Prior et al_2010_recruitment bottleneck.pdf (168.31 kB)
Experimental evidence that fire causes a tree recruitment bottleneck in an Australian tropical savanna
journal contributionposted on 2023-05-17, 04:30 authored by Lynda PriorLynda Prior, Williams, RJ, David BowmanDavid Bowman
A fire-mediated recruitment bottleneck provides a possible explanation for the coexistence of trees andgrasses in mesic savannas. The key element of this hypothesis is that saplings are particularly vulnerable to fire because they are small enough to be top-killed by grass fires, but unlike juveniles, they take several years to recover their original size. This limits the number of recruits into the adult size classes. Thus savanna vegetation may be maintained by a feedback whereby fire restricts the density of adult trees and allows a grass layer to develop, which provides fuel for subsequent fires. Here, we use results from a landscape-scale fire experiment in tropical Australia, to explore the possible existence of a recruitment bottleneck. This experiment compared tree recruitment and survival over 4 y under regimes of no fire, annual early and annual late dry-season fire. Stemmortality decreased with increasing stem height in the fire treatments but not in the unburnt treatment. Tree recruitment was 76–84% lower in the fire treatments than the unburnt treatment. Such fire-induced stem loss of saplings and reduced recruitment to the canopy layer in this eucalypt savanna are consistent with the predictions of the fire-mediated recruitment bottleneck hypothesis.
Publication titleJournal of Tropical Ecology
Department/SchoolSchool of Natural Sciences
PublisherCambridge Univ Press
Place of publication40 West 20Th St, New York, USA, Ny, 10011-4211
Rights statementCopyright © 2010 Cambridge University Press & LD Prior et. al.