EcologyLesson 1 of 1 in the course Succession and disturbance

Trophic Cascades: Pathways, History, Examples, and Ecological Complexity

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

A trophic cascade occurs when a change at one level of a food web indirectly affects other levels. These effects can shape the abundance of organisms and the condition of entire ecosystems.

A trophic level is a position in a food web, such as producer, herbivore, or predator. A trophic cascade is an indirect interaction in which a change affecting one trophic level influences other levels through feeding relationships.

All flashcards

What is a trophic level?
A position in a food web, such as primary producer, herbivore, or predator.
What makes an ecological effect a trophic cascade?
A change at one trophic level indirectly influences organisms at other levels through food-web interactions.
How does a top-down cascade work?
A higher-level consumer affects organisms below it. Predators may reduce herbivores, relieving plants of some grazing pressure.
What drives a bottom-up cascade?
Changes in resources or primary producers affect the food and energy available to higher trophic levels.
What is a subsidy cascade?
It occurs when food from outside a habitat supplements a local population and may alter interactions there.

Quiz questions

  1. What is a trophic cascade?Answer: A chain of indirect effects across trophic levels following a change in a species' abundance or influence.
  2. In a top-down cascade, which part of the food web initiates the effects?Answer: A consumer or predator at a higher trophic level.
  3. What may happen to plants when predators reduce herbivore abundance?Answer: Plants may experience less herbivory and increase in abundance or growth.
  4. In the lake example, what is the likely indirect effect of increasing large piscivorous fish?Answer: Smaller fish may decline, zooplankton may rise, and phytoplankton may fall.
  5. Forest animals increase after feeding in a neighboring crop field. What kind of cascade could follow?Answer: A subsidy cascade, because external food can increase a local population and affect resident species.

Based on the Wikipedia article Trophic cascade, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

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