Figure 4

Trend of the skewness (third standardized moment) of the SAD as a function of the number of transects. The symbols in red are for high- and in black for low- dispersal ability arthropod species groups of Terceira and Pico islands. The circles and triangles correspond to the mean values of the skewness calculated from the SAD obtained from all possible addition of transects using the concentric procedure as explained in the Methods. The dot and dashed lines correspond to 2 standard deviation confidence intervals. The two rightmost bold dots are the skewness estimated from extrapolated SADs and the arrow bars correspond to two standard deviations.