space-time diagram of Hawai’ian islands!0!5! 4! 3! 2! 1!time (mya)!island size (km2)!inter-island dispersal + speciation!continental source areas intra-island speciation!long-distance dispersal!Sakai et al. 1995 EcologyLinder 2003 Biol. ReviewAssembly of plant communities: migration in space vs. time 0 -1 -2 -200 Time before present Space ...N&W North America!time!spatial extent!space-time diagram of California!California!other continents!Mexico!exotics!Other continents!1000 ya natives!200 mya X radiation!5 mya immigration!pre-existing!W North America!time (mya)!0!5-10!spatial extent!space-time diagram of California!California!other continents!Mexico!CA floristic!province!long distance!dispersal!overland!dispersal!ocean!exotics!geographic stasis!S S A A A = anticlimatic S = synclimaticArrival modes!• Long distance dispersal (islands and continents)!• Secular migration (overland dispersal through gradual establishment of populations into new area) (regions within continents)!• Geographic stasis (climatic biomes with temporal baseline)!from: Harrison and Grace 2007 Amer. Nat. RESULTSEvolutionary changes in leaf size and SLA accompanying transition to mediterranean-type climate:!Clade Anacardiac. Ericaceae Rhamnaceae Rosaceae Lineage Malosma Rhus (2 spp.) Arbutus Xylococcus Comarostaphylis Arctostaphylos Ceanothus Cercocarpus Lyonothamnus Adenostoma Prunus Heteromeles Leaf size 0 0 0 0 0 (neg) 0 0 0 NEG 0 0 SLA 0 0 0 NEG (neg) 0 0 0 (neg) (neg) NEG NEG Putative origin Subtropical Desert Subtropical Subtropical Subtropical Subtropical Subtropical? W North America W North America Temperate Temp/subtropical Temperate 0 = no change (neg) = NS reduction NEG = significant reduction Ackerly 2004 Amer. Nat.Taxon age and the assembly of mediterranean-type floras (Herrera 1992) old: ‘genera having either contemporary intercontinental range disjunctions or Pliocene fossil records…’ young: ‘genera lack both features’ old genera tend to be: sclerophyllous vertebrate-dispersed fleshy-fruited large-seeded. courtesy UC Berkeley Bot Garden Arbutus unedoNon rank-based restatement of Herrera’s conclusions:!‘old’ = lineages that exhibit ancestral traits that predate the mediterranean-type environment, such as: vertebrate dispersal, etc.!‘young’ = lineages that have undergone recent adaptive shifts to derived states, including drought-deciduous leaves, small seeds, etc.!This is a conclusion about ancestral and derived traits, not about ‘taxon age’!Valiente-Banuet et al. 2006 PNASValiente-Banuet and Verdú 2007 Ecol LettValiente-Banuet and Verdú 2007 Ecol
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