Name Current Event Ecology

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Current Event Assignment

On a separate piece of notebook paper. Write a good paragraph summarizing the article and relating it to biology. This should be thoughtful and more than one sentence of your paragraph. Place quotes around anything you take directly from the article.

Write a second paragraph that is your reaction or connection to the article. This does not have to be as long, but remember a paragraph is at least 5 well written sentences.

Check for grammar and spelling errors. Type if you write messy. Tear off fringes if you are writing on notebook paper.

plants may regenerate from root fragments that

are carried downstream and deposited along river

margins. Those remnants of the old landscape

came to be known as “biological legacies,”

and their influence on the new landscape was

significant. They serve as source populations for

species to recolonize the disturbed area.

Research conducted by scientists at Mount St.

Helens has advanced our understanding of how to

manage an area after a disturbance. For example,

the biological legacies mentioned earlier were

found to strongly influence the plant and animal

communities that developed after the eruption.

This discovery has led to revised thinking about

how trees should be harvested. The importance of

leaving some live and dead trees within areas being

harvested is now well understood.

Understory herbs, shrubs, and saplings of shade tolerant

trees from the previous old-growth forest

survived the blast in numerous scattered patches

under a protective cover of snow. Now 15 to 25

feet tall, late-successional species such as Pacific

silver fir and mountain hemlock, and shorter stature

big huckleberry and vine maple grow intermixed

with sun-loving early colonizers such as lupine,

fireweed and pearly everlasting. Such observations

have furthered our understanding of succession.

As red alder trees and lupines became established,

they influenced succession. Because alder can also

fix nitrogen, they improve the fertility of the soil

like the lupine plant. Also, the rapidly growing alder

trees created shade and added organic material

to the ground surface. This contribution allowed

shade-tolerant plant species to become established.

Thirty years after the eruption, red alder is a

dominant tree.

Despite the establishment of vegetation over the

past 30 years, scientists predict that it will likely

take several hundred years for the blast area to

look the way it did before the eruption. Before

the eruption, the forest canopy was dominated

by old-growth Douglas fir, western and mountain

hemlock and Pacific silver fir, with many species of

moss, lichens, herbs, and shrubs in the understory.

Scientists will continue to study the blast area

and to document the return of plant and animal

communities for many years to come.

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