Scaling of ramet size and spacing in seagrasses: Implications for stand development

The scaling between shoot mass and spacer length was examined across 23 seagrass species by compiling field and literature data on architectural and stand features. The distance between shoots programmed in seagrass architecture was scaled at the 0.24 power of shoot mass. The predicted distance between neighboring shoots resulting from the scaling relationship investigated was compared with the spacing observed in 79 crowded natural seagrass stands. Seagrass architecture predicted 50% of the variability of the distance between neighbors observed in natural stands. Moreover, the growth programme of seagrass species predicted 29% of the variance of maximum aboveground biomass developed by seagrass meadows. The close agreement between the shoot density and biomass developed by closed natural stands and that predicted from seagrass architecture suggested that the upper limit to density and aboveground biomass, such as that defined by the self-thinning law, is already imprinted within the basic architecture of seagrasses (i.e. spacer length in between consecutive shoots).