Extended Data Fig. 2: Schematic of the methods used to compare floodplain and terra firme tree compositions, illustrated for two grid cells.
From: One sixth of Amazonian tree diversity is dependent on river floodplains
(a) Forest plot inventories (colored dots) were separated into várzea, igapó and terra firme categories, and species abundance information for separate várzea, igapó and terra firme grids was calculated at each 1-degree cell (only two shown), using distance-weighted interpolations of inventory plot data from an approximately 300 km circular window (red lines). (b) Floodplain and terra firme grids were overlaid and species turnover computed at analogous (vertically overlapping) cells. (c) Spatially-continuous grids of species turnover for várzea-terra firme and igapó-terra firme comparisons. The number of cells where species turnover is calculated depends on the spatial distribution of floodplain inventories and how it overlaps with terra firme inventories. This included 301 cells and 347 cells for várzea-terra firme and igapó-terra firme comparisons, respectively. In an alternative procedure of calculating species turnover, the interpolation step was excluded and cell compositional data was pooled only from plots located inside cells. For this second approach, the resulting number of cells where species turnover was calculated was 25 and 22 for várzea-terra firme and igapó-terra firme comparisons, respectively.
