Ecology:
Fire

Without recurring fires, all (California) grasslands would eventually be taken over by woody species.

—(Biswell 1989:195)

Fire as a Disturbance

Although fire is a physical disturbance of the landscape that occurs in almost all natural terrestrial ecosystems, modern ecologists only began to consider fire an important factor in plant community composition after 1947 (Whelan 1995:1).

Fire is an important part of the prairie ecosystem. It clears thatch, recycles nutrients, creates openings for seedlings, destroys colonizing shrubs and trees, and destroys bacterial and fungal pathogens.  The direct (e.g. flames, heat) and the indirect effects (e.g. nutrients, changes in soil chemistry) of fire can have both negative and positive consequences for different species and communities.

Interestingly, fire is unlike other physical disturbances, such as drought and flooding, for the nature of the fire itself is influenced by the composition of the plant community (Daubenmire 1968). For example, the low stature fine fuels (grasses and forbs) in grassland fires usually burn more rapidly and more completely than the dense woody trees in (Biswell 1989).

The pattern, frequency and intensity of fire in a community is called the fire regime. The four main factors used to describe the fire regime in grasslands are (Keeley 2002):

Strategies for Surviving Fire in Coastal Prairie

Cue for Germination

Flowering and mast seeding

Resprouting

Many herbaceous perennial plants have an advantage over most woody plants because their growing buds and storage organs (e.g. rhizomes, tap roots, tubers, bulbs, corms) are insulated from killing heat beneath the soil surface (Russell, et al. 1999).   When the top portion of the plant is destroyed by fire, the plant retains the ability and resources to re-sprout and grow. Underground structures store the energy needed to grow when the fire has passed and rains begin.

Tufted hairgrass survives fire by re-sprouting from basal buds located in the root crown; the tufted leaves protect the root crown from heat and fire damage (Biswell 1989).

Avoidance

Herbaceous perennial plants have an advantage over woody plants because their growing buds are insulated from killing heat beneath the soil surface (Biswell 1989).

Species that can escape or otherwise survive the fires may thrive in post-fire landscapes. Forage (grasses, sedge, rushes, forbs, and browse from shrubs) on burned areas is often more palatable, more nutritious, and more available to grazing and browsing animals than the forage on unburned areas (Reiner 2007).