Biomass and density of native stands of Durvillaea potatorum (southern bullkelp) in south eastern Australia

Abstract

ABSTRACT: To date, there have been no large-scale surveys of the density or biomass of Durvlllaea stands in south eastern Australia. This paper presents data from the first such survey and provides evidence to suggest that Durvillaea potato run^ stands support an except~onally high biomass relative to many other marine and terrestrial ecosystems. The differences in density and biomass have been reviewed for populations of D. potatorum harvested throughout its distribution In south eastern Australia. Densities vary between 0.8 and 23.5 plants m-2, biomasses range from 4 to 108 kg m-2. These results are comparable to, but in the upper range of, the values observed for other species of brown algae. The level of concordance of D. potatorum populations to the 3/2 power law has been assessed. D. potatorum populations breach the boundary condition Implied by the 3/2 power law when log(k) = 4.3; if thls law does hold for D. potatorum populations the appropriate log(k) value is likely to be around 5.0, suggesting a carrylng capacity in these systems of up to 100 kg m-2. This is ca 5 times higher than that reported