Figure 1
Hypothesised relationships between tsunami and genetic diversity within and among local populations of C. rugulosa. (a) Within a local population. The x-axis shows elapsed time from the establishment of a population. The left y-axis represents genetic diversity within an above-ground population. The green line indicates increases and decreases in genetic diversity within a local population through time. A white circle on the green line corresponds to the onset of seed production (individual maturation). The right y-axis indicates seed bank genetic diversity and the black dashed line indicates the genetic diversity of seeds maintained in the soil. Red arrows indicate disturbance events that destroy sandbars and create new ones. Disturbance frequency (assuming that a tsunami occurs once every several decades) is indicated by the appearance of red arrows through time. An arrow represents the magnitude of a disturbance. (b) The relationship between disturbance and gene flow in the meta-population (among local populations). Squares A to D represent geographically separated watersheds, while circles within squares indicate a presumed population within the watershed. Solid arrows indicate gene flow among populations and dashed arrows represent gene flow by disturbance. A question mark indicates whether the possibility of genetic mixture among distant populations will occur or not.
