LECTURE 10 Deforestation & Desertification

Human Footprint

Measures energy quantities, resources, and products consumed by a human during his/her lifetime

Anthropogenic Stressors

 Pollution or Environmental changes caused by human activities. 

Soil

mixture of mineral fragments, organic material, water, and air.

Soil importance

• Stores water and nutrients needed for plant growth

• Provides habitat for organisms (plants, insects, earthworms, fungi, bacteria)

• Supports food webs since plants (producers) depend on soil

• Anchors plant roots and stabilizes plants

• Involved in nutrient cycling through decomposers

• Water retention depends on texture & structure

• Porosity: Space between particles; more pores → more water storage

Porosity

 the space between soil particles. 

Humus

 organic component of soil

Topsoil

rich in humus and minerals

Subsoil

rich in minerals, little to no humus

Weathered Rock Fragments

 little to no plant or animal life

Bedrock

solid rock below soil

Types of Land Use

1. Roads and railways

2. Agriculture use land

3. Housing and residents

 Land Degradation

Process by which human activity and natural processes (ex. drought) damage land to the point that it can no longer support the local ecosystem.

Deforestation

 Removal of trees and vegetation from an area.

Desertification

 Land degradation where land becomes desert-like and unable to support life.

Urbanization

 Growth of urban areas caused by people moving into the cities

Urban Sprawl

Expansion of cities into surrounding rural land. (occurs at the edge of a city or town)

Erosion

 Movement of soil by wind, water, or gravity.

Forest importance

Forests support biodiversity, provide resources, and maintain environmental balance.

True

75% freshwater comes from forest watersheds

31%

Forests cover _____ of land

 Why Trees Matter

• Carbon storage

• Soil conservation

• Water cycle regulation

• Air pollution absorption

Causes of Deforestation

• Direct: logging, farming, mining, cattle, oil extraction

• Natural: floods, fires, hurricanes

Indirect: population growth, poor governance, conflict

Controlling Deforestation

• Stop illegal logging

• Protect forests by law

• Sustainable forestry

• Ecotourism and education

Main causes of deforestation

• Overgrazing

• Deforestation

• Poor agricultural practices

• Drought

• Climate change 

Sahel desertification causes

Climate change, deforestation, poor agriculture, population growth, political issues, monsoon variability, aerosols

Dust Bowl (1930s) causes

Overplowing, overgrazing, drought, population growth, monoculture, soil erosion, economic crisis

Impact of Desertification

• Extreme poverty

• Food insecurity & Hunger

• Biodiversity loss

• Increase to drought & Water stress

• Increase emissions of GHG

• Deforestation

• Instability & crises

• Migration

Solutions to desertification

• Plant trees

• Improve soil quality

• Water management

• Magic stones / bunds

• Drip irrigation