Assessing Spatial Distribution of Benthic Macroinvertebrate Communities Associated with Surrounding Land Cover and Water Quality

Round 1

Reviewer 1 Report

This manuscript is problematic in the format/organization.  This problem begins in the abstract.  The first half of the abstract is not presented as an abstract. The introduction is not well organized and some parts are repeated. Many statements lack clarity, for example, lines 51-54, line 69 - what does it mean to illuminate structures and functions...

What is the purpose of lines 74-75?

The first part of section 2.2 (Data collection) continues to discuss the sampling sites. The first few figure captions should include information on the sub-watersheds. 

Parts of section 2.3 would be useful in the paper's Introduction.

For the Results and Discussion, the raw data should be presented first.  

Overall, I found this paper difficult to navigate. 

I would be happy to evaluate this paper again after it is properly organized. 

 

Author Response

This manuscript is problematic in the format/organization. This problem begins in the abstract. The first half of the abstract is not presented as an abstract.

The abstract has been written more succinctly and concisely. We hope that the current revision provides readers with a clear description of our research. The edited text has been highlighted in the revised manuscript.

 

The introduction is not well organized and some parts are repeated.

We revised the introduction accordingly. Some repeated statements have been removed and simplified. The edited text has been highlighted in the revised manuscript.

 

Many statements lack clarity, for example, lines 51-54,

Many sentences have been modified and rewritten for clarification of the meaning. For example, the sentence (Line 51-54) has been revised as “Given the recently advanced satellite technology, easily obtainable/accessible data to land use information are highly cost-efficient, relative to field-based water quality measurement”.

 

Line 69 - what does it mean to illuminate structures and functions...

We rewrote the last paragraph, such as “We also analyze and evaluate sensitivities of benthic communities in different taxonomical levels (e.g., order, genus, and species). Furthermore, we anticipate finding out more useful data information to effectively characterize distribution of benthic macroinvertebrates, and thus shed light upon rapid assessment for stream health and integrity”.

 

What is the purpose of lines 74-75?

We were trying to clarify the research ethics in doing our study. Now the sentence has been removed.

 

The first part of section 2.2 (Data collection) continues to discuss the sampling sites.

Thank you for the comment. I understand why the reviewer says so. However, please also understand that this description is directly related to data sources and sampling networks within the catchment. So we would like to keep it as it was, in order to help readers understand our data better.

 

The first few figure captions should include information on the sub-watersheds. 

Thank you for the comment. We accepted this comment for Figure 1 and Figure 2. The captions have been revised accordingly.

 

Parts of section 2.3 would be useful in the paper's Introduction.

As recommended, we briefly mentioned about the indices in the introduction. We still leave most details in the method section.

 

For the Results and Discussion, the raw data should be presented first.

We re-organized the section, as recommended, rephrasing the unclear sentences and statements.

 

Overall, I found this paper difficult to navigate. I would be happy to evaluate this paper again after it is properly organized. 

Thank you again for the valuable and constructive comments.

Reviewer 2 Report

The work and the manuscript is of high quality. I have a minor comment.

Usually, the multivariate analysis methods (e.g. CCA) require some preliminary tests before their selection and application. For example, the general protocol before using CCA (unimodal method) is to run a Detrended Correspondence Analysis (DCA). If  the dominant gradient length of DCA is >4, then CCA is the appropriate method, if it is <3 then Redundancy Analysis (RDA) (linear method) is required (ter Braak & Smilauer, 2002; Lepš & Šmilauer, 2003). From my experience, when your data belong only to one watershed usually CCA is the most appropriate method, but when they belong to different watersheds usually RDA is the most appropriate method. This happens because inside a watershed the unimodal responses are more profound due to the distribution of study sites along topographic gradients. Due to the fact that your sites belong to different watersheds, an RDA might give better results. Have you made such preliminary tests. If yes add some lines about it. I would appreciate if you split your results and discussion in two separate sections. Check also the structure and the discussion of this study (Aschonitis et al., 2016) to get some ideas. 

 

ter Braak, C. J. F. & P. Smilauer, 2002. CANOCO Reference Manual and CanoDraw for Windows User’s Guide Version 4.5. Biometris-Plant Research International, Wageningen and České Budějovice.

Lepš, J. & P. Šmilauer, 2003. Multivariate analysis of ecological data using CANOCO.  Cambridge University Press, 269 p.

Aschonitis, V.G., Feld, C.K., Castaldelli, G., Turin, P., Visonà, E., Fano, E.A., 2016. Environmental stressor gradients hierarchically regulate macrozoobenthic community turnover in lotic systems of Northern Italy. Hydrobiologia, 765 (1), pp. 131-147.

 

Author Response

The work and the manuscript is of high quality. I have a minor comment.

Thank you for the valuable comments and positive response.

 

Usually, the multivariate analysis methods (e.g. CCA) require some preliminary tests before their selection and application. For example, the general protocol before using CCA (unimodal method) is to run a Detrended Correspondence Analysis (DCA). If the dominant gradient length of DCA is >4, then CCA is the appropriate method, if it is <3 then Redundancy Analysis (RDA) (linear method) is required (ter Braak & Smilauer, 2002; Lepš & Šmilauer, 2003). From my experience, when your data belong only to one watershed usually CCA is the most appropriate method, but when they belong to different watersheds usually RDA is the most appropriate method. This happens because inside a watershed the unimodal responses are more profound due to the distribution of study sites along topographic gradients. Due to the fact that your sites belong to different watersheds, an RDA might give better results. Have you made such preliminary tests. If yes add some lines about it. I would appreciate if you split your results and discussion in two separate sections. Check also the structure and the discussion of this study (Aschonitis et al., 2016) to get some ideas.

 

We appreciate the anonymous reviewer for this valuable comment. As recommended, we have calculated the length of gradient based on DCA. The dominant length was 4.16. We briefly describe the analytical procedure with the recommended references (ter Braak & Smilauer, 2002; Lepš & Šmilauer, 2003). This is also very useful information for our research in the future. We also re-organizing the discussion, citing the recommended reference (Aschonitis et al., 2016).

Round 2

Reviewer 1 Report

The manuscript is much improved.  Here are some concerns:

Abstract –

“assess spatial distribution of benthic macroinvertebrate communities in response to surrounding environmental factors related to land use and water quality.” Can the authors make a statement of what macroinvertebrate communities are known to respond to environmental factors?  In other words, make a statement as to why this information is useful.

“In 2017… ..in May and September 2017”  No need to repeat the year.

“.. and the second (15.5%) appeared water quality.”  Can you clarify “appeared?”

“..efficient proxy of ambient condition..”  conditions? In this sentence, why are specific macroinvertebrates mentioned without the corresponding land use information?

The last statement is vague.  Can the authors be more specific about the outcome of their study? Remove “In consequence.”

 

Introduction –

This section still need work. 

The first sentence of the second paragraph is just a restatement of the first paragraph information. Better to begin with “Stream health based on benthic communities can be spatially……”

Please re-state “Nevertheless, slow changes of land use patterns can be still limited to explicitly account for temporal dynamics of target biota of our interest.” Is this statement necessary?

Last sentence “Finally, we anticipate finding out more useful data information to effectively characterize distribution of benthic macroinvertebrates, and thus shed light upon rapid assessment for stream health and integrity.” Again, this is difficult to interpret.

 

Materials and Methods –

Line 83, conditions/ bring

 

Results and Discussion –

“Incoming nutrients seem dissolved forms of nitrogen and phosphorus, because we observed several increases of NH3-N, NO3-N, and PO4-P (Figure 3).” This is another statement that is unclear.

Please clarify: “Thus, it was difficult to distinguish spatial variation of ecological characteristics based merely on the indices”

“compared five biotic indices, and most values of biotic indices were not statistically significant across all the study sites (Figure 3).”

 

Are weather factors influential: rainfall (the phrase “after summer rainfall” was used many times), temperature, water flow?

Adjust columns in Table 1.

The authors should make a statement about what constitutes high levels (considered pollution) vs higher levels of water quality indicators.  The quantitative evaluation is missing.  What level of nitrogen compounds/ phosphorus is considered detrimental to the organisms?

“Plenty of literatures have reported…”  literature papers

Author Response

Abstract –

“assess spatial distribution of benthic macroinvertebrate communities in response to surrounding environmental factors related to land use and water quality.” Can the authors make a statement of what macroinvertebrate communities are known to respond to environmental factors?  In other words, make a statement as to why this information is useful.

We think that the current information about the benthic macroinvertebrate communities is specific (ex. Asellus, Gammarus, Simulium, Coleoptera, Diptera, etc.). However, we agree to include the punchline as conclusion. We added the conclusive sentence in the end. “Finally, we conclude that easily accessible information, such as land use data, aids to effectively characterize distribution of benthic macroinvertebrates, and thus enables us to rapidly assess stream health and integrity.”

 

“In 2017… ..in May and September 2017”  No need to repeat the year.

We removed it.

 

“.. and the second (15.5%) appeared water quality.”  Can you clarify “appeared?”

We reworded it.

 

“..efficient proxy of ambient condition..”  conditions? In this sentence, why are specific macroinvertebrates mentioned without the corresponding land use information?

We specified the ambient condition as water quality conditions.

 

The last statement is vague.  Can the authors be more specific about the outcome of their study? Remove “In consequence.”

Yes, we removed the phrase, and modified the last two sentences.

 

Introduction –

 

The first sentence of the second paragraph is just a restatement of the first paragraph information. Better to begin with “Stream health based on benthic communities can be spatially……”

We revised it as recommended.

 

Please re-state “Nevertheless, slow changes of land use patterns can be still limited to explicitly account for temporal dynamics of target biota of our interest.” Is this statement necessary?

We revised the sentence, considering the reviewer’s comment.

 

Last sentence “Finally, we anticipate finding out more useful data information to effectively characterize distribution of benthic macroinvertebrates, and thus shed light upon rapid assessment for stream health and integrity.” Again, this is difficult to interpret.

We shortened the last sentence and rephrased it.

 

Materials and Methods –

 

Line 83, conditions/ bring

We corrected it.

 

Results and Discussion –

 

“Incoming nutrients seem dissolved forms of nitrogen and phosphorus, because we observed several increases of NH3-N, NO3-N, and PO4-P (Figure 3).” This is another statement that is unclear.

We rephrased the sentence: “We speculate that incoming nutrients are more dissolved forms of nitrogen and phosphorus than particulate, because we observed frequent increases……”.

 

Please clarify: “Thus, it was difficult to distinguish spatial variation of ecological characteristics based merely on the indices” “compared five biotic indices, and most values of biotic indices were not statistically significant across all the study sites (Figure 3).”

The sentence has been revised.

 

Are weather factors influential: rainfall (the phrase “after summer rainfall” was used many times), temperature, water flow?

Yes, it is one of the climatic discrimination between the two surveys. Figure 2 shows the difference of rainfall between two time periods.

 

Adjust columns in Table 1.

The columns have been re-adjusted.

 

The authors should make a statement about what constitutes high levels (considered pollution) vs higher levels of water quality indicators.  The quantitative evaluation is missing.  What level of nitrogen compounds/ phosphorus is considered detrimental to the organisms?

We described the results based on relative comparison. However, we also provided the quantitative criteria depending on the context. For example, we explained Chl-a based on different trophic level. We provided a specific concentration for corresponding trophic level.

 

“Plenty of literatures have reported…”  literature papers

We corrected it as recommended.

Reviewer 2 Report

The authors significantly improved their paper according to the reviewer comments. Everything is fine in the paper except Table 1, which is quite confusing. What do you mean relative abundance? I couldn't understand how these percentages are connected. Please explain better Table 1, what are these values.

Author Response

The authors significantly improved their paper according to the reviewer comments. Everything is fine in the paper except Table 1, which is quite confusing. What do you mean relative abundance? I couldn't understand how these percentages are connected. Please explain better Table 1, what are these values.

Table 1 is comparable with Figure 4. Figure 4 is based on absolute abundance. However it is quite difficult to compare percent compositions. Thus, Table 1 is helpful to distinguish the percent ratios of each benthic group. We believe that this is quite a general term, so we would like to keep the current format. Thank you for the valuable comments.