Food webs

Question 1

What is a food web?

Answer 1

Description of the trophic interactions within an ecosystem
=> shows how energy moves through the ecosystem

• The assembly and organization of living organisms and FOOD RESOURCES into networks describing the ENERGY and NUTRIENT FLOW in the soil system

Question 2

What is a trophic level?

Answer 2

Consists of organisms with similar functions, morphology, feeding habits, ecological niches etc.

Soil food web is made of:

• Producers
• Consumers
• Decomposers

Question 3

What are different types of webs?

Answer 3

Connectedness web
- Identifies diets of different organisms of a food web

Energy flow web
- Augments the connectedness web with estimates of flux rates

Functional web
- Identifies interactions of organisms accounting for the response of the system to disturbances such as species removals

Question 4

What is the impact of more trophic levels?

Answer 4

More trophic levels=> increases complexity of food web => more stable

Each species is less dependant on a single resource in more complex systems, providing more buffer to environmental fluctuations.

Question 5

What is the difference between traditional soil food webs and new soil food webs?

Answer 5

Traditional:

• Distinct channels (usually root, bacterial and fungal)
• Trophic cascade effects rarely occur
• If they do, thought to be the bottom-up controlled

Revised soil food webs:

• Distinct channels may not exist
• Trophic cascade effect can ripple through the food web
• Mix of top-down and bottom up