MEPS 158:131-138 (1997)  -  doi:10.3354/meps158131

The patch dynamics (recruitment, growth and mortality) of seagrass Cymodocea nodosa were examined at the landscape scale (i.e. the scale at which disturbances occur) by means of 3-dimensional (X, Y dimensions and depth) mapping of shoot internal density and age structure within the basic units (patches) forming the landscape. Highly skewed patch size and age distributions indicated a high exponential patch mortality rate (m = 0.82 ± 0.07 yr^-1) and a slightly higher exponential patch recruitment rate (1.04 yr^-1) that ensures the maintenance and fast turnover of this population of patches. Patch growth (i.e. increase in number of shoots per patch) proceeded at an exponential growth rate of 2.28 ± 0.14 yr^-1, indicating a doubling time of 111 d for the shoot population within each patch. Moreover, average patch growth rate accelerates with increasing patch size and age. This self-acceleration of patch growth means that this seagrass species has a remarkable potential for rapid space occupation due to its intense clonal growth. The results obtained emphasize the power of a landscape approach for describing the intense dynamics of colonising seagrass populations.

Seagrass patch dynamics · Landscape scale · Three-dimensional mapping · Size and age distributions · Pareto distribution