Grassland+biome+2011

Grassland+biome+2011 - Terrestrial Biomes: Terrestrial...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Terrestrial Biomes: Terrestrial Biomes: Grasslands and Savannas James Bartolome Outline Outline Introduction to grasses and grasslands Examples of grasslands and savannas Why grasses are so successful How grassland ecosystems function Grassland productivity The effects of fire and grazing on grasslands Mesic Valley Grassland in Mesic Valley Grassland in northeastern San Joaquin Valley Some Definitions Some Definitions Grassland– A biome type characterized by non­woody vegetation, usually from the grass family Savanna – a grassland with scattered trees Grass– a large (10,000 species) monophyletic family of flowering plants Rangelands– grasslands, savannas, and shrublands, about 50% of the world’s land area Outline Outline Introduction to grasses and grasslands Examples of grasslands and savannas Why grasses are so successful How grassland ecosystems function Grassland productivity The effects of fire and grazing on grasslands Patagonian steppe Patagonian steppe Perennial­dominated Coastal Prairie Perennial­dominated Coastal Prairie at Point Molate East African savanna East African savanna Alpine landscape Pyrenees Stoneman Meadow Stoneman Meadow Panicum turgidum “grassland” Mali Outline Outline Introduction to grasses and grasslands Examples of grasslands and savannas Why grasses are so successful How grassland ecosystems function Grassland productivity The effects of fire and grazing on grasslands Origins of grasses and grasslands Origins of grasses and grasslands Grasses originated in late cretaceous in southern hemisphere. First fossils are pollen from 65 million years ago and phytoliths from 67 million. Major expansion and diversification in Miocene (12­10 mya) was associated with worldwide climate change and also changes in CO2. Grasses, especially their phytoliths, become abundant in fossil record after about 6 mya. Dumbell­shaped opal phytoliths in Dumbell­shaped opal phytoliths in Nassella lepida leaf Why are grasses so successful? Why are grasses so successful? Modular growth form and intercalary meristems provide both tolerance and avoidance of defoliation by fire or grazing animals Ability to adapt to seasonal water stress Evolution of C4 photosynthesis Bluebunch wheatgrass grassland, Oregon Modular organization of grass plant Modular organization of grass plant Outline Outline Introduction to grasses and grasslands Examples of grasslands and savannas Why grasses are so successful How grassland ecosystems function Grassland productivity The effects of fire and grazing on grasslands Grassland ecosystem Grassland ecosystem 1 Primary producers (Grasses) 2 Primary consumers (Herbivores) Decomposers (Detritivores) Secondary consumers (Carnivores) Giraffe Giraffe sacacia weavers termite s Productivity and diversity Productivity and diversity relationships among biomes Biome g Biomass/m2/yr g C/m2/yr Biodiversity Tropical Forest 1900 850 very high Temperate Forest 1250 550 medium Savanna 900 400 medium Boreal Forest 800 350 low Mediterranean Shrubland 700 300 medium Temperate Grassland 600 250 medium Tundra 150 70 low Desert 90 40 low Cultivated 650 300 very low Wetlands 2000 900 low Lakes 250 110 low Waterbuck at Kenyan Lakeshore Ponderosa pine, open park, bison Ponderosa pine, open park, bison Pastoralists as secondary consumers Pastoralists as secondary consumers Low intensity forage use in Sub­ Low intensity forage use in Sub­ Saharan grassland Outline Outline Introduction to grasses and grasslands Examples of grasslands and savannas Why grasses are so successful How grassland ecosystems function Grassland productivity The effects of fire and grazing on grasslands Grassland ecosystem Grassland ecosystem 1 Primary producers (Grasses) 2 Primary consumers (Herbivores) Decomposers (Detritivores) Secondary consumers (Carnivores) Prescribed fire for barbed goat grass Prescribed fire for barbed goat grass control and native grass enhancement Californian oak savanna Californian oak savanna Elephants in Acacia savanna Elephants in former Acacia savanna Elephants in former Acacia savanna Crocuses in alpine grassland Crocuses in alpine grassland References References Bartolome, J.W. 1987. California grassland and oak savannah. Rangelands 9:122­125. Huntsinger, L. and J.W. Bartolome. 2004. Grasslands.pgs.606­609. IN: Shepard Krech III, J.R. McNeill, and Carolyn Merchant (eds). Encyclopedia of World Environmental History, Routledge Press, New York. ...
View Full Document

Ask a homework question - tutors are online