title: Evolution of geographical place and niche space: Patterns of diversification in the North American sedge (Cyperaceae) flora.
abstract: The role of geography and ecology in speciation are often discussed in the context of phylogenetic niche conservatism (PNC), the propensity of lineages to retain ancestral niche related traits. However, a recent paradigm shift focuses instead on measuring divergence of these traits in conjunction with patterns of speciation. Under this framework, we analyzed the diversification of North America's third most diverse family, Cyperaceae ("sedges"), using a modified Parsimony Analysis of Endemicity approach to identify floristic regions and ordination statistics to quantify species distribution in a continuous manner. Utilizing over 200,000 georeferenced specimens, we characterized the geographical distribution and climatic and edaphic niche space occupied by each species. We constructed a supermatrix phylogeny of the North American sedge flora, aided in part by the sequencing of all sedges of Wisconsin, and employed a multifaceted approach to assess the role of geographical and ecological divergence on lineage diversification. In addition to measuring phylogenetic signal for these traits, we also measured pairwise phylogenetic distance of species within floristic regions, calculated rates of speciation, and tested for correlations of speciation rate to tempo of geographical and ecological evolution. Our analyses consistently show that evolutionarily related species tend to be geographically unrelated. Rates of geographical and ecological diversification are closely linked to tempo of speciation, and exploration of geographical place coincides with divergence in ecological niche space. We highlight the benefits of treating geography in a continuous manner, and stress the importance of employing a diverse suite of analytical approaches in testing hypotheses regarding the evolution of range and niche.
authors.affiliation: Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA. Electronic address: dspalink@wisc.edu.
authors.forename: Daniel
authors.initials: D
authors.lastname: Spalink
authors.affiliation: Department of Biology, University of Nebraska at Kearny, 905 West 25th Street, Kearny, NE 68849, USA.
authors.forename: Bryan T
authors.initials: BT
authors.lastname: Drew
authors.affiliation: Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Pace
authors.affiliation: Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA.
authors.forename: John G
authors.initials: JG
authors.lastname: Zaborsky
authors.affiliation: College of Life Sciences, Zhejiang University, #388 Yuhangtang Rd., Xihu District, Hangzhou 310058, Zhejiang, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA.
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Cameron
authors.affiliation: Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Givnish
authors.affiliation: Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Sytsma
mesh_terms: D031255:Carex Plant / Q000145:classification* / Q000235:genetics*; D029785:Cyperaceae / Q000145:classification / Q000235:genetics; D017753:Ecosystem; D019143:Evolution, Molecular; D049810:Genetic Speciation; D005843:Geography; D009656:North America; D010641:Phenotype; D010802:Phylogeny; D058974:Phylogeography; D014481:United States
keywords: Biogeography; Museum collections; Phylogenetic niche conservatism; Phylogenetic signal; Range and niche evolution; Rates of evolution