Tundra and AlpineTundra Biomes Tundras are characteristic of Arctic or Alpine regions where theseverity of environmental conditions excludes tree growth. 30 days of10°C ave. temperature and 8 mos cold season.Tundra Biomes Arctic tundra occurs north of the boreal forest or taiga and thus form atreeless ring south of the zone of permanent ice (North America,Greenland, Eurasia).Tundra Biomes In the Antarctica, tundra area is very small because of the lack of largecontinental masses. Develops only on certain small Antarctic islands suchas South George and MacQuarie Island on several spots on the mostnortherly extension of Antarctica proper (only 2 flowering plants!)Antarctic Peninsula - 600 mi or 1000 km fromSouth AmericaOnly 2 angiosperms - Antarctichairgrass, pearlwort - on north facingslopes with moss and liverwortsDeschampsia antarcticaColobanthus quitensisTussock Poa litorosa in subantarticCampbell IslandMegaherb Pleurophyllum speciosumin subantartic Campbell IslandTundra Biomes In the wet subAntarctic, tussocks and megaherbs are characteristicTundra Biomes Alpine regions include Rocky Mountains, European Alps, Himalayas,and Austral-antarctic area (South Island, also Tasmania, Snowy Mts. inAustralia).Alpine summit, Bighorn NatlForest, 9000ft, Wyomingwith Ranunculus adoneus(snow buttercup)Alpine tundra, Summit Lake, SWIdaho Springs, CO - Rydbergiagrandiflora, Polygonumbistortoides (American bistort)Tundra Biomes Exclude tropical ‘puna’ in Andes and similar high elevation peaks inEast Africa (will deal with later). Links of Austral-antarctic region withpuna (Azorella, Umbelliferae).Azorella (Apiaceae)Peru - puna, 4300 ftTundra Biomes Low precipitation; less than 400 mm peryear, usually only up to 150 mm — less rainthan most subtropical deserts! Subzero temperatures most of the year. Ashort vegetative period of generally less than50 days between spring and autumn frost.Tundra Biomes Permanently frozen sub-soil. Permafrost of variable depth. Consequences are physical barrier to roots, low temperatures suppressdecomposition and promotes peat, and retard water percolation and promotesswampy or boggy conditionsLocations of permafrost in tundraand high borealTundra Biomes Life forms: chamaephytes (incl. subshrubs) and hemicryptophytes by farthe dominant forms, often cushionsTasmanian (Mt. Anne), montanecushions, largest in the world,Abrotanella, Asteraceae, 12 ftacross with 106 stemsMoss campion (Silene acaulis) and purplesaxifrage (Saxifraga oppositifolia) at SvalbardTundra Biomes Life forms: grasses and sedges dominate (e.g., North America: Poaarctica, alpine meadow grass; Carex bigelowii, rigid sedge)Carex bigelowii -arctic sedgePoa arctica - alpine meadow grassTundra Biomes Life forms: vegetative reproduction common (bulbils or vivipary; eg.Polygonum viviparum, alpine bistort)Poa alpina var. viviparaPolygonum viviparum - alpine bistortTundra Biomes Life forms: apomixis, wind and fly/bee pollinated (incidence of open bowlflowers with conspicuous marks increases towards the arcticSt. Paul Island, Alaska tundraRanunculus - buttercupTundra Biomes Life forms: apomixis, wind and fly/bee pollinated (incidence of open bowlflowers with conspicuous marks increases towards the arcticSaxifraga - saxifragePapaver - poppyCerastium - chickweedFrequency of polyploids (black %) inthe floras of various territories in theNorthern Hemisphere (from Love andLove, 1974)Tundra Biomes Life forms: PolyploidySpitsbergenTundra Biomes Life forms: Polyploidyhttp://www.arcticatlas.org/atlas/cavm/cavmbz/index.shtml High arctic - herbs Middle arctic - dwarfshrub Low arctic - shrubbyheath, small treesTundra BiomesMean July temperature: 0-3 °CSummer warmth index <6 °CHerb subzoneTundra SubBiomesFog-shrouded islands neararctic icepackDominated by herbs - the“high arctic”Papaver - poppyDominant plant growth forms:Cushion forbs, mosses, lichensNumber of vascular plantspecies in local flora <50Tundra SubBiomesHerb subzoneMean July temperature: 3-5 °CSummer warmth index: 6-9 °CTransitional to subzone C andtogether they have been calledthe “middle arctic”Prostrate shrub (or Dryas)subzoneTundra SubBiomesDryas - mountain avens(Rosaceae) & pollenDominant plant growth form:Prostrate dwarf shrubsNumber of vascular plantspecies in local flora: 50-100Prostrate shrub (or Dryas)subzoneTundra SubBiomesDryas octopetalaSalix herbacea - least willowSalix polaris - polar willowCerastium regellii - chickweedMean July temperature: 5-7 °CSummer warmth index: 9-12 °Chemi-prostrate dwarf-shrub (orCassiope) subzoneTundra SubBiomesCassiope tetragona(Ericaceae) - Arctic bellheatherDominant plant growth forms:Hemi-prostrate dwarf shrubs,sedgesNumber of vascular plantspecies in local flora: 75-150hemi-prostrate dwarf-shrub (orCassiope) subzoneTundra SubBiomesCassiope tetragona(Ericaceae) - Arctic bellheatherCarex bigelowii -arctic sedgeJuncus trifidus - rushMean July temperature: 7-9 °CSummer warmth index: 12-20°CDominant plant growth forms:Erect dwarf shrubs, sedges,mossesNumber of vascular plantspecies in local flora: 125-250Erect-shrub (or Betula nana)subzoneTundra SubBiomesMean July temperature: 9-12 °CSummer warmth index: 20-35°CDominant plant growth forms:Low shrubs, tussock sedges,mossesNumber of vascular plantspecies in local flora: 200-500Low shrub (or Alnus) subzoneTundra SubBiomesRhododendron lapponicum in WisconsinTundra Biomes Floristics: Circum-boreal distribution common, Amphi-atlantic, Amphi-pacific often the case as wellin ScandanaviaTundra Biomes Floristics: Circum-boreal distribution common, Amphi-atlantic, Amphi-pacific often the case as well — sometimes as different varietiesVaccinium vitis-idaea var. minus(mountain cranberry in NorthAmerica)Vaccinium vitis-idaea var. vitis-idaea (lingon in Eurasia)Tundra Biomes Faunistics: Circum-boreal distribution common as with caribou (NorthAmerica) and reindeer (Eurasia) — slightly different looking but same speciesRangifer tarandus (actually a number of subspecies)Tundra Biomes Faunistics: other Circum-boreal distributionsArctic hareArctic foxArctic squirrelMuskoxTundra Biomes Floristics: Alpine vegetation does not form continuous expanses but arebest characterized as islandsEagles Nest Wilderness, ColoradoAlpine meadow distribution -European alpsSalix arctica - Alpine willowCerastium - chickweed, Colorado Rocky Mts.Tundra Biomes Floristics: Alpine vegetation shows very