Thesis topics | Urban Ecosystems | University of Helsinki

Can you establish a biodiverse urban meadow?

Cities in Europe and Finland have been interested in creating biodiverse urban meadows by reducing management intensity in lawns or by sowing native meadow plants. However, little is known about what has come out of these experiments in practice. As a master’s student, you will aim to understand the plant communities created in meadowing projects in the cities of Helsinki, Espoo, Vantaa and Kauniainen, collecting field data during the summer of 2023. Have they been able to create biodiverse meadow vegetation? How do they compare to other kinds of urban open vegetation in the area?

Carabid beetles in urban greenspace

Contact: Johan Kotze, Heikki Setälä, or Basile Finand

Ground beetles have been used in various urban ecological research questions. The group is well-known, and responds rapidly to various disturbances. We offer various MSc thesis topics related to the response of these beetles to urbanisation, including i) how body size of these beetles vary in various types of urban greenspace, ii) linking contemporary carabid beetle assembly to historical urban landscape configuration, iii) exploring whether some traits (characteristics) of carabid beetle are influenced by urbanisation. The MSc student(s) will join our recently-appointed postdoc and senior members of the group to do fieldwork primarily in Helsinki, but opportunities are also available for fieldwork in Lahti.

The impacts of turning lawns into meadows

Contact: Anna Oldén

Unused lawns could be turned into biodiverse meadow-like habitats by changing their management and possibly modifying the topsoil and sowing meadow species. Different methods of this transformation are expected to have varying impacts on the price of the transformation, the development of the plant community, soil properties, greenhouse gas emissions and the aesthetics of the site. An experiment was set up in autumn 2022 in the lawns of Lammi Biological Station. Four different topsoil treatments are tested with or without the sowing of a hemiparasitic plant that should weaken the lawn vegetation. Each of these eight treatment combinations are repeated on eight different blocks. During the summer of 2023 you could study the impacts of the treatments on greenhouse gas emissions and/or soil properties.

Hungry Microbes: Do clippings from lawn mowing deplete or increase soil carbon pools?

Contact: Alexander Stelzer, Johan Kotze, or Heikki Setälä

Soil organic carbon is the fuel for many biogenic processes. Hence, it is an accepted indicator for soil and plant health. Lawn mowing in urban parks enhances grass/herb growth and reintroduces clippings and their carbon back into the soil. Intuitively, carbon pools in the soil should increase when carbon from grass litter enters the soils as the clippings decompose and then eventually equilibrate to the carbon level before the mowing. However, the addition of new litter has been observed to decrease C in the soils across various ecosystems. This may happen when the biomass and activity of soil microbiota increases due to litter addition to the soil. Our current understand suggests that soil microbes get fueled with fresh labile carbon and consequently metabolize also the “old” and more stable carbon pools. Whether this, so called, priming effect takes place in urban parks is not known. In this thesis, you will monitor soil carbon pools for three lawn mowing treatments within urban parks in Lahti. You will explore how the soil responds when no clippings, the normal or the double amount of clippings are reintroduced into park lawn soil. This thesis comprises of field work from spring to early fall 2023 and subsequent laboratory analyses. In the lab you will quantify the carbon pools depending on their lability in the decomposition process.

Can biochar be used to reduce the impact of dogs in urban parks?

Contact: John Allen, Heikki Setälä or Johan Kotze

Research from our group and others has shown that domestic dogs are a significant source of nitrogen in urban greenspaces. Not only does this input degrade the aesthetics of city parks, it also results in increased fluxes of nitrogenous gases from the impacted soils and may contribute to pollution of ground and surface waters. Biochar has been shown to significantly reduce the leaching of nutrients from soils and could help to mitigate these impacts.

As an MSc student you will work in collaboration with the research team to design and implement a study to examine the effectiveness of biochar amendments to soils in urban greenspaces and to determine if they can be used to sequester and treat excess nitrogen deposition by dogs.

Completed PhD theses:

Yuan Wang (2023): Cultural Ecosystem Services of urban forests: a delivery from biodiversity, through the landscape, to beneficiaries

Viljami Viippola (2022): Effects of tree cover on local air pollutant levels in near-road environments

Changyi Lu (2021): Plant-soil feedbacks as affecting ecosystem services in urban greenspaces

Kukka Kyrö (2021): Vegetated roofs as habitats for arthropods in urban areas

Norbertas Noreika (2016): On the deterioration and restoration of mire invertebrate communities

Jarmo Saarikivi (2016): Biodiversity in golf courses and its contribution to the diversity of open green spaces in an urban setting

Kaisa Hauru (2015): Eco-experiential quality of urban forests: combining ecological, restorative and aesthetic perspectives

Leena Hamberg (2009): The effects of habitat edges and trampling intensity on vegetation in urban forests

Completed MSc theses:

Sem de Waard (2023): Detecting recent and historically fragmented forest patches in the Helsinki City Region, Finland

Riku Kangasniemi (2023): Specialists in the city – Indicator species as a tool for assessing the ecological quality of urban grasslands