Abstract Detail

Physiology & Ecophysiology

RUSSO, SABRINA E [1], Chan, Ju Ping [1].

Variation in trait plasticity among Bornean tree species with contrasting ecological strategies.

Phenotypic plasticity allows organisms to respond optimally to their environment, which is important for sessile organisms like plants. Because variable environments select for phenotypic plasticity, generalist species that occupy multiple habitats should have greater within-species variation in their responses to environmental variation, compared to habitat specialists. Less well examined is the idea that habitats with plentiful resources, in which species with fast-growth strategies are favored, may also select for greater plasticity. We tested these ideas in a Bornean tropical rain forest with three year-old seedlings of 13 tree species representing three soil specialization groups (clay specialists, sandy loam specialists, and generalists) reciprocally grown from locally collected seed in two soil types (clay versus sandy loam) and light environments (high versus low insolation). We quantified within-species variation (plasticity) in 17 functional traits and six measures of growth rate across these four treatment combinations for each species. While their genotypes were unknown, seedlings were half-siblings from several mothers, distributed roughly evenly across treatment combinations, allowing us to partition phenotypic variation into what is explained by environmental treatment, species’ soil specialization, and their interaction. We found that specialists of the more fertile clay soil type and generalists, which are found on both soils, were more plastic than specialists of the less fertile sandy loam. On average, trait plasticity due to light was greater than plasticity due to soil. While growth rates were generally more plastic than traits, greater trait plasticity was associated with greater variation in growth rates. The magnitude of plasticity not only differed among traits and species with contrasting ecological strategies, but also in response to the type of environmental variation. Moreover, within species variation in traits across contrasting soil and light environments translated into far greater variation in growth rates, suggesting a non-additive effect of plasticity on whole-plant phenotypic integration. Thus, within species trait variation in response to a heterogeneous environment is not only complex, but has effects on demography that would ultimately have implications for how tree species are distributed along environmental gradients.

1 - University of Nebraska, School of Biological Sciences, Manter Hall, Lincoln, NE, 68588-0118, USA

Keywords:
Functional traits
Southeast Asia
Dipterocarpaceae
Tropical forest.

Presentation Type: Oral Paper
Session: 23, Physiology & Ecophysiology
Location: Fort Worth Ballroom 6/Omni Hotel
Date: Tuesday, June 27th, 2017
Time: 10:15 AM
Number: 23006
Abstract ID:364
Candidate for Awards:None