PARENT SESSION
Contributed Oral Session 45: Evolutionary / Theoretical Ecology : Genotypes and Phenotypes
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 519 A, Level 5, Palais des congrès de Montréal
Shallow-soil endemics: Is their rarity related to a reduction in phenotypic plasticity?
Williams, Aleida*,1, Poot, Pieter1, Lambers, Hans1, 1 The University of Western Australia, Crawley, Western Australia, Australia
ABSTRACT- Variation in a plant's phenotypic plasticity may underlie plant species distribution and abundance, yet it has rarely been considered when investigating causes of plant rarity. In this study we compare the phenotypic plasticity of rare species endemic to shallow-soiled, drought-prone habitats, with that of their common congeners. Hakea oldfieldii and H. tuberculata are two rare endemics which are restricted to small patches in southwest Australia where ironstone rock rises to within 10 cm of the soil surface. Our research has shown that these species have a specific root foraging strategy that makes them extremely efficient in finding cracks in the underlying rock which would provide access to deep water. In their drought-prone Mediterranean environment, this strategy is essential to survive the first summer droughts. In the present study we compare the plasticity of biomass allocation, spatial allocation of roots and rates of photosynthesis of rare Hakea species and their common congeners, in response to light intensity and nutrient availability. We hypothesize that the specialised rare ironstone species are less plastic for the measured traits, and that this reduction in plasticity is responsible for their decreased success in neighbouring environments.
Key words: phenotypic plasticity, rarity, specialised, Hakea