PARENT SESSION
Oral Session #27: Fire Ecology.
Presiding: C. Allen
Tuesday, August 6. 8:00 AM to 11:30 AM. Graham Meeting Room, TCC.
Fire and floral diversity of southern African grasslands.
BOND, W J1, UYS, R G*,1, EVERSON, T M2, 1 UNIVERSITY OF CAPE TOWN, CAPE TOWN, SOUTH AFRICA2 UNIVERSITY OF NATAL, PIETERMARITZBURG, SOUTH AFRICA
ABSTRACT- Southern African grasslands contain a rich, distinct flora including many rare and endemic non-grass (forb) taxa. The grasslands, which resemble American prairies, are often subject to frequent fires. We explored the effects of different fire regimes on plant species in three long term burning experiments that had been running for 20, 26 and 48 years respectively. No significant difference in species richness was found at each site, across treatments including fire protection and burns ranging from annual to every five years, applied across a range of seasons. Ordination techniques, however, uncovered two suites of species, a fire-tolerant and a fire-intolerant flora. Within the fire-tolerant flora, environmental gradients were found to have a greater influence on composition across sites than burn treatments. Similarity comparisons also showed that the species composition of replicates of the burn treatments were not always significantly different from the remaining species pool at the site. Therefore, contrary to studies in North American prairies, the rich, endemic forb flora of the grasslands tolerates a wide diversity of fire regimes. Many of these species depend on fire and decline when it is excluded for long periods. The fire-intolerant flora, mostly woody species seral to forests, however, needs to be recognised and incorporated into conservation planning.
KEY WORDS: fire, grassland