Jan Hjort


Physical Geography

56 peer reviewed publications in international journals. The publications have been cited 1078 times, of which the most cited publication accounts for 152 citations. The author has a h-index of 19.00. (Scopus)


I’m a Professor of Physical Geography broadly interested in Arctic, boreal and alpine environments. My research interests include geodiversity, permafrost and periglacial processes, biodiversity, physical geography of urban environments as well as spatial patterns of ecosystem services. Methodologically, the main approach is geospatial data-based statistical analysis. I have participated in 14 multidisciplinary projects (PI/Finnish PI in 9 projects). Examples of current research activities include: director of the INFRAHAZARD (Geomorphic sensitivity of the Arctic region: geohazards and infrastructure) research consortium and principal investigator of the GEOBIO (The potential of geodiversity information in biodiversity assessments) project. Moreover, I’m the national correspondent for Global Terrestrial Network for Permafrost and national representative for International Permafrost Association. I’m supervising or have supervised three postdoctoral researchers, eleven PhD students and over 60 MSc students at the University of Oulu. More information about the Physical Geography Research Group.

Research interests

  • Geodiversity
  • Geomorphology
  • Permafrost and periglacial processes
  • Biodiversity and biogeography
  • Physical geography of urban environments
  • Spatial patterns of ecosystem services

Selected publications

Hjort, J., Karjalainen, O., Aalto, J., Westermann, S., Romanovsky, V.E., Nelson, F.E., Etzelmüller, B. & M. Luoto (2018). Degrading permafrost puts Arctic infrastructure at risk by mid-century. Nature Communications 9: 5147. DOI:10.1038/s41467-018-07557-4

Kärnä, O.-M., Heino, J., Grönroos, M. & J. Hjort (2018). The added value of geodiversity indices in explaining variation of stream macroinvertebrate diversity. Ecological Indicators 94, 420–429.

Aalto, J., Karjalainen, O., Hjort, J. & M. Luoto (2018). Statistical forecasting of current and future circum-Arctic ground temperatures and active layer thickness. Geophysical Research Letters 45, 4889-4898.

Alahuhta, J., Ala-Hulkko, T., Tukiainen, H., Purola, L., Akujärvi, A., Lampinen, R. & J. Hjort (2018). The role of geodiversity in providing ecosystem services at broad scales. Ecological Indicators 91, 47–56.

Bailey, J.J, Boyd, D.S., Hjort, J., Lavers, C.P. & R. Field (2017). Modelling native and alien vascular plant species richness: at which scales is geodiversity most relevant? Global Ecology and Biogeography 26, 763–776.

Gisnås, K., Etzelmüller, B., Lussana, C., Hjort, J., Sannel, A.B.K., Isaksen, K., Westermann, S., Kuhry, P., Christiansen, H.H., Frampton, A. & J. Åkerman (2017). Permafrost map for Norway, Sweden and Finland. Permafrost and Periglacial Processes 28, 359–378.

Tukiainen, H., Bailey, J.J., Kangas, K., Field, R. & J. Hjort (2017). Combining geodiversity with climate and topography to account for threatened species richness. Conservation Biology 31, 364–375.

Varanka, S. & J. Hjort (2017). Spatio-temporal aspects of the environmental factors affecting water quality in boreal rivers. Environmental Earth Sciences 76, 21.

Hjort, J., Suomi, J. & J. Käyhkö (2016). Extreme urban-rural temperatures in the coastal city of Turku, Finland: Quantification and visualization based on a generalized additive model. Science of the Total Environment 569–570, 507–517.

Ala-Hulkko, T., Kotavaara, O., Alahuhta, J., Helle, P. & J. Hjort (2016). Introducing accessibility analysis in mapping cultural ecosystem services. Ecological Indicators 66, 416–427.

Hjort, J., Hugg, T.T., Antikainen, H., Rusanen, J., Sofiev, M., Kukkonen, J., Jaakkola, M.S. & J.J.K. Jaakkola (2016). Fine-scale exposure to allergenic pollen in the urban environment: evaluation of land use regression approach. Environmental Health Perspectives 124, 619–626. 

Hjort, J., Gordon, J.E., Gray, M. & M.L. Hunter Jr. (2015). Why geodiversity matters in valuing nature’s stage. Conservation Biology 29, 630–639.

Hjort, J., Ujanen, J., Parviainen, M., Tolgensbakk, J. & B. Etzelmüller (2014). Transferability of geomorphological distribution models: evaluation using solifluction features in subarctic and Arctic regions. Geomorphology 204, 165–176.

Hjort, J. & M. Luoto. (2013). Statistical methods for geomorphic distribution modeling. In: Shroder, J., Jr., Baas, A.C.W. (Eds.). Treatise on Geomorphology. Academic Press, San Diego, 59–73.

Hjort, J., Heikkinen, R.K. & M. Luoto (2012). Inclusion of explicit measures of geodiversity improve biodiversity models in a boreal landscape. Biodiversity and Conservation 21, 3487–3506.

Virtanen, R., Luoto, M., Rämä, T., Mikkola, K., Hjort, J., Grytnes, J.-A. & J. Birks (2010). Recent vegetation changes in the high latitude tree line ecotone are controlled by geomorphologic disturbance, productivity and diversity. Global Ecology and Biogeography 19, 810–821.

Christiansen, H.H., Etzelmüller, B., Isaksen, K., Juliussen, H., Farbrot, H., Humlum, O., Johansson, M., Ingeman-Nielsen, T., Kristensen, L., Hjort, J., Holmlund, P., Sannel, A.B.K., Sigsgaard, C., Åkerman, H.J., Foged, N., Blirka, L.H., Pernosky, M.A. & R. Ødegård (2010). The Thermal State of Permafrost in the Nordic area during IPY 2007-2009. Permafrost and Periglacial Processes 21, 156–181.

Hjort, J. & M. Luoto (2010). Geodiversity of high-latitude landscapes in northern Finland. Geomorphology 115, 109–116.

Hjort, J. & M. Luoto (2009). Interaction of geomorphic and ecologic features across altitudinal zones in a subarctic landscape. Geomorphology 112, 324–333.

Hjort, J. & M. Marmion (2008). Effects of sample size on the accuracy of geomorphological models. Geomorphology 102, 341–350.

Hjort, J. (2006). Environmental factors affecting the occurrence of periglacial landforms in Finnish Lapland: a numerical approach (PhD Thesis). Shaker Verlag, Aachen. 162 p.

Selected projects

INFRAHAZARD: Geomorphic sensitivity of the Arctic region: geohazards and infrastructure




GEOBIO: The potential of geodiversity information in biodiversity assessments



APTA: The influence of air pollution, pollen and ambient temperature on asthma and allergies in changing climate