Abstract Detail

Biogeography

Fehlberg, Shannon D [1], Prather, L. Alan [2], Ferguson, Carolyn J. [3].

Environmental niche differentiation in three diploid-polyploid complexes in southwestern Phlox (Polemoniaceae).

Polyploids are commonly thought to occupy distinct environmental niches relative to their diploid progenitors. However, there is a general lack of consensus on how polyploidy affects environmental niche. Some studies suggest that polyploids possess broader ecological tolerances or occupy harsher environmental conditions. One useful approach for comparing environmental niches relative to ploidy is species distribution modeling, where niche breadth and overlap can be measured and the environmental axes along which niches differ can be characterized. Here we report on an investigation of environmental niche differentiation among ploidy levels in three diploid-polyploid complexes in the genus Phlox from mountainous areas of the desert southwest. Phlox amabilis, P. nana, and P. woodhousei offer an excellent opportunity to examine hypotheses of niche differentiation in multiple, co-distributed, closely related polyploid complexes, each comprising diploid, tetraploid and hexaploid populations. Using flow cytometry linked with chromosome counts, we determined ploidy level across more than 150 populations. We extracted climate, elevation, and soil data at the geographic coordinates of each population. Climate and soil data were tested for collinearity using a Spearman rank correlation test. We also explored simulations designed to assist in determining the minimum number of records necessary for accurate species distribution models. Following these tests, we used uncorrelated data to build MaxEnt models of environmental niche. We compared models using Schoener’s D and Hellinger distance I. To help visualize niche differences among ploidy levels, we further performed principle components analysis (PCA) of climate data for each complex. Results indicate that the environmental niches for diploids and tetraploids were generally more similar to each other than either were to hexaploid niches, with hexaploids occupying cooler, wetter habitats. Differences in modeled niche breadth among ploidy levels, as well as geographic structuring evident in PCA, suggest that the genetic makeup of higher ploidy levels plays an important role in determining environmental niche. Our overall findings for Phlox are presented and discussed in light of implications for our understanding of how polyploidy affects environmental niche.

1 - Desert Botanical Garden, 1201 N. Galvin Pkwy., Phoenix, AZ, 85008, USA
2 - Michigan State University, PLANT BIOLOGY, Plant Biology Laboratories, 612 Wilson Rd, Rm 48, East Lansing, MI, 48824-1312, USA
3 - Kansas State University, Herbarium and Division of Biology, Ackert Hall, Manhattan, KS, 66506-4901, USA

Keywords:
Polemoniaceae
polyploidy
ecological niche modeling
niche segregation.

Presentation Type: Oral Paper
Session: 30, Biogeography I
Location: 203/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 5:00 PM
Number: 30014
Abstract ID:388
Candidate for Awards:None