Origin and diversification of the California flora

re-examining classic hypotheses with molecular phylogenies

Lesley T Lancaster, Kathleen M Kay

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

The California Floristic Province exhibits one of the richest floras on the planet, with more than 5500 native plant species, approximately 40% of which are endemic. Despite its impressive diversity and the attention it has garnered from ecologists and evolutionary biologists, historical causes of species richness and endemism in California remain poorly understood. Using a phylogenetic analysis of 16 angiosperm clades, each containing California natives in addition to species found only outside California, we show that CA's current biodiversity primarily results from low extinction rates, as opposed to elevated speciation or immigration rates. Speciation rates in California were lowest among Arcto-Tertiary lineages (i.e., those colonizing California from the north, during the Tertiary), but extinction rates were universally low across California native plants of all historical, geographic origins. In contrast to long-accepted ideas, we find that California diversification rates were generally unaffected by the onset of the Mediterranean climate. However, the Mediterranean climate coincided with immigration of many desert species, validating one previous hypothesis regarding origins of CA's plant diversity. This study implicates topographic complexity and climatic buffering as key, long-standing features of CA's landscape favoring plant species persistence and diversification, and highlights California as an important refuge under changing climates.

Original languageEnglish
Pages (from-to)1041-54
Number of pages14
JournalEvolution
Volume67
Issue number4
Early online date31 Jan 2013
DOIs
Publication statusPublished - Apr 2013

Fingerprint

Phylogeny
phylogeny
flora
immigration
Climate
extinction
Emigration and Immigration
Mediterranean climate
endemism
buffering
angiosperm
floristics
refuge
planet
persistence
desert
species richness
Planets
rate
Angiosperms

Keywords

  • Angiosperms
  • Biodiversity
  • California
  • Climate
  • Evolution, Molecular
  • Extinction, Biological
  • Genetic Speciation
  • Phylogeny
  • Phylogeography
  • Fossils
  • Biogeography
  • Macroevolution
  • Phylogenetics
  • Speciation

Cite this

Origin and diversification of the California flora : re-examining classic hypotheses with molecular phylogenies. / Lancaster, Lesley T; Kay, Kathleen M.

In: Evolution, Vol. 67, No. 4, 04.2013, p. 1041-54.

Research output: Contribution to journalArticle

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