Natural & Human Disturbances that Affect an Ecosystem

Lesson Transcript
Instructor: Lisa Roundy

Lisa has taught at all levels from kindergarten to college and has a master's degree in human relations.

Ecosystems are often forced to change in response to natural and human disturbances. In this lesson, we'll explore how these changes can be negative and positive.

Balance in an Ecosystem

Imagine you purchase an aquarium and fill it with some sand, a few aquatic plants, and some small rocks. Add water and a couple of fish to the aquarium and voila! Your miniature ecosystem is complete.

An ecosystem consists of the living and non-living things that interact with one another in a particular location. In the example above, the fish and plants both live in the water, plants provide oxygen for the fish and rocks provide them with shelter, and the fish nibble at the plants and prevent overgrowth. All of the elements of the ecosystem you have created are in harmony. When this type of stability exists in an ecosystem, we call it a balanced ecosystem.

Unfortunately, ecosystems do not always remain in balance. Environmental changes can alter the stability of an ecosystem, creating unbalanced ecosystems. This may be helpful to an ecosystem in some instances, but it also can be destructive. Think of how the ecosystem in your aquarium benefits when you clean the water. Now imagine how your aquarium's ecosystem might suffer if all of the plants were to die.

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: What is a Food Web? - Definition & Explanation

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:02 Balance in an Ecosystem
  • 1:03 Natural Disturbances
  • 3:00 Human Disturbances
  • 4:13 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed

Natural Disturbances

Natural disturbances are one way an ecosystem can become unbalanced. As the name implies, natural disturbances have natural causes, such as weather, geological forces, or biological changes. Fires and floods are examples of natural disturbances that force change upon an ecosystem. Natural disturbances are also caused by diseases, severe storms, insects, volcanic activity, earthquakes, droughts, and long-term freezing.

Let's say you go on vacation for a week and leave your aquarium. While you are gone, a blizzard hits and your house loses power and heat for the week. Temperatures drop to near freezing inside your home for a number of days. Your aquarium is small, so the effect of the cold is similar to long-term freezing in a larger ecosystem. The water temperature falls below the temperature the fish needed to survive, and when you return home, all of the fish in the aquarium have died.

Natural disturbances can do a lot of damage to an ecosystem, even killing plants or animals, as in the aquarium example. But natural disturbances are nothing new, and the effects are usually temporary and the ecosystem will eventually recover. It may be the same after it recovers, or it may include new plants and animals that balance out the ecosystem as it adjusts to the new environmental conditions. It may be hard to imagine ecosystems recovering after some natural events. For example, if you've ever stood among charred trees and blackened ground after a forest fire, you know that fires and other natural disturbances can do a tremendous amount of damage.

However, in some cases, natural disturbances can be beneficial to an ecosystem. There are even some ecosystems that have adapted to become dependent on natural disturbances to maintain their balance. For example, longleaf pine forests depend on occasional fires to control undergrowth in the forest. Without a forest fire clearing the way for new seedlings to grow, the tiny new trees are unable to compete with the thick brush and die.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it now
Create an account to start this course today
Used by over 30 million students worldwide
Create an account