Our researchers and master's students & interns

Susanna Lehvävirta

Ecology (PhD, Adjunct Prof.), group leader

My research is interdisciplinary and problem-driven. This means that as I am interested in trying to find solutions for nature conservation, the main questions of my research are often inspired by practical problems and gaps in knowledge. To find optimal solutions one usually needs a holistic approach to understand the ecosystem. Furthermore, in order to apply research results in conservation, different fields of science are often needed to understand the human society, i.e. it’s values, decision making, juridical barriers etc. For collaborations, research inquiries, and dissertations, please feel free to contact me by sending an email ( Click the TUHAT research portal link to find more information.

Johan Kotze

Invertebrates and statistical analyses (PhD, Adjunct Prof.)

My research interests include the responses of invertebrate and plant communities to urbanisation.  To this end I concentrate on the effects of various urban features, such as habitat edges, trampling intensity, and greenspace fragmentation in general, on communities in remnant urban forests, meadow habitats, vegetated roofs and mires. Additionally, during the past years I have become interested in using urban soils as in situ laboratories to investigate decomposition and soil quality, and to involve students and citizen scientists to learn about the importance of soil biodiversity and ecological processes. Feel free to contact me via email ( More information about my research in TUHAT research portal.

Kirsi Kuoppamäki

Runoff quality and quantity (PhD, Adjunct Prof.)

My research background is in aquatic ecology, with the focus on food web interactions in eutrophic lakes subject to various restoration efforts. However, rehabilitation is not sustainable as long as external loading is not adequately controlled, which, in turn, is not possible until the degree of various sources of pollution is known. The loading of nutrients and other contaminants from urban sources is a topic worth studying, as cities are disproportionately located next to aquatic ecosystems. Urbanised ecosystems, characterised by surfaces impervious to water, have low capacity to provide ecosystem services, such as surface runoff drainage. Green infrastructure, such as vegetated roofs, may have great potential for managing urban runoff, but the performance of such solutions in cold climate has received limited attention in scientific research. My aim is to find sustainable, ecological solutions to build resilient cities. In addition, I pursue my long-term research on aquatic food webs with the main focus on zooplankton. Teaching activities have played a major role in my academic career. Feel free to contact me via email ( and see TUHAT research portal and the ORCiD page to find more information about my research and activities. I am a member also in the Urban Ecosystems research group.

Long Xie

Plant symbiotic microbes (postdoc)

Green roof research has been gaining its popularity and importance in academia more and more. However, if plants could not survive on vegetated roofs, none of the researches could be conducted at all. So my researches focus on growth and survival of vegetated roof plants since my Master’s thesis, specifically applying plant-growth-promoting-microbes in the soil to achieve or partially achieve the goal. I focused on two commonly used beneficial microbes: Bacillus amyloliquefaciens (bacterium) and Rhizophagus irregularis (arbuscular mycorrhizal fungus, formerly known as Glomus intraradices) on vascular plants (berry plants, ornamental plants, and grass). I have been working both in greenhouse and vegetated roof conditions for different experimental layouts. Contact me via email (

Kukka Kyrö

Invertebrates (MSc, doctoral student)

My research focuses on vegetated roofs as habitats for urban arthropods. I’m interested in taxonomic and trait composition of roof fauna and study how biophysical roof characteristics and landscape composition affect the arthropod communities. I’m also interested in temporal patterns in the roof fauna and follow arthropod colonization on newly established vegetated roofs. Feel free to contact me via email me ( and see TUHAT research portal to find more information.

Xi Shu

Landscape Architecture (MSc, doctoral student)

My research focus on how to increase biodiversity in human-dominated landscape, which consists of three parts. The first one is quantitative analysis of human’s needs especially on those who don’t have a strong voice in the society. The second part considers how to use native plants to create habitats for non-human species in human-created landscape -vegetated roofs and walls. The third part aims to balance human and non-human species’ needs in a design programme. Contact me via email (

Taina Suonio

Policy instruments (MSc)

Taina is an environmental biologist, landscape designer and horticulturist. She holds a BSc in Environmental Biology and a Masters degree in Environmental Change and Policy from the University of Helsinki. Her research concentrates particularly on the environmental change and policy with regard to green roofs in urban areas. She is currently working as chairperson on the Green Roof Strategy of the City of Vantaa, Finland’s fourth largest city, located in the greater Helsinki region. Taina is considered a leading pioneer in Finland on green roofs, and she takes pride in the work in this field. She sees it as improving the quality of our lives but also as an absolute necessity in the face of the megatrend of urbanisation, with a view of preserving and supporting the biodiversity our natural environment.

Marja Mesimäki

User-perspective, adoption of green roofs, associate leader (MSc, doctoral student) 

My field of expertise is environmental sociology and environmental social science, specifically urban questions and qualitative methods.  My research issues concern values, meanings and experiences related to urban vegetated roofs, future-oriented co-design, and implementation of scientific knowledge in planning processes. I have studied urbanites’ mental images of different kinds of vegetated roof solutions, on-roof experiences (e.g. restorative), and how vegetated roofs are adopted and realized in large construction processes. In broader context, I am exploring tools to integrate user perspective into urban greening, using vegetated roofs as model spaces. I am developing future-oriented methods for studying expectations for vegetatedgreen roofs, based on e.g. the method of empathy-based stories, MEBS, to be used in the context of participatory planning and design. At the moment, I am working on case-studies in a comprehensive service center/assisted living, and a residential house with different vegetated roof solutions in Helsinki. I am cooperating with several national and international researchers, for e.g. developing the methods. Feel free to contact me via email (! See TUHAT research portal to find more information.

Juhamatti Niemi-Kapee

Moss roofs (MSc, doctoral student)

I have a background in ecology with a M.Sc. from the University of Helsinki. My Bachelor’s thesis focused on vegetated roofs in general. In my Master’s thesis I studied vegetated roofs in more detail focusing on mosses. Currently as a PhD student I’m studying moss species and substrate properties on vegetated roofs. I also have a degree and work experience as a international wilderness guide.

My research focuses on novel ultra light solutions concerning mosses on vegetated roofs. I want to explore how we can benefit from the extraordinary characteristics of mosses which allow them to survive and flourish in a hostile environments such as human made artificial landscapes.

I started my PhD in 2014 with the supervision of adjunct professors Susanna Lehvävirta and Johannes Enroth. At the moment I have two research roofs in Helsinki - the roofs are located in Kaisaniemi Botanical garden and in Meilahti Sports center. These roofs cover altogether more than 5000 m2. My research is funded by Kone foundation. If you have questions or ideas, please do not hesitate to contact me via email ( More information in TUHAT research portal.

Miia Jauni

Vegetation (PhD, post doc)

My research interests lie in the field of biodiversity, community and invasion ecology of plants and GIS. I am especially interested in the impact of environmental conditions on the occurrence and diversity of plant species. Previously, I have studied plant diversity and invasions at community and population levels and assessed how environmental conditions (e.g. disturbance, climate) and species characteristics affect plant communities in natural and man-made habitats. Vegetated roofs provide a new, man-made habitat for plants. I explore how environmental conditions (e.g. substrate) contribute to plant community composition and to the success of individual plant species at vegetated roofs. Furthermore, I am interested in whether vegetated roofs can maintain biodiversity of native plant species or are they easily invaded by non-native species. Feel free to contact me via email ( More information in TUHAT research portal.

Marleena Hagner

Substrate properties and soil animals (PhD, post doc)

In my master thesis I studied the repellent effect of birch oil distillate on the land snail Arianta arbustorum. In my PhD work I continued working on the same topic: the effects birch oil distillate as a molluscicide and its ecotoxicological effects Recently, I have been studying the use of biochar as a soil amendment and its impacts on the plant growth and leaching of nutrients and pesticides from agricultural soils. Currently I also study the functioning of green roofs under Finnish climatic conditions by exploring the properties of green roofs that give rise to an active soil animal community, efficient cycling of nutrients and carbon, plant growth and management of stormwater in green roofs. I am interested in the plant growth and runoff quality and quantity in green roofs established by using recycled materials, biochar and mycorrhiza amendment. I am also working as a researcher in the Plant Health team in Natural Resources Institute Finland (Luke). Feel free to contact me via email ( More information in TUHAT research portal. I am a member also in the Urban Ecosystems research group.

Master students


  • Renan Benicke: outdoor spaces for children (University of Münster)
  • Iiris Lettojärvi
  • Ida Torvinen