Lecture 21Biomes – Savannas and Temperate GrasslandsText Reference – Chapter 32: Global EcologyForest BiomesTropical Rain ForestTemperate Deciduous ForestNorthern Coniferous Forest (Taiga or Boreal forest)GrasslandsSavannasTemperate Grassland (Prairie)“Extreme” BiomesTundraDesertSavannasTropical grasslands with scattered trees; located in equatorial regions where rainfall is too little to sustain trees and most shrubs; grasses flourish and herbivorous, grazing animals; most plant species are “fire-adapted” and drought resistantGeography and LocationEquatorial regions where rainfall is seasonalClimateWarm to hot temperature throughout the year; rainfall is seasonal; “dry season” may be 7-8 months longSoil QualityVariation in soil quality, fires recycle nutrients but soils often low in humus and nutrients can be leached; human and changes in animal activity have affected savanna soil qualityPrecipitation and Water AvailabilityRainfall seasonal, may be 7-8 month dry season; presents a major challenge for plants and animalsSpecies Diversity (Richness)Few trees and shrubs, herbaceous perennial grasses and euphorbias; thorn acacias; lower diversity than tropical rain forest and generally temperate forestCharacteristic PlantsPlant AdaptationsSavanna grasses – fire and drought adaptedThorn acacias – ants live in thorns; eat nectar and protein structures on leaves; remove fungal spores, clip leaves, attack herbivoresAnimals of the African savanna include elephants, giraffes, zebra, antelopes, wild dogs, lionsEnvironmental ImpactBlack market trade; conversion of grasslands to agricultural use and grazing for domesticated animalsBiomesForest BiomesTropical Rain ForestTemperate Deciduous ForestNorthern Coniferous Forest (Taiga or Boreal forest)GrasslandsSavannasTemperate Grassland (Prairie)“Extreme” BiomesTundraDesertTemperate GrasslandsGrasses dominate; Prairies and plains of North America, pampas of Argentina, steppes of Russia, veldts of South AfricaGeography and LocationPrairies and plains of North America, pampas of Argentina, steppes of Russia, veldts of South AfricaClimateMost temperate grasslands have distinct seasons; the more northern regions have severe winters; rainfall somewhat seasonal with summer months have more rain; relatively dry winters and moist summers; periodic droughts common. Very high windsSoil QualityDeep, fertile soils; abundant burrowing animals and soil organisms contribute to soil fertility; fires recycle nutrients. Soil is poor, very thin top soil because of low productivity. Extremely low in humus, low in nutrient because you get a lot of snow, when it melts you get a leeching effect. Permofrost – don’t have to go down really farPrecipitation and Water AvailabilityUsually seasonal with summer months getting most water, droughts commonSpecies Diversity (Richness)Less than temperate regions; grasses and euphorbias dominate; grazing animalsPlantsGrasses and euphorbiasLichens and MossesPlant AdaptationsGrasses have fibrous root systems and are fire-adapted, perennialAnimalsAmerican bison, prairie dogs, prairie chickensEnvironmental ImpactConversion to cropland; over hunting of animalsExxon Valdez Oil Spill – spilled over a 2 week period and took a while to stop the leak. Alaska wDesert:All deserts don’t have very much pacipitation. They could be located 30BIOL 420 1st Edition Lecture 21Biomes – Savannas and Temperate Grasslands Text Reference – Chapter 32: Global Ecology Forest Biomes Tropical Rain Forest Temperate Deciduous Forest Northern Coniferous Forest (Taiga or Boreal forest) Grasslands Savannas Temperate Grassland (Prairie) “Extreme” Biomes Tundra Desert Savannas Tropical grasslands with scattered trees; located in equatorial regions where rainfall is toolittle to sustain trees and most shrubs; grasses flourish and herbivorous, grazing animals; most plant species are “fire-adapted” and drought resistant Geography and Location Equatorial regions where rainfall is seasonal Climate Warm to hot temperature throughout the year; rainfall is seasonal; “dry season” may be 7-8 months long Soil Quality Variation in soil quality, fires recycle nutrients but soils often low in humus and nutrients can be leached; human and changes in animal activity have affected savanna soil quality Precipitation and Water Availability Rainfall seasonal, may be 7-8 month dry season; presents a major challenge for plants and animals Species Diversity (Richness) Few trees and shrubs, herbaceous perennial grasses and euphorbias; thorn acacias;lower diversity than tropical rain forest and generally temperate forest  Characteristic Plants Plant Adaptations Savanna grasses – fire and drought adapted Thorn acacias – ants live in thorns; eat nectar and protein structures on leaves; remove fungal spores, clip leaves, attack herbivores Animals of the African savanna include elephants, giraffes, zebra, antelopes, wild dogs, lions Environmental Impact Black market trade; conversion of grasslands to agricultural use and grazing for domesticated animals Biomes  Forest Biomes Tropical Rain Forest Temperate Deciduous Forest Northern Coniferous Forest (Taiga or Boreal forest) Grasslands Savannas Temperate Grassland (Prairie) “Extreme” Biomes Tundra Desert Temperate Grasslands Grasses dominate; Prairies and plains of North America, pampas of Argentina, steppes of Russia, veldts of South Africa Geography and Location Prairies and plains of North America, pampas of Argentina, steppes of Russia, veldts of South Africa Climate Most temperate grasslands have distinct seasons; the more northern regions have severe winters; rainfall somewhat seasonal with summer months have more rain; relatively dry winters and moist summers; periodic droughts common. Very high winds Soil Quality  Deep, fertile soils; abundant burrowing animals and soil organisms contribute to soil fertility; fires recycle nutrients. Soil is poor, very thin top soil because of low productivity. Extremely low in humus, low in nutrient because you get a lot of snow, when it melts you get a leeching effect. Permofrost – don’t have to go down really far  Precipitation and Water Availability Usually seasonal with summer months getting