The effect of fire frequency on the sclerophyll vegetation of the West Head, New South Wales

Abstract

AbstractThe effect of fire frequency on the relative abundance of obligate‐seeders and vegetative‐regenerators was studied in 15 pairs of sites on the West Head, NSW. Each site pair consisted of a site which had been burnt frequently over the past 20 years and a nearby site which had been burnt less frequently. The data were collected in two phases. First, the relative abundance of the two overall groups of vegetative‐regenerators and obligate‐seeders was recorded by measuring the projective cover of live foliage. The presence or absence of particular species was then measured. For all the site pairs the projective cover of live foliage of obligate‐seeders was dramatically less in the frequently burnt sites. Some obligate‐seeder shrub species were absent from frequently burnt sites and the vegetation structure was simplified. In 11 of the 15 site pairs there was an increase in the projective cover of live foliage of vegetative‐regenerators in the frequently burnt sites, while in the remaining four site pairs there were no significant differences between the infrequently and frequently burnt sites. Overall, the increases in the relative abundance of vegetative‐regenerators made by high fire frequencies were not as large as the decreases in the relative abundance of obligate‐seeders.