Name: ___________________________________ Period: _______ Date: ________
Ecological Succession Laboratory Living Environment
Disturbance and Succession
What do you think would happen if the grass in your yard or a local park were never cut again? At first you’d be wading though a lot of tall grass.
Gradually, the seeds of nearby plants would be carried by the wind and settle in the grass. Soon, you’d have lots of plants growing along with the grass, and after many years, it would become a small forest. This slow replacement of one kind of habitat (your yard or a park) by another
habitat (a forest) is called succession. Succession is going on all the time; it’s part of nature. Succession turns abandoned farmland into forest, changes small ponds into dry land, and helps areas burnt by fires to become green again.
Any process, whether natural or man-made, that destroys habitats is
called a disturbance. It may take ten years or even a few hundred years, after a disturbance, for succession to return things to the way they originally were in an affected ecosystem. For example, in New York it takes at least 250 years for an old growth forest to recover from a disturbance! Sometimes a habitat or community never recovers from a disturbance; for example, a wetland that is drained and filled, for new houses or parking lots, can never again become a wetland. In Rochester, over 80% of our wetlands have been filled or drained.
In real life, succession after a disturbance may take hundreds of years to re-build a habitat. Instead of waiting that long, we will make a model of succession in which a pond gradually becomes a forest. Over the course of a few weeks, you will observe the changes your ecosystem undergoes and relate these changes to that of our local meadow communities.
Materials
 Aluminum-foil pan
 Soil
 Gravel
 Petri dish
 Spray bottle
 Grass seed
 Flower seeds/birdseed
 Tape
 Marker
 Ruler

Procedure
To set-up your ecosystem:
1.
Obtain an aluminum-foil pan and place 1 cm of gravel in the bottom
(for drainage).
2.
Cover the gravel with about 4 cm of soil (forming a meadow).
3.
Write the names of the members of your group on a piece of tape and attach it to the side of the pan for identification purposes.
4.
Place one side of a petri dish in the soil towards the center of your tray so that the top lip of the dish is level with the soil surface. Sprinkle a small amount of soil on the bottom of the petri dish (forming a pond).
5.
Slowly pour water into the aluminum foil pan until the petri dish is full.
Lightly spray the meadow with the water bottle until the soil is damp.
6.
Sprinkle a handful of grass seeds over the entire surface of the pan, including the pond.
7.
Place your ecosystem next to the window.
To observe your ecosystem:
8.
Observe your ecosystem everyday (5 minutes at the beginning of
EVERY class). Record observations in your data table.
9.
Continue sprinkling grass seed over the meadow and pond every 3-4 days (representing the blowing of seeds into the meadow from other ecosystems).
10.
Lightly water the meadow and pond with the plant sprayer once a week (representing rainfall). Do not refill the pond!
11.
After 1 week, sprinkle some flower seeds or birdseed on the soil along with the grass seed (representing the gradual invasion of shrubs and trees into the meadow habitat). Over time your meadow will transform into a forest.
12.
Continue observations for a total of 2 weeks.

6
5
4
3
Data
Experimental
Day
2
1
10
9
8
7
Date Pond Observations Meadow Observations

Analysis Questions
1.
In your own words, write the purpose of this activity.
2.
What environmental factors were necessary for the survival or most organisms?
3.
How long did it take for the seeds on land to begin to grow?
4.
What happened to the seeds that fell in the pond while it had water in it?
5.
What happened to the seeds that fell in the pond after it had dried up?
6.
How long did it take for the pond to dry up?
7.
What causes successional changes to occur in a community?
8.
What biological (biotic) or physical (abiotic) factors could cause successional changes in an ecosystem?
9.
What events might cause a real pond to become a forest?
10.
What kinds of organisms might live in the meadow habitat you created? Would you expect these same animals to live there once the forest plants started to grow?