Abstract Detail

Ecophysiology

Ávila-Lovera, Eleinis [1], Goldsmith, Gregory R [2], Kay, Kathleen M [3], Funk, Jennifer L [2].

Using functional traits to understand adaptation and speciation in tropical understory herbs.

Plant functional strategies can be described by a suite of correlated physiological, morphological and structural traits. Differences in these strategies can provide insights into how plants differentiate and become new species. In particular, where plant function varies in response to climate, it can help us disentangle to what extent climate may contribute to speciation. We studied leaf, stem, rhizome and fine root traits of 13 species from the tropical spiral ginger genus Costus (Costaceae) across a variety of environments in Costa Rica, with multiple sister species pairs occurring at contrasting elevations, to answer the following questions: 1) What is the variation in aboveground and belowground traits? 2) Are these two axes of variation related? 3) How do functional traits vary as a function of climate? We performed separate Principal Component Analyses (PCA) on the above- and below-ground traits to extract axes of aboveground and belowground variation (first principal component accounted for 61.3% and 74.9% of the total variation in the aboveground and belowground PCAs, respectively). We found no relationship between the axes, indicating that species with a “fast strategy” in the aboveground spectrum do not necessarily have a “fast strategy” in the belowground spectrum. However, we did find significant relationships among leaf, stem and rhizome traits. For example, species with high stem and rhizome density also have low stomatal conductance, indicating a conservative strategy of water use. These species occupy high elevation sites that are characterized by low precipitation and temperature, and high precipitation seasonality. Together, our results suggest that there are no discernible whole-plant functional strategies, but that some leaf, stem and rhizome traits vary predictably with climate. If these trait differences are genetically based, they may represent functional trade-offs that contribute to ecogeographic isolation between incipient species.

1 - Chapman University, Biological Sciences, One University Drive, Orange, CA, 92866, United States
2 - Chapman University, Biological Sciences, One University Drive, Orange, CA, 92866, USA
3 - University of California, Santa Cruz, Ecology and Evolutionary Biology, 130 McAllister Way, Santa Cruz, CA, 95060, USA

Keywords:
ecophysiology
stem density
stomatal conductance
aboveground
belowground.

Presentation Type: Oral Paper
Session: ECOPH2, Ecophysiology II
Location: San Pedro 2/Starr Pass
Date: Tuesday, July 30th, 2019
Time: 1:45 PM
Number: ECOPH2002
Abstract ID:752
Candidate for Awards:None