FloristicsHistorical Biogeography• Historical biogeography is the flipside to ecological biogeography• Most of its practitioners are not geographers but systematistsspecializing on specific groups of organisms“What lives where and why?”1. Descriptive — distributions and areas (floristic geography)Three phases of historical biogeography are usually seen:• Historical biogeography is the flipside to ecological biogeography• Most of its practitioners are not geographers but systematistsspecializing on specific groups of organisms2. Narrative — using historical (geological and evolutionary)events and ad hoc assumptions as a basis for explaining a givendistribution pattern (including dispersal biogeography)“What lives where and why?”Three phases of historical biogeography are usually seen:Historical Biogeography• Historical biogeography is the flipside to ecological biogeography• Most of its practitioners are not geographers but systematistsspecializing on specific groups of organisms3. Analytical — comparison of the patterns of relationships ofdifferent groups of organisms occupying similar areas to findcommon biogeographic patterns• vicariance biogeography• cladistic biogeography• phylogenetic biogeography“What lives where and why?”Three phases of historical biogeography are usually seen:Historical BiogeographyFloristic BiogeographyBasic to the study of floristics is knowledge of thegeographic distribution of organisms• Most obvious feature of geographic distributions is thatthey are limited• No species is completely cosmopolitan, or foundworldwide• Most species and genera, and even many families andorders are confined to restricted regions such as a continentAmborella trichopoda is endemicto New CaledoniaFloristic BiogeographyBasic to the study of floristics is knowledge of thegeographic distribution of organisms• Most obvious feature of geographic distributions is thatthey are limited• No species is completely cosmopolitan, or foundworldwide• Most species and genera, and even many families andorders are confined to restricted regions such as a continentPicea glauca is endemic to borealforest of North America; Picea(spruce genus) is restricted to theNorth HemisphereBasic to the study of floristics is knowledge of thegeographic distribution of organisms• Most obvious feature of geographic distributions is thatthey are limited• No species is completely cosmopolitan, or foundworldwide• Most species and genera, and even many families andorders are confined to restricted regions such as a continentGunnera (Gunneraceae) has awider but still patchy distribution(Hawaiian species shown here)Floristic BiogeographyDistribution PatternsEvery species (or higher taxa) has a particular distribution that varies in threeimportant features:• range: entire region or area of occurrenceClematis fremontii (Ranunculaceae) isrestricted to three midwestern statesleatherflowerEvery species (or higher taxa) has a particular distribution that varies in threeimportant features:• range: entire region or area of occurrence• degree of geographical continuityClematis fremontii (Ranunculaceae) isdiscontinuous in distribution across itsrange as it is restricted to limestone gladesDistribution PatternsEvery species (or higher taxa) has a particular distribution that varies in threeimportant features:• range: entire region or area of occurrence• degree of geographical continuity• frequency of occurrenceClematis fremontii (Ranunculaceae) isfrequent, but aggregated, in individuallimestone gladesDistribution PatternsWhat are the limits to distributions?• climatic: temperature, light, wetness• topographic: mountains, oceans• biotic: competition, predation, coevolution• history: age, dispersal, sunderingDistribution PatternsWhat are the limits to distributions?• climatic: temperature, light, wetness• topographic: mountains, oceans• biotic: competition, predation, coevolution• history: age, dispersal, sunderingPalm family is limited by frost due to their single growing point at end of the stemDistribution PatternsWhat are the limits to distributions?• climatic: temperature, light, wetness• topographic: mountains, oceans• biotic: competition, predation, coevolution• history: age, dispersal, sunderingDistribution PatternsBiotic requirements force the distributions of kinglets and redback voles to match that of theextent of coniferous boreal forests• Endemics• Continuous• Disjuncts (discontinuous)What kinds of distribution patterns are seen?aquatic Ceratophyllum demersum (coon’s-tail) is widespread, continuous, nearly cosmopolitanDistribution PatternsWhat kinds of distribution patterns are seen?Nothofagus (southern beech) is endemicto several temperate southernhemisphere areas, thus disjunctDistribution Patterns• Endemics• Continuous• Disjuncts (discontinuous)What kinds of distribution patterns are seen?Osmorhiza chilensis (mountain sweet cicely) shows an amphi-tropical disjunction and awestern North American - Great Lakes – eastern N. American disjunction• Endemics• Continuous• Disjuncts (discontinuous)Distribution PatternsWhat kinds of distribution patterns are seen?Empetrum (crowberries) of boreal and tundra and Larrea (creosote) of deserts also showamphi-tropical disjunctions• Endemics• Continuous• Disjuncts (discontinuous)Distribution PatternsWhat kinds of distribution patterns are seen?1 species of Pitcairnia in west AfricaFamily Bromeliaceae (pineapples) shows continuous distribution throughout much of tropicaland subtropical America, endemic to this region, except for peculiar disjunct in West AfricaDistribution Patterns• Endemics• Continuous• Disjuncts (discontinuous)What kinds of distribution patterns are seen?• Endemics• Continuous• Disjuncts (discontinuous)Distribution PatternsFamily Humiraceae shows same peculiar disjunct in West AfricaFamily Humiraceae shows same peculiar disjunct in West Africa - why? (not a floristic question)S. amazonica -water dispersedWhat kinds of distribution patterns are seen?• each occupies a precise area or range firstdetermined by history• actual ranges are limited by ecological orbiological barriersDistribution Patterns• Endemics• Continuous• Disjuncts (discontinuous)• all eight taxa described survive and reproduce inaccordance to specific environmental requirementsLythrum salicaria - purple loosestrife• for invasive weeds, perhaps