Chapter 20 - Terrestrial Biomes

Inputs and Outputs of Ecosystems

• Inputs:

  • Insolation

  • Precipitation

  • Earth materials

• Actions:

  • Evolution and speciation

  • Community interactions

• Outputs:

  • Endemic species

  • Earth’s terrestrial biomes

Human–Earth Connections

• Invasive species

• Anthropogenic biomes

• Climate change

Current Status of Earth's Tropical Rain Forests

• Tropical rain forests are experiencing increased deforestation driven by:

  • Agriculture, ranching, and development.

  • Climate change exacerbates the situation, leading to habitat fragmentation.

Key Learning Concepts

• Biogeographic Realms:

  • Locate and discuss specifications of major biogeographic realms around the world.

• Classification of Plant Communities:

  • Understand how environmental factors like climate and soil influence the formation of biomes.

• Impact of Non-native Species:

  • Discuss examples of non-native species and their effects on biodiversity, along with strategies for conservation.

• Earth's Major Terrestrial Biomes:

  • Summary and map location of 10 primary biomes on Earth.

The Semien Mountains, Ethiopia

• Notable for its unique ecosystem

  • Home to giant lobelia (Lobelia deckenii).

  • Adapted to high altitude conditions, including regular snowfall, intense solar radiation, and cold temperatures.

Ecological Corridors for Wildlife

• Grizzly Bears in Cabinet Mountains, Montana:

  • Population isolated due to landscape fragmentation (roads, agriculture, and development).

  • Genetic diversity is being promoted through seasonal capture and relocation programs for better breeding.

  • Cats or grizzlies need ecological corridors for survival and gene flow.

Historical Grizzly Population Decline

• Decline to 2% of previous range by the 1970s leading to endangerment status.

• Population recovery efforts initiated due to endangered species list but connectivity issues remain.

Habitat Fragmentation

• Impact on biodiversity results in species isolation, referred to as "island biogeography"; larger protected areas can better avoid extinction.

Yellowstone to Yukon Conservation Corridor

• Project aims to connect wildlife habitats across significant distances for species like grizzly bears and other fauna.

Biogeographic Patterns and Biodiversity

• Understanding distribution patterns offers insight into species' evolutionary patterns; each biome possesses distinct climate and soil characteristics.

• Zoogeography and phytogeography focus on animal and plant distributions respectively.

Human Impacts on Biomes

• Human activities have altered nearly all ecosystems, creating anthropogenic biomes.

• Distinct geographical realms exist, shaped mainly by evolutionary processes and geological history.

Key Vegetation Types and Biomes

• Major categories of vegetation include:

  1. Forest

  2. Savanna

  3. Shrubland

  4. Grassland

  5. Desert

  6. Tundra

Additional Characteristics of Each Biome

• Rain forest:

  • High biomass, multilayered canopies.

• Seasonal forests:

  • Defined wet/dry seasons, predominantly deciduous trees.

• Grasslands:

  • Dominance of grass species, essential for grazing animals.

• Deserts:

  • Specialized xerophytic plants adapted to extreme conditions.

• Tundras:

  • Dwarf shrubs, permafrost, and short growing seasons typically predominate.

Human Modifications to Natural Ecosystems

• Urbanization, overfarming, deforestation, and natural resource extraction heavily impact remaining ecosystems.

Conservation Strategies and Policies

• Strategies must balance biodiversity conservation with sustainable human development; this includes:

  • Establishment of wildlife corridors, parks, and refuges to ensure habitat connectivity.

  • Implement policies against invasive species and habitat destruction.

Community Dynamics

• Conservation biogeography focuses on understanding how to maintain biodiversity amidst human influence and climate shifts.