Avian Community Structure and Spatial Distribution in Anthropogenic Landscapes in Central Mexico

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review of the manuscript entitled “Avian community structure and spatial distribution in anthropogenic landscapes in central Mexico”

 

The manuscript concerns the analysis of the diversity of bird communities in 5 suburban areas of Mexico City. The manuscript has quite a lot of potential. A study was carried out between 2019 and 2022, which resulted in numerous data. The paper shows general assessments of taxonomic diversity (Hi) and species richness between the 5 selected sites for the total birds group, and with a distinction between residents and migrants and aquatic and terrestrial birds. The second aspect is the presentation of the similarity between species richness (heat maps and no-metric multidimensional scaling) for different microhabitats, feeding guilds, residency status etc. This is an interesting analysis but should be better linked to the objectives of the work. Some statistical methods of data analysis were implemented, but unfortunately, the data analysis carried out is not in line with the aims and objectives of the paper stated as “The study also examined, quantified and compared the avian diversity, composition, and abundance in various sites among highly contrasting human-dominated habitats (e.g., urban, semi-urban, and rural areas). Hypothesized that habitat heterogeneity leads to significant differences in species diversity and richness........”'. No such analysis is reflected in the paper. The description of the sites selected for the study shows a mosaic of different land cover types (urban, semi-urban and rural) together with microhabitat structures. However, no specified factors are banding the degree of heterogeneity. There is no analysis of sites in this context or the context of habitats with different gradients of urbanisation. Hence, the conclusions from the analysis and discussion of the data are not entirely derived correctly. The analyses of the material should be modified to suit the objectives or the introduction should be rewritten to more precisely define the objectives of the work, which are reflected in the data presented. Some of the methods of data analysis are not fully described and it is difficult to comment on the correctness of their use. In the context of the factors identified, the analysis should be based on linear and non-linear multivariate analyses.

 

Comments:

Lines 45-48 ….indicator of ecosystems health….. ?? The reference to source works {5,6] and especially the reference to the given ecological factors is not quite properly linked to the referred term ‘ecosystem health’. A healthy ecosystem is intact in terms of its physical, chemical and biological components and their interrelationships, making it resistant to change and stressors. It is a system in which ecological processes are fairly stable. The analysis of factors influencing the health of an ecosystem consists of examining the components of an ecosystem that make it sufficiently flexible and resilient, to perturbations. I suggest rewording this paragraph and better defining those aspects that are part of the research concept and later come up in the discussion, and suggest using more precise terms used in ecology for the stability of ecological systems linked to the hypotheses put forward.

 

Lines 89-96: - this paragraph should be rephrased as I indicated above in the context of analysis and precise research questions.

 

Line 96: Please insert “in before other habitats

 

Lines 166- 178: The transect method was used to assess bird community structure, but a transect only 50 m wide was used. Were only individuals observed within the 50 m transect space recorded, or were individuals observed and recorded outside the transect as well? Many of the species observed are birds with fairly long escape distances. Whether the detectability of birds was tested primarily according to the habitat type and distance that the 50 m wide transect was chosen, attack detectability together with the association with diurnal activity (surveys conducted over a wide time range 6:00-12:00). It is not precisely explained. It is a pity that the author did not use the Distance sampling method, better suited to this type of survey.

The second aspect I would ask for clarification. It is the aspect of species detection and marking. As a rule, we record birds' voices faster than we observe them, so for quantitative data analysis we should use accurate data, and there is no description in the manuscript of whether voices were recorded all the time to identify them. Did this only apply to any species that were problematic to identify? There is probably no point in stating what keys were used to identify species. This should be a basic skill of the researcher when conducting this type of research.

 

Line 185: I suggest using the term feeding guilds. Such a term is used further on in the presentation of the data (see lines 278, 294 etc.).

 

Lines 197-198: this should be described in fieldwork methods. I suggest moving and linking to the study methods description.

 

Lines 211-212: - why was factor analysis/major effects not used? While this is understandable in the context of the analysis of the variation in the variables studied between habitat types (see Fig. 3 A-D), a two-way analysis would have been appropriate for the multiple factor analyses (Fig. 3-E and F).

 

Line 211: - which version of the Tukey test was used? (see lines 269-270)

 

Line 212: - there is no seasonal variation analysis in the manuscript, and even less so in the Anova models

 

Line 213: - the context of the sentence does not allow a clear assessment - of whether the criterion of conformity of the distributions to the normal distribution was tested in all compared samples. There is no information on whether the distributions in the samples conformed to the normal distribution and allowed for parametric testing (e.g. Fig. 3A --it may appear that the assumptions were not met, but I do not know what the figure represents. There is no caption/legend indicating what data are presented in box-plot form, I can only suspect that the mean value is the median.

If the distributions were tested for concordance using the Shapiro-Wilk test, there is no need to provide information on the analysis of Q-Q plots and histograms.

There is no information on the homogeneity of variance analysis, an important assumption for the ANOVA analysis.

 

Figure 2: The information is the methodological aspect. Other analyses may be omitted and presented in the context of the research questions posed.

 

Lines 238-239: please check this data. The data is incorrect in the context of the description ‘... did not differ’. The probability levels are p =0.02 and p=0.002 - If these data and probabilities are correct then the interpretation of the test result is incorrect.

 

Line 251: and further in this paragraph (0.82) - what is this information? This should be clearly presented - so that the reader does not have to guess. Is this a Bray-Curtis similarity?

 

Line 251: why part of the sentence is presented in bold?

 

Lines 251-262: this part of the description is not very readable in the context of the data presented - suggest rewording

 

Figure 4: illegible signatures

 

Lines 262-265: the description is a little unclear. The ANOSIM test checks the null hypothesis, that the similarity between sites is greater than or equal to the similarity within each site. Comparisons are always pairwise.

 

Line 348 please insert the English name - Black-crowned Night Heron

 

Lines 393-396: this conclusion is not based on research, but is only an aspect of the discussion.

Lines 402-404: is a methodological aspect - should be moved to methods

 

In Appendix 1

The species names below should be corrected. Should be:

Larus delawarensis

Myiarchus cinerascens

Parkesia noveboracensis

Zonotrichia leucophrys

Comments on the Quality of English Language

-

Author Response

The author very much appreciates and again the time you took to process the manuscript as well as the time of your review and for their helpful comments, which have certainly improved this manuscript.

The manuscript concerns the analysis of the diversity of bird communities in 5 suburban areas of Mexico City. The manuscript has quite a lot of potential. A study was carried out between 2019 and 2022, which resulted in numerous data. The paper shows general assessments of taxonomic diversity (Hi) and species richness between the 5 selected sites for the total birds group, and with a distinction between residents and migrants and aquatic and terrestrial birds. The second aspect is the presentation of the similarity between species richness (heat maps and no-metric multidimensional scaling) for different microhabitats, feeding guilds, residency status etc. This is an interesting analysis but should be better linked to the objectives of the work. Some statistical methods of data analysis were implemented, but unfortunately, the data analysis carried out is not in line with the aims and objectives of the paper stated as “The study also examined, quantified and compared the avian diversity, composition, and abundance in various sites among highly contrasting human-dominated habitats (e.g., urban, semi-urban, and rural areas). Hypothesized that habitat heterogeneity leads to significant differences in species diversity and richness........”'. No such analysis is reflected in the paper. The description of the sites selected for the study shows a mosaic of different land cover types (urban, semi-urban and rural) together with microhabitat structures. However, no specified factors are banding the degree of heterogeneity. There is no analysis of sites in this context or the context of habitats with different gradients of urbanisation. Hence, the conclusions from the analysis and discussion of the data are not entirely derived correctly. The analyses of the material should be modified to suit the objectives or the introduction should be rewritten to more precisely define the objectives of the work, which are reflected in the data presented. Some of the methods of data analysis are not fully described and it is difficult to comment on the correctness of their use. In the context of the factors identified, the analysis should be based on linear and non-linear multivariate analyses.

R: Everything was adjusted according to the objectives of the study, adding an analysis to determine the effects of season (rainy, warm-dry, or cool-dry) and environmental variables of the study sites on the avian diversity variables.

Comments:

Lines 45-48 ….indicator of ecosystems health….. ?? The reference to source works {5,6] and especially the reference to the given ecological factors is not quite properly linked to the referred term ‘ecosystem health’. A healthy ecosystem is intact in terms of its physical, chemical and biological components and their interrelationships, making it resistant to change and stressors. It is a system in which ecological processes are fairly stable. The analysis of factors influencing the health of an ecosystem consists of examining the components of an ecosystem that make it sufficiently flexible and resilient, to perturbations. I suggest rewording this paragraph and better defining those aspects that are part of the research concept and later come up in the discussion, and suggest using more precise terms used in ecology for the stability of ecological systems linked to the hypotheses put forward.

R: This was modified, and appropriate references to the study's objectives were added.

Lines 89-96: - this paragraph should be rephrased as I indicated above in the context of analysis and precise research questions.

 R: This was modified according to the objectives of the study.

 

Lines 166- 178: The transect method was used to assess bird community structure, but a transect only 50 m wide was used. Were only individuals observed within the 50 m transect space recorded, or were individuals observed and recorded outside the transect as well? Many of the species observed are birds with fairly long escape distances. Whether the detectability of birds was tested primarily according to the habitat type and distance that the 50 m wide transect was chosen, attack detectability together with the association with diurnal activity (surveys conducted over a wide time range 6:00-12:00). It is not precisely explained. It is a pity that the author did not use the Distance sampling method, better suited to this type of survey.

R: This was corrected. All individuals were observed and recorded along the transect with a variable width, given that some species have variable flight distances.

The second aspect I would ask for clarification. It is the aspect of species detection and marking. As a rule, we record birds' voices faster than we observe them, so for quantitative data analysis we should use accurate data, and there is no description in the manuscript of whether voices were recorded all the time to identify them. Did this only apply to any species that were problematic to identify? There is probably no point in stating what keys were used to identify species. This should be a basic skill of the researcher when conducting this type of research.

R: It should be noted that this was only used to identify some birds’ voices, therefore and as a suggestion from the reviewer this part was removed.

Line 185: I suggest using the term feeding guilds. Such a term is used further on in the presentation of the data (see lines 278, 294 etc.).

R: The term feeding guilds was used.

Lines 197-198: this should be described in fieldwork methods. I suggest moving and linking to the study methods description.

R: This was removed in fieldwork methods

Lines 211-212: - why was factor analysis/major effects not used? While this is understandable in the context of the analysis of the variation in the variables studied between habitat types (see Fig. 3 A-D), a two-way analysis would have been appropriate for the multiple factor analyses (Fig. 3-E and F).

R: The analysis was adjusted, in order to determine the effects of season (rainy, warm-dry, or cool-dry) and environmental variables of the study sites on the avian diversity variables.

Line 212: - there is no seasonal variation analysis in the manuscript, and even less so in the Anova models

 R: The analysis was adjusted, in order to determine the effects of season (rainy, warm-dry, or cool-dry) and environmental variables of the study sites on the avian diversity variables.

Line 213: - the context of the sentence does not allow a clear assessment - of whether the criterion of conformity of the distributions to the normal distribution was tested in all compared samples. There is no information on whether the distributions in the samples conformed to the normal distribution and allowed for parametric testing (e.g. Fig. 3A --it may appear that the assumptions were not met, but I do not know what the figure represents. There is no caption/legend indicating what data are presented in box-plot form, I can only suspect that the mean value is the median.

R: The analysis was adjusted, in order to determine the effects of season (rainy, warm-dry, or cool-dry) and environmental variables of the study sites on the avian diversity variables.

If the distributions were tested for concordance using the Shapiro-Wilk test, there is no need to provide information on the analysis of Q-Q plots and histograms.

R: This was deleted

There is no information on the homogeneity of variance analysis, an important assumption for the ANOVA analysis.

R: The analysis was adjusted, in order to determine the effects of season (rainy, warm-dry, or cool-dry) and environmental variables of the study sites on the avian diversity variables.

Lines 238-239: please check this data. The data is incorrect in the context of the description ‘... did not differ’. The probability levels are p =0.02 and p=0.002 - If these data and probabilities are correct then the interpretation of the test result is incorrect.

R: this was modified.

Line 251: and further in this paragraph (0.82) - what is this information? This should be clearly presented - so that the reader does not have to guess. Is this a Bray-Curtis similarity?

R: This was corrected

Line 251: why part of the sentence is presented in bold?

R: This was corrected

Lines 251-262: this part of the description is not very readable in the context of the data presented - suggest rewording

 R: This was corrected

Figure 4: illegible signatures

  R: This was corrected

Lines 262-265: the description is a little unclear. The ANOSIM test checks the null hypothesis, that the similarity between sites is greater than or equal to the similarity within each site. Comparisons are always pairwise.

R: this was modified.

 Line 348 please insert the English name - Black-crowned Night Heron

R: the English name was inserted 

Lines 393-396: this conclusion is not based on research, but is only an aspect of the discussion.

R: I agree with this reviewer's comment

Lines 402-404: is a methodological aspect - should be moved to methods

R: These sentences moved to methods

In Appendix 1

The species names below should be corrected. Should be:

Larus delawarensis

Myiarchus cinerascens

Parkesia noveboracensis

Zonotrichia leucophrys

R: These species names were corrected 

 

 

 

 

 

Reviewer 2 Report

Comments and Suggestions for Authors

I have completed my review of the manuscript titled “Avian Community Structure and Spatial Distribution in Anthropogenic Landscapes in Central Mexico,” which was submitted to Birds.

This study aims to investigate the impact of urbanization on bird species diversity and richness within a peri-urban landscape in Mexico. While I believe that the manuscript merits publication, I would like to suggest that the authors address a few recommendations I have made. In particular, I recommend incorporating urban metrics to provide a clearer description of the surveyed areas along urbanization gradients.

Simple Summary
Lines 14-15. I believe the rational of this sentence should be inverted, because it is the
heterogeneity of the habitats which determines species’ patterns.
Introduction

Lines 56-66. I suggest using this paragraph to characterize the study area and remove it
from the introduction.

Lines 67-86. I suggest this paragraph be segregated and further detailed in two main ideas,
which are currently mixed. It should first explain about the impacts of urbanization, and
then the following paragraph should focus on its eRects on the bird communities. The first
paragraph (lines 42-55) should be placed in this scenario. I also believe that more about
the birds are needed. What are the main consequences for birds that inhabit urban areas?

Finally, some important references are missing, such as (please, review more studies on
birds, urbanization and the Neotropics):
Marzlu', John M. "Worldwide urbanization and its e'ects on birds." Avian ecology and
conservation in an urbanizing world (2001): 19-47.

Line 93. The null hypothesis would be not to find diRerences in natural and urbanized
habitats. The hypothesis the author presents “variety of bird assemblages might be higher
in native vegetation remnants and wetland habitats than other habitats” could be properly
referenced. I found it strange for a study which aims to compared urbanized environments
to hypothesize about wetlands.

Material and Methods
I suggest the author include another section clearly defining how each site was
categorized according to anthropogenic levels. The author stated that the aim of this study
was to evaluate the effect of urbanization on bird species diversity and richness, but while
reading the methods, I could not visualize any gradient of anthropogenic environments.
Was the objective to describe how the bird communities were distributed over a large
area, or was it to describe how different levels of urbanization influenced the presence of
the bird species? Please, make the objective as clear as possible.

Line 152 - Figure 1. The mosaic has some blank spaces, which I suggest being filled with
other images from the study areas. There is no number 1 in the green map. And the
legends within the images should be only in the figure legend. Each image should also beidentified with letterings.

Line 190. “…per species at each”. Each site?

Line 194. All estimators are biased, but instead, their diRerent premises could be
accounted for, and the author should choose the one which adheres best to his data.

Please check such diRerences e.g.,
Chao, Anne, and Chun-Huo Chiu. "Species richness: estimation and comparison." Wiley
StatsRef: statistics reference online 1 (2016): 26.

Line 195. Please, mention the R environment (R Core Team), not the RStudio Software.

Results
Lines 223-224. These are discussion.

I understand the several analyses, but I would also expect to find similar diRerences
among any other habitats, which are always heterogeneous, especially in Neotropical
regions. I recommend the author uses at least one urban metric (e.g., asphalting level,
human density, distance to the nearest source-areas, number of buildings etc.) to include
in the analyses and try to determine if actual urban metrics could drive bird presence
patterns.

Discussion

The first paragraphs discuss what was expected to find in heterogeneous habitats, but I
would recommend the author focus on urban metrics instead. Also, some of the
references used in the discussion were studies which were not conducted in urban areas,
which, to me, include a relevant bias, since natural and urban environments are
completely different.

Conclusion

It could be reduced and focused on the author’s own results. In addition, when the
authors states that he “found the highest diversity in water-bodies with heterogeneous
environments and significant decreases in avian diversity were recorded in the semi-urban
and urban habitats”, I find that to be extremely relevant. However, it is based on the
species richness and diversity indices compared to habitats which were qualitatively
characterized. If these habitats were classified to urban metrics, I believe the results could
be improved and much more robust.

Comments on the Quality of English Language

I am not an English native speaker, but I do believe that the text can be improved.

Author Response

The author very much appreciates and again the time you took to process the manuscript as well as the time of your review and for their helpful comments, which have certainly improved this manuscript.

I have completed my review of the manuscript titled “Avian Community Structure and Spatial Distribution in Anthropogenic Landscapes in Central Mexico,” which was submitted to Birds.

This study aims to investigate the impact of urbanization on bird species diversity and richness within a peri-urban landscape in Mexico. While I believe that the manuscript merits publication, I would like to suggest that the authors address a few recommendations I have made. In particular, I recommend incorporating urban metrics to provide a clearer description of the surveyed areas along urbanization gradients.

R: Urban metrics were incorporated to provide a clearer description of the studied areas along urbanization gradients.

Simple Summary
Lines 14-15. I believe the rational of this sentence should be inverted, because it is the
heterogeneity of the habitats which determines species’ patterns.
R: This was corrected

Introduction

Lines 56-66. I suggest using this paragraph to characterize the study area and remove it
from the introduction.

R: These sentences were removed.

Lines 67-86. I suggest this paragraph be segregated and further detailed in two main ideas,
which are currently mixed. It should first explain about the impacts of urbanization, and
then the following paragraph should focus on its eRects on the bird communities. The first
paragraph (lines 42-55) should be placed in this scenario. I also believe that more about
the birds are needed. What are the main consequences for birds that inhabit urban areas?

R: This was modified.

Finally, some important references are missing, such as (please, review more studies on
birds, urbanization and the Neotropics):
Marzlu', John M. "Worldwide urbanization and its e'ects on birds." Avian ecology and
conservation in an urbanizing world (2001): 19-47.

R: this was added.

Line 93. The null hypothesis would be not to find diRerences in natural and urbanized
habitats. The hypothesis the author presents “variety of bird assemblages might be higher
in native vegetation remnants and wetland habitats than other habitats” could be properly
referenced. I found it strange for a study which aims to compared urbanized environments
to hypothesize about wetlands.

R: This was modified.

Material and Methods
I suggest the author include another section clearly defining how each site was
categorized according to anthropogenic levels. The author stated that the aim of this study
was to evaluate the effect of urbanization on bird species diversity and richness, but while
reading the methods, I could not visualize any gradient of anthropogenic environments.
Was the objective to describe how the bird communities were distributed over a large
area, or was it to describe how different levels of urbanization influenced the presence of
the bird species? Please, make the objective as clear as possible.

R: This was modified. The analysis was adjusted, in order to determine the effects of season (rainy, warm-dry, or cool-dry) and environmental variables of the study sites on the avian diversity variables.

Line 152 - Figure 1. The mosaic has some blank spaces, which I suggest being filled with
other images from the study areas. There is no number 1 in the green map. And the
legends within the images should be only in the figure legend. Each image should also beidentified with letterings.

R: This was corrected

Line 190. “…per species at each”. Each site?

R: This was corrected

Line 194. All estimators are biased, but instead, their diRerent premises could be
accounted for, and the author should choose the one which adheres best to his data.

R: I agree with this reviewer's comment

Please check such diRerences e.g.,
Chao, Anne, and Chun-Huo Chiu. "Species richness: estimation and comparison." Wiley
StatsRef: statistics reference online 1 (2016): 26.

Line 195. Please, mention the R environment (R Core Team), not the RStudio Software.

R: RStudio was used and added the corresponding reference

Results
Lines 223-224. These are discussion.
R: This was removed.
I understand the several analyses, but I would also expect to find similar diRerences
among any other habitats, which are always heterogeneous, especially in Neotropical
regions. I recommend the author uses at least one urban metric (e.g., asphalting level,
human density, distance to the nearest source-areas, number of buildings etc.) to include
in the analyses and try to determine if actual urban metrics could drive bird presence
patterns.

R: Urban metrics were incorporated to provide a clearer description of the studied areas along urbanization gradients.

Discussion

The first paragraphs discuss what was expected to find in heterogeneous habitats, but I
would recommend the author focus on urban metrics instead. Also, some of the
references used in the discussion were studies which were not conducted in urban areas,
which, to me, include a relevant bias, since natural and urban environments are
completely different.

R: This was modified, and references to urban environments were added.

Conclusion

It could be reduced and focused on the author’s own results. In addition, when the
authors states that he “found the highest diversity in water-bodies with heterogeneous
environments and significant decreases in avian diversity were recorded in the semi-urban
and urban habitats”, I find that to be extremely relevant. However, it is based on the
species richness and diversity indices compared to habitats which were qualitatively
characterized. If these habitats were classified to urban metrics, I believe the results could
be improved and much more robust.

R: This was modified according to urban metrics.

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors, thanks for taking the comments seriously and especially for adapting the analysis methods to the data structure and re-analysing the results obtained. There is now a different quality to the manuscript. Proper methods of hypothesis testing have been introduced, allowing correct conclusions to be drawn; the authors have clarified doubts that arose earlier and corrected many paragraphs of the manuscript. In my opinion, the paper can be published in its present form. 

Reviewer 2 Report

Comments and Suggestions for Authors

Dear editor,

after verifying the author's modifications, I believe the concerns raised by the reviewers were fully addressed.