Study III. The intake of protein and fat met the recommendations for endurance athletes, but the intake of carbohydrates was below them (6–10 g·kg-1·day-1) throughout the study, even though it slightly improved. At the end of the intervention, the athletes in the mobile app group consumed 5.4 g·kg-1·day-1 of carbohydrates and the athletes in the other group 5.0 g·kg-1·day-1. Many psychological, social and economic factors affect what we eat. Improved knowledge does not automatically lead to better food choices if the intention to perform the behavioural change is lacking. The duration of the intervention may also have been too short for notable behavioural changes. In addition, already at the beginning of the study the diet of the athletes was better than that of the general Finnish population, thus leaving less room for dietary improvements. Nutrition knowledge improved after only three education sessions and food diary feedback, but the mobile app did not further improve this learning. Thus, if sport clubs and other sport organizations dedicated even a relatively small amount of time and other resources to structured, targeted, motivational and science-based nutrition education, it may promote positive changes in nutrition knowledge. As athletes make use of the skills they learn during their sports careers in their everyday lives as well as when training other athletes, receiving influential nutrition education could also benefit their performance and health in the future.
  • Tienhaara, Annika (Helsingin yliopisto, 2020)
    The diversity of agricultural genetic resources (AgGR) is the foundation of food security. A diverse gene pool enables adaptation to changing conditions and is therefore essential, for example, to responding to climate change. However, during the past decades, intensification of agriculture has led to genetic erosion. Previously common animal breeds and plant varieties are becoming rare or extinct throughout the world as they are being replaced with small ranges of more productive specialized breeds and varieties. Yet, indigenous breeds and varieties have a wide range of socio-economic, cultural, ecological and genetic values and, in fact, the importance of conserving genetic resources has been acknowledged in global agreements and national policy programs. Nonetheless, as the resources available for conservation are limited, information on the value of AgGR is needed in order to compare the costs and benefits of conservation and to support decision making. Benefits from the conservation of AgGR can be measured from citizens’ and consumers’ preferences. This dissertation provides new, policy-relevant information on citizens’ and consumers’ willingness to pay for conservation and sustainable use of AgGR. Three stated preference methods were used to examine the value that citizens and consumers place on AgGR. Consumers’ willingness to purchase Finncattle meat and their willingness to pay for it was studied with contingent behavior and contingent valuation methods. In turn, willingness to support a conservation program for AgGR was examined with contingent valuation and choice experiment methods. In addition, heterogeneity in preferences and the effect of information use were analyzed. The results show strong support for the conservation of AgGR. There is a high will-ingness to purchase Finncattle meat among Finnish consumers, and a share of respondents is willing to pay +20-26% more for Finncattle meat compared to conventional meat. Studies also revealed that over 70% of the respondents supported an AgGR conservation program despite the increased cost related to it. Average willingness to pay for the program was €50-170 depending on the method of calculation. However, there was significant heterogeneity among respondents’ preferences. This is important to take into account, as ignoring the heterogeneity can lead to overestimation of benefit estimates. This dissertation provides new information on the benefit estimates of the AgGR conservation in Finland, which has not been studied before. It also contributes to the globally scarce literature on citizens’ and consumers’ preferences related to AgGR. The results of this dissertation can be used in cost–benefit analysis and they can assist in designing optimal AgGR conservation policies.
  • Kulha, Niko (Unigrafia, 2020)
    Global environmental change and other anthropogenic changes, such as changes in disturbance regimes alter the structure and dynamics of boreal old-growth forests. Changes in these forests greatly influence key ecosystem properties such as biodiversity and carbon cycle. Hence, understanding the development of the remaining natural boreal forests is particularly important. This thesis examines how boreal forest structure varies in space and changes over time. Forest structure was examined in three natural boreal forest landscapes in northern Fennoscandia and two landscapes in eastern North America. Canopy cover that was visually interpreted from stereopairs of aerial photographs taken between the years 1959 and 2011 was used as a surrogate measure of forest structure to quantify and examine spatial variation and/or temporal change, and Bayesian inference was used to separate credible ecological phenomena from the noise caused by visual interpretation error. This thesis presents and applies a novel methodology to study changes in forest structure. We calibrated visual canopy cover interpretations made from time series of aerial photographs with canopy cover reconstructions that were based on field- and tree-ring measurements. We successfully identified credible changes in forest structure in each studied landscape, but also noted that the visual interpretation of canopy cover was prone to systematic and random error that depended on, e.g., aerial photo quality. Due to this error, changes that occurred at the level of an individual tree could not be credibly discerned. Still, the methodology can be used to detect both abrupt and slow continuous changes in forest ecosystems. The methodology was extended to examine spatial variation in forest structure. The results revealed variation in forest structure at multiple spatial scales which showed similarities despite the differences in dominant tree species and disturbance regimes between the studied landscapes. The variability was connected with scale-dependent driving processes that also showed similarities among the landscapes. Last, the methodology was applied to study how varying scale of observation influences how changes in forest structure are perceived over different periods of time. This multi-scale change analysis revealed a synchronous and prevalent cover increase at large spatial scales in the majority of the studied landscapes, and canopy cover decrease and increase in areas that were subjects to disturbances. Changes of variable direction and magnitude were detected at smaller spatial scales in each studied landscape. The results indicated that historical aerial photographs are a valuable resource in studying how forest ecosystems develop, but the notable errors in their visual interpretation need to be taken into account in analysis of change. The results aligned with the hierarchy theory and the hierarchical patch dynamics concept by showing that the structure of natural boreal forests vary and change at discernible spatial scales, and showed that these scales can be identified and quantified objectively. While gap- and patch-scale changes were important, the most notable changes occurred at large spatial scales, contradicting the conventional view that changes in the structure of natural boreal forests are mostly due to gap dynamics. This suggests that the studied forests are currently responding to large scale drivers that cause trend-like increase in their canopy cover and consequently in biomass.
  • Lehto, Marja (Helsingin yliopisto, 2020)
    Fresh-cut vegetables have been cleaned, peeled, chopped, sliced, or diced and then packaged but not heated. The fresh-cut vegetable processing industry uses large volumes of water. This water is utilized by hygiene and cleaning processes and for cooling of the products. Knowledge has been lacking about waters created and the water use in different stages of the fresh-cut vegetable processing. Obtaining information about the water use and waste water production is important for recocnizing critical phases for risk management and for evaluating the need of water treatments. The aim of this study was to improve the processing of fresh-cut vegetables through collecting information on the hygienic level of waters and vegetables, decontamination methods and their efficacy, water use and waste waters which helps companies to improve their processes and self-monitoring activities. One aim of this study was to also evaluate on-farm waste water treatment systems carrying out peeling of vegetables. Water consumption, measured in six fresh-cut processing companies in this study, was 2.0–6.5 m3/t per finished product. The water consumption varied in the same company between months and according to season, volumes of vegetables processed, and the quality of raw material. Through regular measurement of water consumption, it is possible to decrease water use in fresh-cut vegetable processing. In the present study, water consumption decreased by 15% over the course of the three-year period examined. This may decrease costs and improve sustainability of the production. Vegetables contain 90‒96% water; the remainder is composed of components such as carbohydrates, proteins and nutrients. In vegetal cells, water is present in different forms; part of this water can easily be removed and a part cannot. Depending on their size, the substances of which vegetables are composed form different kinds of solutions in combination with water. Most of the organic load and nutrients of the vegetables processed were released into water from the peeling of root vegetables, whereas the volume of the water came primarily from the rinsing and washing of vegetables. Washing is an important step in fresh-cut vegetable processing; it removes soil and debris, and reduces microbial populations residing on the vegetable surface. Washing is often the only step that can remove foreign material and tissue exudates, as well as inactivate pathogens. Water plays a dual role in the fresh-cut vegetable processing: it both reduces and transmits microorganisms to vegetables. The high quality of water used in processing is important, and can be attained through water decontamination or by using new potable water that is changed continuously during the process. The high operational cost of water use has resulted in the industry-wide common practice of the reuse or recirculation of process water. Fresh-cut vegetables may be contaminated by pathogens in different stages and different ways after harvest. Pathogenic microorganisms can cause severe outbreaks of foodborne disease. The microbiological quality of vegetables changes during processing. The total microbial counts in peeled and cut carrots were lower than in whole washed carrots, but higher in grated than in cut carrots. The total microbial count was lower in process water than in wash water of carrots. Pathogenic Yersinia enterocolitica was detected in many carrot and water samples by sensitive RT-PCR, but not by the cultivation method. The data concerning treatment of process water of fresh-cut wagetable processing is quite scarce, in particular concerning the effect of treatments on yersinia. Water decontamination methods neutral electrolyzed water (NEW), chlorine dioxide (ClO2), organic acids and UV-C was evaluated, specially on yersinia, E. coli and Candida lambica (yeast) in this study. The effect of decontamination on different microbes in water differs with, e.g., time, concentration, decontamination method, and turbidity of water. Technically- and economically effective chlorine-alternative decontamination technologies are the goal of the fresh-cut industry. In Finland, and in many other EU countries as well, chemical treatments of vegetable process waters are restricted in food legislation, but allowed in other countries. Published information concerning the functioning and feasibility of small on-farm waste water treatment plants are few. Waste water generated from vegetable production contains high concentrations of biochemical oxygen demand (BOD) and suspended solids (SS). One aim of this study was to evaluate on-farm waste water treatment systems carrying out peeling of vegetables. Primary treatments of waste water remove coarse solids, reduce organic matter content and adjust pH. Secondary, biological, wastewater treatment removes soluble organic matter and nutrients from water. Biological waste water treatment, such as a sequencing batch reactor or a trickling filter, are used for treating of vegetable processing waste water in small scale companies in rural areas. In the case of both systems, the requirements set in legislation were met. Tertiary treatment can be used if waste water is reused in subsequent vegetable processing or recycled for irrigation of food crops. Fresh-cut vegetable processing companies produce high-quality fresh-cut produce with appropriate inputs and processes. Each company must establish its own specific validation protocols for evaluating their processes. The aim is to minimize the risks and produce healthy, safe, fresh and easy-to-use vegetables for consumers.
  • Karambiri, Mawa (Helsingin yliopisto, 2019)
    Democracy as the government of the people by the people and for the people, equally represented is one of the most contested claims worldwide yet cherished by many and associated with a universal human right. The word “democracy” did not appear in the global participatory forest policy i.e., the shifting of global forest paradigm toward more participation in the 1970s. However, one of the core ideas of democracy, namely the right of local people to participate in the decision making over the use and management of their forest resources underpinned the policy proposal. Donors and international development agencies subscribed to these principles and aimed to translate them into local contexts. Likewise, central government in sub-Sahara Africa, specifically in Burkina Faso undertook political decentralization reforms and participatory forest management programmes to implement these principles of inclusion and self-determination at the local level. However, in practice, participatory forest policy and decentralization still await an effective devolution of decision-making authority to local people and the improvement of their livelihoods. In addition, the state and non-state policy translators as above continue to choose processes, plan and implement environmental projects, often in partnerships with other than the democratically elected bodies. In doing so, they risk privatizing common resources, undermine democratization, shrink the public domain and limit citizenship and the spaces available for local people’s engagement in forest management. While literature exists on those issues, it remains unclear how these three dimensions of local democracy i.e., representation, citizenship and public domain operate under environmental interventions in the context of Burkina Faso. Therefore, I ask how participatory forest policy is translated at the local level in sub-Sahara Africa, specifically in Burkina Faso. How do the translation processes influence local democracy? I adopted a policy translation perspective and the theoretical lens of the “choice and recognition” framework to assess the democracy effects of forestry interventions namely on local peoples’ representation, citizenship and the public domain. I investigated these three components of local democracy through four articles included in this dissertation using qualitative research methods. The results showed that in Burkina Faso, global forest policy was translated at the local level through political decentralization reforms and participatory forestry projects. The choices of local institutions made by the project implementers influenced the substantive representation of local people’s interests and the effectiveness of forest restoration outcomes (Article II). The forestry interventions unintentionally produced uneven forms of citizenship, turning citizens into denizens i.e., those whose citizenships was revoked (Article III). Lastly, Articles IV and I depicted the multi-layered and complex dynamics in the public domain, continually contested by both customary and post-colonial state logics. From the findings, it can be inferred that participatory forestry has the potential to strengthen local democracy through political decentralisation. However, the current policy translation processes can undermine democratisation. Thus, I recommend to more systematically pay attention and integrate indicators of local democracy when trying to apply global forest policies in a local context.
  • Nathanail, Alexis (Helsingin yliopisto, 2019)
    Fungi are capable of producing an array of heterogenous toxic secondary metabolites, i.e. mycotoxins, which may acutely or chronically impact human and animal health following the consumption of contaminated agricultural commodities. Mycotoxins, like most xenobiotics, are prone to structural alterations via metabolic processes in living organisms but can also undergo changes during food manufacturing. The resulting compounds, defined as “modified mycotoxins”, possess distinct chemical properties, with potentially unique toxicological characteristics, and often coexist with their precursor forms in food- and feedstuffs. The impetus of this Ph.D. thesis largely stems from the dearth of evidence available on these compounds and aspires to contribute evidence for addressing the underlying debate: Are modified mycotoxins relevant to food/feed safety? In this context, liquid chromatography–tandem mass spectrometric methods, employing fit-for-purpose sample preparation approaches, were developed and validated for the simultaneous determination of Fusarium mycotoxins and their modified forms. At first, conventional sample preparation techniques commonly utilised in mycotoxin analyses were evaluated against automated on-line sample clean-up. On-line clean-up and the standard “extract and shoot” approach offered optimal overall performance and achieved compliance with legislative criteria. The natural occurrence of the Fusarium mycotoxins HT-2 toxin, T-2 toxin, deoxynivalenol, nivalenol, zearalenone and derivatives thereof was investigated by conducting a nationwide survey of Finnish barley, oats and wheat grains. Deoxynivalenol was the most abundant mycotoxin (in 93% of the cereal samples), and at unusually high levels compared to adjacent years, followed by the modified mycotoxin deoxynivalenol-3-glucoside (81%). All 10 additional modified mycotoxins included in the method were detectable at widely varying concentrations. The relative proportions of modified/parent mycotoxins were mostly between 15–55%. Furthermore, the metabolism of HT-2 toxin and T-2 toxin was studied in barley and wheat. Specifically, tracing of their metabolism was accomplished by untargeted metabolomics based on stable isotopic labelling and liquid chromatography–high resolution mass spectrometry. Structural elucidation of the detected compounds indicated the presence of several novel modified mycotoxins, including glucoside, malonyl-glucoside, acetyl and feruloyl conjugates of the parent toxins. Time course kinetics of the in planta metabolites revealed the HT-2 toxin-3-glucoside as the primary detoxification product, which was rapidly formed in both crops. The experiments also determined the extent of metabolism of the parent toxins, while highlighting those modified forms present at harvest. Lastly, the metabolic fate of HT-2 toxin, T-2 toxin, deoxynivalenol and deoxynivalenol-3-glucoside was investigated during a four-day beer brewing fermentation with lager yeast. Yeast tolerated high toxin levels and was able to remove 9–34% of dosed toxins from wort by adsorption and/or biotransformation. The original contribution of this work can be summarised as the discovery of several novel modified Fusarium mycotoxins and related metabolic pathways, generation of essential natural occurrence data and gaining of further insight into mycotoxin-plant/fungal interactions, all of which were facilitated by state-of-the-art analytical tools.
  • Rissanen, Kaisa (Helsingin yliopisto, 2019)
    Trees have various mechanisms for avoiding and mitigating biotic and abiotic stresses. Resin is one such mechanism, and it is essential for conifer trees. Conifer resin is also a large pool of monoterpenes that – similarly to other biogenic volatile organic compounds (BVOCs) produced by plants, e.g. methanol, acetone and acetaldehyde – play important roles in tree signalling and atmospheric chemistry once emitted to ambient air. BVOC emissions from various tree parts and resin dynamics depend on environmental variables, with intrinsic effects on conifer defence. This thesis aims to clarify the environmental and physiological drivers of resin dynamics and BVOC emissions from the shoots and stem of mature boreal Scots pines (Pinus sylvestris) in field conditions, with special attention given to the effect of tree water relations. Resin pressure dynamics were studied using pressure transducers and BVOC emissions using an online mass spectrometer and dynamic chamber system. Resin and monoterpene emission compositions were analysed based on gas chromatography measurements. Temperature explained resin pressures and BVOC emissions from both the shoots and stems of Scots pine in the short term. Over a longer period, resin pressures and stem monoterpene emissions decreased with decreasing soil water availability and water potential in stem. In addition, the emission dynamics of water-soluble acetaldehyde, methanol, and acetone from the shoots and stem were connected to transpiration rate and soil water content, indicating an important effect of their transport in the xylem sap. These results show that although often overlooked, tree stems are an important source of BVOCs and that even relatively small changes in water availability may alter BVOC and resin dynamics despite their strong short-term temperature control. This information may help to understand the potential susceptibility of conifer trees to biotic stresses in various environmental conditions and improve BVOC emission modelling by accounting for stem emission dynamics.
  • Malkamäki, Arttu (Helsingin yliopisto, 2019)
    Because of the pace and magnitude of land cover change, terrestrial ecosystems across the globe are under unprecedented pressure. Industrial production of wood in large-scale tree plantations is one of the drivers of this change. The development of funds of natural capital on private lands for marketable commodities, however, often comes at the expense of other non-marketable benefits that people derive from ecosystems. The disturbances to existing ecosystems and social systems caused by the establishment of plantations can be drastic. Identifying factors that foster and impede actors and institutions to solve problems and address injustices thus becomes crucial for advancing sustainability through changes in policies and practices. This dissertation synthesises findings from four articles. It takes on the task of filling two gaps in the previous scholarly literature: the first concerning the human impacts of large-scale tree plantations (articles I and II); the second concerning the different institutions that shape their governance (articles III and IV). It also brings these contributions together under a framework for empirical analysis, which combines and structures key concepts of environmental social sciences ranging from systems ecology to sociology. Both qualitative and quantitative research methods have been used in the four articles. Article I presents the findings from a systematic review of the impacts of large-scale tree plantations for local communities. The review shows that impacts are frequently grounded in the process of land acquisition for plantations and the subsequent loss of livelihoods. Plantations have often caused more losses of livelihoods than created jobs. Article I also identifies gaps in the evidence base. Article II applies the concept of resilience and qualitative content analysis to analyse the Uruguayan beekeepers’ experiences of and responses to land cover change to plantations. The results show that the community faces this change as multiple interlinked challenges (e.g., lower honey yields and higher costs), to which they generally have a limited capacity to adapt. Both articles III and IV use data from the domain of South African tree plantation policy. Based on an analysis of policy beliefs, the former identifies two competing coalitions: a dominant business-as-usual coalition, of which ideas a minority justice and change coalition challenges. Article III also clarifies the role that beliefs concerning specific policy instruments play in coalition formation. Article IV focuses on policy learning – the acquisition and dissemination of information between actors with diverse knowledge. It tests hypotheses concerning actors’ information exchange behaviour and finds that actors tend to exchange information and build trust with those who think alike. However, its findings support the idea that co-participation in policy forums enables policy learning. Large-scale tree plantations have often caused negative impacts for local communities. The unfolding of impacts, however, also depends on the context (e.g., land use rights). The impacts are in many ways rooted in the governance of plantations, the dynamics of which can be better understood through coalition formation and policy learning.
  • Yang, Zhen (Helsingin yliopisto, 2019)
    Role of lipid-modifying enzymes in oat and faba bean Increasing utilization of plant materials and especially their proteins is a global trend. One of the challenges in using grains and legumes as sources of protein is the off-flavour that is associated with them. Many of the undesirable flavour compounds are formed from lipids as a result of complex enzymatic and chemical reactions. To understand and control lipid-modifying enzymes is essential to prolong the shelf life of cereal and legume ingredients and products, and raise consumer acceptance towards them. The aim of this thesis was to study the role of lipid-modifying enzymes in oat and faba bean. To reach this aim, the levels of and variations in the lipid-modifying enzyme activities present in oat and faba bean seeds from selected cultivars and cultivation years were studied (Study I). In addition, the formation of non-volatile oxidised fatty acids (NVOFAs) by lipid-modifying enzymes in oat was investigated (Study II). Finally, the role of lipid-modifying enzymes in the formation of volatile off-flavour compounds in faba bean foods was studied (Study III). The results of Study I showed the presence of marked lipase and peroxygenase activities oat, while lipase and lipoxygenase (LOX) activities occurred in faba bean. The enzyme activities were affected by sample cultivars and cultivation years. Lipase activity in faba bean was surprisingly high, and it could effectively start lipid-derived off-flavour formation as soon as the seed structure is broken and it has access to inherent or added lipids as substrates. Study II showed that NVOFAs occurred in the flours of non-heat treated oat grains, and their amounts increased remarkably during the storage of oat samples. The formation of NVOFAs was in line with the release of free fatty acids by oat lipase. In addition, the formation of NVOFAs in the flour of heat-treated oat grains was quite small. In the third study, the optimum pH of faba bean lipase was found at 7.5-8, and for LOX the optimum pH was at 6. The LOX pathway produced various types and amounts of volatile lipid oxidation products using different substrates. In addition, adding rapeseed oil in emulsions increased the formation of volatile lipid oxidation products, and adding rapeseed oil fatty acids increased it even more. This study also showed that the pH levels greatly affected the extent of the reactions. Overall, this thesis evaluated the role of reactions catalysed by lipid-modifying enzymes together with chemical lipid oxidation for their potential to form lipid-derived off-flavours in oat and faba bean. The lipid-modifying enzymes should be properly inactivated to prevent the causing of potential problems. By studying comprehensively the lipid modifying enzymes, we are able to produce knowledge which assists in developing high-quality oat and faba bean based foods.
  • Arte, Elisa (Helsingin yliopisto, 2019)
    Wheat is the world’s most important staple food, providing one-fifth of the daily protein consumed globally. However, the majority of wheat is used as refined flour, in which the nutritionally superior bran layers and germ are removed during milling, thus producing yearly a massive amount of underutilised food side streams. Better exploitation of the side streams and development of new plant-based protein ingredients are required to ensure the future global demand for food protein. This study aimed to examine hydrolytic enzymes and lactic acid fermentation as tools to improve the bioavailability, nutritional quality and technological properties of wheat bran proteins for food applications. The study showed that proteolytic activity, either by endogenous or exogenous enzymes, was crucial for increasing protein liberation and solubilisation from wheat bran, whereas microbial activity was required for improving the nutritional quality of the proteins. The application of commercial carbohydrases or proteases was able to either solubilise the bran cell walls or the proteins from the residues of endosperm in bran but was not effective in liberating proteins within aleurone cells. The endogenous enzymes of wheat bran, activated by chemical acidification, increased the protein solubilisation up to 75% with a simultaneous increase in in vitro protein digestibility (from 14% to 20%). However, bioprocessing by lactic acid bacteria (LAB), yeast and cell wall-degrading enzymes (Depol 761P and Viscoferm) was found as the most beneficial and microbiologically safe method to improve the solubilisation and nutritional quality of bran proteins. This bioprocessing meth-od resulted in a protein solubilisation of 52% and significantly improved the in vitro protein digestibility to 39%. In this work, the bioprocessing of wheat bran by LAB and yeast, with and without cell wall-degrading enzymes and phytase prior to the production of protein isolates, was found to influence the biochemical and technological properties of the bran proteins. The bioprocessed protein isolates had significantly higher protein content (80%), presumably due to the degradation of starch and soluble arabinoxylans during the bioprocessing. In general, the bioprocessing of bran resulted in a lower protein solubilisation of the protein isolates and had no influence on the emulsifying properties of the isolates in oil-in-water emulsions. However, bioprocessing by lactic acid fermentation together with cell wall-degrading enzymes almost doubled the foaming stability. Furthermore, wheat breads were made by substituting 20% of the total energy by proteins from the isolates. Wheat breads enriched with the lactic acid fermented bran protein isolate was found to have the most optimal technological characteristics, showing delayed staling and lower firmness during four days’ storage in comparison to bread enriched with a protein isolate produced without bioprocessing. In conclusion, by utilising lactic acid fermentation in combination with selected hydrolytic enzymes, the aleurone cell walls can be degraded and the proteins liberated for microbial modification, leading to improved protein bioavailability, nutritional quality and technological functionality. This study is the first to show the potential of using bioprocessing for the development of new wheat bran-based protein ingredient for food applications.
  • Pokki, Heidi (2019)
    Fish stocks in the Baltic Sea are an important natural resource for Finland; targeted by both commercial and recreational fishermen. Fisheries managers require data on the economic value of commercial and recreational fisheries for decision making and to assess the economic sustainability of fisheries. The volume of recreational catch of salmon in Finland is greater than the volume of commercial catch. However, there is marginally information available on the recreational value of salmon angling. These data deficiencies hinder the possibility of fishery managers to make optimal regulatory decisions concerning fish stocks. Additionally, the angler preferences and related angler profiles should be consid-ered in the decision making process as the reaction to different management measures can vary considerably depending on the angler type. This thesis contributes to the alleviation of the existing data deficiencies by contributing knowledge on the economic state of marine commercial fisheries and on the economic value of salmon angling. Defining an economic value is often ambiguous as the valuation methods involve inaccuracies which affect the reliability of the estimates. Therefore, it would be benefi-cial for the data end users to understand the consequences of the choices made in the estimation process in order to interpret the results correctly for decision making. In this thesis, the application of two different valuation methods: the perpetual in-ventory method and the travel cost method is described for defining the value of capital and recreational fishing in Finland. The perpetual inventory method is applied for estimating the capital value of the marine commercial fishing fleet of Finland. The thesis describes the justification for the choices made in the estimation process and how these choices affect the results. In addition, the differences between economic and financial analysis are discussed. Moreover, the thesis describes the value estimation of salmon angling in the River Teno and the River Tornionjoki employing the travel cost method. The studies use a two-step estimation procedure, which considers the potential endogeneity of on-site time per fishing trip. The case study of salmon angling in the River Tornionjoki explores the influence of angler profiles on the fishing behavior; the length of a fishing trip and the number of trips taken. The results show that the importance of increasing catch rate for the recreational benefit obtained by the angler is smaller than expected and the importance of salmon catch differs between the Teno and Tornionjoki rivers. In the River Teno, the experience of catching salmon in the previous season increased, on average, the number of fishing trips during the following season. In the River Tornionjoki the higher catch rate reduced the average number of fishing trips and the length of a trip during the season. The results presented in this thesis can be utilized for e.g. bio-economic modeling, assessing the sustainability of commercial fisheries of Finland, evaluating the implementation of EU common fisheries policy, and defining river specific fishing regulations.

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