Vulnerability and Resilience of Ecosystems

• All ecosystems function in a state of dynamic equilibrium.

• This state of dynamic equilibrium is the product of the interrelationship of the elements in the ecosystem:

- The atmosphere- The hydrosphere- The biosphere- The lithosphere• Change occurs because the interaction of minerals,

energy and communities varies over time.

• The interdependence of these elements also makes an ecosystem vulnerable.

• The level of vulnerability depends on how small a change is needed in any element to upset the equilibrium.

• Ecosystems, therefore, are not equally at risk – some are more resilient than others.

Causes of Ecosystem Vulnerability

• Location – latitude, distance from the sea, altitude

• Extent – microclimatic variations created by the physical features of an area

• Biodiversity – genetic, species, ecosystem

• Linkages – interdependence: the greater the interdependence within an ecosystem, the greater its ability to absorb change.

Activities / Homework1. Describe an example of a microclimatic feature of a

location that can create distinctive ecosystems2. Describe how ‘extent’ can cause ecosystem

vulnerability.3. How do the three levels of biodiversity affect the

vulnerability of an ecosystem.4. Explain the effects of food webs and food chains on

the vulnerability of an ecosystem.5. Define the term resilience.6. Why do ecosystems rich in biodiversity have greater

resilience ?7. With the aid of a diagram, explain how ‘stress’ impacts

on the functioning of an ecosystem.