Grasslands and Their Global Significance

Introduction to Grass

• Grasses are dominant across all biomes except icesheets.
• They form the basis of the world's grasslands: Meadow, Prairie, Pampas, Veldt, and Steppe.
• Definition: Non-woody plants with hollow stems, bladed leaves, and bundled seed heads.
• Over 12,000 species exist, evolving since the end of the Cretaceous period 66 million years ago.
• Able to colonize poor soils, survive fires, and outcompete other plants.

Characteristics of Grasslands

• Fully dominant in prairies and steppes.
• Occur in temperate, drier climates; mid-latitudes, or high altitudes like the Himalayas and Andes.
• Historical conditions such as fire and grazing have limited tree growth.
• No single Koppen climate type; represented in B, C, and D climate groups.
• Holdridge Lifezones chart classifies grasslands as 'steppe'.

Regional Terms for Grasslands

• Prairie: North America's grasslands, "meadow" in French.
• Steppe: Eurasia's grasslands, from Russian terminology.
• Pampas: South American grasslands, Quechua for "plain".
• Veldt: Eastern South Africa’s open country, meaning "field" in Afrikaans.

Ecology and Adaptations

• Grass height varies with rainfall and soil drainage.
• Tallgrass species can have roots as deep as their height.
• Meadows bloom in color during the plant reproductive season.

Global Distribution of Grasslands

• North America: Prairies from Canada to USA central states.
• South America: Puna, Pampas, and grasslands in Southern Patagonia.
• Africa: Veldt in eastern South Africa.
• New Zealand: Tussock grasslands due to poor soils and rain shadow.
• Middle East: Isolated pockets in Turkey and southern Caucasus.
• Eurasia: Vast Steppe plains from Ukraine to Mongolia.

Biodiversity and Fauna

• High species diversity with regional variations (e.g., Big bluestem, Stipa).
• Historically supported large herds of grazing animals (e.g., Bison, horses).

Human Interaction and Agriculture

• Grasslands largely replaced by agricultural lands.
• Agriculture has "adjusted" grasslands, converting them to cereal crop production.
• Key cereal crops (wheat, corn, rice) are domesticated grass species.
• Grass family vital for human civilization.

Conclusion

• Grasslands are crucial to both natural ecosystems and human agriculture.
• Prelude to next exploration: temperate forests.

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