Browsing by study line "Ekologia ja evoluutiobiologia"
Now showing items 41-54 of 54
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(2022)Climatic cycles lead to changes in habitat suitability, which in turn can lead to allopatry, i.e. isolation, between populations. Lack of gene flow between allopatric populations causes them to diverge through accumulation of genetic differences that can create incompatibilities between lineages upon secondary contact in the form of lowered survivability or reproduction rate in hybrids. Incompatible genes act as reproductive barriers and keep lineages isolated by selection against hybrids, while gene flow and recombination work as a counterforce to selection promoting admixture. Reproductive barriers like these are most often found inside hybrid zones and are well demonstrated in nature, but the isolating effect of individual genetic incompatibilities on genome-wide gene flow is still an open question. Here we test if selection counteracting gene flow maintains a narrow hybrid zone between two subspecies of the meadow grasshopper Pseudochorthippus parallelus. We targeted 0,01 % of the 13 GB genome, recovering a 29,1 mean coverage per locus per individual in targeted regions, when mapping against a transcriptome. We find that, for the nuclear markers, the hybrid zone is narrower than expected under a neutral scenario of no selection, suggesting that it is maintained by selection against hybrids. We also find significant isolation by distance, suggesting gene flow across the hybrid zone despite selection against hybrids. Different parts of the genome show significant excess or deficit of heterozygotes, suggesting that selection and gene flow are heterogeneous throughout the genome. Combined, our results show that reproductive isolation between recently diverged lineages can evolve quickly despite gene flow in neutral and positively selected sites.
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(2023)With growing fragmentation of elephant habitats across the world, elephants are coming in closer contact with humans, leading to increasing human-elephant conflict over limited space and resources. Laikipia county in Kenya represents one such region where conflict with elephants has been (and continues to be) a widespread problem, stemming from intense land-use zoning since the 1970s. This conflict mainly takes the form of crop raiding by elephants in community farmlands adjoining conservation areas. Electric fencing has been the widely used conflict management tool in the region to prevent elephants from entering croplands. However, the establishment of electric fences can often have hidden political underpinnings, both caused by and resulting in conflicting interests of different land users. As human-elephant conflict is multidimensional, it is essential to incorporate both human and wildlife dimensions when assessing the effectiveness of electric fences in conflict mitigation. While there is a growing body of research on the ecological effects of electric fences, the role of social perceptions in long-term fence effectiveness is often neglected. In this study, I therefore conducted a combined social and ecological assessment of electric fences in Laikipia. For this, I evaluated the perceptions of three local communities (Mutara, Ex Erok and Lorien) towards two major electric fences in Laikipia: the West Laikipia Fence and the Lorien Community Fence. I conducted 188 individual interviews with farmers (and opportunistically pastoralists) in all three communities, comprising questions on demographics, human-elephant conflict, electric fences, and involvement of communities in fence management. I then combined this information with data on fence breaking and crop raiding behaviour of elephants to effectively inform electric fence management strategies in the region. First, I looked at changes in the perceptions of Mutara and Ex Erok between 2016-2022, following upgrades made to the West Laikipia Fence after 2016, through a comparison of results with previous research. Second, I investigated potential factors influencing community perceptions towards fence effectiveness. Third, I mapped fence break and crop raiding hotspots in the three communities. And fourth, I determined the environmental factors affecting crop raiding intensity. Both Mutara and Ex Erok showed more positive perceptions towards fence effectiveness in 2022 as compared to 2016. The main factor found to influence fence perceptions was community involvement in fence management. Communities involved in fence management had more positive fence perceptions than those with no involvement. Crop raiding hotspot mapping revealed that some areas within each community were more affected by crop raiding than others. Fence break hotspot mapping identified fence sections of the West Laikipia Fence more prone to breakages by elephants. Finally, crop raiding intensity in a given farm was found to be strongly affected by the diversity of crops grown there, and weakly by its distance from the nearest roads and electric fences. My results therefore contribute to a better understanding of patterns of crop raiding and fence breakages of elephants in Laikipia. My findings highlight the importance of including sociological data from local communities in assessments of electric fence effectiveness, and also provide empirical evidence on the importance of involving local communities in electric fence management. The findings from this study can serve as a reference to relevant stakeholders for future improvements in electric fence management in Laikipia and elsewhere.
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(2021)The Glanville fritillary (Melitaea cinxia) butterfly inhabiting the fragmented meadows and pastures in the Åland Islands, Finland, has a classic metapopulation structure: its long-term persistence depends on frequent re-colonization events counter-balancing the extinctions of local populations. The spatial structure and the temporal dynamics of the metapopulation are likely to influence genetic variation within and among local population networks. With high population turnover, population declines accelerate genetic drift, potentially leading to a reduction in neutral genetic diversity. This loss is likely to be counteracted with immigration bringing in new alleles especially in well-connected populations. Dispersal has indeed been shown to be a key mechanism in maintaining genetic variation and adaptive potential in fragmented landscapes. In my MSc-thesis, I am utilizing long-term monitoring and genetic data collected from semi-independent networks from the main Åland region (Saltivik) and from two isolated island networks Föglö and Sottunga. Specifically, I investigate how genetic variation varies in time and space, in relation to demographic change and whether the responses vary among well- and poorly-connected networks and/or between island and mainland networks. My results showed that the total number of nests fluctuated in all the networks across time. Heterozygosity appeared to track the changes in population abundance but this tracking varied among the networks. Although connectivity did not explain the change in heterozygosity during the decline years, allele frequencies shifted over time and the speed of change in allele frequencies differed among networks.
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(2023)Grasslands occur on every continent except Antarctica and are a key part of agricultural and urban landscapes in many parts of the world. In Finland, many of the grassland species are threatened nowadays. Fragmentation, worsening quality and shrinking area of habitats are the biggest threats to grassland species. Many grassland plants, however, can be found in urban habitats such as road verges, different meadows and rocky outcrops. Suitable urban habitats could be important for these species if the degradation of their habitats continues elsewhere. Indicator species could provide information about the ecological quality of urban habitats and thus the suitability for grassland specialists. My aim for this thesis was to determine how indicator species can be used to assess the ecological quality of urban grasslands by answering the following research questions: 1. Does habitat type affect the abundance and occurrence of known quality indicator species of semi-natural grasslands? 2. Which species are characteristic to different urban grassland habitat types? 3. How different sites relate to each other in terms of vegetation? 4. How do the measures used to answer the other three questions compare together? I collected vegetation data from 28 study sites in the cities of Espoo, Helsinki and Vantaa, southern Finland. In addition, a dataset consisting of 116 sites from these cities, collected by another person, was included here. The study sites were divided into eight habitat types: dry and mesic landscape grasslands, dry and mesic road verges, dry and mesic valuable grasslands, rocky outcrops and valuable rocky outcrops. From all study sites, I collected a list of plant species observed within a standardized time frame by doing an on-site vegetation inventory. In addition, I observed the frequencies of plant species within 1 x 1 m vegetation quadrats. I used one-way ANOVA and Tukey-Kramer test as well as Welch’s ANOVA and Games-Howell test to study the effect of habitat type on abundance and occurrence of semi-natural grassland indicator species. I used IndVal to identify which species are indicators for the habitat types and their combinations. I used NMDS to study the grouping of different habitat types and their species. Habitat type affects the abundances and occurrences of semi-natural grassland indicator species in urban settings and these species can be used in evaluation of the ecological quality of urban grasslands. Indicator species produced from observed data seem to have a limited potential in evaluating the ecological quality of urban grasslands, but they provide a good method for classifying urban grassland habitats, especially valuable rocky outcrops and valuable grasslands. Study sites do form groups according to their vegetation, but these groups do not entirely follow the habitat type division used in the study. With right standardization for the use, indicator species can be a valuable tool in assessing the ecological quality of urban grasslands.
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(2023)Urbanisation is rapidly increasing, along with the use of artificial lighting, which poses a growing threat to wildlife, especially nocturnal fauna. Bats are nocturnal mammals that prey on light-sensitive insects, making them particularly vulnerable to the effects of artificial light sources. Responses to artificial lights vary among bat species, with some being strongly repelled while others appear to benefit from them. However, little attention has been given to the impact of light pollution on bats in northerly latitudes, where bright summer nights may influence the effects of artificial light on these animals. In my thesis I compared the presence of bats in artificially illuminated and unilluminated areas in urban parks in Southern Finland. To see the effect of bright nights in the early summer I collected acoustic data during two time periods: bright early summer (June), and dark late summer (August). My aim was to determine if different bat species respond differently to artificial light, if lamp type affects their response, and how natural light influences their activity patterns. I found that northern bats (E. nilssonii) were drawn to street lights in both early and late summer, and they seemed to prefer HPS (high-pressure sodium) lamps to LED (light emitting diode) lamps. Conversely, more light shy bats from the genus Myotis strictly avoided street lamps at all times. The strongest effect of natural light on bats was observed on their activity patterns: the timing of peak activity shifted considerably along with changes in natural light conditions. My results indicate possible changes in the responses of nocturnal wildlife to the changes in spectral composition of illumination along with increasing popularity of LEDs. The significant differences in the responses of different bat taxa to illumination highlight the importance of conservation of dark spaces and times.
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(2022)Talousmetsissä on huomattavasti vähemmän lahopuuta kuin luonnontilaisissa metsissä. Noin 25 % metsälajeista on riippuvaisia lahopuusta, ja lahopuun väheneminen on syynä monen lajin uhanalaisuuteen. Talousmetsiin on luotu lisää lahopuuta tekopökkelöiden avulla. Tekopökkelöitä tehdään harvennus- tai päätehakkuissa katkaisemalla puu noin 1–5 m korkeudelta. Tekopökkelöiden teko on yleistynyt 1990-luvulta lähtien, mutta niitä hyödyntävää lajistoa, etenkin lintuja, on tutkittu Suomessa vasta vähän. Tutkin, mitkä lintulajit käyttävät teko- ja luonnonpökkelöitä ja eroavatko niiden lajistot toisistaan. Lisäksi tutkin, millaisia pökkelöitä linnut käyttävät. Keräsin tutkimusaineistoni Viitasaarelta Keski-Suomesta tuoreilta päätehakkuilta, vanhoilta päätehakkuilta ja harvennushakkuilta. Laskin yhteensä 78 tekopökkelöstä ja 69 luonnonpökkelöstä (puulajeina kuusi ja koivu) lintujen syönnösjälkien ja pesäkolojen määrän sekä määritin ne tehneet lajit. Mittasin myös pökkelöistä ja tutkimuskuvioista ympäristömuuttujia selvittääkseni, millaisia pökkelöitä linnut käyttävät. Tutkimuskuvioilla ja niiden lähistöllä suoritettiin lisäksi lintujen linjalaskennat, jotta pystyin vertaamaan, eroavatko tutkimuskuvioiden lintulajiston laji- tai parimäärät lähialueen lintulajistosta. Vertasin tutkimusalueen linjalaskenta-aineistoa myös pohjoisen Keski-Suomen lintujen vakiolinjalaskenta-aineistoon saadakseni tietää, eroaako tutkimusalue yleisesti pohjoisen Keski-Suomen lintulajistosta laji- tai parimäärän suhteen. Käytin tilastollisissa analyyseissä lineaarisia sekamalleja ja yleistettyjä lineaarisia sekamalleja. Tutkimukseni perusteella linnut käyttävät tekopökkelöitä pesintään ja ruokailuun. Suurin osa syönnösjäljistä ja koloista oli tikkojen tekemiä, todennäköisesti käpytikan. Pökkelötyypillä (teko- tai luonnonpökkelö) ei ollut tilastollisesti merkitsevää yhteyttä pökkelön syönnösjälkien tai pesäkolojen määrään. Pökkelöllä oli tilastollisesti merkitsevästi enemmän syönnösjälkiä, kun pökkelö oli korkeampi, paksumpi, pidemmälle lahonnut, kaarnan peittävyys oli alhaisempi tai pökkelö sijaitsi lähellä metsän reunaa. Kolojen määrä oli tilastollisesti merkitsevästi suurempi, kun pökkelö oli korkeampi, paksumpi tai kun metsäkuviolla oli vähemmän maalahopuuta. Kolojen tai syönnösjälkien määrään ei vaikuttanut tilastollisesti merkitsevästi se, sijaitsiko pökkelö harvennushakkuulla vai päätehakkuulla säästöpuuryhmässä, keskellä päätehakkuuta tai päätehakkuun reunassa. Linjalaskennoissa tutkimuskuvioiden lintulajisto ei eronnut laji- tai parimäärältään lähialueen linnustosta. Tutkimusalueen lintulajisto ei myöskään poikennut pohjoisen Keski-Suomen linnustosta lajimäärältään, joten tuloksiani voi pitää yleistettävissä laajemminkin. Parimäärät olivat tutkimusalueen laskentalinjoilla alhaisempia, koska linjat olivat lyhyempiä kuin vakiolinjat. Tulosteni perusteella linnut hyötyvät eniten korkeammista ja paksummista tekopökkelöistä, jotka sijaitsevat lähellä metsän reunaa. Ajan myötä pökkelön lahotessa siitä tulee paremmin lintujen käyttöön soveltuva.
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(2023)Metsätalouden seurauksena lahopuu on vähentynyt Suomen metsissä ja siten useat lahopuusta riippuvaiset lajit ovat päätyneet uhanalaisiksi. Lahopuun määrän lisäämiseksi metsähakkuiden yhteydessä on alettu jättämään säästöpuita ja tekopökkelöitä. Tekopökkelöt hyödyttävät lahotessaan lahopuusta riippuvaisia lajeja, kuten kolopesiviä myrkkypistiäisiä. Kolopesivät myrkkypistiäiset rakentavat pesänsä yleensä kovakuoriaisten puiden runkoihin kaivamiin koloihin. Tässä tutkimuksessa selvitettiin, millaista myrkkypistiäislajistoa tekopökkelöt tukevat, millaiset ja miten sijoitetut tekopökkelöt ovat hyödyllisimpiä myrkkypistiäisille, onko tekopökkelön vai ympäristön laatu merkittävämpää myrkkypistiäisille ja eroavatko eri ekologisten ryhmien (mesipistiäiset, petoina elävät myrkkypistiäiset ja pesäloiset) myrkkypistiäiset pesäpaikkavaatimuksiltaan. Tutkimuksen aineisto kerättiin kesällä 2021 Keski-Suomessa Viitasaarella, kuusivaltaisilta eri tavoin käsitellyiltä metsäkuviolta. Kuvioista kahdeksan oli harvennuksia, tuoreita päätehakkuita kahdeksan ja vanhoja päätehakkuita kymmenen. Tekopökkelöiden myrkkypistiäislajistoa tutkittiin keinopesien avulla. Keinopesät koostuivat muoviputkilosta, jonka sisällä oli eri kokoisia järviruo’on (Phragmites australis) korsia, monenlaisten myrkkypistiäislajien houkuttelemiseksi. Keinopesiä kiinnitettiin yhteensä 120 kappaletta teko- ja luonnonpökkelöihin, sekä kantoihin. Puulajeina oli kuusi ja koivu, sekä yksi haapa. Pökkelöistä ja metsäkuvioilta mitattiin niiden laatua kuvaavia muuttujia. Keinopesät olivat maastossa keväästä syksyyn, jolloin ne haettiin säilytykseen ulkovarastoon. Keinopesät siirrettiin huoneenlämpöön alkuvuonna 2022 pistiäisten aikuiseksi kehittymisen vauhdittamiseksi. Korret avattiin ja aikuiset myrkkypistiäiset tunnistettiin pesittäin lajilleen mikroskooppia apuna käyttäen. Tilastolliset analyysit suoritettiin R-Studiolla. Yksilö- ja lajimäärän muutoksia suhteessa selittäviin muuttujiin arvioitiin yleistetyillä lineaarisilla sekamalleilla (GLMM). Selittävinä muuttujina toimivat lämpötila, pökkelön korkeus, kaarnan peittävyys, alustan tyyppi, puulaji, lahopuun määrä, ravintokasvien määrä, hakkuutyyppi, pökkelön sijainti ja pesäkolojen määrä. Myrkkypistiäislajiyhteisöjen erilaisuutta arvioitiin NMDS-analyysillä. Sen avulla havainnollistettiin lajiyhteisöjen erilaisuutta eri hakkuutyyppien välillä. Keinopesistä löydettiin kolopesiviä myrkkypistiäisiä ja niiden myrkkypistiäispesäloisia yhteensä yli 3000 yksilöä. Petoina eläviä myrkkypistiäisiä löytyi eniten harvennusmetsistä, joissa oli alhaisempi lämpötila kuin tuoreilla ja vanhoilla päätehakkuilla. Mesipistiäisiä, jotka ruokailevat sekä toukka että aikuisvaiheessa medellä ja siitepölyllä, löytyi eniten tuoreilta ja vanhoilta päätehakkuilta. Näillä kuvioilla oli korkeamman lämpötilan lisäksi aurinkoisempaa ja enemmän ravintokasveja kuin harvennusmetsissä. Kaikkia myrkkypistiäisiä löytyi eniten korkeilta pökkelöiltä, joiden rungoilla oli vain vähän kaarnaa. Myrkkypistiäiset suosivat enemmän teko- ja luonnonpökkelöitä kuin kantoja. Pökkelön ympäristön ominaisuudet olivat kuitenkin tärkeämpiä kuin pökkelön ominaisuudet niin lajimäärälle kuin yksilörunsaudelle. Koska eri ekologisten ryhmien lajit suosivat erilaisia elinympäristöjä, tekopökkelöitä kannattaa jatkossakin tehdä sekä pääte- että harvennushakkuiden yhteydessä. Tekopökkelöitä tehdessä kannattaa myös huomioida niiden monipuolinen sijoittuminen reunoille ja keskelle hakkuuta, jotta niitä jää hakkuualueelle monenlaisiin ympäristöoloihin. Tekopökkelö tulisi katkaista mahdollisimman korkealta, sillä korkeisiin pökkelöihin mahtuu enemmän pesiä kuin mataliin ja matalat pökkelöt ovat alttiimpia kosteudelle, sekä pesien homehtumiselle kuin korkeat pökkelöt.
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(2022)Light pollution, or artificial light at night, is a globally increasing environmental problem that threatens especially nocturnal organisms dependent on darkness. Modern lighting technology offers opportunities for mitigation of the ecological impacts of light pollution, but effective implementation requires better understanding of how different artificial light qualities, such as light spectrum, influence its effects on wildlife. The common glow-worm, Lampyris noctiluca, is an example of a species believed to be suffering from light pollution. Artificial light has been found to interfere with glow-worm reproduction by decreasing the success of females in attracting males with their glow. In this study, I investigated how the color (spectrum) of artificial light affects the attraction of male glow-worms towards a female mimicking stimulus, in order to find out whether certain colors of artificial light are less detrimental to glow-worm reproduction than others. I used dummy female traps to capture male glow-worms in the field and compared the catch success of traps in different treatments: illuminated from above with blue, white, yellow or red artificial light, or left unilluminated as a control. I also conducted a laboratory experiment where male glow-worms were given two choices. One of the choices was an unilluminated dummy female, and the other was either a dummy female illuminated with yellow or red light, or a red light illuminated area with no dummy female. Traps illuminated with short wavelength artificial light (blue and white) caught significantly fewer males than unilluminated traps or traps illuminated with long wavelength artificial light (yellow and red). There was no significant difference in the number of males caught between unilluminated traps and traps illuminated with long wavelength artificial light. In the laboratory, males significantly preferred an unilluminated dummy female over a dummy female illuminated with yellow light. However, the males chose a red light illuminated dummy female or area more often than an unilluminated dummy female, although this difference in preference was not significant. The results show that mate attraction in the glow-worm is influenced by artificial light color, with short wavelength artificial light decreasing the mate attraction success of female glow-worms more than long wavelength artificial light. This could point to yellow-tinted artificial lighting presenting an ecologically friendly alternative to cool white lighting. However, the specifics of how long wavelength artificial light affects male glow-worm perception of female attractiveness are still unclear. Furthermore, male glow-worms show signs of attraction towards long wavelength artificial light, which could form an evolutionary trap for them. The impacts of artificial light spectrum on organisms are thus not straightforward, but can vary depending on both species and situation.
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(2022)Fear has far-reaching physiological and behavioural effects for animals, altering their foraging efficiency, parental care and breeding success. Extensive research shows that an animal’s perceived risk of predation, for example, can have fitness effects equivalent to direct killing. However, less work has explored the effects of fear induced by other natural enemies. Here I investigated by field experiment how the perceived risk of brood parasitism by common cuckoos (Cuculus canorus) affects behaviour of reed warblers (Acrocephalus scirpaceus), one of the favourite host species. Previous work shows that reed warblers upregulate behavioural defences based on social information about parasitism risk, but it is not known whether this alters their behaviour outside of an encounter with a cuckoo. Therefore, I manipulated social information about parasitism risk using models and alarm-call playbacks, and measured differences in vigilance behaviour depending on the amount of social information provided (high, medium, low, no risk). I found that vigilance increased when the perception of parasitism risk increased, both during social information presentations and 6 days later during incubation (when the nest is no longer at risk of parasitism). The findings suggest that when perceived risks are high, incubation behaviour is adapted to reduce parasitism risk. Additionally, the cues indicating increased parasitism risk reduced the fledging success, possibly due to the increased stress and the time allocated into vigilance rather than parental care. Therefore, these changes in incubation behaviour impact individual fitness. Further study is required into the behavioural changes in parenting during chick rearing from the increased perception of parasitism risk.
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The Effects of Soil Treatments and Yellow Rattle on the Soil Properties of Newly Established Meadows (2024)My master’s thesis aims to determine the impact of soil treatments and the hemi-parasite Rhinanthus minor (yellow rattle) on the soil properties of newly established perennial wildflower meadow. As urbanization and urban green spaces increase, the need for viable methods for establishing biodiverse meadows on existing lawns grows. I joined a lawn to meadow project based at Lammi Biological Station wherein four soil treatments (untreated, scarified, overturned, and replaced with meadow substrate) were employed in eight meadow blocks. Within those blocks, yellow rattle was sown into half of the plots to determine if it can hamper the growth of competitive grass species. My aim was to explore the meadow blocks’ chemical soil properties (phosphate, nitrate + nitrite, ammonium, total carbon, total nitrogen, and pH). The soil properties were measured using LECO analysis, photometric analysis, and a pH meter. In the newly established meadows at Lammi biological stations, there is evidence that soil properties do change as a result of different soil treatments and the introduction of a hemi-parasitic plant. The initial soil properties show that soil turnover results in increased nitrate + nitrite and decreased total nitrogen compared to untreated meadow soil and lawn controls, respectively. Meadow soils replaced with a substrate exhibited nutrient poor conditions typical of low nutrient preferring meadow plants. The effects of yellow rattle on aboveground community structure are not investigated here, but after the first growing season, its presence increased nitrate + nitrite in the first ten cm of soil. Nitrogen mineralization as a result of grass introduced to soil microbes and nutrient dense yellow rattle leaves may be the cause of these changes to the soil properties. Meadow establishment can take 3 – 5 years, so the use of these methods should continue to be observed. I would expect larger differences to manifest as the experiment continues, namely, decreased soil nutrients as more growing seasons pass.
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(2023)Non-native species can have complex effects on the abundance of native species potentially altering the functioning of ecosystems negatively. Invasive species can outcompete local species competing for resources, ultimately causing the extinction of local species. Inter- and intraspecific competition can be especially vigorous for limited resources. Invasive species have been thought to be a leading cause in native species extinction, and their effects on native species can be especially pronounced during reproductive crucial life-history stages, such as nest-building. Based on previous information about invasive species and their effects on ecosystems, and previous studies conducted related to invasive species, I conducted an experiment at the Tvärminne zoological station in Hanko, southern Finland during May and June of 2021. I conducted a laboratory experiment in which the test species used were the invasive fish species round goby, that has increased its range across the Baltic Sea rapidly, and the native fish species sand goby. The purpose was to see, if there was any effect the invasive species has on the nesting success and motivation of the native species. Methods included five different treatments in aquariums. The results did not differ statistically between different treatments, length was close to statistical significance. However, these results do not demonstrate, that the round goby has no effect on the nest building motivation of sand gobies. Some factors of the experimental setup might have been faulty, and future studies with a larger sample are needed to examine the effects of competition on native species’ abundance.
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(2022)Domesticated horses have been used for various tasks over their thousands of years of shared history with humans. To be able to perform these tasks every horse needs to learn the needed skills, and this requires systematic training. Training of adult horses has been studied for a long time and comparisons between the efficacy of different training methods have been done. There have also been some studies comparing how much and when young foals need to be handled for them to grow into easily trainable adults. From adult horses it is known that emotional state affects cognitive processes and with that also their learning efficiency and speed. The early stages of training young horses have not been studied very well. There is no clear picture about how young horses feel during training and how that affects their learning. In my thesis I studied young horses’ emotional states while learning new tasks and how that affects their learning. I followed the early training of 19 young horses (11 one-year-olds and 8 two- and three-year-olds) by videotaping five training sessions and collecting saliva samples before and after three of those sessions to analyse cortisol and oxytocin. From the videos I analysed how fast horses responded to trainer’s asks and how unfocused they were. From the hormone samples I measure the change in cortisol and oxytocin levels during training. Salivary cortisol has been widely used to measure acute stress. Oxytocin on the other hand is a newer indicator for positive emotions. To the best of my knowledge salivary oxytocin has never been used in horses. My data showed that the horses learned the required tasks: they became quicker at their responses and focused better during the course of training. Because my data was quite small and individual variation in the hormone levels was high, the results might have been affected by these factors. Linear mixed effect models showed that higher oxytocin levels before training session predicted quicker responses during training and lower levels after training predicted lower focusedness. Bigger increase in cortisol levels during training compared to the before level explained quicker responses and better focusedness, but higher levels before training resulted to lower focusedness and slower responses. This is in line with previous studies of adult horses, that showed that horses in a better emotional state and with less stress learn faster and are more interested in working with humans. This shows that it is important to not only focus on physical wellbeing but also mental wellbeing from early on in horses’ life.
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(2024)Lignin is a key macromolecule in many land plants and plays a role in structural support, water conduction, and defence (Vanholme et al., 2010). In most vascular plants, lignin makes up a significant portion of the total plant biomass, about 20-30% (Robinson, 1990). This is important to consider for a variety of reasons, including the large energetic and monetary cost that the forestry industry incurs when removing lignin from tree biomass during processing. Despite its cost to paper and pulp mills, lignin has large potential in the pharmaceutical, construction, and packaging fields, among others (Albuquerque et al., 2021). With proper bioengineering, lignin could even replace fossil fuels as a feedstock in bioplastics production. However, current research and knowledge of lignification, the process wherein lignin deposition occurs in the plant, is lacking when it comes to our ability to produce commercially viable plants with manipulated lignin properties on a large scale. These gaps in knowledge are why it is important to study species with unusual lignin formation, such as the small North American shrub Dirca palustris, commonly known as eastern leatherwood. Such efforts will enable comparative analyses that will improve our understanding of lignification. Previous work on leatherwood has found that the space between adjacent cell walls, known as the middle lamella, is deficient in lignin even after cell wall lignification has concluded, despite the middle lamellae in most other vascular plant species being highly enriched in lignin (Mottiar et al., 2020). This thesis expands upon that finding by determining through histochemical staining, autofluorescence in confocal microscopy, and transmission electron microscopy, that leatherwood is almost completely devoid of lignin in the middle lamella. Histochemical staining and laser excitation were also used to investigate lignin deficiencies in other leatherwood tissues: root, leaf petiole, and peduncle, the small stem that supports flowers and developing fruit. To provide some context for the lignin patterns in leatherwood, both leatherwood and a distant relative, Daphne mezereum, commonly known as daphne, were studied in this work. The results indicate that lignin deficiencies in the middle lamella of fibres may be unique to the Dirca genus as they do not occur in daphne and, therefore, are not necessarily present throughout the entire Thymelaeaceae family. Research was also done with another important macromolecule, pectin, to assess if leatherwood might also have a unique distribution of pectin. Immunostaining revealed that pectin in leatherwood is found in the middle lamella, the same area where lignin is deficient. This new information highlights the need for more research, especially molecular studies, regarding the spatiotemporal relationship between pectin and lignin biosynthesis. Further work is needed to elucidate the underlying genetic factors for leatherwood’s unique lignin patterning, and potentially unveil pectin’s role in the initiation of lignification.
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(2021)Tiivistelmä Referat – Abstract One of the major fundamental ecological questions is the composition of a species diet. The diet of a species is crucially linked to finding out its environmental requirements, and information about the possible changes in the diet is needed when studying the impact of environmental changes such as climate change on species. Siberian flying squirrel (Pteromys volans), classified as endangered in Finland, is a species living in coniferous and mixed forests. More precise information about the dietary habits of the species is needed to support conservation. The aim of my thesis was to investigate the diet composition and diet diversity of adult flying squirrels using DNA barcoding of their excrement pellets, a technique that provides highly accurate information quickly and effectively. The main research questions were whether the diet varies between sexes and seasons, whether diet has an influence on body condition and breeding success of the females, and whether diet diversity is related to the amount of suitable forest habitat near the nests. We collected faecal samples from 51 different flying squirrel individuals from two different study areas near the cities of Vaasa and Pietarsaari in June of 2020. Another set of samples from 8 individuals was collected in November 2020 in Vaasa. The collected samples were sent to a laboratory in Turku, where the DNA barcoding was conducted. I then made further statistical analyses from the laboratory results using general linear models to test my study questions. Although the sample size was too small to obtain statistically significant results for all the research questions, my results indicated that the diet of the Siberian flying squirrel differs between males and females just like its other living habits. Male flying squirrels have more diverse diet than female flying squirrels which have more specific and narrow diet, as they also have smaller home ranges during the breeding season and are more linked to their nesting forest patch compared to males. The aspect that female flying squirrels are more specialists during breeding time is crucial for the species conservation planning. DNA barcoding studies with bigger sample sizes should be done to further investigate the relationship between diet diversity and individual’s body condition and to ascertain the statistical significance to the results of this study.
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