Abstract Detail

Paleobotany

Carlson, McKenzie [1], Rottersman, Maria [2], Bedoya, Ana Maria [3], Brightly, William [4], Stromberg, Caroline [5].

Habitat-Driven Evolution of Seed Dispersal Strategies in Onion Grasses.

Seed dispersal is a crucial stage in the plant lifecycle, with broad influences on community composition, ecological succession, and response to climate change. Given its importance, documenting the factors that contribute to the evolution of varied dispersal modes and promote convergence on specific dispersal strategies is vital to understanding plant ecology. Here, we explore whether habitat is among these factors. Habitats vary in how they are distributed across space and time, as are potential dispersers, which may influence which dispersal strategies are most successful. To investigate this relationship, we studied the genus Melica (melic and onion grasses), and its relatives in tribe Meliceae. These grasses are a useful case study, as they live in a range of habitats and have remarkably morphologically diverse dispersal structures (diaspores). Additionally, among them are several distinct shapes related to wind dispersal, a strategy that has apparently evolved several times in the tribe. We tested the hypothesis that evolution in morphological traits associated with seed dispersal is correlated with changes in habitat. In particular, we hypothesize that the evolution of wind dispersed seeds follows transitions into open or disturbed habitats.
A total of 170 diaspores, representing 28 species (14 Melica and 14 outgroup) were collected from herbarium vouchers. We assessed wind dispersal potential by quantifying falling velocity. Falling velocity and average plant height were used to compute dispersal kernels from which we extracted the expected wind dispersal distance for the median diaspore for each species. Habitat data were obtained for each species using georeferenced occurrence records and global landcover maps. Phylogenetic relationships of the sampled Meliceae were inferred under Bayesian inference using nuclear and plastid markers. Our results indicate that higher wind dispersal potentials (but not predicted wind dispersal distance) are associated with greater degrees of anthropogenic disturbance and suggest that changes in habitat have occurred in conjunction with changes in seed dispersal traits.

1 - 5654 11th Ave NE, Seattle, WA, 98105, United States
2 - 5225 15th Ave NE, Unit C, Seattle, WA, 98105, USA
3 - University of Washington, Biology, Seattle, WA, 98115, USA
4 - 2208 NW 64th St, Seattle, WA, 98107, United States
5 - University Of Washington, Department Of Biology, Life Sciences Building, Box 351800, Seattle, WA, 98195, United States

Keywords:
Seed Dispersal
Grasses
habitat
evolution
Melica
anemochory.

Presentation Type: Poster
Session: P3, Paleobotany Posters
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 5:00 PM(EDT)
Number: P3PB003
Abstract ID:1077
Candidate for Awards:None