Abstract
Savanna is a species-rich biome, that includes many modern mammal lineages and C4 grass (Poaceae) species. The greater productivity and grazing pressure associated with savannas is likely attributable to the foliar traits of the grasses they support. Thus, it is important to understand the complex relationships between the abiotic environment, foliar attributes and the floristic composition of savanna grasses, and the supported grazer densities. We sampled 37 grass communities in the Kruger National Park (South Africa) across three soil types and along a rainfall gradient and found that these communities lack strong phylogenetic structure. We then measured specific leaf area and leaf tensile strength for 384 individuals representing 66 species and found that both traits were strongly phylogenetically structured and associated with both rainfall and soil type. Finally, we found that grazer densities in the Park are correlated with the foliar traits of the associated grass communities, but the resolution of our data do not allow for a thorough analysis of this association. Our results demonstrate the complex interactions between climate, soils and grazer densities relative to C4 grass functional traits.
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Acknowledgements
We are grateful to M. van der Bank for logistical support, Izak Smit for comments on the manuscript and for making the grazer data available, and to four anonymous reviewers for helpful comments on the manuscript. YBK was supported by a Smuts Postdoctoral Fellowship from the University of Cape Town. FCB acknowledges a grant from the Claude Leon foundation. All authors declare no conflict of interest.
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Communicated by William E. Rogers.
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Bouchenak-Khelladi, Y., February, E.C., Verboom, G.A. et al. C4 grass functional traits are correlated with biotic and abiotic gradients in an African savanna. Plant Ecol 221, 241–254 (2020). https://doi.org/10.1007/s11258-020-01007-2
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DOI: https://doi.org/10.1007/s11258-020-01007-2