Desertification
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Desertification. Rachel Vincent, Adam Ali, Yuna Farah Ecosystems Ecology Spring 2014. What IS Desertification?. “Conversion of productive, arable areas to non-productive” Change in… Soil Properties Vegetation Climate Results in…

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Desertification

Desertification

Rachel Vincent, Adam Ali, Yuna Farah

Ecosystems Ecology

Spring 2014


What is desertification

What IS Desertification?

“Conversion of productive, arable areas to non-productive”

Change in…

Soil Properties

Vegetation

Climate

Results in…

Loss of ecosystem services  food security, carbon sequestration, supply of forage, fibers & wood, maintenance of biodiversity

Stress in human societies


What s the nature of desertification

What’s the Nature of Desertification?

  • Occurs mainly in arid, semi-arid and sub-humid areas

  • Drylandsare very vulnerable to changes

  • A form of land degradation

    • Reduction of biological or economic productivity of dry lands

    • Consequences = loss of soil fertility

    • Degrades dry but productive land so that it can no longer sustain life

  • Affects large dryland areas  1/3 of world population resides in drylands

  • If disturbances (climatic change or human causes) are severe enough, land productivity might not reversible


Causes of desertification

Causes of Desertification

  • Human Causes

    • Contribute the most

    • Overgrazing

    • Over-cultivation

    • Tillage

    • Irrigation

      • Inefficient irrigation

      • Over-irrigation

    • Deforestation

    • Population

      • Growth & migration

  • Climatic Causes

    • Aridification fertile regions becoming increasingly dry

    • Precipitation  limited rainfall

      • Water scarcity

    • Increases in drought

    • Anthropogenic increase in greenhouse gases

      • Affect precipitation pattern


Why is this important to people

Why is this important to people?

Increase of bare soil

General decrease in ecosystem services & productivity

Shifts in types of vegetation


What are the causes of desertification

What are the Causes of Desertification?

Poor land management

Anthropogenic forces  migration & conflicts

Climate change


Desertification has resulted in

Desertification has resulted in…

  • Agricultural declines

  • Famines

  • Loss of income

    • US loses $42 billion yearly

  • Reduction in resilience

    • Due to climactic variability


How does this problem alter the flow of energy water and nutrients throughout the system

How does this problem alter the flow of energy, water, and nutrients throughout the system?

  • Less vegetation > more erosion/ dust emissions

    • High levels of dust in the atmosphere can lead to cooling

    • Dust emissions reduce precipitation and impede plant growth

  • Less vegetation > less evapotranspiration > less precipitation recycling

  • Less vegetation > less transpiration from plants, same amount of evaporation (unproductive) and can lead to salt accumulation


How does this problem alter the flow of energy water and nutrients throughout the system1

How does this problem alter the flow of energy, water, and nutrients throughout the system?

  • Increased run-off and evaporation > less water for infiltration and transpiration

  • Loss of vegetation > change in atmospheric CO2

  • Increased albedo from vegetation loss

  • Surface temperature increase from decrease soil moisture

  • High temp/low precipitation leads to low soil organic matter

  • Soil degradation > infertile soil


How to address and remediate desertification

How to Address and Remediate Desertification

Identification

Mitigation

Control

Reversal


Identification

Identification

Biophysical

Land cover change

Biodiversity

Soil fertility

Economic

Market efficiency

Decreasing crop yields

Social

Increasing migration from rural to urban areas

Declining health

Political

Declining state power

Immigration-related issues


Mitigation

Mitigation

  • “The success of biophysical remediation and mitigation measures depends on the the existence of favorable societal conditions…Local and ‘stakeholder involvement’ appear to be crucial”

    • COLLECTIVE ACTION!


Control

Control

Importance of identification and monitoring

Soil, wind, water erosion control

Ex: mulching crop residues, create vegetation shelterbelts controls wind erosion

Manage grazing and livestock mobility  maintains biodiversity


Reversal

Reversal

IMPOSSIBLE TO REVERSE BUT…

Improve agriculture & promote sustainability of resources

Soil erosion control

Salinity remediation

Manage grazing/livestock

Biodiversity among crops

Improve & introduce better manmade systems/management


References

References

  • Bakr, Noura, David C. Weindorf, Mohamen H. Bahnassy, Mohamend M, El-Badawi. “Multi-temporal assessment of land sensitivity to desertification in a fragile agro-ecosystem: Environmental indicators.” Ecological Indicators 15 (2012): 271-280. Print Verón, S.R., J.M. Paruelo, M. Oesterheld. “Assessing desertification.” Journal of Arid Environments 66 (2006): 752-763. Print.

  • D’Odorico, Paolo, AbinashBhattachan, Kyle F. Davis, Sujith Ravi, and Christiane W. Runyan. "Global Desertification: Drivers and Feedbacks." Advances in Water Resources 51 (2013): 326-44. Print.

  • Jiang, Zhongcheng, YanqingLian, and Xiaoqun Qin. "Rocky Desertification in Southwest China: Impacts, Causes, and Restoration." Earth-Science Reviews 132 (2014): 1-12. Print.

  • King, Caroline, and David S.g. Thomas. "Monitoring Environmental Change and Degradation in the Irrigated Oases of the Northern Sahara." Journal of Arid Environments 103 (2014): 36-45. Print.

  • Sivakumar, M.V.K. “Interactions between climate and desertification.” Agricultural and Forest Meterology 142 (2007): 143-155. Print

  • Zhao, Ha-Lin, Jin Li, Ren-Tao Liu, Rui-Lian Zhou, HaoQu, and Cheng-Chen Pan. "Effects of Desertification on Temporal and Spatial Distribution of Soil Macro-arthropods in Horqin Sandy Grassland, Inner Mongolia." Geoderma 223-225 (2014): 62-67. Print.


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