David Roy Clements, PhD

Professor of Biology; Assistant Dean, Faculty of Natural and Applied Sciences (Research)
My life calling is “To bring people closer to creation, so to reconcile them to their Creator.” This calling is rooted in a lifetime of seeking to know and love nature and forged in my research and teaching in invasive species ecology and conservation and sharing the wonder of it all with others.

Clements completed his BSc in Ecology and Evolution at Western University, PhD at Queen’s University on integrated pest management and postdoc at University of Guelph on integrated weed management. Clements teaches botany and ecology, including field courses on Salt Spring Island and Hawai’i. His research on invasive riparian plants, Garry oak ecosystems and climate change has yielded more than 80 scientific publications. He manages TWU’s field research sites: the Ecosystem Study Area, the Blaauw Eco Forest and the Crow’s Nest Ecological Research Area on Salt Spring Island. He frequently visits Yunnan Province in China studying the global invasive plant, mile-a-minute. He did a sabbatical at Charles Sturt University in Australia in 2018. A founding board member of the Christian environmental organization, A Rocha Canada, Clements still serves on the science advisory committee. He is actively involved in the Canadian Weed Science Society (President in 2013-2014), the Weed Science Society of America and many other scientific societies and served as an associate editor for the Canadian Journal of Plant Science, Weed Research, Pacific Science, Agronomy, and Invasive Plant Science and Management. He edits a series on invasive species for Pacific Science and is co-editor for a series in Invasive Plant Science and Management on the biology of invasive plants. He edited two books “Global Plant Invasions” (Springer) and “Persistence Strategies of Weeds” (Wiley) published in 2022. He is actively involved in local stewardship groups and writes the Green Beat column for the Langley Advance Times newspaper. See his blog at https://create.twu.ca/clements/

  • PhD (Queen's University, Kingston, ON; 1991)
  • BSc (University of Western Ontario, London, ON;1986)


My research is related to invasive species, agronomic weeds, and conservation, especially in light of anthropogenic influences such as climate change, in the following categories: Invasive species biology and ecology, Weed science, Agroecology, Climate change, Riparian ecology, Garry oak ecosystems

  • NSERC Discovery Development Grant, "Will increased temperatures and flooding under climate change escalate invasion in riparian habitats?" $30,000 (2021-2023).
  • Derby Reach Brae Island Partnership grant to research the Langley Bog. $3,100.80 (2021).
  • NSERC Alliance Grant, “Habitat suitability and climate modelling for predicting the risk of new invasive plants in Metro Vancouver” with Invasive Species council of Metro Vancouver, Metro Vancouver, BC Ministry of Agriculture. $87,000 (2021-2022).
  • City of Burnaby contract extension for research at the impact of climate change on invasive species. $8,400 (2020-2021).
  • SSHRC Grant, “Integrated Creative Practices (ICP) for Research Innovation and Mobilization.” P.I. Joshua Hale, co-applicants Dr. Kelly Arbeau TWU Assistant Professor of Psychology, and Dr. David Clements TWU Professor of Biology. $55,523 (2020-2022).
  • City of Burnaby contract to study climate change resilience in Burnaby’s Central Park. $55,000, (2019-2020).
  • Australian Endeavour Research Fellowship Award, Genetics of Mikania micrantha. $18,500 Australian dollars.
  • NSERC Discovery Development Grant, “Does ecotype variation in invasive species foster adaptation to local climates and ultimately to climate change?” $20,000 (2017-2019).


Awards & Honors

  • Canadian Weed Science Society Excellence in Weed Science recipient (2014)
  • Langley Environmental Partners Society Stewardship Volunteer of the Year Award Recipient (2009)

Recent Publications

  • Clements, D.R., Upadhyaya, M., Joshi, S., and Shrestha, A. (2022) Global Plant Invasions. Springer Nature Publishing. 381 pp.
  • Upadhyaya, M., Clements, D.R. and Shrestha A. (2022) Persistence Strategies of Weeds. John Wiley & Sons Limited. 378 pp.
  • Xu G, Shen S, Zhang Y, Clements DR, Yang S, Wen L, Zhang F, Dong L. (2022) Effects of various nitrogen regimes on the ability of rapeseed (Brassica napus L.) to suppress littleseed canarygrass (Phalaris minor Retz.). Agronomy 12(3):713. https://doi.org/10.3390/agronomy12030713
  • Shen S, Xu G, Li D, Yang S, Jin G, Liu S, Clements DR, Chen A, Zhang F, Wen L, Tao Q (2021) Adventitious roots support population expansion of the invasive plant Mikania micrantha Kunth. Physiologia Plantarum. https://doi.org/10.1111/ppl.13487
  • Shen S, Xu G, Li D, Yang S, Jin G, Liu S, Clements DR, Chen A, Rao J, Wen L, Tao Q, Zhang S, Yang J, and Zhang F (2021) Potential use of Helianthus tuberosus to suppress the invasive alien plant Ageratina adenophora under different shade levels. BMC Ecology and Evolution 21, 85. https://doi.org/10.1186/s12862-021-01826-5
  • Clements DR, Jones VL (2021) Rapid evolution of invasive weeds under climate change: Present evidence and future research needs. Frontiers in Agronomy 3:10. https://doi.org/10.3389/fagro.2021.664034
  • Clements DR., Jones VL (2021). Ten ways that weed evolution defies human management efforts amidst a changing climate. Agronomy 11(2): 284. https://doi.org/10.3390/agronomy11020284
  • Kriticos DJ, Clements DR, and DiTommaso A (2020). Biology of Invasive Plants: a new series within Invasive Plant Science and Management. Invasive Plant Science and Management, 13(3), 115-119. https://doi.org/10.1017/inp.2020.25
  • Shen S, Xu G, Yang Y, Yu X, Li D, Yang S, Jin G, Liu S, Clements DR, Chen A, Zhang F (2020) Increased suppressive effect of Ipomoea batatas (sweet potato) on Mikania micrantha (mile-a-minute) under high fertilization levels. Management of Biological Invasions, 11(3):560-575. https://doi.org/10.3391/mbi.2020.11.3.14
  • Xu G, Shen S, Zhang Y, Clements DR, Yang S, Li J, Dong L, Zhang F, Jin G, Gao Y (2019) Designing cropping systems to improve the management of the invasive weed Phalaris minor Retz. Agronomy 9(12), 809. https://doi.org/10.3390/agronomy9120809


Affiliations & Memberships

  • A Rocha Canada-Christians in Conservation. Founding board member (1996-2011)
  • A Rocha Canada-Christians in Conservation. Science Advisory board member (2010-present)
  • American Scientific Affiliation/ Canadian Christian and Scientific Affiliation. Member
  • Canadian Weed Science Society. Past-President; chair of Biology of Weeds committee, four years with the Awards committee; chair of Biology and Ecology section (2015-2018)
  • Weed Science Society of America. Endowment Committee (2013-2017), Early Career Scientists Award Committee (2017-2021)
  • The Northwest Scientific Association
  • Soil and Water Conservation Society. Treasurer, BC chapter (2004-2013)
  • Invasive Species Council of BC. Member, research and development committee, planning committee member for 2017 Research meeting in Kamloops, BC
  • Plant Canada, board member (2011-2020)
  • Research committee, Garry Oak Ecosystems Recovery Team
  • Stakeholders group, Derek Double Day Arboretum (2008-2012)
  • Langley Field Naturalists, Board member (2010-2011)
  • Langley Environmental Partners Society. Board of directors (2001-2009); Chair (2008-2009)
  • Salmon River Enhancement Society. Board of directors, (1997-2010, 2014-present)

  • BIOL 103/104 Introduction to Biology
  • BIOL 113/114 Principles of Biology
  • BIOL 212/312 Biology of Vascular Plants
  • BIOL 214/314 Biology of Non-Vascular Plants
  • BIOL 216/316 Plant Ecology
  • BIOL 318 Tropical Botany
  • BIOL 360 Invertebrate Zoology
  • BIOL 381 General Ecology
  • BIOL 390 Biology & Faith
  • BIOL 400 Directed Studies in Biology
  • BIOL 409/410 or ENVS 409/410 Senior Thesis supervisor
  • BIOL 482 Applied Ecology
  • GENV 374/375 Internship coordinator
  • IDIS 400 (Interdisciplinary) mentor
  • NATS 481/487/490 Natural and Applied Science capstone course