Ecosystem Disturbances and Ecosystem ServicesChapter 3

Ecosystem Disturbances• A large part of environmental science is studying what

happens when natural or anthropogenic disturbances occur or predicting what will happen when they do

What is a WATERSHED?

It is an area of LAND that water flows across or through downstream on its way to a stream, lake or ocean.

The watershed acts like a funnel collecting all the water within an area into a larger waterway.

It is also called a Drainage Basin

Watershed Study- Hubbard Creek• Deforested watershed vs. forested watershed• Take aways: • 1) disturbances in ecosystems disrupt natural

cycling and systems• 2) Forests/vegetation are important for

accumulation and maintenance of soil nutrients

Case Study- Haiti

Case Study- Haiti• Take aways-• 1) poorer nations often rely on cheaper fuels such as

raw or less processed biomass like trees and charcoal• 2) positive feedback loop - - less trees = more erosion =

less vegetation• 3) #2 has economic impacts - - less farming, greater

impact from natural disasters, less jobs• 4) Finding innovative solutions to environmental issues

must strike a balance and must acknowledge the connectivity between the environment, human health and well being, and the economy• -Related story: Wangaari Maathaihttp

://www.greenbeltmovement.org/wangari-maathai

Resistance vs. Resilience

• Resistance – how much a disturbance affects flows of energy and matter• -a disturbance that affects populations and

communities but not the flow of energy and matter we say it has high resistance• More biodiversity = greater resistance

Resistance vs. Resilience• Resiliance – how quickly an ecosystem can

recover and return to its original state• - more biodiversity = greater resilience

• Intermediate Disturbance Hypothesis • Take away – the more diverse an ecosystem is the

better off it is!

• Restoration Ecology – studies how to reverse effects and restore original ecosystem services• EX: wetland remediation

Ecosystem Services• Ecosystems provide all of our essential needs: clean

water, shelter, clean air, etc.• Instrumental value – value based on if the entity can be

useful, act as a tool, or provide a service.• Can often associate a monetary value with it• EX: Water purification• Provisions• Regulating services• Support services• Resilience• Cultural Services

• Intrinsic value – moral value or benefit