Also see in the attached pdf:

This paper examines the degree to which segment-scale flood regime characteristics interact with floodplain topography (landforms and distance from channel) to influence the functional diversity and composition of woody riparian plant species along multiple river reaches in the midwestern US (Michigan). The paper shows that the effects of landform elevation and distance to river on riparian plant community functional diversity are constrained by the hydrogeomorphic characteristics of the river segment. Hence, managers should not assume that relative landform elevations or position in the floodplain will have the same relationship with riparian plant communities on all river segments but will be contingent on the segment scale flood regime.

This is a very solid paper overall and should make a useful contribution to the literature. However, I have a few questions or comments that I would like the authors to consider.

First, the authors discuss the role of flood regimes in influencing stress or resource abundance and competition (two of the three axes in Grimes’ triangle) in the Introduction (e.g., Lines 79, 84, and elsewhere), but largely ignore the disturbance role of floods in influencing plant community composition and functional traits. The disturbance and stress effects of floods, and the plant functional traits that they favor, are somewhat different. Hence, I suggest that the authors more explicitly discuss the role of disturbance and its implications for floodplain forest composition and the traits of those floodplain plants within the Introduction (and perhaps the Discussion).

Second, naming the segment types based on dominant tree species (e.g., lines 101-107, 197) and then analyzing plant functional trait differences among them gives a slight appearance of circularity in approach and reasoning. The authors indicate, however, that the segment types are based on hydrogeomorphic differences and interpret these differences in the Discussion section. I imagine that the hydrogeomorphic differences among the segment types and how these are classified were documented in the Baker and Wiley (2004, 2009) papers. However, it would be helpful to the reader to show or more clearly describe those differences in flood regime (or other hydrogeomorphic characteristics) here in this paper as well, perhaps through figures or tables in the Supplementary Materials.

More detailed editorial comments are below:

You could consider including a study area map.

Line 143 – It is actually Table S1 that indicates the seven species that were excluded.
Lines 233 and 442 – seems consistent with Intermediate Disturbance Hypothesis
Table 1 – Just a note that the light shading that is used for relationships that are significant at p<0.1 is rather difficult to see. You might consider bolding the italicized text for this.
Lines 261-262 – As I noted earlier, statements like these could appear a little circular, given that the hydrogeomorphic segments are named after (and perhaps classified based on?) forest types. See my earlier notes on providing information on the hydrogeomorphic differences among the segment types.
Figure 2 – It would be better to explain more clearly what the different trait axes are in the figure (maybe in the figure description), rather than making the reader have to look up this information in the Supplementary Materials. Also, DT appears to be on both the x and y axes. Does it refer to something different on the x axis?
Line 328 – what do you mean by a relatively stable river system?
Lines 341-344 – what about disturbance? Or is this implied by the statement about dispersal? As mentioned earlier, the authors seem to largely leave out consideration of disturbance and its relationship with plant functional traits in river floodplain ecosystems.
Lines 348-349 – I thought that MOH and BSM did not have significant relationships of functional trait diversity with the relative elevation of landforms or lateral position in the floodplain.
Line 362 – As noted above, it would be nice to have some data on differences in hydrology among segment types to support these statements.
Lines 471-472 – The authors could have more explicitly quantified these hydrologic regimes in this paper, as these are the basis of the six segment types.

You have adequately addressed my original concerns. I have no other major suggestions. However, I found three very minor glitches that you might want to fix now or in the galley proofs:

On lines 293 and 294, does "a" represent alpha (statistical significance level)?

There may be some minor revisions needed in the references. I think that the citation of D.T Scott et al. is indicated as 2020 in the text, but 2019 in the lit cited. The citation of M.L. Scott et al. is out of order, alphabetically.

In Table S5, the p-value of 0.0408 under WFV and WRM for FDis should be bolded as well.