Carbon stocks in fynbos, pastures and vineyards on the Agulhas Plain, South Africa: a preliminary assessment

Abstract

Large tracts of fynbos on the Agulhas Plain are being converted to agriculture. Carbon (C) stocks in fynbos, pastures and vineyards were measured in this preliminary study to determine whether conservation of fynbos results in greater C storage relative to agricultural land uses. Fynbos had greater aboveground C than pastures (12.7 ± 1.7 vs 0.8 ± 0.3 t C ha⁻¹), greater root C than pastures and vineyards (13.0 ± 11.7, 4.9 ± 1.4 and 0.2 ± 0.2 t C ha⁻¹, respectively), less soil organic C than pastures (1.26 ± 0.14 vs 2.06 ± 0.22%) and less total soil C than pastures (66.7 ± 7.2 vs 99.2 ± 10.9 t C ha⁻¹). The results indicate that conversion of fynbos into pastures is unlikely to result in a net loss of C stocks because reductions in aboveground biomass, litter and root C are recovered through gains in soil C. Conversion of fynbos into vineyards is likely to result in a net loss of approximately 23 t C ha⁻¹ in aboveground and root biomass.