The first paragraph of the discussion adeptly summarizes the most important and interesting findings of this study. It may be better to highlight this finding in the title.
In figures 2 and 4 the backgrounds of the individual density ridges are opaque instead of transparent and therefore occlude other data and the grey shading for the confidence interval. Figures 2 and 4 may be more clear to readers if the biomes in panel are sorted by latitudinal band and therefore match the sorting in panel b. Distinguishing realms in panel a could also be improved. Several members of our group initially thought it was a mistake that the space next to "marine" in the Realm legend was blank. Authors may consider distinguishing realm with 3 more distinct line types.
In figure 5, panel b, we believe that the color should be set to discrete rather than continuous. Out interpretation of the description of these results calls for 2 shades of blue and 2 shades of green, but there appear to be 3+ shades of blue and green.
On line 69, "reliable" should be "reliably."
We found it extremely interesting that the overall trend in biodiversity loss was not significantly different than zero. It is absolutely fascinating that while global biodiversity is decreasing, local biodiversity is essentially remaining the same due to species turnover. We would love to hear more of the authors interpretation possible consequences. We are especially curious about what these results may mean for ecosystem function over time. Do the authors feel that that ecosystem function will be maintained even in an era of extinction due to this turnover effect?