FIGURE 4. The Jaccard's similarity index (JSI) as a function of topological distance between DTA pairs.
From the following article:
Neutral metacommunity models predict fish diversity patterns in Mississippi–Missouri basin
Rachata Muneepeerakul, Enrico Bertuzzo, Heather J. Lynch, William F. Fagan, Andrea Rinaldo & Ignacio Rodriguez-Iturbe
Nature 453, 220-222(8 May 2008)
doi:10.1038/nature06813
The overall decay of JSI characterizes 
diversity7; the squares with error bars represent the average values with the range between the 25th and 75th quantiles of the empirical data, and the line represents the average values of the model results. Note that the JSI does not vanish, even for widely separated DTA pairs.