Monitoring Net Land Take in a Metropolitan Region—Portugal

Abstract:

1)     The Abstract needs improvement in terms of conveying the main research problem, the main aim of the study, and the methodology.

2)      The Abstract should explicitly indicate the research's originality and highlight its contribution to the international literature.

The abstract was revised to take these aspects into account, but we couldn't go into too much detail because we had already exceeded the maximum word limit imposed by the journal.

3)      Page 1, line 9: Please remove “the” before the abbreviation of “AMP”.

Amended.

Keywords:

4)      The authors should avoid using keywords that already mentioned in the title (e.g., and take) and replace them with new relevant words in the text.

Amended.

Introduction:

5)    The authors should avoid using pronouns such as “we”, “our” and “us” in the whole text (e.g., line 132).

Amended.

6)   Page 2, lines 31-36: This statement is too long. Consider to split it into two sentences.

Amended.

7)   Page 2, lines 62-67: The mention of “green recycling” and “grey recycling” might benefit from a brief explanation.

This text was changed to the following.

Green recycling differs from other types of urban land reuse because it restores some of the functions provided by soil in its healthy state that are essential for improving living conditions and adapting to climate change in urban areas. Densification and grey recycling are potential solutions for evading land take because they make it possible to accommodate more people and promote economic diversity in cities, taking advantage of existing infrastructures.

8)   When discussing densification and recycling as potential solutions, consider providing examples or case studies to illustrate their practical applications.

Given the length of the manuscript, we have chosen not to give examples. However, lines 140-146 of the manuscript also explain that increasing the density of soil sealing within artificial land, i.e., increasing densification and grey recycling in urban centres, are potential solutions for meeting the European target because they do not increase the surface area of artificial land. However, given that the intensification of soil sealing has detrimental effects that compromises the environmental sustainability of urban zones, said intensification will have to be made up for by increases in green recycling, re-naturalisation of artificial areas and adoption of nature-based solutions [5,23].

9)   Check the consistency of terminology. For instance, “land take” is also referred to as “land consumption” and “land artificialization”. Ensure a consistent use of terms throughout the document.

Checked.

10)   There are very short paragraphs throughout the Introduction. I recommend merging these paragraphs while maintaining the coherence of the contents.

Amended.

11)   The significance of the study should be added in the Introduction. The authors should be able to highlight the need for the study.

Lines 195-208 explain that based on an assessment of land use changes in the AMP and its city council areas in the 2007-2018 period and of soil sealing levels in 2018, this study identifies the regional driving forces of net land take and analyses the region's performance in meeting the EU 2050 target, in support of the definition of both, as well as customised interventions to decrease net land take and soil sealing and targets (non-existent, so far) recommended by the EU Soil Strategy for 2030. Consequently, it aims to support the development of a "no net land take" policy for the AMP by 2050.

The assessment combines indicators defined by the SML proposal [26] and population data to aid decision-making. In addition to providing more clarity on the European target, the study shows regional and municipal authorities how to assess the processes of interest for achievement thereof. The contents presented, particularly the novel indicators explored, can serve as an example for European regions that have not yet begun to monitor this target. Moreover, the study aims to raise awareness of the processes addressed among decision-makers and public authorities involved in spatial planning.

12)   Why is it timeliness to explore such a study?

Realising the goal of no net land take requires a reformulation of the urban development trajectories pursued in the past.

13)   What makes this study different from other studies in the world?

To support the definition of strategies to reduce land take and soil sealing, the study assesses the potential for intensifying land use within urban areas without jeopardising their biodiversity. This assessment was based on the levels of soil sealing within urban areas and the unsealed artificial surface area per capita.

14)  Are the findings different from prior academic studies that were conducted elsewhere, if any?

As far as we know, only one study [5] has explored soil sealing indicators within urban areas to assess their potential to intensify land use without decreasing biodiversity. However, it did not integrate population data or analyse the rates and drivers of net land take, which our research does. The inclusion of population data contextualises the indicators proposed by [5] and raises knowledge gaps that require further research.

Materials and Methods:

15)   Page 4, line 177: Clarify the acronym “COS” the first time it's introduced.

Amended.

16)   In describing the Land and Ecosystem Accounting (LEAC) system, briefly explain its role and relevance to the study.

Amended.

17)   Consider providing a brief explanation of the Imperviousness Density (IMD) and its significance to the study.

Amended.

18)   The description of the Metropolitan Area of Porto (AMP) is informative. However, including a brief mention of why this area was chosen for the study could be useful.

This is explained at the beginning of section 1.2 on lines 189-194.

19)   Page 7, lines 284-287: When mentioning laws and regulations, consider providing the publication year for each to give the reader a sense of the timeline of changes.

Checked.

Results:

20)   Overall, the Results section is well-written and provides a detailed account of the experimental procedures and results but consider if any parts can be made more concise without losing essential information.

Due to issues raised by other reviewers, we had to add results on soil sealing in this section. However, we have revised the text to make it more concise.

21)   All figures and tables should be cited in the main text.

Checked.

22)   The text refers to “artificial land” and “sealed land.” Clarify if these terms are used interchangeably or if they represent distinct concepts

Section 2.1 (on lines 241-244) clarifies that the study assumes that artificial land is representative of urban or developed areas, which consist of the land use classes for artificial areas (described as artificial surfaces by some land cover maps). Non-artificial, non-urban or undeveloped land is representative of the remaining land use classes. Artificial land usually includes both sealed and non-sealed soil.

Discussion and Conclusions:

23)   Explicitly mention the novelty or contribution of your study.

28)   In Conclusion, it is important to emphasize the novelty of the study, which distinguishes it from previous research.

The unsealed artificial surface area per capita indicator is undoubtedly innovative while raising concern about the threshold of sealed/unsealed artificial land per capita that ensures that cities do not experience declines in biodiversity.

25)   Pages 14 and 15, lines 462-469: This statement is too long.

Please revise and split it into two sentences.

Amended.

26)   In the Conclusion, the focus should be on restating the main results and demonstrating how the research questions have been thoroughly examined and explained.

When revising this section, we took these aspects into account.

27)   To enhance the section, it is important to enrich it with paragraphs discussing the international policy implications of the study's findings.

29) Additionally, it is crucial to discuss both the theoretical and practical implications of the study's findings.

30) How the study contributes to the existing theoretical framework and its potential applications in real-world settings.

It is concluded that assessing the degree of soil sealing within urban areas is essential for deciding on the interventions to be carried out to decrease net land take. Accordingly, this evaluation should support any "no net land take" policy. The Soil Monitoring Law could also request the degree of soil sealing within urban areas to be assessed, as it provides information about soil health in those areas.

24)   Add limitations of the study to the end of the section.

31) Moreover, it is recommended to outline possible avenues for future studies that can build upon the current research and address any remaining gaps or unanswered questions.

At the end of this section, the study's limitations, information gaps and issues that require further research are identified.

Introduction:

1)     In the introduction section, the author mentions "(P.36)\(P.50)..." What does this refer to?

Amended. All references to pages have been removed when text citations are not used.

Materials and Methods:

2)     I suggest that the author include a flowchart in the methods section to provide an overview of the research methodology.

We chose not to include the flowchart describing the methodology adopted due to the large number of figures already in the manuscript and its length.

Discussion and Conclusions:

3)     It is advisable to separate the Discussion and Conclusions sections. The conclusions section should be clear and concise.

Although we did not subdivide this section in two, it has been thoroughly reorganised. The main conclusions of the study, as well as its limitations and the gaps in knowledge identified, are addressed in its final paragraphs (lines 694-717).

Results:

4)     For all the bar charts in the manuscript, the author should appropriately label the data within the figures.

We don't fully understand your comment. Figures become less legible if we label each bar with its value.

General comments

1)      The terminology should be revised, as the use of some nouns for different context and meaning, (i.e., land, soil, artificial) ingenerates a certain confusion, in whereas a concept is related to land use or ground use.

Most of the land cover mentions have been changed to land use. In addition, section 2.1 clarifies that the study assumes that artificial land is representative of urban or developed areas, which consist of the land use classes for artificial areas (described as artificial surfaces by some land cover maps). Non-artificial, non-urban or undeveloped land is representative of the remaining land use classes. Artificial land usually includes both sealed and non-sealed soil.

2)      The manuscript requires a thorough revision, proofed by someone proficient in English.

The text has been proofread by someone proficient in English.

3)      The structure of the paper requires a review.

Although the manuscript structure has not been substantially modified, it is thought that the changes made to the abstract and the clarification of contents in the different sections have made it more objective and its discussion more coherent.

Introduction:

4)      Lines 141-146. The reference to the experience in Reggio Emilia, and land use should recall the general legislation of the country, as the ZTO, the homogeneous Territorial Zones, introduced by circ 1444/68, gave the base for destination of areas, and therefore to define zones for agricultural, industrialized and urbanised destination.

Amended to: The definition of homogeneous territorial zones, provided for by Decree 1444 of 2 April 1968, was implemented by the General Urban Plan (Piano Urbanistico Generale) to reduce the areas zoned for urban uses, which had not yet been built upon.

5)      I would advise for reference the following: DOI: 10.2495/UT130631A comparison of urban planning systems between the UK and Italy: Commercial development and city logistic plan

After reading this reference, the authors did not understand how its content could add value to their research. They therefore chose not to cite it.

Materials and Methods:

6)     I would strongly advise to dedicate a chapter for the illustration of data, models, methods and expected results, and a subsequent chapter, or paragraph, to summarise the results.

The changes made to sections 2. and 3. are thought to fulfil the request.

Results:

7)      The chapter of results should present the results, and not the description of the proposed study areas, which should be presented in a previous chapter.

Most of the description in question has been moved to point 2.2 (Study area) of the Materials and Methods section. The results on soil sealing level within artificial land have been improved and integrated into the last point of the Results section (Artificial land, soil sealing and population dynamics).

General comments

1)      Improve the novelty and contribution of your study.

2)      Provide novel insights, methodologies, or perspectives to justify the publication of the similar study.

As mentioned above, the assessment of soil sealing levels within urban areas has, as far as we know, only been addressed by one study [5]. In evaluating the potential for land use intensification in the urban areas of the AMP, the authors used these indicators and analysed other correlative indicators integrating population data. The unsealed artificial surface area per capita indicator is undoubtedly innovative while raising concern about the threshold of sealed/unsealed artificial land per capita that ensures that cities do not experience declines in biodiversity.

3)      What is the contribution of this work to the advancement of knowledge in the field?

It is concluded that assessing the degree of soil sealing within urban areas is essential for deciding on the interventions to be carried out to decrease net land take. Accordingly, this evaluation should support any "no net land take" policy. The Soil Monitoring Law could also request the degree of soil sealing within urban areas to be assessed, as it provides information about soil health in those areas.

4)      Explain how your current study builds on your previous work.

The following text has been added to section 1.2. This study starts from a prior net land take assessment developed by the authors for mainland Portugal and its NUTS III regions [4]. This assessment revealed that the Porto Metropolitan Area (Área Metropolitana do Porto, AMP) had the highest rate of land take of the mainland regions, which justified a more in-depth analysis of the regional drivers and a municipal appraisal of the processes of interest, with the inclusion of indicators on soil sealing.

1)    Page 2, lines 83-85:

This statement “Green recycling differs from other types of urban land reuse because it restores some of the functions provided soil in its healthy state that are essential for improving living conditions and adapting to climate change in urban areas.” Should be revised for more clarity.

The statement was replaced by the following.

This latter type of land recycling allows for the recovery of some of the services and functions provided by soil (e.g. the storage of organic carbon and the regularisation of the water cycle) while also helping to improve environmental conditions in cities and mitigating some of the impacts of climate change.

2)      Page 3, lines 140-142:

In this sentence “This proposal seeks to create an appropriate framework for the sustainable management of this natural resource towards achieving the goal of healthy soils throughout the EU by 2050.” “proposal” should be revised to “study”.

This sentence refers to the SML proposal, not the study. To make it more explicit, the sentence has been reworded as follows.

Towards achieving healthy soils throughout the EU by 2050, the SML proposal seeks to create an appropriate regulatory framework for the sustainable management of this natural resource. For this purpose, it establishes obligations to monitor and assess soil health and to analyse the effectiveness of actions taken to remediate (regenerate) soil in rural and urban areas.

3)      Page 4, lines 154-156:

This sentence “These authors propose using the soil sealing rate within artificial land (urban areas) to support the definition of land take reduction strategies” could be merged with the previous sentence.

The sentence in question has been merged with the previous sentence as follows.

Although the SML recognises that soil sealing should be assessed in addition to land take, the proposal does not state that soil sealing should be differentiated between urban and rural areas, as suggested by Decoville and Feltgen [5], who propose using soil sealing rate within artificial land (urban areas) to support the definition of land take reduction strategies.

4)    Page 24- lines 679-680:

This statement “The national land use/land cover maps (COS) from 2007 and 2018 were used base data in assessing land use changes in the AMP.” Need to be reformulated.

The statement was reworded as follows.

The 2007 and 2018 national land use/land cover maps (COS) were used to assess land use changes in the AMP.

5)   The Discussion and conclusion section is too long. I suggest to separate these sections for more clarity and better readability.

This section has been split into two, as suggested.

6)   In the discussion section: a) State the main results of the study (do not repeat the inputs of the results section); b) Compare and interpret these results in detail with the findings of recent studies; and c) At the end of this section, the main limitations of the study should be discussed.

The discussion section was revised according to these recommendations. However, to explain our outcomes and compare them with those of the Functional Urban Areas of the EU-27 and the UK, we had to repeat some of the results already described in the previous section.

7)   In the Conclusion, the focus should be on restating the main results and demonstrating how the research questions have been thoroughly examined and explained.

The text in the conclusions section has been based on these recommendations.

8)   To enhance the Conclusion section, it is important to enrich it with paragraphs discussing the international policy implications of the study's findings.

As the share of soil sealing in most urban areas of the AMP is already significantly high, the study shows that compliance with the EU's 2050 target, which requires intensifying land use in those areas, does not meet the objectives of the SML (achieving healthy soils throughout the EU by 2050). It is therefore proposed that the target set in 2011 be updated to a more contextualised objective aligned with biodiversity goals for cities, which should consider the level of soil sealing and demographic pressure in urban areas. It is also considered that the SML should be more specific in the mandatory monitoring indicators, requiring the differentiation of soil sealing levels inside and outside urban areas.

9)   Additionally, it is crucial to discuss both the theoretical and practical implications of the study's findings at the end of the Conclusion section and show how the study contributes to the existing theoretical framework and its potential applications in real-world settings.

The study concludes there isn't a standardised path for all European regions to reach the net land take target. The diversity of regional contexts demands objective assessments and the formulation of specific strategies adapted to each region. The research identifies some of the indicators that should be assessed and highlights the importance of considering the degree of soil sealing in urban areas to define interventions that meet the European target.

1)    I suggest that the author include a flowchart in the methods section to provide an overview of the research methodology.

The requested flowchart is shown in Figure 1 of the manuscript.

2)    It is advisable to separate the Discussion and Conclusions sections. The conclusions section should be clear and concise.

The section that included the discussion and conclusion of the manuscript was subdivided into two, as recommended.

3)    Appropriately label the data within figures containing bar charts.

Most of the bar graphs in the results section, namely those of figures 10 to 12, have been changed accordingly. Due to the complexity of its execution, Figure 8 has not been modified.