title: Effects of four decades of fire manipulation on woody vegetation structure in Savanna.
abstract: The amount of carbon stored in savannas represents a significant uncertainty in global carbon budgets, primarily because fire causes actual biomass to differ from potential biomass. We analyzed the structural response of woody plants to long-term experimental burning in savannas. The experiment uses a randomized block design to examine fire exclusion and the season and frequency of burn in 192 7-ha experimental plots located in four different savanna ecosystems. Although previous studies would lead us to expect tree density to respond to the fire regime, our results, obtained from four different savanna ecosystems, suggest that the density of woody individuals was unresponsive to fire. The relative dominance of small trees was, however, highly responsive to fire regime. The observed shift in the structure of tree populations has potentially large impacts on the carbon balance. However, the response of tree biomass to fire of the different savannas studied were different, making it difficult to generalize about the extent to which fire can be used to manipulate carbon sequestration in savannas. This study provides evidence that savannas are demographically resilient to fire, but structurally responsive.
authors.affiliation: Lehrstuhl für Vegetationsökologie, Technische Universität München, 85354 Freising, Germany. higgins@wzw.tum.de
authors.forename: Steven I
authors.initials: SI
authors.lastname: Higgins
authors.forename: William J
authors.initials: WJ
authors.lastname: Bond
authors.forename: Edmund C
authors.initials: EC
authors.lastname: February
authors.forename: Andries
authors.initials: A
authors.lastname: Bronn
authors.forename: Douglas I W
authors.initials: DI
authors.lastname: Euston-Brown
authors.forename: Beukes
authors.initials: B
authors.lastname: Enslin
authors.forename: Navashni
authors.initials: N
authors.lastname: Govender
authors.forename: Louise
authors.initials: L
authors.lastname: Rademan
authors.forename: Sean
authors.initials: S
authors.lastname: O'Regan
authors.forename: Andre L F
authors.initials: AL
authors.lastname: Potgieter
authors.forename: Simon
authors.initials: S
authors.lastname: Scheiter
authors.forename: Richard
authors.initials: R
authors.lastname: Sowry
authors.forename: Lynn
authors.initials: L
authors.lastname: Trollope
authors.forename: Winston S W
authors.initials: WS
authors.lastname: Trollope
mesh_terms: D018533:Biomass; D002244:Carbon / Q000378:metabolism*; D003247:Conservation of Natural Resources; D017753:Ecosystem; D005390:Fires; D006109:Poaceae / Q000254:growth & development*; D011157:Population Dynamics; D011897:Random Allocation; D012621:Seasons; D014197:Trees / Q000502:physiology*
chemical_list: D002244:Carbon