Abstract Detail

Ecological Section

Byers, Diane L. [1], Rippel, Tyler M. [2], Philips, Robert W. [2].

Soil traits impact on female frequency of a gynodioecious prairie plant, Lobelia spicata.

We have been studying the effect of habitat fragmentation of the Midwestern prairie on the reproductive success of prairie plants including the gynodioecious species Lobelia spicata. In this highly fragmented ecosystem, we found that genetic drift significantly contributes to the highly variable female frequency (2% to 85%). As this variation in female frequency impacts the seed production of the plants, understanding the factors underlying this change in the female frequency is key for this species and preservation of the biodiversity in the prairies. While genetic drift impacts the female frequency it is not the only factor. We also noticed the different types of prairies (characterized by soils, species composition, topography and other traits) differed in the frequency of female plants. In particular we found that tallgrass prairies with rich blacksoils had significantly more females, while the loess hill prairies had significantly fewer female plants. We proposed that some aspects of these soils select for this higher female frequency in blacksoils but lower in the loess soils. The differences in resource allocation and demands between the sexes may be underlying this pattern. As a first step, we conducted a survey in 28 prairies in Illinois and Indiana characterizing the soil texture, percent organic matter and major nutrients as well as the population size and female frequency of the plants. While the soil texture did not significantly affect the female frequency, there was a positive effect of the percent organic matter, nitrate and potassium on female frequency. Of these factors, percent organic matter had the most impact on increasing female frequency. This pattern may be reflecting the greater resource requirements by female plants to mature greater number or quality of seeds. The female frequency is also by affected the population size, where the larger size populations have more female plants. In our presentation we will also propose some alternative hypotheses involving other aspects of the environment which may be impacting the different sexes.

1 - Illinois State University, Department Of Biological Sciences, Campus Box 4120, Normal, IL, 61790-4120, USA
2 - Illinios State University, Biological Sciences, Campus Box 4120, Normal, IL, 61790-4120, USA

Keywords:
gynodioecy
Prairie
environmental sex specific selection
soils
female frequency.

Presentation Type: Oral Paper:Papers for Sections
Session: 21
Location: Salon 17/18/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 2:45 PM
Number: 21006
Abstract ID:506
Candidate for Awards:None