ABS10561

Succeeding in invasion: the role of early growth and phenology on Gunnera tinctoria


  • Oral Presentation
  • Plant Ecology and Biodiversity
  • 13 Jun 2018 13:10
  • FS-G01, UCD Agriculture and food science Centre
  • View all IPSAM abstracts

Mauricio Cruz Mantoani*
School of Biology and Environmental Science, Earth Institute, University College Dublin

Margherita Gioria
School of Biology and Environmental Science, Earth Institute, University College Dublin

Bruce Osborne
School of Biology and Environmental Science, Earth Institute, University College Dublin

*Presenting Author


Whilst it is often assumed that invasive alien plants are better competitors than the resident species they replace the evidence for this is at best equivocal. Recent work indicates that many invaders avoid direct competition by exploiting windows of opportunity early or late in the growing season, when the growth of native species is constrained by environmental or ontogenetic factors. To examine whether Gunnera tinctoria Molina (Mirb.), a significant invasive species in Ireland, has an advantage in terms of early/late phenology, we monitored the growth and reproduction of invasive plants and the native species, Juncus effusus L., on Achill Island, Co. Mayo. The appearance of leaves of G. tinctoria occurred earlier than J. effusus in 2016 (one week) and 2018 (ten days), but not in 2017, where the resident species initiated leaf growth two weeks before the invader. The emergence of leaf, petiole and reproductive organs in G. tinctoria was associated with pre-formed structures located inside the rhizome and this facilitated early emergence and growth, with maximum canopy development occurring just before summer. Inter annual differences in leaf emergence were related to water availability, with earlier emergence and expansion of leaves associated with high water availability. Presumably, this reflects the high water cost of growth and leaf expansion in large plants. Although mature plants lose their leaves during the winter, seedlings retain the ability to produce new leaves during this period. Our results indicate that G. tinctoria has the ability to out shade resident species through early growth under sub optimal conditions, although this capability may be reduced if there is low water availability. However, the timing of the emergence and growth of shoots may be less critical for mature long lived plants given their large size and may be more important during the initial stages of establishment.