Aquatic Macroinvertebrates as Indicators of Climate Change in the Riparian Environments of the Mediterranean Region

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors and Editor

The manuscript entitled “Aquatic macroinvertebrates as indicators of climate change in riparian environments of the Mediterranean region.” explores the critical issue of the impact of climate change on riparian ecosystems, with a special emphasis on the use of aquatic macroinvertebrates as bioindicators.

Given that the Mediterranean region is among the most vulnerable to climate change, this research is highly relevant and contributes to a deeper understanding of ecological changes in this sensitive environment.

The main strength of the paper is the application of the PRISMA methodology in a systematic literature review, thus ensuring a comprehensive and reliable synthesis of existing knowledge. The author’s approach is particularly valuable in assessing the responses of macroinvertebrates to increasing temperatures, decreasing precipitation, and hydrological changes, including extreme droughts and floods.

Notably, the study primarily focuses on three key orders of macroinvertebrates: Plecoptera, Trichoptera, and Ephemeroptera. The significant variations in the time spans of the reviewed studies highlight the long-recognized effects of climate change on these communities. However, despite the importance of long-term studies in understanding the impacts of climate change, unfortunately the number of available studies remains relatively limited.

It is recommended to include the authorship alongside the Latin names of aquatic macroinvertebrate species upon their first mention in the text.

This review is well structured and contributes valuable insights to the scientific community, and I recommend its acceptance.

Best regard,

Rewier

Author Response

Response to Reviewer 1 Comments

                       

We sincerely thank the reviewers for their insightful and constructive feedback, which has significantly strengthened our manuscript. Below, we outline the revisions made in response to their comments:

 

Point-by-point response to Comments and Suggestions for Authors

 

Comments: Dear Authors and Editor

The manuscript entitled “Aquatic macroinvertebrates as indicators of climate change in riparian environments of the Mediterranean region.” explores the critical issue of the impact of climate change on riparian ecosystems, with a special emphasis on the use of aquatic macroinvertebrates as bioindicators.

Given that the Mediterranean region is among the most vulnerable to climate change, this research is highly relevant and contributes to a deeper understanding of ecological changes in this sensitive environment.

The main strength of the paper is the application of the PRISMA methodology in a systematic literature review, thus ensuring a comprehensive and reliable synthesis of existing knowledge. The author’s approach is particularly valuable in assessing the responses of macroinvertebrates to increasing temperatures, decreasing precipitation, and hydrological changes, including extreme droughts and floods.

Notably, the study primarily focuses on three key orders of macroinvertebrates: Plecoptera, Trichoptera, and Ephemeroptera. The significant variations in the time spans of the reviewed studies highlight the long-recognized effects of climate change on these communities. However, despite the importance of long-term studies in understanding the impacts of climate change, unfortunately the number of available studies remains relatively limited.

It is recommended to include the authorship alongside the Latin names of aquatic macroinvertebrate species upon their first mention in the text.

This review is well structured and contributes valuable insights to the scientific community, and I recommend its acceptance.

Best regard,

Rewier

 

Response 1: Thank you very much for the comments. We have included the authorship along with the Latin names of the aquatic macroinvertebrate species in their first mention as recommended. This modification can be seen in lines 505-506, 512, 515 and 518.

Reviewer 2 Report

Comments and Suggestions for Authors

The is a good, succinct account of an interesting [worrying] problem. I did not see any errors or problems and the only shortcoming perhaps is that it is based solely on a review of literature and maybe some specific case-study work would stress the relevance more keenly. The Conclusions section is rather abrupt.

However, in setting the scene of likely adverse impacts of climate change on a particularly vulnerable taxonomic group, this is a good paper. I wonder if there are other comparable reviews for other taxa in the Mediterranean which might be interesting, and also, are there any taxa in the study focus that might benefit. Presumably species may also colonise in from other areas as the climate envelope shifts - and these may compete with the endemic species already under pressure. Perhaps some of these issues might be briefly considered in an expanded Conclusions section.

Additional comments on: Aquatic macroinvertebrates as indicators of climate change in riparian environments of the Mediterranean region

This is a carefully thought out review paper of the use of aquatic indicators of environmental change and in this case the use of macro-invertebrates to reflect climate predicted change in terrestrial river systems around the Mediterranean. The introduction is effective in setting the scene and establishing the research questions and context. The core issue is the predicted impacts of expected climate change scenarios on the distribution and abundance of species particularly rare endemics.

There are no illustrations beyond a single table with a flow-chart  and it would be informative to include a selection of images of the habitats in question and of the taxonomic groups under review.

The Methodology is satisfactory, and a broad range of relevant literature was identified. The authors found and screened over 400 papers to eventually review around 40. They note the limited literature on the topic in the case-study region, and hence this paper is an original contribution which helps close a gap in the current knowledge.

However, there are numerous reviews on ecological and landscape change in and around the Mediterranean though not specifically on aquatic macroinvertebrates. Whilst not relevant to the review per se,  these might be reference as context to Mediterranean studies more widely and serve to embed this study in the wider literature.

I do wonder about other factors coming into play with trends towards urbanisation on the one hand and land-use / agricultural change on the other. Some of this may be driven by long-term climate change too and may to a degree affect the impacts of change scenarios. I feel that these should at least be considered in the Discussion. [Generally, I would separate out the Results and the Discussion, but I am unsure of the journal policy on this].

Overall, this a good, succinct account of an interesting [and indeed worrying] problem. I did not see any errors or problems in the broad methodology and the only shortcoming perhaps is that it is based solely on a review of literature and maybe some specific case-study work would stress the relevance more keenly. The scope of the review might be broadened as noted above, and the Results might be usefully summarised at the end of the Discussion to highlight the main ‘take-home’ messages relating the research questions posed.

Relevant illustrations might be informative particularly to a non-Mediterranean reader.

As noted previously, the Conclusions section is rather abrupt and might usefully be both expanded and focused on core questions and the findings from the review. A short contribution in terms of ‘future work and research directions’ would be helpful.

 However, in setting the scene of likely adverse impacts of climate change on a particularly vulnerable taxonomic group, this is an effective contribution which with additions as noted can be a significant contribution to the literature on likely responses to climate change scenarios.

As discussed above, I wonder if there are any comparable reviews for other taxa in the Mediterranean which might be interesting to at least provide a wider context.  Also, are there any specific taxa in the focus of this study that might benefit from the predicted climate changes? Presumably species may also colonise in from other areas as the climate envelope shifts - and these may compete with the endemic species already under pressure. Perhaps some of these issues might be briefly considered in an expanded Conclusions section. The roles of interactions between endemic species maybe in decline and competition with exotic and colonising species may be interesting. Even if there is no relevant literature available, this might be worth at least considering in your conclusions and recommendations. There will be examples in the worldwide literature and cases of say the invasion into parts of Europe by exotic crayfish species and their impacts on other species and on ecosystem function. Furthermore, what do climate change scenarios imply for these recombinant species interactions?

 

 

 

 

 

 

Author Response

Response to Reviewer 2 Comments

 

                       

We sincerely thank the reviewers for their insightful and constructive feedback, which has significantly strengthened our manuscript. Below, we outline the revisions made in response to their comments:

 

Point-by-point response to Comments and Suggestions for Authors

Comments 1: The is a good, succinct account of an interesting [worrying] problem. I did not see any errors or problems and the only shortcoming perhaps is that it is based solely on a review of literature and maybe some specific case-study work would stress the relevance more keenly. The Conclusions section is rather abrupt.

However, in setting the scene of likely adverse impacts of climate change on a particularly vulnerable taxonomic group, this is a good paper. I wonder if there are other comparable reviews for other taxa in the Mediterranean which might be interesting, and also, are there any taxa in the study focus that might benefit. Presumably species may also colonise in from other areas as the climate envelope shifts - and these may compete with the endemic species already under pressure. Perhaps some of these issues might be briefly considered in an expanded Conclusions section.

 

Response 1: Thank you very much for your comments. The conclusions section has been expanded to emphasise the changes that will occur in macroinvertebrate communities, such as homogenisation, the increase in the distribution area of certain species, as well as the increase in competitors that will negatively affect endemic species. The possible disappearance or modification of the distribution of species more adapted to low water temperatures has also been highlighted in the conclusions. The changes made can be seen in lines 597 – 609.

 

Comments 2: This is a carefully thought out review paper of the use of aquatic indicators of environmental change and in this case the use of macro-invertebrates to reflect climate predicted change in terrestrial river systems around the Mediterranean. The introduction is effective in setting the scene and establishing the research questions and context. The core issue is the predicted impacts of expected climate change scenarios on the distribution and abundance of species particularly rare endemics.

There are no illustrations beyond a single table with a flow-chart  and it would be informative to include a selection of images of the habitats in question and of the taxonomic groups under review.

 

Response 2: At the end of the introduction, photos of two rivers belonging to the Mediterranean region in Spain and photos of 4 taxonomic groups of aquatic macroinvertebrates have been added, lines 137 - 145.

 

Comments 3: The Methodology is satisfactory, and a broad range of relevant literature was identified. The authors found and screened over 400 papers to eventually review around 40. They note the limited literature on the topic in the case-study region, and hence this paper is an original contribution which helps close a gap in the current knowledge.

However, there are numerous reviews on ecological and landscape change in and around the Mediterranean though not specifically on aquatic macroinvertebrates. Whilst not relevant to the review per se,  these might be reference as context to Mediterranean studies more widely and serve to embed this study in the wider literature.

 

Response 3: Thank you for your comments. When the bibliographic search was carried out, studies were found on the effect of land use change and macroinvertebrate communities. These studies were discarded because they were not directly related to the effects of climate change (increase in temperature, decrease in precipitation, and increase in the frequency of extreme events).

 

Comments 4: I do wonder about other factors coming into play with trends towards urbanisation on the one hand and land-use / agricultural change on the other. Some of this may be driven by long-term climate change too and may to a degree affect the impacts of change scenarios. I feel that these should at least be considered in the Discussion. [Generally, I would separate out the Results and the Discussion, but I am unsure of the journal policy on this].

Overall, this a good, succinct account of an interesting [and indeed worrying] problem. I did not see any errors or problems in the broad methodology and the only shortcoming perhaps is that it is based solely on a review of literature and maybe some specific case-study work would stress the relevance more keenly. The scope of the review might be broadened as noted above, and the Results might be usefully summarised at the end of the Discussion to highlight the main ‘take-home’ messages relating the research questions posed.

 

Response 4: In this study we wanted to focus on the direct effects of climate change on aquatic macroinvertebrates. The change in land use, agriculture and trends towards urbanization are not direct effects of this climate change, since they are a product of multiple factors, although there are multiple studies that show that they affect aquatic macroinvertebrate communities.

While the format of the journal allows for combining results and discussion, subheadings (e.g., *3.1. Temperature Effects) have been refined to improve readability.

 

Comments 5: Relevant illustrations might be informative particularly to a non-Mediterranean reader.

 

Response 5: Thanks for the contribution, relevant illustrations have been added in the introduction, lines 137 - 145.

 

Comments 6: As noted previously, the Conclusions section is rather abrupt and might usefully be both expanded and focused on core questions and the findings from the review. A short contribution in terms of ‘future work and research directions’ would be helpful.

However, in setting the scene of likely adverse impacts of climate change on a particularly vulnerable taxonomic group, this is an effective contribution which with additions as noted can be a significant contribution to the literature on likely responses to climate change scenarios.

 

Response 6: In addition to the modifications in the conclusions mentioned above, a new paragraph has been added on future lines of research and future work (lines 610 - 619).

 

Comments 7: As discussed above, I wonder if there are any comparable reviews for other taxa in the Mediterranean which might be interesting to at least provide a wider context.  Also, are there any specific taxa in the focus of this study that might benefit from the predicted climate changes? Presumably species may also colonise in from other areas as the climate envelope shifts - and these may compete with the endemic species already under pressure. Perhaps some of these issues might be briefly considered in an expanded Conclusions section. The roles of interactions between endemic species maybe in decline and competition with exotic and colonising species may be interesting. Even if there is no relevant literature available, this might be worth at least considering in your conclusions and recommendations. There will be examples in the worldwide literature and cases of say the invasion into parts of Europe by exotic crayfish species and their impacts on other species and on ecosystem function. Furthermore, what do climate change scenarios imply for these recombinant species interactions?

 

Response 7: As mentioned in the study, taxa will respond differently to the effects of climate change. For example, taxa such as Diptera and Mollusca will benefit from climate change, because they contain generalist and colonizing species. On the other hand, endemic and highly specialized taxa will be negatively affected by the changes that occur in their habitats. Furthermore, due to the changes produced by climate change, degradation of habitats occurs, no longer being suitable for certain species, but being favorable for others, producing displacements and increases in the distribution areas of some species and favoring the invasion of exotic species. All this has been reflected in the modifications that have been made in the conclusions section (lines 597 - 617)

 

Reviewer 3 Report

Comments and Suggestions for Authors

In this article, we can follow the changes in macroinvertebrate species under climate change. The study is primarily a literature review, summarising the findings of relevant publications on the subject to date. This type of approach is very useful, as it is necessary to collect results and compare experiences.

The results are not surprising, however, as climate change is adversely affecting almost all species of flora and fauna, with their numbers declining, their habitats being transformed and the environment becoming unfavourable for species with low tolerance levels to the point of extinction. At the same time, it is important to study species and taxa that can be used as indicators to monitor the consequences of climate change.

A shortcoming of the study is that little is said about the analogies that could serve as a warning for other areas. Given that the Mediterranean region is one of the areas most severely and first affected by the negative impacts of climate change, areas further north will face similar problems, albeit with a delay of a few years or decades. For this reason, it would also be useful to examine what lessons can be learned from the study of macroinvertebrate species for other regions?

In addition, the Conclusions section is too short and it would be worthwhile to expand a little on the main findings.

 

Author Response

We sincerely thank the reviewers for their insightful and constructive feedback, which has significantly strengthened our manuscript. Below, we outline the revisions made in response to their comments:

 

Point-by-point response to Comments and Suggestions for Authors

 

Comments 1: In this article, we can follow the changes in macroinvertebrate species under climate change. The study is primarily a literature review, summarising the findings of relevant publications on the subject to date. This type of approach is very useful, as it is necessary to collect results and compare experiences.

 

Response 1: Thank you very much.

 

Comments 2: The results are not surprising, however, as climate change is adversely affecting almost all species of flora and fauna, with their numbers declining, their habitats being transformed and the environment becoming unfavourable for species with low tolerance levels to the point of extinction. At the same time, it is important to study species and taxa that can be used as indicators to monitor the consequences of climate change.

 

Response 2: As you mentioned, the majority of flora and fauna are being negatively affected by climate change, aquatic macroinvetebrates being one of these groups. The importance of this group is that they are widely used as bioindicators of water quality, which is why they have been studied and are used in standardized methodologies. Therefore, they can be a very useful tool to understand how climate change affects riparian ecosystems, and even as a management tool for conservation.

 

Comments 3: A shortcoming of the study is that little is said about the analogies that could serve as a warning for other areas. Given that the Mediterranean region is one of the areas most severely and first affected by the negative impacts of climate change, areas further north will face similar problems, albeit with a delay of a few years or decades. For this reason, it would also be useful to examine what lessons can be learned from the study of macroinvertebrate species for other regions?

 

Response 3: Thank you very much for the comment. Sections 3.1, 3.2 and 3.3 explain the effects of climate change on macroinvertebrates at a global level, focusing on the Mediterranean region in section 3.4. We have made this distinction to understand globally how macroinvertebrates are affected by climate change, in order to have a more complete and global vision of the effects observed in the Mediterranean region. As you mention, the Mediterranean region is one of the first regions that will suffer climate change, so it is expected that the effects will be observed sooner than in other regions, so this knowledge can be very useful to adopt measures for management and conservation in other regions. This approach has been mentioned in the conclusions section, on line 619 - 623.

 

Comments 4: In addition, the Conclusions section is too short and it would be worthwhile to expand a little on the main findings.

 

Response 3: The conclusions section has been expanded with a greater description of the findings, as well as future lines of research and future work (lines 597 - 623).