Abstract Detail

Systematics Section/ASPT

Spalink, Daniel [1], Drew, Bryan T. [2], Zaborsky, John [3], Cameron, Kenneth [4], SYTSMA , KENNETH JAY [5].

Evolution of niche space and place: reconstructing the ecological and biogeographical diversification of the North American Sedges (Cyperaceae).

Whether to the enthusiast’s delight or the taxonomy student’s plight, the sedge family (Cyperaceae) is one of the most taxonomically diverse groups in North America. Sedges are found in nearly every terrestrial habitat on the continent, spanning geographical barriers, soil types, and climes. In this study, we investigate the ecological and geographical processes that have contributed to this diversity. We present a dated supermatrix phylogeny of over 620 North American sedges based on 22 genes, incorporating both de novo barcode sequences (rbcL, matK, ndhF, and trnLF) as well as data from GenBank. Using 300,000 geo-referenced specimens from herbaria throughout the continent and a suite of climatic and soil variables, we also develop ecological niche models for these species using the program MAXENT, and identify areas of endemism under optimality criteria with the program NDM/VNDM. Although our sampling is geographically biased and excludes relatives from other continents, we use these data to identify ecological and geographical shifts that have occurred among the North America sedges with the understanding that similar patterns are likely mirrored in Cyperaceae worldwide. We conduct phylogenetic principal component analyses using the R package “adephylo” and find a strong phylogenetic signal exhibited by the first two components, suggesting niche conservatism among the North American sedges. However, analysis of the climate and soil variables independently reveals that temperature layers are strongly conserved, but soil and precipitation regimes possess no phylogenetic signal. We identify statistically significant niche shifts using the R package “surface”, and test for correlated evolution between niche and geography with the package “caper”. Ultimately, we discuss the complex interaction among these traits and their relative roles in the diversification of the North American sedge flora.

1 - University of Wisconsin-Madison, Department of Botany, 430 Lincoln Drive, Madison, WI, 53706, USA
2 - Department of Biology, University of Florida, Gainesville, FL 32611-85
3 - University of Wisconsin-Madison, Botany, 430 Lincoln Drive, Madison, WI, 53706, USA
4 - University Of Wisconsin, Department Of Botany, 154 Birge Hall, 450 Lincoln Drive, Madison, WI, 53706, USA
5 - University Of Wisconsin, Department Of Botany, Birge Hall, 430 Lincoln Drive, Madison, WI, 53706, USA

Keywords:
Cyperaceae
niche evolution
Biogeography
chronogram
supermatrix
community phylogenetics.

Presentation Type: Oral Paper:Papers for Sections
Session: 17
Location: Payette/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 10:15 AM
Number: 17009
Abstract ID:605
Candidate for Awards:George R. Cooley Award