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Dr. Michael Mercier ENVSOCTY 2RU3

Regional Geography of the United States

Physical Geography of the United States
III: Hydrology, Vegetation & Ecoregions

Introduction

  • Overview of the physical environment in regions.
  • Important concepts discussed:
    • Regionalization
    • Natural vegetation and the character of a region

Patterns of Natural Vegetation

Regions

  • Uncertainty?
    • Regions are seen as intellectual creations.
  • Ecoregions
    • Definition: areas characterized by similar landforms, climate, and biota.
Water Resources and America
  • Importance of lake and river systems for settlement and economic success.
    • Historical significance for Indigenous communities and early American settlers.
Hydrological (Water) Regions
  • Major hydrological regions of the US:
    • Great Lakes/St. Lawrence River
    • Gulf/Atlantic
    • Atlantic
    • Pacific

Summary/Conclusion

  • Recap of major themes discussed.
    • Importance of understanding natural vegetation and hydrology.
  • Readings: Chapter 2 Lecture Outline

Detailed Explanation of Vegetation Zones

Human Economic Ties with Vegetation Zones

  1. Connections between specific vegetation zones and human economic activity.

    • Example of natural vegetation patterns influenced by human activity.

  2. Human impact on natural plant distribution.

    • Biodiversity in nature vs. monoculture in human environments.
    • Notable introduction of conspicuous plants that overshadow native species.

Vegetation Linkages with Climate and Landforms

  • The interaction of vegetation types with climate and topographic environments.
    • Various patterns of natural vegetation are influenced by these factors.
Primary Forms of Vegetation

  1. Forests (Trees)

    • Distinction between:
      • Hardwoods
      • Softwoods
    • Additional Classification:
      • Deciduous
      • Coniferous

  2. Grasslands

    • Characterized by insufficient precipitation.
    • Two types of grasses:
      • Tall grasses
      • Short grasses

  3. Shrublands

    • Found in arid or semi-arid conditions.

Classification of Natural Vegetation Regions of the US

  • Regions include:
    • Needleleaf evergreen forest
    • Mixed broadleaf deciduous and needleleaf evergreen forest
    • Broadleaf deciduous forest
    • Prairie grassland
    • Broadleaf evergreen shrubland
    • Mediterranean shrubland

Variability in Vegetation Regions

  • Unlike climate and topographic regions, vegetation region boundaries are less precise and exhibit more variability.

Ecoregions Defined

  • Ecoregions: Reflect biomes, bioregions, and areas with similar ecological characteristics.
  • Level One Ecoregions include:
    • Arctic Cordillera
    • Tundra
    • Taiga and Boreal forests
    • Northwestern forested mountains
    • Marine west coast forest
    • Eastern temperate forests
    • Great Plains
    • Deserts and steppes
    • Mediterranean California
    • Southern semi-arid highlands
    • Tropical dry and wet forests

Importance of Water Resources in America

Key Functions of Water Resources

  • Water resources serve several important roles:
    • Drinking
    • Irrigation
    • Transportation
    • Power generation
    • Industry
    • Recreation

Challenges in Water Resource Management

  • Management of water resources is currently one of the biggest challenges facing the U.S.:
    • Ogallala Aquifer in the Great Plains.
    • Colorado River, particularly Lake Mead.
    • Water management issues in the California Central Valley.
    • Challenges with the Great Lakes and polluted rivers.

Overview of Hydrological Regions

Major Hydrological Regions

  • Hydrological Region Definition: Areas defined by their water flow systems.
    • Great Lakes/St. Lawrence River
    • Gulf/Atlantic drainage system
    • Atlantic drainage system
    • Pacific drainage system

Lakes, River Systems, and Canals

  • Integral to human settlement and economic activity, examples include:
    1. Great Lakes, St. Lawrence & Mississippi river systems.
    2. Urban centers developed along the fall line:
    • Important falls where a river crosses an area of changing elevation.
    • Significant cities along the fall line: Philadelphia, Wilmington.
  1. Flood control: Management of river systems like the Tennessee River.
  2. Policies regarding water management in the western United States.

Conclusion and Recap

  • Natural vegetation is summarized into three categories:
    • Forests
    • Grasses
    • Shrubs
  • Each category has unique climatic and topographic conditions.
  • Water sources have been significant throughout American history, particularly concerning settlement and economic development.
  • Review of major hydrological regions and management challenges ahead.

Next Class

  • Overview and exploration of the topics discussed.