Blue question mark

Once an ecosystem is destroyed, can it be revived?
— Thomas G., Grade 5

Conservation biologist Felicity Arengo answers this question:

Hi Thomas,

It depends. First let's look at the reasons that ecosystems can become destroyed. 

There are several things that can happen within an ecosystem that can change it. For example, a forest fire will significantly change the plant and animal communities that live there. Organisms from flowers to insects to large mammals will be affected. 

Actions from outside the ecosystem can also affect it. For example, fertilizer runoff from a farm field can pollute a stream or a pond that's downstream. 

When the actions that change and degrade ecosystems are widespread and intense, they can destroy an ecosystem. You can imagine how this might be possible for a small pond, but large ecosystems can be destroyed too.

The Aral Sea in Central Asia, for example, was once the fourth largest lake in the world. But in the last few decades, massive amounts of water were diverted to grow cotton. And the lake began to shrink dramatically. At the same time, pesticides were sprayed onto fields in the watershed by airplanes. These human actions caused the loss of 90% of the sea's source waters and two thirds of its surface area. The water is now four times as salty. The Aral Sea is now considered to be in its final death throws, with very little chance of recovery.

Aral sea

Once a large lake, the Aral Sea is now mostly desert.

While some ecosystems cannot survive, others can "bounce back" and recover. Even the less resilient ecosystems can slowly recover. But it will require a lot of investment and time to restore them back to how they once were.

In general, many steps are involved in order to restore, enhance, or create healthy ecosystems. This includes planting native vegetation, rebuilding habitat  structure, and restoring the appropriate water flows and soils.

The marshlands of Mesopotamia before and after revitalization

Some ecosystems can bounce back! The marshlands of Mesopotamia were damaged when water was drained during the 1991 Gulf War. Recently, local people reflooded this ecosystem, and it is recovering well.

Around the world, people are more and more aware of habitat destruction and its devastating affects. Scientists and governments are working to restore destroyed habitats.

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Felicity Arengo

Felicity Arengo

Job Title: 
Associate Director, Center for Biodiversity & Conservation

Known For: 
Felicity is a conservation biologist. She studies flamingos in the wetlands of the Americas. She works with local scientists to create ways to protect animals and their habitats.

Cool Fact:
Felicity knows exactly where her flamingos are! She puts a transmitter on the back of each flamingo she is studying. She then tracks their movement with satellites and maps the data using computer models.

Image Credits:
Aral Sea over time, courtesy of NASA/GSFC; Mesopotamia environment before and after, © Curtis J. Richardson/Duke University Wetland Center; Felicity Arengo, courtesy of AMNH / Felicity Arengo.