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Peter Ryser

Peter Ryser

Full Professor

Science, Engineering and Architecture
S-624, Science Building Sudbury Campus


I studied Biology at ETH Zurich. My Ph.D. thesis was on interactions between plants in species-rich grasslands under the supervision of Andreas Gigon. I spent lots of time in the field watching the seedlings grow and die, which triggered the wish, not only to be able to observe the survival or death, but also to ask the plants "How are you?". I learned how to ask this question, and how to hear the plants' answer during my postdoctoral stay in Utrecht, the Netherlands, where work with Hans Lambers brought me to my current research track on whole plant ecophysiology, including the roots. I continued this work in Zurich and for the last 12 years I have been working at Laurentian University studying factors which underlie the ecological diversity of wetland species. The diversity of sedges, rushes, bulrushes, beaked rushes, twig-rushes, spike rushes, burr-reeds, cattails etc. in these habitats, all with a similar growth form but different ecological requirements, make them perfect for comparative functional ecology trying to understand how they are adapted to their environment. When living in Sudbury, one is confronted by the legacy of industrial damage in the past, and I also investigate the effects of heavy metal contamination on plants.


  • Dipl.Sc.Nat., Natural Sciences, ETH Zurich
  • Dr.Sc.Nat. Biology, ETH Zurich
  • Habilitation and Venia Legendi in Plant Ecology, ETH Zurich

On The Web


I investigate plant functional traits which underlie variation in species ecological behaviour, focusing on biomass turnover, i.e. on the one hand growth rate and resource acquisition, and on the other hand, organ life span and resource conservation. My current research projects deal with plants of Northern Ontario wetlands emphasizing below ground traits such as root turnover. I also investigate plant responses to soil heavy metal contamination.


  • Teaching

    BIOL2356E Principles of Ecology

    BIOL3317E Plant Ecophysiology

    BIOL4317E Plant-Animal Interactions

    BIOL5316E Ecophysiology of Plant Stress


    • Freschet G.T., Roumet C., Comas L.H., Weemstra M., et al. 2021. Root traits as drivers of plant and ecosystem functioning: current understanding, pitfalls and future research needs. New Phytologist (Early view). 
    • Ryser, P., Puig, S., Müller, M. and Munné-Bosch, S., 2020. Abscisic acid responses match the different patterns of autumn senescence in roots and leaves of Iris versicolor and Sparganium emersum. Environmental and Experimental Botany, p.104097.
    • Courchesne, D.N., Wilson, A.Z. and Ryser, P., 2020. Regional distribution patterns of wetland monocots with different root turnover strategies are associated with local variation in soil temperature. New Phytologist 226, 86-97.
    • Byne, K. and Ryser, P., 2020. Spring temperatures affect senescence and N uptake in autumn and N storage for winter in Rhynchospora alba (Cyperaceae). Journal of Experimental Botany 71, 1551-1561.
    • Nieman, T., Hoogzaad, Y., Marcotte, S.J. and Ryser, P., 2018. Contrasting root overwintering strategies of perennial wetland monocots. Botany 96, 653-661.
    • Kim, J.H., Lee, S.I., Kim, B.R., Choi, I.Y., Ryser, P. and Kim, N.S. 2017. Chloroplast genomes of Lilium lancifolium, L. amabile, L. callosum, and L. philadelphicum: Molecular characterization and their use in phylogenetic analysis in the genus Lilium and other allied genera in the order Liliales. PloS one 12, p.e0186788
    • Santala K.R., Monet S., McCaffrey T., Campbell D. and Ryser P. 2016. Using turf transplants to reintroduce native forest understory plants into smelter-disturbed forests. Restoration Ecology 24, 346-353. doi: 10.1111/rec.12316