Spatial patterns in the effects of fire on savanna vegetation three-dimensional structure

Shaun R. Levick, Gregory P. Asner, Izak P.J. Smit

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Spatial variability in the effects of fire on savanna vegetation structure is seldom considered in ecology, despite the inherent heterogeneity of savanna landscapes. Much has been learned about the effects of fire on vegetation structure from long-term field experiments, but these are often of limited spatial extent and do not encompass different hillslope catena elements. We mapped vegetation three-dimensional (3-D) structure over 21 000 ha in nine savanna landscapes (six on granite, three on basalt), each with contrasting long-term fire histories (higher and lower fire frequency), as defined from a combination of satellite imagery and 67 years of management records. Higher fire frequency areas contained less woody canopy cover than their lower fire frequency counterparts in all landscapes, and woody cover reduction increased linearly with increasing difference in fire frequency (r2=0.58, P=0.004). Vegetation height displayed a more heterogeneous response to difference in fire frequency, with taller canopies present in the higher fire frequency areas of the wetter sites. Vegetation 3-Dstructural differences between areas of higher and lower fire frequency differed between geological substrates and varied spatially across hillslopes. Fire had the greatest relative impact on vegetation structure on nutrient-rich basalt substrates, and it imparted different structural responses upon vegetation in upland, midslope, and lowland topographic positions. These results highlight the complexity of fire- vegetation relationships in savanna systems, and they suggest that underlying landscape heterogeneity needs more explicit incorporation into fire management policies.

Original languageEnglish (US)
Pages (from-to)2110-2121
Number of pages12
JournalEcological Applications
Volume22
Issue number8
DOIs
StatePublished - Dec 1 2012
Externally publishedYes

Fingerprint

savanna
vegetation
vegetation structure
hillslope
effect
basalt
canopy
substrate
catena
fire history
structural response
fire management
satellite imagery
granite
ecology
nutrient

Keywords

  • Catena
  • Fire frequency
  • Heterogeneity
  • Kruger National Park
  • Landscape
  • LiDAR
  • Management
  • Savanna structure
  • South Africa
  • Topography

ASJC Scopus subject areas

  • Ecology

Cite this

Spatial patterns in the effects of fire on savanna vegetation three-dimensional structure. / Levick, Shaun R.; Asner, Gregory P.; Smit, Izak P.J.

In: Ecological Applications, Vol. 22, No. 8, 01.12.2012, p. 2110-2121.

Research output: Contribution to journalArticle

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