Hot Topic

Climate change: alters plant recruitment from seed

Tuesday, 20 October 2015  | 

Key Points

  • Plants use environmental cues to trigger when and where seeds germinate.
  • Changes in local environments, such as those driven by global climate change, have the potential to disrupt recruitment patterns in plants.
  • Altered recruitment may change plant community composition, especially after disturbance.
  • Planning for unexpected seed responses to global warming may require seeds to be conserved in off site seed banks, with the use of assisted plant migration as a last resort.

Authors: Dr. Anne Cochrane (WA Department of Parks and Wildlife), Dr. Adrienne Nicotra (Australian National University), Dr. Mark Ooi (University of Wollongong). Contact: 

Most plant species rely on seeds for recruitment and persistence in the landscape. Local environments have a strong influence on seed germination and so shifts in temperature and moisture caused by rapid environmental change may affect when, where and whether plants will recruit. Small increases in temperature, changes to rainfall seasonality or slight reductions in moisture availability during the growing season may threaten populations of some plant species. Impacts of changing environmental conditions on seeds have already been documented and include reduced germination with soil warming, shifts in the timing of germination, reduced seedling survival and shortened survival of seeds in the soil. Global climate change will also alter fire regimes, in turn leading to probable declines in seed production, seedling survival and seed-bank viability. Although episodic disturbances like fire are normal in some systems, providing recruitment opportunities, changed environmental conditions may radically alter vegetation characteristics and composition. Shifts in the timing of germination will influence population dynamics, community composition and species geographic ranges. Some species will face a high risk of local population extinction, possibly leading to biodiversity decline over time. Together these changes may require modification to seed use in agriculture and in ecological restoration. Species with germination strategies that vary among individuals or across populations may be more robust and ultimately have a lower extinction risk. Although there is strong evidence that plant species and communities are threatened by climate change through effects on recruitment, currently, we do not know for sure which communities are most at risk. Planning for unexpected seed responses to global warming, particularly in vulnerable ecosystems already experiencing wide temperature and moisture extremes, may require ex-situ seed conservation and assisted plant migration.

More on this Hot Topic:

– Plain-English factsheet (PDF) –
– Link to peer-reviewed article via Austral Ecology –

If you have recently published an update on this topic, please contact the HT author for your research to be considered for addition to the evidence review.

 

Supporting Research

Title
Aims
Cochrane A., Daws M. I. & Hay F. R. (2011) Seed-based approach for identifying flora at risk from climate warming. Austral Ecology 36, 923-35.
To assess the thermal limits for germination and early seedling growth in a range of perennial plant species endemic to southern Western Australia,and many restricted to the summits of the major mountain range in the region.
Cochrane A., Yates C. J., Hoyle G. L. & Nicotra A. B. (2015) Will among-population variation in seed traits improve the chance of species persistence under climate change? Global Ecology and Biogeography 24, 12-24.
To investigate how temperature and moisture affect early stages of plant development in four Banksia species collected from a longitudinal climate gradient in southwest Western Australia.
Ooi M. K. J. (2012) Seed bank persistence and climate change. Seed Science Research 22, S53-S60.
Evaluates the mechanistic effects of climate change on seed bank dynamics, with a focus on disturbance driven ecosystems.
Cochrane A., Yates C. J., Hoyle G. L. & Nicotra A. B. (2015) Will among-population variation in seed traits improve the chance of species persistence under climate change? Global Ecology and Biogeography 24, 12-24.
Review and synthesize current knowledge of among-population variation in seed traits in order to highlight the role that seed traits might play in buffering species against climate change, in addition to identifying gaps in knowledge
Walck J. L., Hidayati S. N., Dixon K. W., Thompson K. E. N. & Poschlod P. (2011) Climate change and plant regeneration from seed. Global Change Biology 17, 2145-61.
To evaluate the effects of climate change on plant regeneration focusing on the fate of seeds after dispersal, especially those features most impacted by temperature and moisture: release from dormancy and germination.
Hudson A. R., Ayre D. J. & Ooi M. K. J. (2015) Physical dormancy in a changing climate. Seed Science Research FirstView, 1-16.
To investigate the level of variation currently known to exist in physical dormancy of seeds at the inter-specific and inter-population level and how this might be affected by the maternal as well as post-dispersal environment.
Mondoni A., Rossi G., Orsenigo S. & Probert R.J. (2012) Climate warming could shift the timing of seed germination in alpine plants. Annals of Botany 110, 155-64.
Assess the effect of warming climate on timing of germination and recruitment success in an alpine system.
Ooi M. K. J., Auld T. D. & Denham A. J. (2009) Climate change and bet-hedging: interactions between increased soil temperatures and seed bank persistence. Global Change Biology 15, 2375-86.
To investigate the mechanisms underlying seed bank persistence under a predicted climate change scenario for several physically and physiologically dormant ephemeral plant species from arid inland Australia.
Tozer M.G. & Ooi M.K.J. (2014) Humidity-regulated dormancy onset in the Fabaceae: a conceptual model and its ecological implications for the Australian wattle Acacia saligna. Annals of Botany 114, 579-90.
To assess the humidity threshold required for onset of physical dormancy in Acacia saligna, and relate this to its ability to form persistent seed banks under current compared to future climatic conditions.
Hoyle G. L., Cordiner H., Good R. B. & Nicotra A. B. (2014) Effects of reduced winter duration on seed dormancy and germination in six populations of the alpine herb Aciphyllya glacialis (Apiaceae). Conservation Physiology 2, 1-11.
To assess the effect of decreasing durations of cold stratification (i.e. conditions representing a shortened winter as predicted under climate change) on germination and dormancy of the Australian alpine herb Aciphylla glacialis.
Hoyle G. L., Venn S. E., Steadman K. J., Good R. B., McAuliffe E. J., Williams E. R. & Nicotra A. B. (2013) Soil warming increases plant species richness but decreases germination from the alpine soil seed bank. Global Change Biology 19, 1549-61.
To assess the impact of soil warming, as predicted under climate change, on germination from an alpine soil seed bank.
Ooi M.K.J., Denham A.J., Santana V.M. & Auld T.D. (2014) Temperature thresholds of physically dormant seeds and plant functional response to fire: variation among species and relative impact of climate change. Ecology and Evolution 4, 656-71.
To identify functional groups of species to understand their susceptibility to climate change, based on the dormancy-breaking temperature thresholds of their seeds.
Briceño V, Hoyle G & Nicotra A (2015) Seeds at risk: How will a changing alpine climate affect regeneration from seeds in alpine areas? Alp Botany 125, 59-68.
To evaluate how a changing climate will impact seeds and seedlings of alpine species