Fire Adaptations

Subject:
Art, Language Arts, and Science

Theme:
Many plants and animals have adaptations that allow them to live in fire-dependent habitats.

OBJECTIVE

Students will be able to:

1. Identify fire effects on plants

2. Identify fire effects on animals

3. Be more aware of how plants and animals adapt to wildland fire

METHOD

Working independently, students design a plant or animal that is adapted for fire survival.

BACKGROUND

To survive a fire, most plants have adaptive traits or abilities that allow them to reproduce or regenerate. Most animals will either flee the fire or, in the case of burrowing animals, move deeper underground. An adaptive trait is a behavior such as a physical feature or other characteristic that helps a plant or animal survive and make the most of its habitat. For example, the saguaro cactus, which inhabits the deserts of southwestern U.S., can store water. This adaptation helps the cactus survive through long periods of drought.

All living things have some traits that are adaptations to disturbances and constraints of their environments. Disturbances include both physical and biological disturbances, including fire.

NOWHERE TO RUN…

While many animals can flee in the face of fire, plants cannot. Plants are unable to run, fly, creep, or crawl out of a fire’s path.

Various species of plants, however, have adaptations to ensure their species’ survival after a fire. To survive a fire, a plant must be able to insulate itself from the heat of the flames. Bark thickness is one of the most important factors determining fire resistance of trees. Ponderosa pine, Douglas Fir, longleaf pine, slash pine, burr oak, and the giant sequoia, are examples of trees with thick bark that acts as insulation.

Small woody plants and shrubs, which normally have thin bark, tend to use the soil as an insulating layer to protect them. Individual plants resist being killed in fires by producing new growth (shoots) from underground roots or tubers.

Some plants protect their buds as an adaptive strategy to survive a fire. Buds can be protected by layers of succulent foliage. The buds of the longleaf pine are protected by a thick cluster of needles. Some plants even protect their buds by locating them within the main stem and roots. A few species of poplar trees in several parts of the world possess this trait.

Retention of seeds by plants until a fire does occur and stimulation of seed dispersal by fire are other examples of fire adaptation. A number of pine species around the world, said to be serotinous, have cones that open only as the result of heat from a fire. Their cones are held closed by a resin that is sensitive to and opens in high temperatures generated by wildland fires.

Serotinous cones will not open to release their seeds until the critical temperature is reached. Lodgepole pine cones (a western U.S. tree) vary from serotinous to free opening. When these trees grow in areas subject to frequent fires, the cones are serotinous. However, if a lodgepole pine grows in an area where fire is less frequent, the pinecones open and release their seeds more often without fire.

FIRE EFFECTS ON WILDLIFE…

Wildlife species have developed different methods or strategies to escape fires. Animals such as deer, bear, and kangaroo, which are accomplished runners and jumpers, use their skills to escape the flames. Other animals such as mice, shrews, snakes, lizards, and tortoises use burrows to escape fire.

Mature birds can fly to a safer area until the flames have passed. However, since nestlings and chicks may be unable to fly, they cannot escape the fire’s path. Their remains attract scavengers and predators, such as wild dogs, foxes, and vultures, to recently burned areas.

Organisms that inhabit the litter or humus layer (top few inches of soil) often decrease after a fire. Some of the insects in the humus layer are considered undesirable because they damage timber stands. Sawflies, red pine cone beetles, and maple leaf cutters are examples of nuisance pests whose numbers are reduced by wildland fires.

Although some insect populations decline as a result of fire, ants seem to thrive. Ant populations have been recorded as more numerous in burned areas than in unburned areas. An important species in grasslands for loosening the soil and burrowing grass seeds, ant populations increase after a prairie fire. Many microbial organisms (decomposers) also increase in numbers following fire.

Plants and animals that have structural and behavioral adaptations to survive in habitats frequented by fire are said to live in a fire dependent community. Plants that are highly adapted to fire are called pyrophytes. Today, people are beginning to recognize that fire is not always destructive. Fire is merely a means of change in ecosystems.

MATERIALS

Paper & Pencils

Crayons or Markers

Three-dimensional art supplies if desired

PROCEDURE

Review the background information with the students. Use plants and animals from your area as examples of species with adaptive strategies to survive fire. Ask each student to design a fictitious plant or animal that has adaptations for fire survival. Have each student draw the plant or animal and give it a name. Ask each student to share his or her feelings about wildland fire with the class and explain how the animal or plant is adapted for a fire community.

EXTENSIONS

1. Have the students interview two adults to find out what the interviewees know about wildland fire. Students should ask the adults if they know of any plants or animals in their area that has adaptations for fire habitats.



2. Assign students a library or Internet "exploration" to find plants or animals that are adapted to living in fire dependent communities.

SOURCE

Fire Ecology

Resource Management Education Unit

Wildfire – a study guide

Discovery Pictures

WEBSITES

National Park Service
http://www.nps.gov/

National Wildland Fire Home Page
http://www.nifc.gov

USDA Forest Service
http://www.fs.fed.us

Discovery Channel School
http://discoveryschool.com.

U.S. Fish and Wildlife Service
http://www.fws.gov/

Bureau of Land Management
http://www.blm.gov

Index to Wildland Fire WWW Catalog http://www.blm.gov/nstc/wildfire/index.html