‘Islands in the Sky’ - Tepuis‘Islands in the Sky’ - Tepuis• Guayana Shield centered in southern Venezuela• 1.2 X 106 m2• sandstone table mountains of Roraima FormationAutana, 1300 mAutana, 1300 mNeblina, 3014 mRoraima, 2723 mKukenán, 2650 m‘Islands in the Sky’ - Tepuis• tepuis basis for Sir Arthur Conan Doyle’s “The LostWorld”• actually home to one of the world’s largest set of plant“carnivores”Heliamphora -sun pitcher‘Islands in the Sky’ - Tepuis• Roraima Formation - Precambrian, highly leached sandy marinesediments laid down 1.5 - 1.8 billions years ago• Roraima Formation upliftedduring formation of Atlantic inCretaceous• tepuis formed with erosion ofmajor river systems (Orinoco)• tepuis are resistant (quartzite)mesas‘Islands in the Sky’ - Tepuis• Roraima Formation - Precambrian, highly leached sandy marinesediments laid down 1.5 - 1.8 billions years ago• Roraima Formation upliftedduring formation of Atlantic inCretaceous• tepuis formed with erosion ofmajor river systems (Orinoco)• tepuis are resistant (quartzite)mesas‘Islands in the Sky’ - Tepuis• Pantepui - biogeographic province proposed by the Phelps for highelevation portion over 1500 m‘Islands in the Sky’ - Tepuis• Pantepui - biogeographic province proposed by the Phelps for highelevation portion over 1500 m• Distinctive biotaTepui vireoRedbanded fruiteaterTepui manakinRanaAsteraceae‘Islands in the Sky’ - Tepuis• Pantepui - biogeographic province proposed by the Phelps for highelevation portion over 1500 m• characterized by a combination of extreme conditions: cool weather,heavy rainfalls, dense clouds, strong winds, high solar radiation, andextremely infertile substratesPantepuiTepui Flora• Heliamphora (Sarraceniaceae) - sun pitcherShown here are two species (A and B) ofBrocchinia that are carnivores in the pineapplefamily.They are closelyrelated to otherspecies in thegenus thatimpound wateror are ant-fed,but notcarnivorous.• Brocchinia (Bromeliaceae) -Tepui FloraTepui Flora• Pantepui flora well characterized althoughmany individual tepuis collected only a fewtimesXyridaceae, EriocaulaceaeBonnetiaceae, RapateaceaeLog Summit AreaP < 0.0001Tepui Flora• Pantepui - island like species/area relationshipRiki Olivares - M.S. thesis0200400600800100012000--599 600--999 1000--1499 1500--3000Lower elevation ranges for Pantepui species (m)Number of species25%18%17%40%Lowlands Uplands HighlandsElevation ranges of Pantepui species(spp above 1500 m)Tepui FloraTepui Flora• Pantepui - 40% of species restricted to pantepuiOverall plant richness and endemismPantepuitaxaShieldendemicsPantepuiendemicsSingle tepuiendemicsFamilies 156 2 0 0Genera 626 80 23(4%)13(2%)Species 2447 1517 1034(42%)617(25%)Tepui FloraRiki Olivares - M.S. thesis• Pantepui - island like endemism• Floristic relationships among tepuis• Is there a biogeographical pattern?Tepui FloraCluster Analysis based on floristic compositionTepui FloraDCA Ordination based on floristic compositioneastwest-northwest-southDCA Ordinationbased on floristiccompositionbasically congruent withcluster analysisTepui Flora• positive significant (P = 0.001) correlation between the floristic distancematrix and the among-tepuis geographic distance matrix (Mantel Test)‘Islands in the Sky’ - Paramo, Afroalpine• convergent biome types across high elevation areas of the tropics• depending on elevation, often occur as ‘islands’‘Islands in the Sky’ - Paramo, Afroalpine• South American paramo and East African afroalpine (‘Ethiopian’)best studied floristically as islands‘Islands in the Sky’ - Paramo, Afroalpine• ecology is harsh and unvarying: ‘winter by night, summer by day’‘Islands in the Sky’ - Paramo, Afroalpine• Convergent life forms occur in both areas as a response tothese ecological conditions‘Islands in the Sky’ - Paramo, AfroalpineLobelia (Lobeliaceae)Dendrosenecio (Asteraceae)Afroalpine• Convergent life forms occur in both areas as a response tothese ecological conditions‘Islands in the Sky’ - Paramo, AfroalpineParamoEspeletia(Asteraceae)Puya (Bromeliaceae)• Convergent life forms occur in both areas as a response tothese ecological conditions‘Islands in the Sky’ - Paramo, AfroalpineParamoLupinus alopecuroides growing withSenecio niveoaureus in a Colombiansuperparamo [4,638 m]Photo: Mauricio Diazgranados• Andean lupines are the current record-holder among plants, with diversificationrates approaching those of some Africanrift-lake cichlids• The extent of the Andean cordillera, itselevational diversity and topographicdissection, and climatic oscillations duringthe Pleistocene likely factors promotinghigh rates of lupine speciation• Convergent life forms occur in both areas as a response tothese ecological conditions‘Islands in the Sky’ - Paramo, Afroalpinetussock grassAcaena (rosette)Viola (cushion)Hypericum (sclerophyll)Erica(sclerophyll)• Biogeography of afroalpine flora - how are the mountains relatedfloristically‘Islands in the Sky’ - Paramo, Afroalpine• Pairwise similarity (shared species) between nine afroalpineregions. Total number of species for each mountain shown inparenthesis and endemics in bold‘Islands in the Sky’ - Paramo, AfroalpineMt. KenyaMt. Kenya• Spatial distribution of nine mountains (A) and cluster diagramshowing floristic relationships based on Jaccard’s coefficientof similarity (B)‘Islands in the Sky’ - Paramo, AfroalpineMt. Kenya• Biogeography of afroalpine flora - radiation of Dendrosenecio: whichpattern?‘Islands in the Sky’ - Paramo, Afroalpine1. Inter-island dispersal followed byelevation shiftsEric Knox2. Multiple dispersals from similarelevations8 speciesadapted to 4life zones (incolor)• Biogeography of afroalpine flora - radiation of Dendrosenecio: whichpattern?‘Islands in the Sky’ - Paramo, AfroalpineMt. Kenya1. Inter-island dispersal followed byelevation shifts• Convergence of species adaptedto similar elevations!Phylogeny superimposed on biogeographyroot2. Multiple dispersals from