|Abstract||Grass populations in tropical savannas are highly resilient in relation to different fire regimes, but the
mechanisms conferring such resilience have been poorly studied. Here we examine one such mechanism, high adult
survival during fire, for three perennial grass species in an Australian savanna: Eriachne triseta Nees ex Steud,
Eriachne avenacea R.Br and Chrysopogon latifolius S.T.Blake.The study examined survivorship after 3 years, at plots
subject to experimental fire regimes (experiencing 0, 1, 2 or 3 fires over the study period) at theTerritory Wildlife
Park near Darwin in the Northern Territory, Australia. Mean survivorship was 79.9%, 64.3% and 62.0% for E.
avenacea, E. triseta and C. latifolius respectively. For the two species of Eriachne, mean survivorship was highest (E.
avenacea, 94.6%; E. triseta, 77.1%) in unburnt plots, whereas survivorship of C. latifolius was highest (71.7%) under
highest fire frequency. However, variation in survivorship among fire regime treatments was not statistically
significant for any of the study species. This negligible difference in survivorship among regimes points to fire
tolerance (sprouting ability) as an important mechanism contributing to the resilience and persistence of perennial
grasses in these savannas. |