Browsing by study line "no specialization"
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(2020)Boreal mires are natural sources of methane and contribute considerably to the global methane budget. Therefore, in order to comprehend the overall impact that these ecosystems have on climate change, it is essential to understand the factors that influence processes involved in methane production and consumption. Factors affecting methane flux vary between different mires, but there is also great spatial and temporal variation in flux within mires. In previous studies, temperature and water table position have been shown to influence methane flux, but vegetation could aid in explaining the small-scale variation. Vegetation can indicate spatial variation in water table position, but also affect methane flux directly by the transportation of methane through plant tissues, and by providing substrate for microorganisms through primary production. Furthermore, redox potential is a poorly studied factor that can reflect if chemical conditions in peat are suitable for methane production or consumption, making it a useful tool in predicting methane flux. In this thesis, I seek to identify if small-scale spatial variation in the methane flux occurs within the studied mire area. In addition, I strive to identify important controllers of the observed spatiotemporal variation in methane flux, with a specific focus on the effect of vegetation properties and redox potential. Methane and carbon dioxide fluxes were measured with the closed chamber technique at a boreal fen in Sodankylä (67°22'06.6"N 26°39'16.0"E) during the growing season in 2019. Flux measurements were carried out at nine measurement plots belonging to three different vegetation types: flark, lawn and string. Coverage and height of plant functional groups were followed during the summer and continuous redox potential was measured for each plot. CH4 fluxes of different plots and vegetation types were compared to study the spatial variation in methane flux. Generalized additive models (GAM) were used to determine which variables are best to explain spatiotemporal variation in methane flux over the growing season. Mean methane flux during the summer was 0.94 ug CH4 m-2 s-1 which is in the same magnitude as observed in a previous study at the fen. Some small-scale spatial variation in the methane fluxes was observed at the study site, with strings having lower flux than flaks and lawns. However, overall the spatial variation was small, while temporal variation in methane flux over the growing season was considerable. The best model, that was a combination of vegetation, redox potential and environmental variables, and it explained 72 % of the observed variation in methane flux. Vascular plant variables were the most important variables in the model, whereas moss functional groups were of lesser importance. Redox potential in deeper peat layers was also important in the model, but redox potential closer to the surface was not found to be significant. Vegetation is an important controller of methane flux, and this information could potentially be used when predicting methane flux over larger areas by using remote sensing to map vegetation characteristics. Redox potential, on the other hand, is relatively easy to measure, and the result suggests that it could provide a useful tool for improving the predictions of methane flux.
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(2015)Panssarisiimalevät ovat suuri, morfologisesti ja ekologisesti monimuotoinen kasviplanktonryhmä.Panssarisiimalevien tuntemus on painottunut suurikokoisiin, yhteyttäviin ja laboratoriossa kasvatettaviin lajeihin, jaerityisesti pienten hetero- ja miksotrofisten panssarisiimalevien monimuotoisuus tunnetaan puutteellisesti. Itämerion maantieteellisesti ja ekologisesti eristynyt merialue. Panssarisiimalevien suhteellinen osuus Itämerenkasviplanktonista on kasvanut viime vuosikymmeninä. Tunnistamisen vaikeuden vuoksi Itämerenkasviplanktonseurannoissa pienikokoiset panssarisiimalevät kuitenkin usein sivuutetaan tai niitä käsitellään yhtenä,vain lahkotasolle määriteltynä ryhmänä. Pfiesteriaceae-heimon lajit ja Karlodinium veneficum ovat pienikokoisiahetero- ja miksotrofisia, mahdollisesti toksisia, haitallisia leväesiintymiä muodostavia panssarisiimaleviä. Näistäpanssarisiimalevistä ei ole vahvistettuja havaintoja Itämerestä. Lajeja pidetään kosmopoliittisina ja niidenasettuminen Itämeren murtoveteen on mahdollista. Tutkimukseni tavoite on selvittää pienikokoisten (alle 20 μm)panssarisiimalevien monimuotoisuutta Itämeressä ja arvioida näiden panssarisiimaleväkantojen suhdetta kantojenmuilta merialueilta eristettyihin lajitovereihin. Aineisto kerättiin Hankoniemen itäpuolelta Tvärminnen eläintieteellisen aseman läheisyydestä ja AhvenanmaanFöglöstä matalista ja suojaisista lahdelmista. Vesinäytteistä eristettiin kuoppalevylle valomikroskoopin avullapieniä (alle 20 μm) panssarisiimaleviä puhdasviljelmiä varten. Menestyksellisesti eristettyjäpanssarisiimaleväkantoja kasvatettiin Itämeren murtoveteen valmistetussa f/2-Si-kasvatusliuoksessa. Tiheiksikasvaneista soluviljelmistä eristin DNAn ja selvitin kantojen suku- ja lajitason identiteetin sekvensoimallaribosomaalisen DNAn SSU-, LSU- ja ITS-alueet. Tutkimuksessa luotujen sekvenssien ja GenBank-tietokannastaladattujen sekvenssien avulla laskin aineistosta neljä fylogeneettistä puuta. Kuvasin havaitut lajit morfologisestipyyhkäisyelektronimikroskoopilla. Toksisuusanalyysejä varten suodatin panssarisiimaleväkannoista näytteetlasikuitusuodattimille, jotka lähetettiin tutkittaviksi Yhdysvaltoihin. Tutkimuksessa eristetyistä 512 panssarisiimalevästä 100 kantaa jakautui kuoppalevyillä. Lopullisiin analyyseihinvalikoitui 12 kantaa. Fylogeneettisten ja morfologisten analyysien perusteella Itämerestä eristetyt kannat kuuluvatCryptoperidiniopsis brodyi-, K. veneficum- ja Pfiesteria piscicida-lajeihin. Itämeren K. veneficum -kantojen eitässä tutkimuksessa havaittu tuottavan karlotoksiineja. Itämerestä eristetyt C.brodyi-, K.veneficum- ja P.piscicida-kannat eivät eroa geneettisesti tai morfologisestimuilta merialueilta eristetyistä lajitovereistaan. Taustalla voi olla jatkuva geenivirta lajien eri populaatioidenvälillä. On myös mahdollista, että ribosomaalinen DNA on liian konservatiivinen alue kuvastamaan lajinsisäistävaihtelua. K. veneficum ja P. piscicida voivat tuottaa toksiineja ja muodostaa haitallisia leväesiintymiä. Vaikkatässä tutkimuksessa toksiinituotantoa ei havaittu, luonnonpopulaatiot voivat sisältää toksisuusfenotyypiltäänerilaisia kantoja, ja haitallisten leväesiintymien seurannan ja ennakoinnin kannalta tulisikin selvittää mahdollisestitoksiineja tuottavien kantojen esiintymistä Itämeressä. Suurin osa tutkimuksessa eristetyistä panssarisiimalevistä eimenestynyt laboratorio-olosuhteissa. Tutkimuksessa havaitut lajit eivät siis todennäköisesti edusta Itämerenpienikokoisten panssarisiimalevien koko monimuotoisuutta. Panssarisiimaleviin kohdistettu ympäristönäytteidensekvensointi eristyneessä ja vesimassoiltaan kerrostuneessa Itämeressä voisikin tuottaa lisätietoa niinpanssarisiimalevien monimuotoisuudesta yleensä kuin niiden erityispiirteistä Itämeressä.
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(2021)Kurtturuusu (Rosa rugosa) on haitallinen vieraslaji Suomessa. Se on levinnyt alkuperäisiltä esiintymisalueiltaan Koillis-Aasiasta Itämeren ja Pohjanmeren rannikolle sekä Pohjois-Amerikan koillisosiin. Se uhkaa luonnon monimuotoisuutta erityisesti merenrannoilla. Suomessa kaikki hiekkarantojen ja dyynien luontotyypit ovat uhanalaisia ja kurtturuusu vaikuttaa erityisesti niiden ekosysteemeihin muodostamalla suuria tiheitä kasvustoja. Kurtturuusukasvustossa muut lajit vähenevät. Vieraslajilain nojalla kurtturuusun kasvattaminen on kielletty, mutta kasvatuskielto astuu voimaan vasta siirtymäajan jälkeen 1.6.2022. Kurtturuusu on suosittu koristepensas. Siitä on myös jalostettu uusia lajikkeita. Niiden kasvatusta kielto ei koske, koska niiden lisääntymiskyvyn on ajateltu olevan heikko. Tutkimuksen tavoitteena oli selvittää kurtturuusun levinneisyyttä Espoon rannoilla sekä tutkia sen lisääntymiskykyä. Tutkimuksessa kartoitettiin Espoon merenrantoja järjestelmällisesti maastossa havainnoiden ja etsittiin niiltä kurtturuusua. Kasvustojen ominaisuuksia tutkittiin ja selvitettiin morfologisten tuntomerkkien avulla, ovatko ne kurtturuusun perusmuotoa vai jotakin jalostettua lajiketta. Kasvustoista valittiin osa tarkempaa siementutkimusta varten. Siementen elinkykyä tutkittiin tetrazoliumtestin avulla ja kelluntakykyä vesiastioissa. Siementutkimuksessa selvitettiin, eroaako kurtturuusun perusmuodon ja jalostettujen lajikkeiden siementuotto tai siementen elinkyky toisistaan ja kuinka hyvin pähkylät kelluvat. Tilastollisina menetelminä käytettiin varianssianalyysiä ja t-testiä. Kurtturuusua kasvoi Espoon rannoilla runsaasti monenlaisilla kasvupaikoilla sekä istutettuna että villiytyneenä. Mantereella sitä oli enemmän kuin saaristossa. Villiytyneenä tai mahdollisesti villiytyneenä kasvoi vain muutamia kasvustoja jalostettuja kurtturuusulajikkeita. Istutettuina niitä oli enemmän. Kurtturuusun siementuotto vaikuttaa olevan suurempi perusmuodolla kuin jalostetuilla lajikkeilla. Perusmuoto tuotti myös keskimäärin enemmän elinkykyisiä siemeniä. Hajonta molemmissa ryhmissä oli kuitenkin suurta. Osa jalostetuista lajikkeita tuotti melko runsaastikin elinkykyisiä siemeniä, toiset taas hyvin vähän. Kurtturuusun pähkylät kelluivat hyvin. Tulokset tukevat käsitystä siitä, että jalostetut kurtturuusulajikkeet eivät olisi yhtä haitallisia kuin perusmuoto. Sekä perusmuodon että jalostettujen lajikkeiden siementuoton ja elinkyvyn hajonta oli kuitenkin suurta. Eri lajikkeiden eroja olisikin tarpeen selvittää järjestelmällisesti. Kurtturuusulla on hyvät edellytykset levitä veden välityksellä uusille kasvupaikoille, koska se kasvaa rannoilla ja sen siementen kelluntakyky on hyvä. Kurtturuusun kartoitus Espoossa auttaa sen torjunnan suunnittelussa myös muissa kaupungeissa.
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(2020)The aim of this study was to examine the leaf endophytic bacteria in Plantago lanceolata. The first aim was to get a comprehensive picture of the bacterial diversity, by screening for the different bacterial genera inside the leaves. Furthermore, I aimed to examine the effect of soil and maternal genotype on the endophytic community within P. lanceolata leaves and search for clues of vertical inheritance of endophytes from parent to offspring via seeds. I studied the endophytic bacteria by extracting DNA from the plant leaves and by trying to amplify any bacterial DNA present to get a view of the bacterial diversity in the leaves. My aim was to compare the bacterial community of the mother plants to that of their offspring and also to compare the bacterial communities of plants grown in different soil conditions. Furthermore, I tried to study how the soil conditions affect the growth of P. lanceolata seedlings. I collected seeds and leaf samples of P. lanceolata from Åland, Southwestern Finland, from a population that is part of the ongoing long-term metapopulation research started in Åland in the early 90’s. I marked 21 plant individuals (hereafter referred to as the “mother plants”) in the field in June, when collecting the first leaf samples. In August I collected all seeds from the same plant individuals and a second set of leaf samples. I also collected soil samples from the same location. With the seeds collected from the wild population I executed a growth experiment in Viikki, Helsinki. I grew one set of seeds in twice autoclaved sand (hereafter referred to as the “sterile soil”) and another set in twice autoclaved sand mixed with soil collected from the Åland population (hereafter referred to as the “environmental soil”). I surface sterilized all seeds and then sowed each in their own growth pot and placed them in a growth chamber. During the experiment I took measurements of the leaves. At end of the growth experiment, I took samples of the leaves and surface sterilized them to exclude any epiphytic microorganisms from the analysis. I also surface sterilized the leaf samples taken from the mother plants. I then extracted DNA from the leaf samples and run PCR to amplify certain regions of the bacterial 16S rDNA gene, that is widely used in bacterial taxonomy. The obtained DNA reads where then clustered into Operational Taxonomic Units (OTUs) and assigned taxonomy using SILVA reference database. Mitochondria and chloroplasts of eukaryotic organisms also harbour 16S rDNA regions, so the challenge of studies looking at endophytic bacteria is to exclude the 16S regions of mitochondria and chloroplasts. This proved to be a problem in my study also. More than 86% of all DNA reads obtained turned out to be from P. lanceolata mitochondria and more than 12% from P. lanceolata chloroplasts. Only a bit more than 1% of the reads were eubacterial. This effectively hindered reliable analysis of the endophyte community. I nevertheless analysed the observed eubacterial diversity although the results must be taken as only preliminary and with utmost caution. The eubacterial reads clustered into 218 OTUs, representing 71 different bacterial genera. Six most common genera constituted over 83% of eubacterial reads. Most of these bacteria, most notably Shewanella, Ralstonia and Halomonas, could be identified as being clearly contaminants and not real endophytes. For the 65 less common bacterial genera I performed community analysis using Bray-Curtis Dissimilarity index and Analysis of Similarities (ANOSIM). The results showed that there was a significant difference between the different soil treatments (P = 0.014, R = 0.3787) and also between the two growth chambers (P = 0.011, R = 0.5493). I found no effect of maternal genotype on the bacterial community. Therefore, I observed no sign of vertical inheritance of endophytes. The growth experiment results showed that germination percentage was significantly lower in the environmental soil than in the sterile soil for all genotypes (F = 10.78, P = 0.0012). However, seedling in the environmental soil grew bigger than the seedlings in the sterile soil (F = 10.91, P < 0.0001). For future studies on similar topics, validating molecular methods before large scale sequencing could yield more reliable results. Size fractionating the DNA products of the first PCR round could exclude most mitochondrial sequences and hence allow better analysis of endophytes. This would enable studying interesting questions on coevolution and ecology of host-endophyte interactions. Although I did find some differences in the bacterial communities of different treatments, these results must be considered with caution and as only preliminary.
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(2020)Hypotheses to explain the emergence and maintenance of trichromacy in primates have long focused on the role of diet, often suggesting trichromats are better able to detect ripe fruits and nutritious leaves. However, many neotropical primate species also need to avoid eating conspicuous food items like insects that have evolved to warn potential predators of their unprofitability. This factor has largely been ignored in work on primate colour vision. We suggest here that dichromatic and trichromatic individuals vary in their ability to learn about conspicuous but unprofitable food and that trichromats could be more effective than dichromats at detecting conspicuous unprofitable prey. To test this hypothesis, three females and one male white-faced saki (Pithecia pithecia) participated in behavioral experiments at Korkeasaari zoo (Helsinki, Finland) where choice boxes were presented marked with two symbols against a green background. Only trichromats could discriminate orange symbols that provided an unprofitable food reward from the more profitable green symbols. Each saki made 80 choices over 10 trials. While we did not detect any evidence for learning about symbol profitability, we found two females significantly avoided the conspicuous prey meaning they received greater food rewards than the dichromat male and one putative dichromat female. Further analysis is needed of the opsin genes of the females in this study to confirm the role of unprofitable food in Saki colour vision.
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Life history effects in the behavior of Svalbard reindeer (Rangifer tarandus platyrhynchus) females (2020)Individuals of long-lived animal species can improve their reproductive success through experience. While individual’s resources available for survival and reproduction decrease toward the end of its lifespan through senescence, terminal investment hypothesis predicts the less likely old individuals reproduce again the more they invest in their current offspring. Experience gained through a long lifespan might have an important role in changing behavior to optimize the use of resources and compensate the effects of senescence. In addition, behavioral plasticity allows animals to respond changes in their habitat within much shorter timespan than on an evolutionary timescale. Svalbard reindeer (Rangifer tarandus platyrhynchus) is a wild subspecies of reindeer. It is only found in Svalbard, a remote archipelago in the Arctic with extreme weather conditions rapidly changing due to climate change. It has been isolated at least 5000 years and adapted to a barren habitat with nearly no hunting, predation or harassment of flying insects. The objective of this study is to investigate the effect of age and a calf at heel in Svalbard reindeer females’ maternal, vigilant, and social behavior and time budget in the light of life history theory and its senescence and terminal investment hypotheses. I carried out the field work for the study in two periods in summer in Semmeldalen valley and the south-western part of Reindalen valley on the island of Spitsbergen, Svalbard. I collected behavioral data on marked individuals by instant scan sampling and focal watch methods, wrote observations down manually and later fed them into computer. In addition, I have used birth year data collected by the long-term monitoring program by the Norwegian Polar Institute. I used generalized linear mixed models to analyze the effects of age and calf at heel to the behavior of females. The main results include that young dams maintained shorter distance to their calf in July than in August, and old females were less vigilant. Younger dams and older females without calves were in smaller groups than older dams and younger females without calves. In addition, females with calves spend proportionately less time lying down than females without calves. Dams maintained a longer distance to the nearest neighbor than females without calves. Older dams spend proportionately more time feeding and in groups in August than younger dams. These results show that the age and calf at heel do play a role in the behavior of Svalbard reindeer females and the effect varies over the course of the short Arctic summer. Experience may make older females more effective mothers by optimize the use of resources for example from vigilance to feeding in a predator-free environment. On the other hand, senescence may affect the amount of energy females can spend on their calves, potentially influencing their survival.
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(2022)Gravity has a modifying effect on plant architecture. The phytohormone auxin is known to transmit the signal of gravity perception from gravity-sensing cells to responsive tissues and cause an asymmetric growth response in the receiving organs. Intercellular auxin flux is mediated by many different transporter proteins, of which PIN-FORMED 3 (PIN3) is known to function as an auxin efflux carrier in gravitropic responses. The expression of PIN3 is known to locate in one cell layer of the shoot endodermis in herbaceous plant species and Populus hybrids. The objective of this study was to determine the location of PIN3 ortholog expression using silver birch (Betula pendula) as a model plant of a woody plant species. Agrobacterium tumefaciens C58 strain GV3101 (pMP90), harbouring binary vector pBpPIN3-erVEN-nosT2 containing erVenus (erVEN-YFP) as a marker gene under the BpPIN3 promoter and terminator nosT2, was used in the study to detect the gene expression. The expression vector was constructed by the Gateway® cloning method and transformed into in vitro shoot explants of silver birch by Agrobacterium-mediated transformation (AMT). In the study, transgenic lines were generated successfully, from which the fluorescence of erVEN was observed in the cross-section of the shoot with a fluorescence stereo microscope. The transgenicity of putative transgenic lines was confirmed by PCR of erVEN. BpPIN3 was likely to be expressed to endodermal tissue in the shoots of silver birch. This study can be considered as a screening step for the localization of BpPIN3 expression. The study facilitates the discovery of factors related to the regulation of PIN3 in tropic responses in woody plant species. This information can in the future be utilized in plant breeding to optimize plant architecture.
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(2021)During the last century, a decline in the canopy-forming foundation species Fucus vesiculosus has been observed in the Baltic Sea. The widely studied typical form of F. vesiculosus, that lives anchored to hard substrata, is at risk of further declines in the following century due to eutrophication and changes in water temperature and salinity. Fucus vesiculosus also exists in the Baltic Sea as a less common free-living form, which lives deposited in sheltered and shallow bays. This free-living form has been left understudied and little is known about their role in the ecosystem or the potential consequences of its disappearance. However, their occurrence may be equally or more under threat in the event of the aforementioned environmental changes. Additionally, it is currently unknown if mats of F. vesiculosus cause anoxia in the sediment below. This thesis will investigate the macroepifaunal and macroinfaunal communities associated to the presence of free-living F. vesiculosus across different sites in both Finland and Sweden. We will also estimate if F. vesiculosus causes anoxia. For this study, replicate frames of F. vesiculosus, including all vegetation and epifaunal community, were collected using mesh bags. Infaunal samples were randomly collected using benthic cores, both under the mat of F. vesiculosus and the adjacent bare soft bottom. All macroinvertebrates were identified to the lowest possible taxa, counted and weighed. Morphological measurements of F. vesiculosus thalli, such as length of thallus and wet weight, were recorded for every frame. Our results showed that the presence of free-living F. vesiculosus has a consistent effect across the two study locations. We found that increasing wet weight of F. vesiculosus significantly increased the abundance and biomass of the macroepifauna. The highest infaunal animal abundance and biomass were found in the bare sediment with high occurrence of opportunistic taxa. However, we found potential evidence to suggest that the presence of F. vesiculosus mats does not cause anoxia in the sediment. This study provides a much-needed first look into the macrofaunal communities associated to the free-living Fucus vesiculosus. Our study demonstrated that free-living F. vesiculosus is a potential foundation species in shallow, sheltered bays of the Baltic Sea by increasing the number of present taxa compared to adjacent bare sediment. Higher F. vesiculosus biomass directly increased the abundance and biomass of the macroepifaunal community, and the presence of free-living Fucus vesiculosus was not found to have significant negative effects on the associated macroinfaunal community.
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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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(2024)Nuclei isolation is a method used e.g. as a part of chromatin structure research. DNA structure can be examined in its 3D form from isolated nuclei because DNA is still wrapped around the histone proteins. Examining the chromatin structure can offer information e.g. about gene expression and how it is regulated. Isolating nuclei from plant cells demand more optimization compared to animal cells because of the cell wall, chloroplasts and secondary metabolites. The presence of organellar DNA can hamper the later DNA analysis. Secondary metabolites can hinder the actual isolation process. Finding the suitable isolation protocol for species of interest may need careful optimization of different aspects. Different species can differ from each other based on the structural and biochemical characteristics and because of this the same protocol may not ensure as good results for them. Different tissue types of the same species may have also differences in their biochemical and structural characteristics. In this thesis work, three different isolation protocols were used for three plant species; Pinus sylvestris, Betula pendula and Arabidopsis thaliana. The purpose of the work was to compare the results from each nuclei isolation protocol. Optimization of isolation protocol for P. sylvestris and B. pendula would help the isolation process for later research. Thesis work was done to get guidance for this optimization. Samples handled with different protocols were different from each other based on the sample concentration (particles/mL) and the average size of isolated particles. Chloroplast contamination was tested with chloroplast specific primers with PCR. None of the samples were free from chloroplasts.
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(2021)The three-spined stickleback (Gasterosteus aculeatus) is a model organism for studies of parallel evolution in the wild; marine stickleback populations have repeatedly colonized and successfully adapted to different brackish and freshwater habitats. During Pleistocene glaciations, three-spined stickleback populations inhabiting high-latitude areas of Europe were eradicated, whereas populations residing in (or moving to) the south persisted in refugia. After the retreat of the ice sheets covering northern Europe, the high-latitude areas became recolonized by migration from south, and hence, today’s northern European populations are relatively young. Population genetic studies of European three-spined sticklebacks have usually been conducted at high-latitude areas where freshwater populations are typically less than 10.000 years old. Few studies have focused on southern populations, where more of the ancestral diversity is likely to reside. These studies have utilized a limited number of microsatellite markers and mtDNA sequence fragments, whereas studies of southern populations focusing on genome-wide diversity, in particular from the edge of the southern distribution limit in the Iberian Peninsula, are still missing. Here, I wanted to cover this gap in knowledge by carrying out an empirical and statistical study with RAD-seq data from southern and northern European populations of three-spined stickleback. The main aims of this study were two-fold. First, to investigate whether the southern European freshwater populations of the three-spined stickleback – which currently lack or have limited connection to ancestral marine populations carrying most of the standing genetic variation (SGV) – have lost genetic diversity due to population bottlenecks and inbreeding as compared to their northern European counterparts. Second, to compare the degree of genetic parallelism in southern vs. northern European populations in genomic regions which have been shown to be consistently associated with freshwater colonization in earlier studies. Under the assumption that the lack of continued access to SGV in the ancestral marine population reduces the likelihood of parallel evolution, I hypothesized that the degree of genetic parallelism in genomic regions subject to positive selection in freshwater environments is lower in the southern than in northern European populations. However, if a reduction in genetic diversity and/or cessation of gene flow between southern European freshwater and marine populations occurred following freshwater adaptation, the opposite pattern could be expected. I paid particular attention to chromosomal inversions associated with marine-freshwater adaptations identified in previous studies. The results confirmed my expectation of reduced genetic diversity in southern as compared to northern European stickleback populations. On the other hand, and contrary to what I expected, analysis of clusters of global parallelism involved in freshwater adaptation revealed that southern European populations exhibit a higher degree of genetic parallelism in response to freshwater colonisation than those from northern Europe. This suggests that the loss of genetic diversity in southern populations has occurred after they had adapted to freshwater environments, explaining the high degree of genetic parallelism in spite of the current low levels of genetic diversity. In addition, it could be that selection pressures in south are more homogenous than in north, which would also explain the higher degree of genetic parallelism observed in southern Europe. The findings presented here, challenge the current paradigm that parallel evolution is unlikely in populations with low genetic diversity and that have experienced recent bottlenecks.
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(2020)Biogeography is a crucial aspect to ecological studies, as an ecosystem is comprised of the physical habitat, the organisms living there, and the interactions of these components. Community structure, and therefore functioning, are inherently of a spatial nature. Spatial structure of populations is often crucial basic knowledge for understanding the evolutionary history, dispersal patterns, and resilience of any given species. One aspect of spatial structure, and the topic covered in this study, is community distance decay, or the rate at which community similarity decreases with physical distance. More of the landscape is constantly being altered by humans on a large scale, so it is increasingly important to understand the effects that these anthroprogenic changes to the environment has on local populations. Studying community distance decay helps form understanding of dispersal and establishment limitations for different organisms, which is necessary for mitigating biodiversity loss. Many studies show that habitat fragmentation and loss has greatly impacted the structure of plant and animal communities, but there has been much less focus on fungal communities. There’s no certainty that fungi is impacted in the same ways, given the different lifestyles and dispersal methods, so the aim of this study is to contribute to the much needed research on fungal community structure at various scales. This aim is addressed by examining fungal community distance decay from small scale of a couple kilometers or less to a fairly large scale encompassing a landscape of primarily urban, forest, and agricultural areas. The five main localities of sampling were in middle and southern Finland: Helsinki, Lahti, Tampere, Jyväskylä, and Joensuu. Sampling locations and plot design were chosen to allow the comparison of communities separated by a mosaic, as well as along a short rural to urban gradient, to assess the effects of habitat type. From each location, six plots were decided, two in urban core, one in urban edge, two in natural core, and one in natural edge. The role of dispersal ability and functional traits in distance decay is also studied by comparing results from two different methods of fungi sampling, which were collecting spores from the air using cyclone samplers, and taking soil cores to gather fungal biomass. All samples were DNA analysed with high-throughput sequencing and the results from the DNA barcoding were used to create OTU clusters, by which the 30 plots could be compared through relative abundances of OTU’s. I determined the similarity of fungal communities using an analysis of similarity (ANOSIM) test in R, where all possible variables (site, habitat type, sample type) were used as a grouping in individual tests, thereby indicating which variable is associated with highest community difference. I also determined the differences in functional groups and major taxonomic levels among locations and sampling method using interactive taxanomic (KRONA) charts. Results showed that there are differences in fungal community structure among habitat type and sampling type. However there was greater difference at the level of plots than site locations, so clear patterns of strong community distance decay with physical distance was not measured in this study. The results suggest that fungal communities can be fairly impacted by human caused habitat change, and individual characteristics, such as dispersal methods or lifestyle, effect the rate of community distance-decay. This provides a valuable early insight into fungal community patterns, which need deeper study to understand the complexities and mechanisms behind them.
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Plant biodiversity and ecosystem functioning in a latitudinal gradient of heath forests in Finland (2024)In this thesis, I study plant biodiversity and ecosystem functioning in Finnish heath forests. To improve the understanding of how terrestrial understory plant biodiversity affects forest ecosystem functioning, I use structural equation modelling with information from climate and landscape land cover, using study areas along a 800 km latitudinal gradient. In addition, I describe the characteristics of the studied plant communities from taxonomical and functional point of view together with related environmental variables. I conducted a field survey during summer 2022. Study area consisted of five regions, ranging from southern Finland to near Arctic Circle: Tvärminne, Helsinki Metropolitan Area, Evo, Konnevesi and Kuusamo. I sampled and identified terrestrial vascular plants, lichens and bryophytes by coverage from 80 vegetation plots of 1 m2 in each region. In total, data consists of 400 vegetation plots and total amount of species was 134. We measured environmental variables in the field or draw them from remote sensing databases. To model the causal pathways among climate, landscape land cover, forest ecosystem functioning measured as Normalized Difference Vegetation Index (NDVI) and terrestrial understory plant biodiversity, I constructed six structural equation models (SEM) with different combinations of taxonomical biodiversity metrics and landscape land cover variables. Based on previous studies I hypothesized that biodiversity is positively related to ecosystem functioning. Models explained 17 – 21 % of observed variation in ecosystem functioning. The most important explanatory variable was the number of growing degree days and the second most was the taxonomical understory biodiversity. To provide functional summary of the studied plant communities, I categorized plant species according to their functional group as well as Grime’s CSR Triangle Theory’s strategy classes. The three strategy classes places species according to their high or low tolerance to stress and disturbance. Three classes are competitors (C), stress-tolerators (S) and ruderals (R). S-strategy was most common in all areas but variation between regions was observed. This emphasizes the importance of functional and compositional dimensions of biodiversity in addition to taxonomical biodiversity since loss or shift in them can lead to lost or altered ecosystem functioning. There is now a broad scientific consensus that biodiversity influences ecosystem functioning and thus the ongoing biodiversity loss is an existential threat to humanity as we depend on functioning ecosystems and their ability to produce ecosystem services. This study is important since it provides indicative empirical evidence from complex real-world ecosystems that has been limited as most biodiversity-ecosystem functioning (BEF) -studies have been experimental. Biodiversity information data also creates benchmarks for future comparison and latitudinal gradients describe how biodiversity varies across space.
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(2024)The many symbiotic microbes associated with plants can represent the first line of defence against viral pathogens, which can have profound impacts on plant health and productivity. Unfortunately, although countless studies have investigated variations in the composition of microbial communities associated with crops, showing benefits in the plants’ nutrient acquisition, stress tolerance or growth promotion, much less is known about how viruses might affect the composition of the microbiota associated with plants, and especially non-crop plants. Furthermore, we also often lack an understanding of how plant viruses are transmitted across their environment. Addressing these knowledge gaps is bringing us closer to better describe and manage the complex relationships between plant microbiota and viral pathogens in their natural environment. The main objective of my Master’s study is to examine variations in the bacterial community associated with a plant in the agricultural landscape, and to identify potential players in microbial community changes. With this in mind, I chose to work with the ribwort plantain, Plantago lanceolata, because it has a widespread distribution, it is present around cultivars, and there is extensive knowledge of its biology and genetics. Thus, P. lanceolata, represents an excellent system for investigating the causes of variation in the plant-associated microbiota. More precisely, I worked with the P. lanceolata population evolving in the Åland Islands, in Southwestern Finland, which has been the target of long-term ecological and evolutionary metapopulation studies. The population is also known for co-evolving with several viral pathogens, and with diverse Hemiptera insects (plant sucking-insects) that have been suggested as possible vectors of the viruses between plants. I collected P. lanceolata leaves, and insects found on P. lanceolata specimens from 28 habitat patches, or meadows, from five localities across the Åland Islands (Geta, Sund, Lemland, Finström, Eckerö). I extracted DNA from a total of 10 leaves per patch, as well as 60 Hemiptera specimens (of several uncharacterized species). I screened for viral infection in all samples by amplifying the viral loci for reverse transcriptase form Plantago latent caulimovirus (cauV) and the replication associated protein gene from Plantago lanceolata latent virus (PlLV). In parallel, I characterized the bacterial communities associated with each plant and insect through metabarcoding of the highly variable V5-V6 region of the 16S rRNA bacterial gene. My MSc's project shows that bacterial species richness (alpha-diversity metric) and community composition (beta-diversity metric) vary between plant and insects. But that they do not vary between the virus-infected and uninfected plants tested, and neither between geographical locations within the Åland Islands. This is the first study investigating the effects of two virus infections on the microbiota of a common weed from the Åland Islands. It provides preliminary data for the study of how the bacterial microbiota of P. lanceolata might respond to virus infections, and how viruses might be transmitted between individual plants.
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(2021)Ilmastonmuutos koettelee ankarimmin planeettamme pohjoisia alueita. Näiden alueiden eliöyhteisöt ovat ennestään erityisen herkkiä ympäristön muutoksille. Vaikka arktisen ympäristön fysikaaliset muutokset ovat jo monin paikoin nähtävillä, ovat tiedot näiden muutosten vaikutuksista alueen eliöyhteisöihin ja ekologisiin vuorovaikutussuhteisiin edelleen hyvin puutteelliset. Pohjoisten keväiden aikaistuminen altistaa yhteisöt fenologiselle irtautumiselle, jossa läheisessä ekologisessa vuorovaikutuksessa olevat lajit ajautuvat esiintymisaikojensa suhteen erilleen. Pölyttäjähyönteisen sekä pölytettävän kukkakasvin tapauksessa tästä voi olla seurauksena pölytystehon väheneminen. Tämän ja ilmastomuutoksen muiden seurausten ennustamiseksi käytetään usein nk. ajan ja tilan rinnastus –menetelmää. Menetelmän oletuksena on, että eliöt reagoivat ympäristötekijöihin samalla tavalla, tapahtuivatpa ne sitten ajallisesti tai paikallisesti. Selvittääkseni, onko arktisella alueella havaittavissa fenologista irtautumista, tarkastelen lapinvuokon sekä lajin pölyttäjäyhteisöön kuuluvan 14 hyönteisheimon fenologiaa Koillis-Grönlannissa. Tarkastellakseni, miten ilmaston vaihtelu vuosien välillä kuvastuu hyönteisaktiviteetin ajoittumiseen ja lajiryhmien väliseen vaihteluun, hyödynnän kahdenkymmenen vuoden aikasarjaa (jatkossa: aikasarja-aineisto). Selvittääkseni, miten ilmaston vaihtelu tilassa heijastuu paikallisiin eroihin pölyttäjäaktiviteetin fenologiaan, seuraan hyönteisaktiviteetin ajoittumisen yhden kasvukauden aikana maaston eri osissa (jatkossa: tila-aineisto). Molemmista aineistoista selvitän, mikä ympäristötekijä määrittää voimakkaimmin pölyttäjäyhteisön fenologiaa, keskittyen lumenlähtöpäivään ja lämpösummaan. Lopuksi arvioin, kuinka hyvin ajallinen ja paikallinen ulottuvuus vastaavat toisiaan. Näin pyrin selvittämään sitä, kuinka käyttökelpoinen ajan ja tilan rinnastus –menetelmä on pohjoisten pölyttäjäyhteisöjen tutkimuksessa. Totesin lumenlähtöpäivän selittävän lapinvuokon pölyttäjäyhteisön fenologiaa kokonaisuutena parhaiten. Tämä pätee sekä tila- että aikasarja-aineistossa. Lumenlähtöpäivän ja lämpösumman vaihdellessa eri lajiryhmien ajoitus muuttuu eri tavoin. Muutokset tilassa ja ajassa olivat lapinvuokon tärkeimpien pölyttäjäryhmien kohdalla suhteellisen yhteneväiset, mutta eräiden muiden ryhmien (esim. kukkakärpästen) kohdalla ja samalla koko yhteisön tasolla ennusteet olivat heikompia. Tulokseni osoittavat, että ilmaston vaihdellessa arktisissa yhteisöissä on nähtävissä fenologista irtautumista. Yhteisön sisällä eri lajiryhmät reagoivat sekä lumenlähtöpäivään että lämpösummaan eri tavoin. Tämä altistaa yhteisöjä fenologiselle irtautumiselle ympäristön edelleen muuttuessa. Pölyttäjäfenologiaa tutkittaessa ajan ja tilan rinnastus -menetelmä näyttää toimivan hyvin lapinvuokon ja tämän kasvilajin tärkeimpien pölyttäjäheimojen kohdalla. Koko yhteisön tasolla rinnastuksen ennusteet ovat kuitenkin puutteelliset, sillä joidenkin ryhmien ennusteet eroavat toisistaan merkittävästi sekä ajassa että tilassa. Tulevaisuudessa tulisikin selvittää tarkemmin sitä, kuinka nyt havaittu pölyttäjäyhteisön fenologinen epäyhtenäisyys heijastuu lajien välisiin vuorovaikutussuhteisiin eri trofiatasojen välillä.
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(2021)Ornamentit ovat hyödyllisiä kumppaniehdokkaiden arvioimisessa ja kilpailussa toisia lisääntymishalukkaita yksilöitä vastaan. Naaraiden ornamenttien kehittymistä edistää koiraan korkeat lisääntymiskustannukset, kuten poikasten hoito ja pesän rakentaminen. Kehitystä rajoittavat naaraan ornamenteista koituvat kustannukset, jotka rajoittavat jälkeläisten määrää ja selviytymistä munasoluihin käytettävissä olevien resurssien kautta. Ihmisten toiminnasta johtuva lisääntyvä rehevöityminen vähentää näkyvyyttä ja siten haittaa ornamenttien käyttöä niin kumppaneiden houkuttelussa ja arvioinnissa kuin samaa sukupuolta olevien kilpailussa. Lisääntymiskauden aikana sekä kolmipiikkikoirailla että naarailla on havaittavissa ornamentteja. Itämeren rehevöitymisen on havaittu vaikuttavan kolmipiikkien lisääntymiseen usealla tavalla, kuten seksuaalivalinnan heikkenemisellä ja muutoksilla munien kuoriutumistodennäköisyyteen. Kolmipiikkinaaraiden ornamentin käyttötarkoitukset ja rehevöitymisen vaikutukset siihen ovat kuitenkin vielä tuntemattomia. Tutkin rehevöitymisen vaikutusta kolmipiikkinaaraan ornamenttiin avoimessa ja suojaisassa habitaatissa sekä ornamentin yhteyttä naaraan hedelmällisyyteen. Selvitin, vaikuttaako ornamentin voimakkuus naaraan kumppaninetsintäaktiivisuuteen, koska ornamentin on aiemmin havaittu kertovan lisääntymismotivaatiosta. Lisäksi testasin, suosivatko koiraat ornamentillisia naaraita ja vaikuttaako näkyvyys koiraan valintaan. Tulosteni mukaan naaraan ornamentti ei ilmaissut naaraan hedelmällisyyttä eikä habitaatin suojaisuus vaikuttanut ornamentin kehitykseen. Ornamentin ylläpito ja kumppaninetsintä ovat molemmat resursseja kuluttavia toimintoja. Saadakseen kumppanin heikompilaatuisen naaraan on mahdollisesti panostettava enemmän koiraan etsimiseen kuin ornamenttiin ja siksi havaitsin heikompiraitaisten naaraiden olevan aktiivisempia kumppaninetsinnässä. Naaraiden ornamentti voimistui naaraan ollessa kosiskelevan koiraan seurassa. Kolmipiikkikoiraat suosivatkin ornamentillisia naaraita ja kykenivät valitsemaan ornamentillisen naaraan näkyvyyden heikkenemisestä huolimatta. Toisaalta näkyvyyden heikkeneminen vähensi koiraan kosiskeluaktiivisuutta. Kolmipiikeillä molemmat sukupuolet käyttävät ornamentteja kumppaninvalinnassa, mutta naaraan ornamentin hyödyt koiraalle vaativat vielä lisää tutkimusta.
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(2023)Land-use change stands behind the current biodiversity crisis and all it entails in terms of ecosystem services. Guinea-Bissau, in West Africa, is originally characterized by a forest- savanna mosaic biome. However, while savannas have long been planted with rice, both rice paddies and forest remnants are now being converted into cashew monocultures – the only cash crop in the country – at unprecedented rates. The ecological impact of such rapid change is largely unknown. To help fill this gap, we examined how three diversity metrics – rarefied species richness, abundance and composition – varied across forest remnants, cashew orchards and rice paddies for amphibians and reptiles in northern Guinea-Bissau. To do so, visual encounter surveys were carried across 21 sampling sites, seven of each habitat type. A total of 703 amphibian and 266 reptile encounters was recorded from nine and 14 taxa, respectively. The results show class-specific responses to habitat type. Amphibians’ diversity in forest remnants and cashew orchards was similar across all metrics, but rice paddies had a higher abundance and unique composition compared to forest remnants. Reptiles’ abundance was highest in cashew orchards and this habitat had a distinct composition, when compared to forest remnants. Rice paddies sustained both lower reptile richness and abundance. Overall, our results are not in agreement with the expected detrimental impacts of cashew expansion, which might be due to the still high heterogeneity of habitat types within the landscape. Rice paddies proved particularly important for amphibians, and for open-habitat reptiles, boosting overall species diversity. In face of the eminent habitat conversion, maintaining heterogeneous landscapes, including the persistence of both forest remnants and rice paddies, will allow minimizing biodiversity loss in West Africa.
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(2017)Yersinia pseudotuberculosis voi aiheuttaa ihmiselle suolistoinfektion, yersinioosin. Se tarttuu kontaminoituneiden elintarvikkeiden välityksellä, ja Suomessa on todettu useita epidemioita viimeisen 20 vuoden aikana. Yersinia-suku kuuluu Enterobacteriaceae-heimoon, ja siihen kuuluu tällä hetkellä 18 lajia. Y. pseudotuberculosis-lajin lisäksi sukuun kuuluu kaksi ihmispatogeenia, Yersinia enterocolitica ja Yersinia pestis. Y. enterocolitica on myös elintarvikevälitteinen patogeeni, Y. pestis puolestaan tunnetaan ruton aiheuttajana. Y. pseudotuberculosis kasvaa hyvin jääkaappilämpötiloissa, jolloin nykyaikaiseen elintarvikehygieniaan oleellisena osana kuuluva kylmäsäilytys ei estä sen lisääntymistä elintarvikkeissa. Sen vuoksi onkin tärkeä tutkia tekijöitä, joilla on merkitystä Y. pseudotuberculosis-bakteerin kylmänsiedossa ja muissa stressiolosuhteissa. RNA-helikaasit ovat proteiineja, jotka avaavat kaksijuosteista RNA:ta. Niihin kuuluu useita proteiiniperheitä, mutta suurin niistä on DEAD-box-helikaasiperhe. DEAD-box-helikaaseja löytyy kaikista eliöryhmistä, ja ne osallistuvat kaikkiin RNA-metabolian vaiheisiin. Ne ovat ATP-riippuvaisia helikaaseja ja ne kykenevät avaamaan vain lyhyitä kaksijuosteisia alueita. Y. pseudotuberculosis IP32953- genomi sisältää viisi DEAD-box-helikaasia koodaavaa geeniä, csdA, dbpA, rhlB, rhlE ja srmB. RhlB osallistuu mRNA-molekyylien hajottamiseen osana RNA-degradosomia. Muut proteiinit osallistuvat pääasiassa ribosomin rakentumiseen. Escherichia coli -bakteerilla aiemmin tehdyn tutkimuksen perusteella tiedetään, että CsdA:n ja SrmB:n puuttuminen soluista saa aikaan kylmäherkän fenotyypin. CsdA:n roolia on tutkittu myös Y. pseudotuberculosis-lajilla, jossa toimimaton CsdA heikentää kasvua kylmässä. Tämän tutkielman tarkoituksena oli tutkia RNA-helikaasien vaikutusta Y. pseudotuberculosis IP32953-kannan kasvuun erilaisissa stressiolosuhteissa. RhlE-, DbpA- ja SrmB-deleetiomutanttikantoja kasvatettiin optimilämpötilan (28 °C) lisäksi kylmässä (3 °C), korkeassa suolapitoisuudessa sekä alhaisessa ja korkeassa pH:ssa. Kasvun aikana mitattiin bakteerien kasvua OD600nm-mittausten avulla, ja aineiston perusteella kannoille piirrettiin kasvukäyrät kaikissa olosuhteissa. Lisäksi aineistosta laskettiin käyrän alle jäävä pinta-ala, jonka perusteella tutkittiin kasvuerojen tilastollista merkitsevyyttä Studentin t-testillä. Kannoille määritettiin myös kasvunopeudet eri olosuhteissa. Deleetiomutanttien kasvussa huomattiin eroa alhaisessa lämpötilassa, jossa kaikki deleetiomutanttikannat tilastollisesti merkitsevästi kasvoivat villityypin kantaa huonommin. Lisäksi ΔsrmB -kanta kasvoi tilastollisesti merkitsevästi heikommin optimilämpötilassa ja korkeassa pH:ssa. Näyttääkin siis siltä, että DEAD-box-helikaasit ovat Y. pseudotuberculosis-bakteerilla suuremmassa roolissa kuin E. coli-bakteerilla, ja niitä tarvitaan erityisesti alhaisissa lämpötiloissa.
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(2020)Viime vuosikymmenien maaseutuympäristöjen muutokset, kuten lisääntynyt maankäytön tehostuminen ja kasvinsuojeluaineiden käyttö, ovat saaneet monet Euroopan maaseutuympäristöjen lintujen kannat taantumaan. Jotta lintukantojen muutoksia voitaisiin ymmärtää ja suojelutoimia suunnitella, on lintujen elämänkierron eri vaiheiden, kuten pesimämenestyksen ja elossasäilyvyyden, sekä selviytymiseen vaikuttavien tekijöiden tutkiminen tärkeää. Myös Suomessa maaseutuympäristöjen linnuston tutkimukselle on tarvetta: uusimmassa Suomen luonnon uhanalaisuusarvioinnissa (2019) uhanalaisia tai silmälläpidettäviä maatalousympäristöjen lintulajeja oli 18, mikä on neljä enemmän kuin neljä vuotta aiemmassa arvioinnissa. Yksi näistä on Suomen voimakkaimmin taantunut maalintulaji, peltosirkku (Emberiza hortulana), jonka kanta on kutistunut 80-luvulta alle yhteen prosenttiin. Tämän tutkielman tavoitteena on selvittää yksilöllisin tunnistein merkittyjen lintujen avulla, onko Suomen aikuisten peltosirkkukoiraiden elossasäilyvyys ollut vuosina 2013–2019 poikkeavan matala, mikä voisi selittää lajin kantojen voimakasta laskua. Tavoitteena on myös tarkastella elossasäilyvyyden vuosittaista ja alueellista vaihtelua, peltosirkkujen kannankehityslukuja, sekä selvittää vaikuttivatko muuttokäyttäytymisen tutkimista varten kiinnitetyt valopaikantimet (loggerit) elossasäilyvyyteen. Tutkielman aineisto on kerätty vuosina 2013–2019 niiltä alueilta, joilla peltosirkun on havaittu pesivän. Aineisto koostuu 210 aikuisen (+1kv; vanhempi kuin ensimmäistä kalenterivuottaan elävä lintu) peltosirkun pyynti-jälleenpyynti-aineistosta, jota käyttäen tehtiin elossasäilyvyysanalyysit, sekä peltosirkkujen reviirikartoituksesta, jota käytettiin kannankehityslukujen laskemiseen. Elossasäilyvyysanalyysit tehtiin käyttäen CJS -mallia (Cormack-Jolly-Seber) MARK -ohjelmassa. Analyysia varten aineistosta poistettiin naaraat, paikkaansa vaihtaneet peltosirkut ja Itä-Suomen vaillinaisesti seuratut yksilöt, sekä muodostettiin kaksi pääanalyysia: koko Suomen analyysi ja alueellinen analyysi. Koko Suomen analyysissa tarkasteltiin, oliko loggerilla vaikutusta linnun elossasäilyvyyteen ja vaihteliko elossasäilyvyys vuosien välillä. Alueellisessa analyysissa Suomen peltosirkut jaettiin kolmeen alueeseen: pohjoiseen, lounaiseen ja eteläiseen. Analyysissa tarkasteltiin, onko elossasäilyvyydessä eroa alueiden välillä ja vaihteleeko elossasäilyvyys vuosien välillä. Lopuksi laskettiin R-ohjelmiston Rtrim -paketilla kannankehitysluvut koko Suomelle sekä alueellisessa analyysissa käytetyille kolmelle alueelle. Analyysin tulos oli että Suomen peltosirkkukoiraiden elossasäilyvyys vuosina 2013–2019 oli 43,3 % koko tutkimusjaksolle. Loggeri vaikutti negatiivisesti elossasäilyvyyteen, mutta alueiden tai vuosien välillä ei ollut merkitsevää vaihtelua. Kannankehitysluvut olivat laskusuuntaisia ja niissä oli alueiden välillä merkitseviä eroja. Koko Suomessa kanta laski 19,4 % vuodessa. Alueista suurin lasku oli lounaassa, jossa kanta laski 26,5 % vuodessa. Suomen peltosirkkukoiraiden elossasäilyvyysanalyysin tulosta verrattiin muiden samankokoisten (10–40g) pitkän matkan muuttavien varpuslintujen julkaistuihin elossasäilyvyyslukuihin (41,9-58,0 %; 15 eri lajia). Vertailun perusteella Suomen peltosirkkukoiraiden elossasäilyvyys ei ole ollut poikkeavan matala, eikä siten vaikuta olevan ainakaan tärkein voimakasta kannanlaskua selittävä tekijä. Tämän tutkielman tulosten mukaan Suomen peltosirkkujen kannanlaskun taustalla on luultavimmin muita tekijöitä kuin aikuisten koiraiden elossasäilyvyys, kuten aikuisten naaraiden tai nuorten lintujen (ensimmäistä kalenterivuottaan elävät linnut) kestämättömän suuri kuolleisuus tai kestävälle populaatiokehitykselle liian heikko pesimätulos. Elossasäilyvyydessä ei havaittu myöskään alueellisia vaihteluita, mutta kannankehitysluvuissa näin oli, minkä perusteella ainakin jotkin populaatiokokoa säätelevät tekijät ilmenevät joillakin pesimäalueilla voimakkaammin kuin toisilla. Näin ollen eritoten pesintämenestykseen vaikuttavia tekijöitä kannattaisi kiireellisesti tutkia, jotta peltosirkun kannankehityksen suunta saataisiin tietoon perustuvan suojelusuunnitelman avulla käännettyä.
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(2021)Natural scientists study a wide variety of species, but whether they have identified all studied samples correctly to species is rarely evaluated. Species misidentification in empirical research can cause significant losses of money, information, and time, and contribute to false results. Thus, I study the abundance of species misidentification and ecologists’ perceptions of such mistakes through a web survey targeting researchers from scientific institutes around the globe (including universities, research societies and museums) who completed their doctoral degree in any ecology-related field of science. I received 117 responses with either work or educational background from 30 countries. I found that species misidentification widely existed in respondents’ research: almost 70% of the respondents noticed species misidentification in their own research, while the estimated proportion of existing studies with species misidentification was 34% (95% CI: 28% - 40%). Although misidentification was mainly found during specimen collection, specimen handling and data analysis, misidentifications in reporting stages (writing, revision and after publishing) could persist until publication. Moreover, according to respondents, reviewers seldom comment about species identification methods or their accuracy, which may affect respondents’ (both leading and not leading a research team) low reporting frequency about the possibility of misidentification. Expert checking, training students, and DNA barcoding are the most prevalent approaches to ensure identification accuracy among respondents. My results imply that species misidentification might be widespread in existing ecological research. Although the problem of species misidentification is widely recognized, such an issue seldom be appropriately handled by respondents. To increase the accuracy of species identification and maintain academic integrity, I suggest that researchers need to focus more on the study species (e.g., sampling process, identification method, and accuracy) when writing and reviewing papers. Furthermore, I appeal for guidelines about reporting species identification methods and their accuracy in papers, as well as research on education about identification skills in universities, as these two topics may constrain the precision of species identification.
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