title: Bud protection: a key trait for species sorting in a forest-savanna mosaic.
abstract: Contrasting fire regimes maintain patch mosaics of savanna, thicket and forest biomes in many African subtropical landscapes. Species dominating each biome are thus expected to display distinct fire-related traits, commonly thought to be bark related. Recent Australian savanna research suggests that bud position, not bark protection alone, determines fire resilience via resprouting. We tested first how bud position influences resprouting ability in 17 tree species. We then compared the effect of both bark-related protection and bud position on the distribution of 63 tree species in 253 transects in all three biomes. Tree species with buds positioned deep under bark had a higher proportion of post-fire aboveground shoot resprouting. Species with low bud protection occurred in fire-prone biomes only if they could root-sucker. The effect of bud protection was supported by a good relationship between species bud protection and distribution across a gradient of fire frequency. Bud protection and high bark production are required to survive frequent fires in savanna. Forests are fire refugia hosting species with little or no bud protection and thin bark. Root-suckering species occur in the three biomes, suggesting that fire is not the only factor filtering this functional type.
authors: Department of Biological Sciences, University of Cape Town, Rondebosch 7701, Cape Town, South Africa.|Kirstenbosch Research Centre, South African National Biodiversity Institute, Private Bag x7, Claremont, 7735, Cape Town, South Africa.
authors: Tristan
authors: T
authors: Charles-Dominique
authors: Department of Biological Sciences, University of Cape Town, Rondebosch 7701, Cape Town, South Africa.
authors: Heath
authors: H
authors: Beckett
authors: Kirstenbosch Research Centre, South African National Biodiversity Institute, Private Bag x7, Claremont, 7735, Cape Town, South Africa.|Department of Botany and Zoology, Stellenbosch University, P/Bag X1, Stellenbosch, Matieland, 7602, South Africa.
authors: Guy F
authors: GF
authors: Midgley
authors: Department of Biological Sciences, University of Cape Town, Rondebosch 7701, Cape Town, South Africa.|South African Environmental Observation Network, National Research Foundation, Private Bag X7, Claremont, 7735, South Africa.
authors: William J
authors: WJ
authors: Bond
mesh_terms: D005390:Fires; D035264:Flowers / Q000502:physiology*; D065928:Forests; D005843:Geography; D065948:Grassland; D024301:Plant Bark / Q000502:physiology; D019655:Quantitative Trait, Heritable; D013019:South Africa; D013045:Species Specificity; D014197:Trees
keywords: R-mode linked to Q-mode (RLQ); bark; biome; bud protection; fire frequency; forest; root-sucker; savanna