What is a trophic cascade?

Short Answer

Expert verified
Answer: A trophic cascade is an ecological phenomenon where changes at one trophic level of an ecosystem, such as the removal or addition of a predator, cause significant changes in the populations of organisms at lower trophic levels. This can result in either direct or indirect effects on the abundance and behavior of other species within the ecosystem. Trophic cascades occur through the interactions between producers, primary consumers, secondary consumers, and tertiary consumers in the ecosystem. An example of a trophic cascade is the reintroduction of gray wolves into Yellowstone National Park, which led to a series of changes in populations and interactions at multiple trophic levels, ultimately improving the overall health and biodiversity of the ecosystem.

Step by step solution

01

Defining Trophic Levels

Trophic levels are the hierarchical levels in an ecosystem, comprising of organisms sharing the same function in the food chain and the same nutritional relationship to the primary sources of energy. In simpler terms, trophic levels represent how organisms within an ecosystem obtain their energy from food sources. There are typically four trophic levels: 1. Producers (plants) - these organisms create their own food through the process of photosynthesis. 2. Primary consumers (herbivores) - these animals eat plants to get their energy 3. Secondary consumers (carnivores) - these animals eat other animals (usually herbivores) for energy 4. Tertiary consumers (apex predators) - these animals eat other carnivores for energy Every time a consumer eats something, energy from the food is transferred up the food chain through the trophic levels.
02

Explaining trophic cascade

A trophic cascade occurs when changes at a higher trophic level (e.g., the removal or addition of a predator) cause significant changes in the populations of organisms at lower trophic levels. This phenomenon can have either direct effects on the abundance of species in the affected ecosystem or indirect effects, such as changes in the behavior and abundance of other species that have not been directly consumed by the predator. Trophic cascades can be either top-down (predator influences prey populations) or bottom-up (changes in plant or prey populations influencing the predators).
03

Providing an Example of Trophic Cascade

A classic example of a trophic cascade is the reintroduction of gray wolves (Canis lupus) into Yellowstone National Park. The wolves, a tertiary consumer, were reintroduced to the park after a 70-year absence. Here's how the trophic cascade occurred: 1. Wolves started preying on the overpopulated elk (primary consumer), which decreased the elk's population. 2. Fewer elk led to a decrease in browsing on plant species such as aspen, cottonwood, and willow trees (producers). This allowed these plants to grow and become more abundant. 3. The increased vegetation provided shelter and food for several species, including beavers, songbirds, and other mammals. 4. Decreased elk population allowed other smaller carnivores (secondary consumers) like coyotes, foxes, and birds of prey to have an increased abundance of smaller prey. 5. The more balanced ecosystem allowed for an increase in biodiversity, improving the overall health of Yellowstone's ecosystem. This example demonstrates that changes at one trophic level (wolves) can cause significant changes in other trophic levels within an ecosystem.
04

Conclusion

In summary, a trophic cascade is an ecological phenomenon wherein changes at one trophic level of an ecosystem initiate a series of changes in populations and interactions at multiple other trophic levels. This can either be top-down or bottom-up, and understanding trophic cascades is crucial for effective ecosystem management and conservation efforts.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

See all solutions

Recommended explanations on Environmental Science Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free