Lecture Notes: Biomes at High Altitudes

Introduction

• Overview of biomes: tropical rainforests, grasslands, deserts, temperate and boreal forests, scrub, tundra.
• Series focuses on lowland regions, now exploring highland biomes.
• Importance of examining ecosystems adapting to altitude.

Impact of Altitude on Temperature

• Troposphere cools as altitude rises (~10°C/km or 5.4°F/1000ft).
• Temperature drop affects plant life depending on sea-level starting temperature, determined by latitude.
• Increasing altitude pushes biomes poleward effectively.

Biome Transitions with Altitude

• Temperate Forests: Shift towards taiga, then alpine tundra, eventually glacial icecap.
• Holdridge Lifezones Chart: Shows altitudinal belts mimicking latitudinal regions.
• Rainfall affects type of altitude biome; higher biomass at higher altitudes due to less evapotranspiration.

Examples by Latitude

• Poles: Ice biomes at sea-level, more ice with increasing altitude (e.g., Antarctica).
• Tundra: Found at higher altitudes in arctic, examples include Greenland.
• Boreal Forest (Taiga): Transitions to tundra with altitude; presence of a tree-line.

Complexity in Temperate and Subtropical Zones

• Variations due to rainfall and other factors.
• Temperate Forests: Transition from broadleaf to coniferous trees, alpine taiga, then tundra.
• Grassland and Scrub: Slopes covered with montane forests, above treeline becomes alpine tundra.
• Sea-level Deserts: High elevation lacks moisture; no forests or tundra.

Tropical Regions

• Lack of seasonal temperature changes affects biomes.
• Sea-level: Tropical rainforest, seasonal forest, or savannah.
• Higher elevations: Specialized forests, cloud forests; unique plant adaptations (e.g., Mount Kenya).

Case Study: Mount Kilimanjaro

• Rises to 5,895m, showcasing transitions from savannah to glaciers.
• Offers a full range of biomes, likened to a miniature version of Earth.

Conclusion

• Highlights the diversity and uniqueness of highland biomes.
• Encouragement to explore further content and engage with the series.