Abstract Detail

Ecology

La Rosa, Raffica [1], Emery, Nancy [1].

Plant adaptation to hydrologically variable environments.

Abstract: Species growing in variable environments may adapt through specializing to a subset of the conditions or evolving plasticity to tolerate a broad range of conditions. We studied three annual Lasthenia (goldfields) species (Asteraceae) that grow in different microhabitats in California vernal pool grasslands. The species occupy habitats that experience different hydrological regimes as the water levels fluctuate throughout the rainy season. A phylogenetic analysis of the hydrological tolerance curves of Lasthenia species from each of three habitat types (bottom, transitional, and upland) found similar optima for all species’ hydrological tolerance curves, which contrasts with the distinct patterns of segregation these species exhibit in their natural environment. Here, we tested the hypothesis that plant species may partition the environment based on its variance, in addition to its mean conditions. To evaluate this hypothesis, we focused on three Lasthenia species that occupy distinct microhabitats within common vernal pool landscapes and experience contrasting patterns of the mean hydrological environment (average days flooded, mean soil water content) and the variance (number of submergence events, variance in soil water content). We predicted that the three species would exhibit unique fitness and trait reaction norms that are adaptive in their respective microhabitats. We grew these three species at 5 different “depth” treatments, which manipulated the mean hydrological environment, and 3 different variance treatments, to test the relative importance of the mean and variance in hydrology in predicting plant fitness, and if each species is adapted to the level of variability that it experiences in the field. We measured lifetime fitness as the number of seeds produced and total biomass production, and measured potentially adaptive physiological traits such as stomatal density, aerenchyma production, and leaf shape.

1 - University of Colorado - Boulder, Ecology and Evolutionary Biology, University of Colorado Boulder, 334 UCB, Boulder, CO, 80309, USA

Keywords:
Environmental variation
adaptation
Vernal pools
Lasthenia
Hydrology.

Presentation Type: Oral Paper
Session: 14, Ecology Section: Plant Functional Traits and Responses
Location: 201/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 4:15 PM
Number: 14009
Abstract ID:808
Candidate for Awards:None