Four Winds Nature Institute
4 Casey Rd. Chittenden, VT 05737
802-483-2917 www.fourwindsinstitute.org
UPPER GRADES CHALLENGE: Ecosystems in Winter
Background: The food supply in winter landscapes differs greatly from what is available in summer, and food chains and webs within an ecosystem will change accordingly. Photosynthesis, the process by which plants harness the sun’s energy to make sugars, comes almost to a halt in winter, and yet it is the basis of every food chain in an ecosystem. Herbivores cannot eat fresh green vegetation in winter because there is none. They must get their energy from food they have stored, or food stored in the buds, fruits, bark and twigs of plants. Carnivores will find their prey in much shorter supply in winter, as many species are dormant, hibernating, or living under the snow, and many birds will have migrated away. Here students create winter food chains and food webs based on the animals that are active in their area in winter and the food sources that would be available, and compare them to the field food web they made in the fall.
Objective: To visualize the food chains in a field or forest ecosystem during winter and notice how they differ from those in summer.
Give each pair or team of students a set of cards on which are written the carnivores and herbivores that are active in your area during the winter, as well as possible plant food sources that would be available during winter, such as those listed below. Ask the children to arrange the cards in food chains or a food web, on a large sheet of paper, and to draw lines showing the food chain connections among them.
Possible foods
Acorns nuts
Seeds
Berries
Young twigs
Insect larvae
Tree buds
Bark
Herbivores
Grey Squirrel
Vole
Mouse
Rabbit
Woodpecker
Deer
Porcupine
Carnivores
Fox
Owl
Housecat
Bobcat
Hawk
Coyote
Fisher
Which animals are herbivores? Which animals are carnivores? What is the basis of winter food chains? (plants – same as in summer) Where does the energy come from for winter food chains? (the sun’s energy – same as in summer – only it is stored in plant products such as nuts, seeds, fruits, buds).
Materials: Sets of 18 cards (labeled as above) for each team of students, large sheet of paper for each team, field guide for each team with information about animal’s feeding preferences in winter.
Four Winds Nature Institute –10/06