Lesson 7

Vacant Lot Ecosystem

 

Lesson Overview:

Many people know that unusual and unique ecosystems in the world, like rainforests and coral reefs, are important to the earth's biodiversity. But scientists also think that it is important for us to conserve the biodiversity all around us. Farms and our own backyards are full of plants and wildlife. Even places with lots of people, like cities, and places that have been disturbed, like vacant lots, support all kinds of life.

 

Activity:

Students will visit a vacant lot in an urban area to observe the plants and wildlife it can support. They will learn that ecosystems exist in many different forms and serve many different purposes in our environment. They will assess human impact on the ecosystem and suggest ways that humans could make the lot a more biodiverse ecosystem.

 

Content Standards Addressed:

Common Core State Standards

 

Materials:

  • Field Books.
  • Pencils.
  • Insect nets (optional).
  • Binoculars, hand lenses (optional).

 

Procedure:

Review the concept of ecosystems and remind students that ecosystems can be almost any size. Introduce the idea of a vacant lot as its own ecosystem.

Point out that an "empty" vacant lot actually supports a variety of life. To make a living in a vacant lot, plants and animals must often make more adaptations than they might in another environment.

Explain that to find out how biodiverse the vacant lot is, the group will be looking for evidence of all the species that live there or pass through, including humans. Then they will note each in the Field Books. They should pay especially close attention to adaptations a plant or animal has made to the human-altered environment. When they find a good example of adaptation, they should draw a close-up picture of it and describe it in their Field Books. For example, they may find a weed growing out of a tire or a crack in an old sidewalk.    

Remind students that when they go to the lot, be sure to put things back the way they were, so they don't disturb the ecosystem. Caution them to avoid trampling or disrupting the lot. Students should find a way to record their findings without disturbing plant life. 

Humans:

Chances are that students will first notice litter or architectural ruins in the environment. A vacant lot often displays humans' bad habits of littering and not cleaning up after themselves. The lot may include the ruins of old buildings, machines, sidewalks and roads. Obsolete and worn out materials, ranging from bits of paper to old bed springs and junk cars, often find their final resting place in a vacant lot.

Living plants and animals on the lot may depend upon the ruins and litter, be altered by them or driven away. Litter and building ruins change the environment in many ways. They block sunlight, increase or decrease moisture, introduce different materials into the soil, compete for growing space and provide shelter. Ask the children to imagine what the vacant lot would be like without the litter, building remnants and other human alterations.

Ask children to find examples of adaptations caused by the ruins and litter. For example, a pigweed which is rooted in the soil, but growing through a sheet of tar paper, does not have to compete for sun, food or water with other plants. The tar paper occupies the space of the would-be competitors. A plant rooted in a small pocket of soil in a brick may not be able to grow elsewhere on the lot.​


A plant bending around a board in order to reach the sunlight looks very different from its brother growing in full sunlight. The students may find plants and animals depending upon litter for support (e.g., twining plants), for increased moisture (slugs, sowbugs, earthworms), for reduced light (moss, mushrooms) and for other benefits. Pigeons, which nest on cliffs in the wild, may find the eaves of abandoned buildings a perfect substitute. Ask students to record one of these fascinating adaptations and record it in their Field Books with a detailed drawing and description.

Also note examples of how nature is changing litter or building materials. Where is decomposition happening? Rotting litter and building materials will change the composition of the soil in some spots. It also provides food for the decomposers and everything that eats the decomposers. What other forces are changing the man-made materials? (gravity; weathering from water, wind, sunlight; and freeze-thaw cycles)

Mammals:

In a vacant lot, mammals are not always seen right away. The best way to look for them is to find animal droppings. Ask: Do dogs, cats or rabbits leave their droppings there? Do they use one particular part of the lot or all of it? Why might they use one section more than others? Why would a cat or other carnivore visit the lot? How would a cat's presence affect the rest of the animal life there?

What evidence is there of herbivores living in the lot? Can you see mouse nests or rabbit trails? What do their droppings look like? Can the students find trails that might have been made by rabbits? (Rabbit trails are usually about four inches wide and found in deep grass that is matted with droppings.) Can they guess where the rabbit was going when he made the trail? Don't forget to look overhead! What mammals might live there? (Squirrels, bats)

 
Birds:
Watch the birds closely and see what they do when they come to the lot. Ask the students why birds might visit the lot. Are there trees or bushes for nesting? Are there seeds, berries or insects for feeding? Have the class look for birds feeding or bird nests. You might take binoculars to make them easier to see. What different species of birds visit the lot? What reasons does each have for being there? 
 

Insects:

Have the students look on the ground, under things, on trees, leaves and other places that might harbor insects.

The students could swing an insect net so that it brushes the surface of the plants. They will be surprised at the insects they didn't know were there. Practice will make them even more successful. Note the insects found in Field Books.  

 ​

Plants:

A variety of plants will probably be found within the lot. Some possibilities are:

  • Clover.
  • Foxtail.
  • Plantain.
  • Yellow goat's beard.
  • Oxalis.
  • Wild grasses.
  • White champion.
  • Goldenrod.
  • Climbing nightshade.
  • Shepherd's purse.
  • Deadly nightshade.
  • Thistle.
  • Dandelion.
  • Wild carrot.
  • Lamb's quarters.
  • Milkweed.
  • Wild rhubarb.
  • Pigweed.
  • Nettle-leafed goose foot.                                                               ​

 

Students might also find seedlings from trees surrounding the lot and domestic flowers that have "escaped" from gardens.​

 
Discuss: Does the same plant grow differently in another part of the lot? Why? What plants are first to grow in building ruins? What tree species are first to grow? Which plants are edible? For humans? For animals?
 
It is not necessary to name the plants during your survey. However, if you wish, a simple pictured "weed" key can be obtained from the library or your local university extension office for identification back in the classroom. Drawing detailed pictures in their Field Books will make identification easier.  
 
 
After Your Exploration:
Back in class, make a three-column list of all the human alterations, animals (mammals, birds and insects), and plants the group saw. How biodiverse does this vacant lot seem to be compared with other environments, like a wooded area, a park, a farm or suburban backyard? (Don't assume the answer - the suburban lawn is one of the least biodiverse environments on earth!)
 
Ecologists believe that even small patches of biodiverse ecosystems are important to make up for disappearing habitats for some species. Larger tracts of land are even better! What could be done to make this lot friendlier to a larger number of species? You may want to refer to this activity later when covered the "Taking Action" section of this program.
 
 
Reproducible: FYI! The HIPPO Dilemma
Make copies of the reproducible. Have students read the text to discover the main threats to ecosystems and biodiversity. They can read independently and answer the Reflect and Review questions on their own. Or read the text aloud and discuss the answers to the questions together.