Browsing by Subject "kasvillisuus"
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(2019)Tutkin tässä pro gradu -tutkielmassani eräiden suomalaisten ruohovartisten kasvilajien ja biohiilen vaikutuksia huleveden määrään ja laatuun. Tutkimuksessa järjestettiin koekasteluita, joiden avulla oli tarkoitus selvittää kasvilajien kykyä vähentää huleveden määrää ja poistaa siitä ravinteita sekä biohiilen vaikutusta huleveden määrään ja laatuun. Kasvillisuuden ja biohiilen vaikutusta on tutkittu aikaisemminkin, mutta erityisesti tiettyihin kasvilajeihin liittyviä tutkimuksia ei ole tehty Suomessa. Tutkimus on osa Luonnonvarakeskuksen Hulevesialueiden kasvit ja kasvualustat (HuleKas) -projektia. Kaupungistuminen lisää talojen, parkkipaikkojen ja teiden rakentamista. Tämä kasvattaa läpäisemättömien pintojen määrää, ja se puolestaan estää veden imeytymisen maan läpi. Kaupungeissa ongelma on ratkaistu rakentamalla hulevesiviemäriverkostoja, mutta erityisesti muuttuva ilmasto lisää sateiden ja sitä kautta huleveden määrää. Rankkasateilla kaupunkien hulevesiviemärit osoittautuvat usein riittämättömiksi. Lisäksi hulevesi huuhtoo epäpuhtaudet kaduilta, ja hulevesi onkin todettu yhdeksi tärkeimmistä hajakuormituksen aiheuttajista. Nyttemmin on kehitetty perinteisten sadevettä pois johtavien viemäriverkostojen rinnalle ekologisempia ja kestävämpiä ratkaisuja. Hulevesi pyritään käsittelemään sen syntysijoilla, ja tähän voidaan päästä rakentamalla erilaisia hulevesirakenteita, kuten hulevesipainanteet tai sadepuutarhat. Hulevesirakenteiden tärkeimmät osat ovat kasvualusta ja kasvillisuus. Hyvällä kasvualustavalinnalla voidaan pidättää mm. fosforin yhdisteitä ja kuparia, kun taas nitraatin pidättyminen vaatii rakennetta peittävää kasvillisuutta ja hapettomia olosuhteita. Kasvillisuuden avulla voidaan myös hidastaa huippuvirtaamia, pidättää kiintoainesta ja poistaa metalleja ja ravinteita hulevedestä. Myös kasvualustan mikrobeilla on tärkeä merkitys ravinteiden sitojina. Tutkimusasetelmani oli astiakoe. Astioihin oli istutettu seitsemää suomalaista luonnon kasvilajia, nurmea ja kontrollina toimivat kasvittomat astiat. Osaan astioista oli lisätty biohiiltä. Tutkimusjakson aikana järjestettiin kolme koekastelua, joissa liuoslannoitteilla lisättyä tekohulevettä kaadettiin jokaiseen astiaan sama määrä. Tämän jälkeen kirjattiin ylös tietyin aikavälein, paljonko vettä astiasta on valunut ulos. Tutkielman aineisto koostuu kahdesta osasta. Ensimmäinen osa muodostuu koekasteluiden valuntatiedoista ja kolmas osa koekasteluiden vesinäytteiden laboratorioanalyyseistä. Parhaita kokonaistypenpidättäjiä olivat viiltosara, jänönsara, korpikaisla, luhtakastikka ja rantatyräkki. Kokonaisfosforin pidätyksessä puolestaan erottuivat viiltosara, korpikaisla, ja rantatyräkki. Kaikki kasvikäsittelyt alensivat tekohuleveden kokonaisfosforin konsentraatiota. Biohiili paransi kaikkien edellä mainittujen kasvilajien ravinteenpidätyskykyä. Myös mikrobitoiminnan merkitys ravinteiden sidonnassa on tärkeä. Eniten vettä koekastelussa käyttivät viiltosara, luhtakastikka sekä jänönsara. Jänönsaran suorituskyky on kiistanalainen johtuen epätasaisesta kastelusta kolmannen jakson aikana. Jaksojen aikaisessa veden käytössä tehokkaina veden käyttäjinä nousevat esiin viiltosara, jänönsara, korpikaisla, luhtakastikka ja rantatyräkki. Kaikki kasvikäsittelyt tuottivat vähemmän valuntaa, kuin kontrolli. Biohiilen avulla voidaan hidastaa valunnan alkamista ja kertymistä.
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(2014)The purpose of this master's thesis was to study environmental impacts of nature-based tourism on vegetation, insect communities, birds and soil nitrogen levels in Käsivarsi wilderness area in the Finnish Lapland. Tourism is the largest industry in the world and nature-based tourism is the fastest growing segment of it. Nature-based tourism takes place in areas that holds great nature values. These areas are often protected to preserve significant nature values from negative impacts of human activities. This controversy creates disharmony between nature tourism and nature conservation. Most popular nature tourism destinations in Finland are state owned national parks and wilderness areas. Wilderness areas are not within strict nature conservation. They are areas defined by law for preserving the typical character of the remaining wilderness areas, preserving native Saami culture and for preserving and developing recreational use of these areas. Studies have shown that nature-based tourism has caused changes by erosion and human disturbance to vegetation, mammals and birds. The key study question was to examine if there are changes in the soil nitrogen levels around huts used by hikers. I was also a point of interest to discover what kind of bird, insect and plant communities occur around these huts. Main interest was to see if there are changes in these communities on a gradient from high human impact areas around the huts to more pristine mountainous areas. The study was performed around five huts with three study lines, which had study points 15, 30, 60, 120, 240, 480 and 960 meters away from the hut. Birds were observed from the same lines but with 200 meter point counting intervals. It was also studied whether the abundance of graminoids was affected by the soil nitrogen levels and if soil nitrogen levels or the abundance of graminoids influenced changes in insect or bird communities. Results show that nature-based tourism has an impact on soil ammonium and nitrate levels. This impact was visible in increased nitrate and ammonium levels on a 30 meter radius area around the huts. The observed fauna and flora around the huts were typical for the mountainous region in the northern Finland. There were no observed invasive species. No species was discovered to have a negative impact from nature-based tourism. Abundance of graminoids increased near the huts whereas plant species richness and vegetation biomass did not. The insect community was more diverse and abundant near the huts. Especially Amara brunnea ground beetle and rove beetles showed a clear increase in numbers near the huts. Birds were also more abundant and species rich near the huts. Especially insect eating bird species as a group were more abundant close to the hut compared to the surrounding study areas. The increased level of ammonium in the soil correlated with the increased graminoid and insect abundances. The increased graminoid abundance correlated also with the observed insect abundance. The influence between nature-based tourism and the changes in soils nitrogen levels and in the insect communities were scientifically demonstrated for the first time in this study. This thesis provides a comprehensive view of the effects that nature-based tourism has in the northern Finnish nature. The generalization of the result was weakened by the fact that the study was conducted only around five different huts and that the studied plant and animal communities were relatively diverse between these huts. The results are still substantial for the nature tourism in Käsivarsi wilderness area. The results can be useful for developing nature tourism infrastructure for the plausible new national park in the area.
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(2022)Environmental factors are important tools in constructing methane flux models and estimations. Among the abiotic factors, plants and their functional groups have been noted to have significant effect on methane fluxes for three reasons. First, the vegetation community compositions express their abiotic environmental factors that affect not only the plants, but also local methanogen and methanotroph communities. Second, the vegetation itself might produce methane emissions and have a direct effect on methane balance. Third, the plant functional groups and species have differences in their chemical and physical properties that support different methanogen communities and therefore have an indirect impact on methane fluxes. In this study, methane fluxes of different plant communities were observed during one growing season in northern boreal catchment area in Muonio. Study focuses to determine the link between methane fluxes and abiotic and biotic environmental factors in different vegetation types. Closed chamber technique was used to measure methane and carbon dioxide fluxes from 23 plots every two weeks in period of June-August. Environmental data, such as moisture, temperature species composition etc. were collected from the plots. Vegetation types for each plot were determined via ordination analysis. Linear mixed-effects regression model and generalized additive model were applied and compared to observe the relationships of methane and environmental factors in different vegetation types. Dataset was divided into four vegetation types in clustering analysis: wet fen, pine bog, spruce swamp and forest. The greatest amount (average 5959 µg/m²/h) and biggest range (standard deviation 5285 µg/m²/h) of methane emissions were observed on wettest fen-like study sites. Peatland types in general acted as net methane sources. The driest, forest-like vegetation type acted as a net methane sink. The amount (average -107 µg/m²/h) and range (standard deviation 117 µg/m²/h) of methane fluxes were very moderate in comparison to peatland types. These effects intensified towards the climax of growing season. The most significant environmental factors were mostly abiotic on driest study sites and the whole plant biomass was more significant biotic methane flux regulating factor than plant functional groups. On wetter study sites, the role of abiotic factors decreased, and plant functional group increased. Graminoids were linked to bigger methane emissions especially on wetter study sites. Forest mosses and different shrub types seemed to have a link with lower methane emissions or methane absorption. The effect of other plant functional groups on methane fluxes varied more, and their role remains unclear. None of the environmental factors could estimate the methane flux alone, and the methane budget seems to be a sum of multiple variables in each vegetation type. The role of plant functional groups varied in different vegetation types and was dependent on surrounding vegetation. More research is needed to get better tools to estimate methane balance and to understand the underlying mechanisms in climate and environmental change.
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