Abstract Detail

Conservation Biology

Luebert, Federico [1], Scherson, Rosa [2].

Does the choice of molecular marker influence spatial patterns of phylogenetic diversity? A study case in the vascular flora of Chile.

Studies on spatial patterns of phylogenetic diversity (PD) generally employ available molecular data to infer the base phylogeny. However, little is known about the effects of different choices of molecular data on PD estimates. By impacting phylogenetic inference, different molecular markers might lead to different geographical distributions of branch lengths, thus influencing spatial patterns of PD. In this study, we aimed at: (1) addressing whether phylogenies based on different molecular markers produce different spatial patterns of PD, (2) if and how these differences were in turn determined by the type of tree (phylogram versus chronogram) and (3) how do topology and branch lengths differentially affect estimates of spatial patterns of PD. We used the vascular flora of Chile as a model system, using an available dataset and phylogeny at the genus level representing 87% of the described genera of the country. We inferred individual phylogenies for each of the markers with the highest coverage (ITS, matK, rbcL, and trnL-trnF) in order to have the largest possible comparable set of taxa. For each tree, we calculated three PD-related metrics: (1) PD sensu Faith (1992) as the sum of the branch lengths connecting the taxa present in a grid cell; (2) PDcorr which is the difference between the normalized values of PD and the normalized richness for every cell, and (3) RPD as the ratio between PD calculated with the original branch lengths of the trees and PD calculated using a comparison tree, in which all branch lengths are equal to the average branch length of the whole tree. All comparisons were conducted using ultrametric and non-ultrametric trees and were projected on a map to visualize spatial patterns. Results suggest that all three measures are influenced by the choice of markers, but that differences are larger for non-ultrametric trees. Average pairwise differences in PD metrics between markers tend to be positively correlated to topological differences. These differences vary less among pairs of markers in ultrametric than in non-ultrametric trees. Likewise, spatial variability of pairwise differences in all PD metrics is greater when using non-ultrametric trees. This study suggests that the choice of molecular marker does affect spatial patterns of PD and related measures. However, by using ultrametric trees the effect of marker choice is less pronounced than when using a phylogram. Funded by Fondecyt 1171586.

1 - Universität Bonn, Nees-Institut für Biodiversität der Pflanzen, Meckenheimer Allee 170 D-53115, Bonn, Germany
2 - University Of Chile, Silviculture And Nature Conservation, Av. Santa Rosa 11315, La Pintana, Santiago, SM, 7850370, Chile

Keywords:
phylogenetic diversity
vascular plants
Evolutionary conservation.

Presentation Type: Oral Paper
Session: CB2, Conservation Ecology 2
Location: Tucson B/Starr Pass
Date: Monday, July 29th, 2019
Time: 1:30 PM
Number: CB2001
Abstract ID:238
Candidate for Awards:None