ENVIRONMENTAL DRIVERS AND ECOLOGICAL CONSEQUENCES OF WITHIN-SPECIES VARIATION IN GERMINATION STRATEGY
Satyanti, A.1,2,3, Guja, L.K.3,4 and Nicotra, A.B.1
1Division of Evolution, Ecology & Genetics, Research School of Biology, Building Number 116, Daley Rd, Acton ACT 2601, The Australian National University, Canberra, ACT, Australia
2Center for Plant Conservation – Botanic Gardens, Indonesian Institute of Sciences, Jalan Ir. Haji Juanda 16003, Bogor, Indonesia
3National Seed Bank, Australian National Botanic Gardens, Clunies Ross St, Acton ACT 2601, Canberra, Australia
4Centre for Australian National Biodiversity Research, CSIRO, Clunies Ross St, Acton ACT 2601, Canberra, Australia
Contact: Annisa Satyanti, firstname.lastname@example.org
Plant establishment and subsequent persistence are strongly influenced by germination strategy, especially in temporally and spatially heterogeneous environments. Germination strategy determines the plant’s ability to synchronise germination timing and seedling emergence to a favourable growing season and thus may be key to persistence under more extreme and variable future climates. However, the determinants of variation in germination strategy are not well resolved. Using a widespread alpine herb Oreomyrrhis eriopoda that varies in germination strategy across its range, we examined which environmental factors drive variation in germination strategy and what the consequences of possessing a certain seed germination strategy are at seedling establishment. We found that the germination patterns of O. eriopoda populations can be broadly classified into four strategies: immediate, staggered, postponed, postponed-deep. Temperature variability (seasonality) at the site of seed collection was the most important determinant of germination strategy, but those patterns depended on the time scale of climatic assessment. Long-term climate and the conditions during seed development were significant predictors of germination strategy whereas the conditions immediately before seed development were less important. Autumn seedlings from populations with an immediate germination strategy and early-germinating seeds of the staggered strategy exhibited a higher leaf production rate than spring seedlings. This study highlights that seed development conditions and long-term temperature seasonality strongly affect germination strategy and suggests potential for both plastic variation and local adaptation in germination among populations of alpine plants. Selection for germination strategy is also correlated with shifts in early seedling vegetative traits and establishment characteristics. The immediate germination strategy is associated with higher temperature seasonality and higher seedling growth. If such within-species variation in germination strategy is common, either as a result of local adaptation or plasticity, it might help to buffer impacts of climate change. Thus, within-species variation in seed germination and seedling traits, and the drivers thereof, warrant consideration when climate change impacts are assessed across communities.