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TOPICS FOR BACHELOR AND MASTER THESES IN 2022/2023 ACADEMIC YEAR

If you are interested in a topic that our workgroup is working on but it is not listed below, you are welcome to contact us and we will find a solution together.

 

BACHELOR'S THESES:

 

Temporal delays in genetic patterns

Studies have often found that some habitats have high species diversity even though the area and quality of that habitat has decreased and fragmentation has increased. However, species diversity will likely decline over time if habitat is not restored. Similar time delays have been observed in the genetic patterns of plants. Based on the literature, the bachelor's thesis examines which and how large time delays have been found in the genetic patterns of plants. Supervisors of the thesis are Tsipe Aavik and Iris Reinula.

 

Morphological characteristics of Primula veris in landscapes with different connectivity

During the last hundred years, the area of meadows in Europe has drastically decreased. This has created a situation where meadows are strongly fragmented in several landscapes. The bachelor's thesis examines whether the morphological characteristics (e.g. the number of flowers or the size of the leaf rosette) of a common meadow plant, cowslip (Primula veris) in a fragmented landscape, can differ from those of a more connected landscape, and what consequences the possible differences can bring. Supervisors of the thesis are Marianne Kaldra and Iris Reinula.

 

The role of genetic diversity in ensuring ecosystem services

Ecosystem services are services provided by nature that benefit humanity. One important pillar of their supply is genetic diversity, which ensures the survival of the species in the long term. Based on the literature, the bachelor's thesis examines whether and how genetic diversity supports the provision of ecosystem services and whether the abundance of ecosystem services could in turn support the genetic diversity of different species. Supervisors of the thesis are Elisabeth Prangel and Iris Reinula.

 

Landscape Genomics

Genetic diversity is one part of the intra-species variation that is necessary for the survival of the species. In changing environmental conditions, the existence of genetic variability is especially necessary, because it allows individuals that are better adapted to certain environmental conditions to cope better in new conditions. The bachelor's thesis provides an overview of the landscape genomics research field, which studies the influence of the environment on genetic variation under natural selection (adaptive). Supervisors of the thesis are Tsipe Aavik and Iris Reinula.

 

The importance of historical legacies for ecosystem condition

Several large-scale drivers, such as climate change and intensified human impact, are strongly influencing our natural and semi-natural ecosystems. At the same time, there are time lags in ecosystems’ reaction to changes. And reasons why the condition of particular ecosystem is poor (or good), are often related to historical legacies in the concrete area and its surrounding landscape. Understanding those historical legacies is of central importance for restoration efforts aiming for improving the ecosystems’ condition. The aim of the batchelor thesis is to give an overview or different positive and negative historical drivers of ecosystem condition and their potential temporal extent.
Supervisors are Triin Reitalu and Elvi Liiv.

Laelatu wooded meadow – ecosystem with long history of moderate human impact. Photo: T. Reitalu

 

The effect of different management regimes on the biodiversity of ditches in agricultural landscapes

Ditches have an important role for harboring biodiversity in the agricultural landscapes. In Estonia, ditches have the largest area among all landscape elements in agricultural areas and are thus essential habitats for numerous plant and animal species both in water and on land. Therefore, we need to know, which management options can benefit different organism groups, including the rare species in the ditches. Topic of the thesis is related to the LIFE IP project “ForEst&Farmland”. Supervisors of the thesis are Krista Takkis ja Kristiina Jürisoo.

 

The effect of conservation headlands and other field margin management options on biodiversity and ecosystem services

Biodiverse agricultural landscapes support sustainable agriculture through pollination and natural pest management services. To benefit functioning ecosystem services, we need to ensure beneficial organisms in field margins, that can be supported by less intensive field margin management. In the bachelor’s thesis we investigate, which methods can be used for less intensive field margin management, how well they support beneficial organisms and if there are any negative sides to the methods. Topic of the thesis is related to the LIFE IP project “ForEst&Farmland”. Supervisors of the thesis are Krista Takkis and Kristiina Jürisoo.

 

How to evaluate the effectiveness of nature restoration?

Wide-scale restoration of degraded ecosystems is essential for stopping biodiversity loss and climate change. However, it is still unclear, which criteria would be the best to estimate the effectiveness of nature restoration and how to quantify it. In the bachelor’s thesis we investigate how to define nature restoration, which indicators have been used to estimate the effectiveness of restoration and how it has been quantified. We estimate, which indicators and methods would be best to use across ecosystems, in order to be able to compare restoration effectiveness in different systems. Supervisor of the thesis is Krista Takkis.

 

Effects of landscape structure on the network of interactions between plants and pollinators

Landscapes that become more monotonous and intensive agricultural practices reduce the biodiversity of agricultural landscapes. In addition to the species diversity and abundance of different groups of organisms, these factors have a significant impact on the interactions between different organisms, including the relationship between plants and the insects that pollinate them. Within the framework of the bachelor's thesis, an overview is given based on the literature of how changes in the landscape structure have affected the networks of relationships between pollinated plants and pollinating insects. The supervisors of the thesis are plant ecologist Tsipe Aavik and pollination ecologist Virve Sõber.

 

Effects of urbanization on plant-pollinator interactions

Increasing urbanization has a significant impact on both pollinators and the flowering plants that depend on them. The impact of urbanization on biodiversity can be both favorable and unfavorable, depending on both the degree of urbanization and the characteristics of the organisms. The bachelor's thesis provides an overview of the scientific literature, which have discussed the relationship between changes in the diversity and abundance of pollinating insects and pollinating plants with the rate of urbanization. The preparation of the thesis will be supervised by pollination ecologist Virve Sõber and plant ecologist Tsipe Aavik.

 

Genetic monitoring of plants in response to ecosystem restoration

Genetic diversity is an important component of biodiversity securing the resilience of populations in an era of environmental change. However, despite its increasing relevance in the light of ongoing climate change, the recovery of genetic diversity is rarely assessed in monitoring programs. The bachelor's thesis will give an overview of the different aspects of restoration success, which can be monitored with the help of plant genetic data. It will also provide an overview of the known monitoring programs relying on temporal assessment of genetic diversity and gene flow of plants. The thesis is part of the international collaboration activities COST G-BiKE (Genomic BIodiversity Knowledge for Resilient Ecosystems) and ConservePlants (An integrated approach to conservation of threatened plants for the 21st Century). The preparation of the thesis will be supervised by Tsipe Aavik.

 

Macrogenetics of plants

Genetic diversity of organisms is one of the main components of biodiversity alongside species and ecosystem diversity. Although the assessment of genetic diversity has become increasingly common in recent years, most research continues to be limited to assessing the fate of one or a few species. Therefore, it is difficult to make generalizations about regional and global patterns of genetic diversity and their determinants. It is also almost impossible to assess whether and to what extent global change, including climate change and the loss of natural habitats, has affected this important component of biodiversity. Macrogenetics is a new discipline that brings together existing research on the genetic diversity of organisms to assess the patterns of this important component of biodiversity and to identify the patterns that determine it. The aim of the bachelor's thesis is to provide a literature-based overview of macrogenetics as a field of science, plant-focused macrogenetic research and the main research results in this field. The supervisor of the work is Tsipe Aavik.

 

History, future and ecological effects of grassland afforestation

In the 1960s, Soviet campaigns decided to afforest and thus make a large number of rich meadow communities "economically viable". Half a century later, the same solution is being proposed for afforesting the few remaining meadows in order to achieve climate goals. Is this an effective method or are there significant shortcomings in afforestation plans? The aim of the bachelor's thesis is to gather knowledge about the history and current state of afforestation of open landscapes and to describe the ecological consequences of afforestation, including the impact on pollinators, soil biota and meadow biodiversity and nature's benefits as a whole. The supervisors of the work are Aveliina Helm and Elisabeth Prangel.

Afforestation campaigns in the 1960s created monotonous "tree fields" on the once species-rich meadows. Forest created on an alvar in Saaremaa.

 

MASTER'S THESES:

Effects of urbanization on plant-pollinator interactions

Increasing urbanization has a significant impact on both pollinators and the flowering plants that depend on them. The impact of urbanization on biodiversity can be both favorable and unfavorable, depending on both the degree of urbanization and the characteristics of the organisms. As part of the master's thesis, the impact of different management techniques on pollinator and plant communities in the green areas of the city of Tartu can be compared. The supervisors of the work are pollination ecologist Virve Sõber and plant ecologist Tsipe Aavik.

 

The effect of the structure of contemporary and historical landscape on the heterostyly of Primula veris

As part of the citizen science campaign “Looking for Cowslips” launched in 2019, data on cowslips (Primula veris) were collected across Estonia also in the spring of 2020. Participants were asked to find out how many flowers of two different types of cowslip are in one place. One type has anthers lower and the style higher (L-type), the other has anthers higher and the style lower (S-type). Plants with such flowers are called heterostylous, and this is one way for plants to prevent self-fertilization, because only pollen from the other type of flower is able to fertilize. In good conditions, both types of flowers are usually about equal, but this balance may be lost due to the loss of habitats suitable for cowslips. Biodiversity patterns usually respond to such landscape changes with a time lag. In the framework of the master's thesis, it will be studied whether we can immediately see an answer to the decline of habitats in patterns of heterostyly. As part of the work, spatial data must be collected using various modern as well as historical maps. The results of the master's thesis are also planned to be formalized as a research article. The supervisors of the work are Tsipe Aavik, Marianne Kaldra and Iris Reinula.

 

Effect of heterostyly on the gene flow of Primula veris

Landscape genetics is a discipline that combines the methods of population genetics and landscape ecology, with the help of which we can assess how environmental conditions and landscape structure affect genetic diversity and the exchange of genetic information, i.e gene flow. In addition to the nature of the landscape between plant populations, gene flow may also depend on other factors. There are two types of flowers of cowslip (Primula veris) studied in our group. One type has anthers lower and the style higher (L-type), another has anthers higher and the style lower (S-type). Plants with such flowers are called heterostylous, and this is one way in which plants prevent self-fertilization, because only pollen from the other type of flower is fertile. But the exception confirms the rule - in some cases, successful reproduction can also occur when pollen is exchanged between two L-type cowslips. This in turn can lead to differences in the gene flow and genetic diversity of S- and L-type flowers. In the face of habitat fragmentation, the pressure of natural selection may eventually favor "less precautionary" L-type grass dolls. The master's thesis examines whether and to what extent the gene flow patterns of S- and L-type individuals differ and how they are affected by the surrounding landscape. The nature of the work is diverse and includes laboratory, map and field work. The supervisors of the work are Tsipe Aavik and Iris Reinula.

 

Plant genetic diversity-species diversity relationships in Estonian alvar grasslands

The majority of conservation activities are focused on maintaining species diversity, because species diversity is often expected to also reflect other components of biodiversity, like genetic diversity. However, it has been found that interactions between the different mechanisms can result in positive or negative correlations between genetic and species diversity or sometimes no correlation at all. The aim of the master's thesis is to study on the basis of already collected data, what is the relationship between the genetic diversity of cowslip (Primula veris) populations and the species diversity of alvar grasslands, and what nature conservation conclusions can be drawn from it. The supervisors of the thesis are Tsipe Aavik and Iris Reinula.

 

The importance of road edges in maintaining biodiversity

In a situation where the meadow communities found in Estonian traditional landscapes have drastically decreased, the road edges offer important habitats for Estonian meadow species. Road edges can also be ecological corridors between fragmented meadow habitats. In the work group, we have previously prepared an overview for the Estonian Road Administration of more environmentally friendly maintenance of road edges, but the condition and role of Estonian road edges in maintaining biodiversity needs more specific attention. The aim of the master's thesis is to map the road edges that support species richness in Estonia, to find out which factors influence the occurrence of high nature value road edges and to identify the role of road edges in ensuring the coherence of meadow communities. The work will also identify areas where nature-friendly roadside maintenance contributes to the creation of habitat corridors and to ensuring the connectivity of landscapes. The work will be carried out as part of the RESTFUNC project and will use both existing map data and fieldwork data collected by the Master's student in the summer of 2022. The supervisors of the work are Aveliina Helm and Triin Reitalu.

Dry grassland species in a road verge in Saaremaa. Photo: T. Reitalu

 

Time lags in the recovery of populations and species interactions 

Recovery of populations and species interactions after the restoration of communities occurs always with a time lag. In a Master’s thesis we test, how the recovery of populations and species interactions depends on landscape history and structure, and the characteristics of species and their interactions. This important work creates new scientific knowledge, looking at systems and processes that have been studied very little in the past. In our work we use data collected from plants, bees and butterflies in the restored alvar grasslands. The work is carried out as part of the RESTFUNC project. Thesis supervisors are researcher Krista Takkis and pollination specialist Jelle Devalez.

 

Restoration of natural benefits in the restoration of communities

The United Nations Decade of Ecosystem Restoration is under way, and there is a strong global focus on restoring functioning ecosystems that ensure the sustainability and preservation of essential nature's benefits, or ecosystem services. However, the recovery of ecosystem services can take some time, causing a significant time lag between restoration activities and the full functioning of ecosystems. The master's thesis answers the question of how quickly the bnature's benefits recover and to what extent the recovery of various ecosystem services depends on the landscape composition, the techniques chosen for restoration and the degree of ecosystem degradation. As a model system, we use Estonian alvar grasslands, where the large-scale restoration activities are just coming to an end. Much of the data already exists, but there is also scope for fieldwork and data collection. The supervisors of the work are Aveliina Helm and Elisabeth Prangel.

 

Restoration of biodiversity and nature's benefits of Estonian and Latvian wooded meadows

A large-scale nature protection project has began 2021, during which 500 hectares of wooded meadows will be restored in Estonia and 200 hectares in Latvia. Wooded meadows are extremely species-rich and rare ecosystems, but their area has decreased more than 1000 times in the last 100 years. Prior to restoration work, we carry out monitoring on non-restored wooded meadows to determine the impact of restoration on different species groups and other important characteristics of wooded meadows. During the fieldwork in the summer of 2023, we will collect data on plants, insects, soil fungi as well as old trees and traditional ways of working. The aim of the master's thesis is to describe the biodiversity of so far little-known groups in wooded meadows and to give recommendations for restoration work. The work will be carried out as part of the WoodMeadowLIFE project. The supervisors are Triin Reitalu and Aveliina Helm.