Browsing by master's degree program "Ekologian ja evoluutiobiologian maisteriohjelma"

Early life conditions have long-term effects on the fitness and survival of individuals. Foetal development is an especially crucial period and even small changes may have large impacts on the development of individuals. Mammal foetuses may be exposed to additional testosterone either from their male littermates or their mother. This additional prenatal androgen exposure leads to masculinization of female features and behavior. In males the effects of additional prenatal androgen exposure are less drastic due to their own testosterone production. The anogenital distance, defined as the distance between the anus and genitalia, has been used to determine the sex of young mammals since males have longer anogenital distances than females. An elongated anogenital distance is an indicator of additional prenatal androgen exposure in females, and in some species also in males. It correlates with for example increased aggressiveness in both females and males. In females a longer anogenital distance has also been connected to delayed puberty and decreased fertility. I studied the effects of additional prenatal androgen exposure on weight and important life-history traits in banded mongooses (Mungos mungo) with data from a long-term study. Banded mongooses are small co-operatively breeding mammals living in family groups of 10-30 individuals across sub-Saharan Africa. Breeding is extremely synchronized within groups and in most cases all pregnant females give birth on the same day. The resulting communal litter is cared for by most adults in the group regardless of relatedness. Adults escort the pups until three months of age, providing the pup with food, grooming and protection. This early life care has long-term fitness benefits for the pups. Pregnant females may change the phenotype of their offspring via maternal effects. When the competition faced by breeding females is more intense, they compensate by investing more resources to their foetuses, making them bigger. Using the anogenital distance as a proxy for additional prenatal androgen exposure, I measured its effects on weight at early life and maturity, the amount of care received as pups and whether the individual reproduced in its lifetime or not. I hypothesized that a longer anogenital distance may be an indicator of increased competitiveness in the banded mongoose. It could lead to a cumulative advantage since more aggressive individuals may be able to access more food and care, which leads to higher maturity weight and lifetime reproductive success. I also measured the effects of resource abundance and intensity of competition during gestation on the anogenital distance of the pups. I hypothesized that mothers may prepare their offspring for future competitive environment by exposing them to androgens during gestation. In males a longer anogenital distance predicted higher weight both at early life and maturity. Higher weight at the beginning of the escorting increased the amount of care received, which in turn increased weight at maturity. A longer anogenital distance therefore has both direct and indirect fitness benefits in male banded mongooses. In females, a longer anogenital distance predicted lighter weight at maturity, suggesting that it may have negative effects on female growth and development. This study offers evidence that additional prenatal androgen exposure has long-term fitness consequences on banded mongooses and that these consequences are sex specific. Future research should focus on confirming the connection between additional prenatal androgen exposure and longer anogenital distance in this species, as well as assessing the effects of prenatal androgen exposure on survival, puberty and growth of especially female individuals.

Animal personality is described as consistent behavioural variation between individuals over long periods of time. Behaviours often connected to animal personality are such as boldness, aggressiveness, and anxiety. In this thesis, the focus was on the behaviours along the shy-bold axis, containing various degrees of boldness expressing behaviour. The study was conducted by using long-term data from the past 30 years on the banded mongoose (Mungos mungo) population in the Mweya Peninsula in the Queen Elizabeth National Park in Uganda. In particular, I used the data on regular weighing events done within the population. As the weighing is not forced on these individuals, the participation percentage on these events can be used to describe an individual’s boldness. I used the participation percentage as a boldness index (values between 0 and 1) for each individual to describe their position on the shy-bold axis. This index was then used to analyse the differences between sexes, and the fitness effects boldness had on the individuals of this population by using proxies of survival, weight at sexual maturity and lifetime reproductive success (LRS). To determine long-term consistency between individuals, I analysed the repeatability of the boldness index. The repeatability of these values showed we can consider this behaviour as an animal personality. From the fitness analyses, it was concluded that boldness had significant positive effects on the fitness proxies used, proposing that bold individuals have higher fitness in this population. While sex did not affect an individual’s boldness, it had significant interactions with boldness, affecting the strength of fitness effects on individuals in weight at sexual maturity and LRS.

Monen eri eläinryhmän edustajat käyttävät sosiaalista informaatiota sekä lajinsisäisesti, että lajienvälisesti erilaisten kelpoisuuteen vaikuttavien päätösten tekemisessä. Sosiaalinen informaatio voidaan jakaa tahallisiin ja tahattomiin signaaleihin ja informaation havainnoija voi käyttää tahattomia signaaleja hyväkseen johtaen siihen, että signaalin tuottaja kärsii huonommasta kelpoisuudesta. Tästä johtuvat valintapaineet voivat luoda informaation peittämisstrategioita signaalin tuottajassa. Tämä voi puolestaan johtaa osapuolten väliseen adaptaatioiden sykliin, jota kutsutaan myös koevolutiiviseksi kilpavarusteluksi. Pesäloiset ja niiden isäntälajit ovat klassinen esimerkki tällaisesta vuorovaikutussuhteesta. Leppälintu (Phoenicurus phoenicurus) on ainoa käen (Cuculus canorus) isäntälaji, joka pesii pelkästään koloissa. Kolopesintä tekee leppälinnusta erityisen isännän, eikä sen puolustautumiskäyttäytymistä ole laajalti tutkittu. Tutkimukseni päähypoteesi on, että leppälinnut piilottavat sosiaalista informaatiota käeltä puolustamalla niiltä pesäänsä vähemmän munintavaiheessa verrattuna haudontavaiheeseen. Aiemmissa tutkimuksissa näitä kahta vaihetta ei olla juurikaan vertailtu, vaikka käki loisii pesän pelkästään isännän munintavaiheessa. Testasin päähypoteesiani kenttäkokeilla, joissa ensin vertailin sitä, miten usein leppälinnut ovat läsnä pesillään muninnan ja haudonnan aikana sekä sitä, miten ne puolustavat molemmissa vaiheissa eri uhkia vastaan: pesäloinen, saalistaja ja kontrolli. Leppälinnut olivat enemmän pesillään haudonnan aikana ja tämä johtuu luultavasti siitä, että silloin linnut ovat panostaneet enemmän pesintäyritykseensä ja siitä, että naaraan täytyy pysyä pesällä pidempiä aikoja. Kaiken kaikkiaan, linnut puolustivat pesiään enemmän haudontavaiheessa, mutta niiden reaktio käkeä vastaan oli alhainen molemmissa vaiheissa. Jos siis leppälinnut peittävät informaatiota käiltä, ne eivät muuta tätä käyttäytymistä muninnan ja haudonnan välillä. Lintujen varoittelu lisääntyi saalistajan läsnä ollessa, mutta muu puolustautuminen ei vaihdellut uhkien mukaan. Tulokseni osoittavat, että saalistus saattaa olla pesäloisintaa suurempi uhka leppälinnuille tai että leppälinnut eivät tunnista käkeä uhkaksi. Kolopesintä vaikuttaa olevan leppälinnun paras puolustus käkeä vastaan, mutta lisää tutkimusta tarvitaan näiden kahden välisen dynamiikan tarkastelemiseksi.

Urbanisation threatens species and biodiversity globally. Consequent habitat loss and habitat fragmentation force species upon one another, inevitably also increasing human-wildlife conflicts. Despite the situation growing dire for many organisms, studies also show species from a variety of taxa being able to adapt to urban environments. Most studies of primates’ ability to adapt to urban environments have been done on diurnal species. To my knowledge, the African lesser bushbaby (Galago moholi) is the only nocturnal primate in which this has been studied. To assess urban adaptability in another nocturnal primate, I present transect and recording data on the abundance of the white-tailed small-eared greater galago (Otolemur garnettii lasiotis) in an urban and rural environment in the biodiversity hotspot Taita Hills, Kenya. Sampling was done in Wundanyi town and Ngangao forest and the two locations were then compared by fitting a negative binomial as well as a Poisson model for recording and transect count data. Additionally, preliminary observations are made regarding behavioural and spectral acoustic adaptation, increased sociality, and colouration coupled traits. My results indicate O. g. lasiotis to be significantly more abundant in the town than in the forest. In the town, I observed a two-fold increase in total number of vocalizations and mean vocalization rate, and a seven-fold increase in total number of sightings and mean encounter rate, as indicated by recordings and transects respectively. This discrepancy in estimated abundance differences in location from transect and recording data (two-fold versus seven-fold) suggest that urban individuals vocalize less than rural individuals. The spectral profile of three vocalization types were studied and urban individuals exhibited significantly higher high frequencies in the clustered squawk vocalization. I found town dwelling individuals to be a part of a larger group or pair considerably more often than forest dwelling individuals. A dark morph, as opposed to a light morph, was significantly more frequently encountered in the urban location, whereas both morphs were encountered almost equally often in the rural location. In summary, O. g. lasiotis seems to be capable of adapting to an urban environment, as indicated by its’ greater abundance in the town than in the forest. My data suggest decreased vocalization rate, increased sociality, and colouration coupled traits being possible adaptations affecting O. g. lasiotis’ capability to inhabit an urban environment. Further research is required to draw conclusions on what factors and adaptations might allow for the high abundance of O. g. lasiotis in the town.

Breeding-dispersal and philopatry are important life-history traits when it comes to the ecology of animals. A number of factors such as sex, age, habitat stability, population density, predation and various environmental factors influence the movement patterns of species. Philopatry, in general, can be used by organisms as a predator avoidance strategy and to improve feeding efficiency. Dispersal on the other hand has been shown to help avoid inbreeding and competition within groups or between kin. Among the different types of dispersal and philopatry, breeding dispersal and site fidelity to breeding sites have been studied in many vertebrates. Many birds and some ungulate species have been the focus of these studies and have shown that breeding success influences site fidelity. Among ungulates, the reindeer genus (Rangifer tarandus spp.) however, has received little attention for this topic. A species of special conservational value is the wild forest reindeer (Rangifer tarandus fennicus), which is a rare, and near-threatened subspecies of reindeer living in Finland. Knowledge of factors influencing the dispersal and site fidelity for this species is lacking but has important implications for the conservation and management of this and other vulnerable species. In my thesis I investigated the philopatry of wild forest reindeer females from eastern Finland and tested if the calving site fidelity was influenced by breeding success, predator pressure and the female’s age. Given the high densities of predators in the study area (Kainuu) and thus high predator pressure on reindeer, I expected (i) the philopatry of the wild forest reindeer female’s to be stronger in areas with higher predator pressure but (ii) higher dispersal movement when wild forest reindeer females had no breeding success the previous year. Additionally, I expected (iii) the dispersal distances of wild forest reindeer females to be negatively correlated with their age. For this study I used long-term GPS monitoring data of 53 collared wild forest reindeer females, which were followed for varying periods (2-6 years) between 2010-2021 from Eastern Finland. I found that the inter-year distances between calving sites per female had a median distance of 2.84 km, confirming that female wild forest reindeer show philopatry to calving sites, as do other reindeer subspecies. Even though the movement ranged from 4.8 m to 36.99 km, showing substantially longer dispersal for some individuals. The model outcomes indicate some association between predation pressure and site fidelity, and reduced philopatry following calf mortality, although none of these associations were significant. The age of the mother did also not show any significant influence on a female’s site fidelity. Nonetheless, these results would suggest that a mother's choice to leave or return to the same calving site might be influenced by the previous year's calf mortality but more complex variables like anthropogenic disturbances, environmental factors, as well as intrinsic factors and the physical condition of the mother most likely also play a role in this.

Promoting carbon sequestration and storage is an important part of climate change mitigation. Soils play a prominent role in this, as they contain the largest terrestrial carbon pools. Urban soils have been shown to contain significant amounts of carbon, and thus, urban green spaces have the potential to contribute to climate regulation through soil carbon sequestration and storage. Many green spaces in cities consist of managed lawns containing significant amounts of soil organic carbon, although management activities such as mowing can also be a source of carbon emissions. A low-maintenance alternative to lawns is urban meadows. The benefits in terms of soil carbon sequestration in urban meadows, however, are still poorly documented. This study aims to contribute to an increased understanding of the ecosystem services urban meadows provide, which is valuable in the planning of urban green infrastructure. I quantified soil organic carbon content in 140 urban meadows of different land use types in the Helsinki Metropolitan Area to determine their value in terms of carbon storage and to compare this with the soil carbon storage in highly managed urban lawns. The meadow types explored included valuable grasslands, which have special nature or cultural values, landscape meadows, road verge grasslands, and rocky outcrops. Soil samples were taken from a depth of 0–10 cm using a soil corer. The soil organic matter content and bulk density were measured. Existing data from the soils of city park lawns in Helsinki were used for comparison in the analysis. The soil organic carbon content in the different meadows, as well as in the lawns, was then analysed using land use type and site productivity as explanatory variables. Results show that park lawn soils have a significantly higher carbon density (kg C per square meter) than any of the meadow types. Out of the meadow sites, valuable grasslands had the highest carbon density. The higher carbon content in park lawn soils may be due to increased productivity due to frequent mowing, as well as the fact that these lawns were likely established on nutrient-rich soil. Interestingly, the highest %C was detected in rocky sites. However, the total carbon stocks of rocky sites are lower due to the soil cover being shallow and large portions of the sites not having soil cover at all. To answer the question of whether a lawn should be converted into a meadow in hopes of increasing carbon sequestration and storage, future studies should focus on meadows that were formerly lawns, and that had the same or similar initial conditions as a typical lawn.

Deforestation is the main threat to biodiversity, ecological integrity and socio-ecological resilience of the of the Amazon biome, one of the most biodiverse places on Earth and home to at least 2 million people. A complex network of diverse protection strategies exists across the Amazon as key component of the global strategy to halt biodiversity loss. Biosphere reserves are a part of this network that aims to create spaces to learn how human communities can develop sustainably, while the protecting the environment, by implementing a zonation system with different degrees of protection We consider that it is necessary to produce relevant efficiency assessments on area-based conservation strategies in this region, and to understand how different protection strategies affect conservation outcomes. We used state-of-the-art matching methods to create a counterfactual deforestation avoidance measure of seven Biosphere reserves the western Amazon: Yasuní, Podocarpus-El Cóndor, Sumaco, Manu, BIOAY, Pilón Lajas and Beni. We obtained diverse efficiency results, some of the studied reserves avoiding large quantities of deforestation to reserves that were attracting deforestation. We found that more strictly protected zones were subjected to significatively lower relative pressure levels and did not have higher deforestation avoidance values. Representativity of the matched treatment area was also lower for these zones, meaning that the matching analysis was more difficult to perform in these areas. These research findings add to growing evidence about the important role of biosphere reserves in buffering against deforestation in one of the world’s most important biodiversity hotspots.

The Miocene epoch (c. 23-5 million years ago) was a noteworthy geological time period in which significant changes took place both in the climate regimes as well as in vegetation characteristics, bringing about novel adaptations in many herbivorous lineages. These adaptations constituted morphological, dietary, and ecological factors in a relatively short period of evolutionary time. Among these herbivores were the proboscideans, the living and extinct elephants, which were among the most dominant and largest herbivores at the time. Despite that proboscideans were diverse and large group of hundreds of species, yet the understanding of dietary and ecological patterns of majority of Miocene sympatric species is still limited. The aim of this study was to analyse the molar surfaces of Miocene proboscideans (e.g. Deinotherium and Gomphotherium) from Eurasia to provide a reconstruction of the feeding preferences of the study species based on observed dental wear. The dental wear indicates the abrasiveness of the diet, thus allowing broad categorization to either browser (<10% grass in the diet), mixed-feeder (10-90% grass in the diet) or grazer (>90% grass in the diet). Secondly, this study aimed for providing estimation of the environmental characteristic and vegetation patterns of the study localities by comparing to the previous studies and to hypsodonty value (proxy of general openness and aridity of the environment). Proboscidean dietary signals from the key localities of Maragheh (Iran) and Pannonian basin (Austria) were compared with the paleobotanical studies. Thus, the general estimation of spatial and temporal variation of the environment characteristics in the study localities were based on these parameters. The materials of fossilized molars were analysed by mesowear angle method, in which the measured angles show the diet abrasiveness due the nutritional targets’ differences. The results allowed the reconstruction of the feeding preferences which suggested that majority of Miocene proboscideans were browsers and browse-dominated mixed feeders or pure mixed-feeders. Instead, Choerolophodon pentelici was found grass-dominant mixed-feeder. The wide spectrum of feeding preferences allowed diet flexibility according available vegetation and also these sympatric species to co-exist by niche partitioning. Thus, demonstrating clearly the connection between diets and environments thought the diet. As a conclusion, in the diet of the paleocommunities of proboscideans had, on average, more grass-dominant components in open and dry environment likely due the presence of grass-dominant vegetation. Instead, in the wet conditions the closed-canopy forest environments enhanced browsing. Further, the results indicated shift in feeding preferences of proboscideans prior to Miocene climate and environment changes. These results are in line with the findings of the previous studies of modern elephants’ diet- environment relationships. The further studies would provide insight to the relative amounts of the grass in the diet of Miocene proboscideans.

Post-transcriptional modifications (PTMs) in RNA are present in all known RNA species and conserved in all kingdoms of life. Transfer RNA (tRNA) has been shown to have numerous conserved modifications, which exemplifies the importance of modifications having impact on the structure of the tRNA and its function as carrier of the amino acids. Ribosomal RNAs (rRNA) are universally modified as well, and modifications are situated at functionally important spots of the ribosome. Given the fact that types and sites of modifications are conserved, it is likely that these modifications have been selected for and that they optimize the ribosomal structure and functions. Stress, such as temperature or infection by a pathogen, is known to change the presence or abundance of modifications in RNA molecules and thereby affect translation efficacy. In line with that, this master’s thesis project sought to gain insight into the dynamics of PTMs in tRNA and rRNA upon oxidative stress, with the goal of utilizing recently optimized UPLC/MS method for identifying modified ribonucleosides. As the specific aim of the thesis was to estimate the change in PTMs in tRNA and rRNA in response to oxidative stress with 0.5 mM and 2 mM hydrogen peroxide H2O2, 3 immediate goals were: (i) to isolate total tRNA from yeast grown in stress conditions, (ii) to isolate rRNA from yeast 80S ribosomes, and (iii) to identify present modifications using mass spectrometry. Yeast was cultured in presence of H2O2 as a stressor in mentioned concentrations, and both treatments considered showed a difference in survival when compared to the control. Rough cell concentration estimates (OD600) did not show the effect of the stressor on cell survival clearly, but when number of viable cells per mL was estimated, it was clear that growth of the stressed yeast cultures was hindered 2 hours after exposure to H2O2 but recovered during the 24 hours. Firstly, using UPLC/MS analysis, 29 modifications were identified in tRNA from control and H2O2 treated yeast. Most identified modifications showed no change in abundance in treatments, which is to be verified with additional replicates. However, distinct dynamics of stress-related change was found for several modifications, revealing additional modifications that may play a role in stress related modificome reprogramming to the previously known signature modifications of oxidative stress. It was expected that recovery of culture growth after 24 hours may be accompanied with modification level recovery. However, that was not demonstrated here as downregulation at 2 hours followed by upregulation at 24 hours was seen for 2-methylthio-N6-methyladenosine, N4-acetylcytidine and 5-methoxycarbonylmethyl-2-thiouridine, and the reverse was shown for N4-methylcytidine. Upregulation in both time points was also shown here for some modifications. Taken together, these results confirm a complex and dynamic control of tRNA modifications in cellular survival responses. Modifications found to be affected by oxidative stress are most frequently located on the wobble position 34 and anticodon loop position 37, so it is expected that changes in their modification levels could directly affect the tRNA function in translation, making them a specific target for future research. Secondly, modifications in rRNA from control yeast cultures were identified, such as expected methylations of all 4 canonical nucleosides. However, further analysis will be needed to confirm the other identified modifications, due to the potential mRNA and tRNA contamination. Optimizing the method for rRNA modifications identifications by acquiring more modified nucleosides specific for the rRNA to use as standards in the analysis, analyzing rRNA types separately and using tandem mass spectrometry would enable getting a deeper understanding of which modifications are present and where they are positioned. Finally, it would enable reliable identification of the signals of novel modifications present in rRNA, such as the tRNA modification 5-carbamoylmethyluridine signal found here. In conclusion, this thesis work lays the foundation to study the evolutionary conserved function of PTM changes during stress as modulators of translation, using the methodological approaches discussed in-depth within the thesis, primarily to confirm the intriguing results found here.

Biodiversity has been declining over the last decades due to land-use changes. Habitat loss and fragmentation are considered the key drivers of biodiversity loss. While evidence indicates that habitat loss has a negative impact on biodiversity, the effect of fragmentation itself is debated. The Habitat Amount Hypothesis proposes that fragmentation per se –more discontinuous habitat distribution but no difference in habitat amount- has no effect or even a positive effect on biodiversity. Studies have looked at its effect on species richness, but its impact on intraspecific genetic diversity is still unknown. In this thesis, I aimed to test this hypothesis using the Glanville fritillary butterfly, which has been extensively monitored in the Åland islands since 1990, as a model system. I studied how fragmentation per se affects genetic diversity of the focal populations, while controlling for the habitat amount within the landscape in the Åland islands. For this, I used an existing dataset for which larvae were sampled during two consecutive years and genotyped for 40 neutral SNPs, and calculated four genetic diversity indices in over 200 habitat patches with relatively high population abundance. Following Martin et al. (2021) protocol, I first defined the scale of effect. Then, to reduce the correlation between total habitat amount and number of habitat fragments, I split my dataset in two sub-datasets. Finally, I assessed for each sub-dataset the differences in genetic diversity between landscapes with different level of fragmentation and total habitat amount. The number of fragments had a neutral effect on the genetic diversity, supporting the habitat amount hypothesis. Moreover, the results suggest that all habitat fragments, even the small ones, are contributing to maintain the genetic diversity of the focal population. The species’ ecology, population dynamics and specific adaptations to a fragmented landscape might have led the Glanville fritillary butterfly to be especially resistant to fragmentation.