Why and how do ecosystems burn?

Abstract

There is an enormous literature on the loss of plant parts to insect and vertebrate herbivores and the morphological and chemical plant defences that have developed to counteract these losses. Herbivores are thought to exert a major impact on plants, both in ecological and evolutionary time scales. Annual losses to herbivores are estimated at more than 10% of plant production in natural communities, which probably exceeds average allocation to plant reproduction (Coley et al., 1985). Fires, by comparison, can remove 80% of the above-ground primary production in many ecosystems. Examples include some grasslands (where most of the grass biomass can be burnt annually) or fynbos shrublands (with above-ground primary productivities around 250gm^-2yr^-1, and fires burning around 3000gm^-2 once every 15 years).