Spatial Changes in Invertebrate Structures as a Factor of Strong Human Activity in the Bed and Catchment Area of a Small Urban Stream

Round 1

Reviewer 1 Report

I think the science and conclusions in this study are sound. My comments regard organization and clarity of language.

Line 10: "The threats to", NOT of

Line 11: instead of "a reduction in the value of", is it better to write "degradation of"?

Line 13: rather than "structures" it's clearer to write "community structures".

Line 14: "in the small urban stream"

Line 15: "in which the mass of"

Line 17: "by humans in the streambed"."

Lines 18-19: The sentence, "An additional and important..." is redundant.

Lines 20-21: "but at a lower scale." delete "of course"

Line 33: "Urban streams flow" delete "Moreover,"

Line 43: Do zooplankton always respond positively to dam impoundments? That seems to be a very sweeping statement.

Lines 47-48: Are small urban streams difficult to research? That hasn't been my experience, maybe it's true in Poland?

Line 61: I assume that Figure 1 shows NW Poland, not SW Poland.

The map in Figure 1 shows sites 1-6. Later in the text they are referred to as U1, U2, M3, M4, D1, D2. It's an effort to connect those two usages, please either edit the map or mention that usage later in the text.

Lines 71-72: "were marshy and contained dead organic matter." no need for parentheses.

Line 77: "sections (D5, D6) were characterized"

Lines 80-82: The last sentence can be reduced to "No field sampling permits with regard to site locations were needed."

Line 119: "A specialist key was" insert A.

Line 129: "The Mann-Whitney" insert The

Line 129 and later: Rather than mention "(P<0.05)" it would be better to mention that you use α<0.05 to determine statistical significance.

Line 137: "It was expected" rather than obvious.

Lines 137-141: I don't understand what you are trying to say in this paragraph. Yes, the reservoir is stagnant and eutrophic, but that's a given for your study, and other similar studies would encounter similar conditions.

Line 146: "was found to increase" rather than "be increased".

Figure 2: Should M5 and M6 be L5 and L6?

Figure 3: Does not to include UPGMA at the top of the figure.

Line 159: "between sites" does not need examined

Line 160: "at sites of" does not need examined

Table 2: The organization of the listing of species is confusing. Is it alphabetized within taxonomic groupings? If so, that should be clearer.

Line 162: Instead of "these organisms", use zooplankton.

Line 177: "At both sites" rather than all.

Line 179: "their abundance decreased" delete was.

Line 181: "found to increase." delete be, and increase rather than increased.

Lines 221-223: A statistical test doesn't really show anything, but is used to test for some data structure and the user has to interpret that result. So I suggest that you rephrase this sentence to say something to the effect of, "The Mann-Whitney U test was used to test for differences in family abundances in different sections of the stream."

Line 230:  "Significant differences were found between"

Line 233: "A Spearman test" insert A.

Line 234: "and taxa abundance." delete the.

Line 236: "it became clear that" delete was understood.

Line 243: "were characteristic of poor quality water (Table 6)."

Line 249: "Orange color stands" not sands.

Line 251: "and blue for very" delete the.

Line 260: "including large" delete the.

Line 275: Rather than just mention pollution, it might be better to write, "pollution in the form of excessive nutrient enrichment."

Lines 285-286: What are the "last site", the "last section"?

Line 291: "at the most downstream" delete last lower.

Line 321: "study flows through a" add s to flow.

Line 331: "the low tax richness" not The

Line 341: "based on ubiquitous taxa of" delete the, spell ubiquitous correctly

Line 346: "affected by human" delete the

Line 349: "Union are obligated to achieve a" rather than "should".

Line 364: "recipient river (especially" insert river.

Line 366: "variables, similar to the findings of Knott" reads better than the original.

 

 

Author Response

All the suggestions of the reviewer were used. The text was improved.

We would use the “P” than “α”. It is much more common symbol.

The POND environmental variables were not taken for the correlation analysis because it is well known than in standing waters the conditions are much different than in stream. It was very difficult to take for example the width, depth and current velocity to compare these two environment.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Editor,

I revised the MS entitled "Spatial changes in invertebrate structures as a factor of strong human activity in bed and catchment area of ​​small urban stream" by Czerniawski et al. The authors claimed that the aim of the study was to determine the impacts of abiotic conditions induced by intensive human activities on the structures of the invertebrates (zooplankton and macroinvertebrates) communities in the small urban stream Bukówka in Szczecin agglomeration (NW Poland).

However, what the authors did in practice, was to characterized the Bukówka stream taking into consideration only a subset of environmental parameters that are not specific of anthropic impact. Nevetheless, the study has the advantage of highlighting the high biodiversity of a small stream in which human interventions of alteration are evident.

I have some requests before suggesting the publication of the MS.

 

They are as follows:

1) Line 51. Please, indicate the country after the name of the stream.

2) Fig. 1. The caption of the figure should be more detailed. In particular, it must be indicated what the numbers means. In addition, I would also associate with the numbers the letters (e.g U, E…) indicated in the paragraph following the figure.

3) Line 84. Paragraph "Environmental factors". It is necessary to specify how often the environmental parameters were measured.

4) Lines 133-134. The consideration that I make here is also linked to the previous point. It is possible to make a correlation between biotic and abiotic parameters only if they have been taken contextually.

5) Lines 135-136. For biological data, the CA should be conducted on the Bray-Curtis distances that maintain information relating to the similarity of the site pairs based on both presence and absence. Euclidean distances, which do not respect this criterion, are not recommended (see Shaw, 2003. Multivariate Statistics for the environmental sciences. Oxford University Press).

6) Figure 2. What do the capital letters A and B represent? Explain, please.

7) Lines 235-237. This sentence is really too general. The authors need to explain better why they considered "not biologically relevant" the environmental variables that showed to be significantly correlated with the biological ones. I also suggest an exploration with multivariate statistics, such as BIOENV or CCA. It is not mandatory to carry out multivariates statiscs but it would help a lotion disentangling the patterns, better than individual correlations, in my opinion.

8) Line 243-244. Again the sentence is too general. Not all readers are aware that some index have classes. For example, I did not know that Margalef's values ​​could be traced back to 5 classes of biological quality. I suggest the authors to provide adequate details in the methodological part of the MS.

9) A general consideration: in the introduction much emphasis was given to the fact that the stream is located in an urban area. Why, then, variables certainly related to anthropogenic pollution, such as nitrates or phosphorus, or DOC, for example, have not been monitored? The authors should either better contextualize the purpose of their study or explain why chemistry other than chloride has not been investigated.

10) The claim that fish have an influence on phytoplankton abundances was not tested in this study. I suggest rewording the sentence to put it hypothetically.

11) The manuscript needs a linguistic revision.

Author Response

All the suggestions of the reviewer were used. The text was improved.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

 see attacherd

Comments for author File: Comments.docx

Author Response

All the suggestions of the reviewer were used. The text was improved.

The POND environmental variables were not taken for the correlation analysis because it is well known than in standing waters the conditions are much different than in stream. It was very difficult to take for example the width, depth and current velocity to compare these two environment.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

See attached comments in red

Comments for author File: Comments.docx

Author Response

*The authors seem to believe there has been little study of the impacts of urbanization on aquatic ecosystems. In the US, at least, this patently untrue, where decades of study provides a substantial inventory of data, models and analysis. See Google Scholar-urban water quality.

 

Response

I agree with this opinion. That sentence was unfortunate, therefore it was changed on: Small urban streams undergo very rapid environmental changes, as these are under the strong influence of local factors that disrupt their functioning, such as human activity in the catchment and in the bed or rapid water runoff from the urban surface.

 

*There should be a quantitative description of the features of urbanization in the watershed that might affect the aquatic ecosystem. This includes population density, type and sizes of industrial and municipal wastewater discharges, and land use elements.

 

Response

I agree with this opinion, but we have not a quantitative description of the urbanization features that were actual in the sampling days. We are aware that it would be much better. However, we would to study the invertebrates in urban stream that is surrounded by agglomeration. This was our aim.

 

*The only reference to any environmental regulations, any role them might have in outcomes or what relationship they have, if any, to this study, comes as an afterthought near the end with mention of a “Water Framework Directive”. This is without context or without knowing what bearing the study has on whatever recommendations are in the “Directive”.

 

Response

I agree with this opinion, this part of sentence was deleted and changed on: “Therefore, urban streams should be given more attention, constantly monitored, and treated with special measures.”

 

*There is no quantitative characterization of what constitutes good or bad ecosystem integrity in terms of the observed water quality and aquatic biology. This type of information is available from the considerable literature that is available.

 

Response

I agree with this opinion. The sentence that integrated these two terms was changed on  “The construction of reservoirs and bed regulation also have a similar effect on the ecological potential in small urban streams as in large rivers, but of course at a lower scale.”  

 

Specific Comments

 

 

Line 64 The map shows a POND, referenced as such in the text, but does not show a Sloneczne Lake.

 

Response

In the study area description we added  to the ‘Słoneczne Lake” the word “Pond” “The sediments of the reservoir – “Słoneczne Lake” (POND) were marshy and also contained dead organic matter."

 

 

Lines 137-140 This is still not clear

 

Response

The POND environmental variables were not taken for the correlation analysis because it is well known than in standing waters the conditions are much different than in stream. It was very difficult to take for example the width, depth and current velocity to compare these two environment. For example, the high abundance of zooplankton in stream site (3) below the pond was very high because zooplankton were washed out from this pond-reservoir. So, statistically it could be that the narrow bed of stream below pond could have much more impact on abundance than wide bed in lower section. It is not possible.

 

 

Line 303 Much is made of the impact of the Oder (Odra?) River on the lower parts of the Bukówka  River, yet there are no data supporting this.

 

Response

We agree with this opinion. However, we have no results from the Oder river, and we must make hypothesis. It is discussion and we have to show all possible reasons of zooplankton occurrence. We are sure that most of these crustaceans are not typical of small-stream fauna and they cannot occur in this stream. We wrote it. I think that this hypothesis is very possible. Maybe we must delete the word “greatest” or “highest”, but then we will cannot to show how important can be the water inlet from Oder to the stream.

 

Line 311 Where in the paper is this “proven”?

 

Response

This sentence was deleted. It have no sense in this paragraph.

Author Response File: Author Response.pdf