Abstract
High levels of edaphic endemism and soil-related beta-diversity in Agulhas Plain fynbos communities suggest that reproductive traits of plants growing on different fynbos soils would be related to differences in soil regime. We investigated reproductive traits in two closely related Proteaceae species-pairs growing on adjacent soil types: Protea obtusifolia and Leucadendron meridianum occurring in shallow pockets of limestone-derived soils, and P. susannae and L. coniferum on the adjacent, uniformly deep colluvial sands.
We found that species growing on the limestone soil comprised smaller plants, with fewer cones and seeds per plant, than species on the colluvial sands. These differences suggest that the small soil pockets of limestone soil limit plant size, in turn limiting the number of reproductive structures. Annual variation in cones and seed was the same in all species. There were no consistent trends in degree of serotiny, or sex allocation across soil types. The higher cone and seed predation levels of both limestone species than the colluvial sands species were ascribed to the higher plant densities of the former leading to lower insect search times. It was concluded that there were no overall patterns in reproductive traits that could be ascribed to differences in soil regime, other than through size-related effects. Fire regime is likely to have played a more important role in determining reproductive traits.
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Department of Statistical Sciences, University of Cape Towm
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Mustart, P.J., Cowling, R.M. & Dunne, T.T. Reproductive traits of two closely related species-pairs on adjacent, different soil types in South African Fynbos. Vegetatio 111, 161–171 (1994). https://doi.org/10.1007/BF00040335
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DOI: https://doi.org/10.1007/BF00040335