Figure 3

Allotaxonograph using rank-turbulence divergence to compare tropical forest tree species abundance on Panama’s Barro Colorado Island (BCI) for 5 year censuses completed in 1985 and 2015 [56]. This system comparison shows relatively little turnover or turbulence. We see none of the sideways flaring of the histogram towards the bottom—turbulence—as we did for Twitter word usage in Fig. 2. A choice of \(\alpha =0\) for rank-turbulence divergence per Eq. (9) produces vertical contour lines that conform well to the histogram. From inspection of both the histogram and the \(\delta D^{\mathrm{R}}_{0,\tau }\) list, the relative decline of a single species of pepper plant, Piper cordulatum [57–60], is the dominant dynamical change in the forest’s composition. See Sect. 5.1 for further notes on the BCI data