Spatial Optimization and Temporal Changes in the Ecological Network: A Case Study of Wanning City, China
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsIn this manuscript, the authors use network analysis to look at the landuse change in Wanning City, China. They find that the fragmentation and habitat quality has decreased over time and suggest an ecological protection framework to improve it. The work is straightforward and well written. The methods are appropriate and adequately described. The results are clear and consistent with what one would expect in a rapidly urbanizing region. Overall, this is a good paper and can be accepted with minor revision. The main suggestion is to expand the discussion. Currently, it reads as a summary or conclusion retelling the results but not comparing the findings with other existing literature or discussing studies limitations or next steps.
Minor typos:
Line 25 should read ", and multiple pointS"
Line 125, isn't it four types of data: LULC, roads, Elevation, and HSA?
Are the HSA values in Table 1 calculated or estimated?
Author Response
Comment #1: In this manuscript, the authors use network analysis to look at the landuse change in Wanning City, China. They find that the fragmentation and habitat quality has decreased over time and suggest an ecological protection framework to improve it. The work is straightforward and well written. The methods are appropriate and adequately described. The results are clear and consistent with what one would expect in a rapidly urbanizing region. Overall, this is a good paper and can be accepted with minor revision. The main suggestion is to expand the discussion. Currently, it reads as a summary or conclusion retelling the results but not comparing the findings with other existing literature or discussing studies limitations or next steps.
Response #1: Thank you for your summary and comment. We appreciate your efforts in reviewing our manuscript.
Comment #2: Minor:
Line 25 should read ", and multiple pointS"
Line 125, isn't it four types of data: LULC, roads, Elevation, and HSA?
Are the HSA values in Table 1 calculated or estimated?
Response #2: Thank you for your summary and comment. We took your suggestion and made changes accordingly. In this research, various factors including land use/land cover type, road infrastructure, landform, proximity to water sources, and distance from major traffic arteries were thoroughly taken into account to develop a comprehensive evaluation index system (refer to Table 1) for assessing habitat suitability on a scale of 0 to 1.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe study convincingly shows that the quality of the ecological network in Wanning has deteriorated over the past twenty years. This is important information for policy makers.
The study seems to be about ecological networks in the city (Wanning city), but the study is probably about a region in which a city is located. That matters quite a bit, because urban ecology is somewhat different (with different policy principles) than rural ecology. Make it clear what you are doing; an outline of the context could be helpful, including images.
Abstract: the solution one belt, four sources etc. is mentioned twice (lines 24 and 28), which is an exaggeration.
Line 59: thereby overcoming limitations arising from incomplete information. Explain how you did that (in the method).
Line 72: The criticism of others working with ecological network theory is that it “may exclude small but ecological crucial patches.” But 2.3.1 explains that this study only includes patches larger than 32 hectares. How can this be reconciled?
From line 86: this is part of the method, not the introduction.
Line 91: What is circuit theory? This is not explained further.
Line 102: “strategies to optimize regional ecological space and enhance ecosystem services”. But this study is not about Ecosystem Services at all, is it? Omit this.
Lines 141 and further: overlaps with what is stated in the introduction.
Line 141 and further: the method does not take into account the requirements that different species impose on the size and quality of the sources and corridors. So now it is mainly a theoretical exercise that has no relation to the actual needs of species. Working with target species that represent a type of animal (or plant) is now very well established in landscape ecology. By not doing this, it is unclear what the true value of this study is.
Line 181: this refers to a target area; what is that? An animal has no deliberate goal in mind when it migrates. This could be another source area, but then the word is not quite well chosen.
Line 181: what does an ecological corridor look like? Does this have a minimum width? According to standard ecological theory, certain animal species also require a certain width of the corridor? In addition, images of the corridors could be very helpful in getting an idea of what we are talking about.
Line 277: Is it the case that the western part of Wanning is a large source area? Or does this just say that the quality of the area is high? Where are the ecological sources within this area?
Line 287: “Wannings ecological corridors are primarily situated in the central and eastern parts of the city”. Where do those corridors lead to, if the sources are only in the west (and almost nothing in the east?). Here too I find it difficult to imagine. Line 342: the identification of the obstacle points is a strong point of this study. The title of this paragraph also promises restoration countermeasures. However, I don't see that in the story and that is a shame. Show what the obstacle points actually look like (not just a color), and explain what you can or should do to solve them. Be specific. Line 360: the same applies to the restoration plan: one belt, four sources, etc. I do not yet see what this means, but I would like you to elaborate more specifically, because it is now unclear why this is the result of the research. This is reflected in line 439 where it speaks cryptically about “optimizing ecological spaces”. What do you mean? Line 375: a distinction is made in importance of the ecological corridors on the basis of their geographical distribution. In some districts they are more important than in others. Why is it like that? It seems to me that you want to have a strong network everywhere. This is reflected in line 448, perhaps a map would be helpful to explain this principle? Line 393: current theory, what does that mean?
Author Response
RESPONSE TO REVIEWER #2
Comment #1: The study convincingly shows that the quality of the ecological network in Wanning has deteriorated over the past twenty years. This is important information for policy makers. The study seems to be about ecological networks in the city (Wanning city), but the study is probably about a region in which a city is located. That matters quite a bit, because urban ecology is somewhat different (with different policy principles) than rural ecology. Make it clear what you are doing; an outline of the context could be helpful, including images.
Abstract: the solution one belt, four sources etc. is mentioned twice (lines 24 and 28), which is an exaggeration.
Response #1: Thank you for your summary and comment. We appreciate your efforts in reviewing our manuscript. We took your suggestion and added the description of “Hence, it is imperative to conduct a thorough examination of the holistic framework and attributes of the ecological network at the municipal and county levels” (lines 84-86) in Introduction to make it clear, and deleted the “one belt, four sources” (lines 28). Hope that we have now produced a better account of our work.
Comment #2: Line 59: thereby overcoming limitations arising from incomplete information. Explain how you did that (in the method).
Response #2: Thank you for your summary and comment. The following is an analysis of existing literature and research conducted by other scholars. Currently, there is a growing interest in the application of landscape ecology and graph theory to investigate ecological networks. The research approach, which integrates landscape ecology and ecological network analysis, enables the spatial assessment of landscapes using available data, such as land use change data. This method addresses challenges associated with the limited availability of information on species predation, reproduction, and migration, and facilitates the long-term monitoring of habitat changes in terms of both quantity and quality.
Reference:
- Cao, Z.; Sun, Y.; Xie, G.; Qiu, P. Study on the evolution of the ecological network in the Haikou coastal zone. Sheng Tai Xue Bao. 2020, 40, 1044–1054.
- Yang, J.; Zeng, C.; Cheng, Y. Spatial influence of ecological networks on land use intensity. Sci. Total Environ. 2020, 717, 137151. doi: 10.1016/j.scitotenv.2020.137151
- He, J.; Pan, Y.; Liu, D. Analysis of the wetland ecological pattern in Wuhan City from the perspective of ecological network. Sheng Tai Xue Bao. 2020, 40, 3590–3601. doi: 10.5846/stxb201903250562
Comment #3: Line 72: The criticism of others working with ecological network theory is that it “may exclude small but ecological crucial patches.” But 2.3.1 explains that this study only includes patches larger than 32 hectares. How can this be reconciled?
Response #3: Thank you for your summary and comment. As depicted in Figure 1, there is a noticeable decrease in both the quantity and overall size of ecological patches as the threshold value increases. Once the threshold reached 32 hectares, the decline in these parameters appeared to stabilize. Conversely, the average habitat suitability value exhibited a gradual increase with the rising threshold value, ultimately stabilizing at approximately 0.9. Consequently, the threshold of 32 hectares was determined to be the minimum area requirement for the ecological source area of Wanning City.
Comment #4: line 86: this is part of the method, not the introduction.
Response #4: Thank you for your summary and comment. We moved this part into the method (lines 142).
Comment #5: Line 91: What is circuit theory? This is not explained further.
Response #5: Thank you for your summary and comment. We added the circuit theory in the 2.3 Methods, “Circuit theory is the study of the relationship between current and various resistors within a circuit board. This method or model of circuit theory yields three significant outcomes: ecological corridor (or ecological circulation channel), ecological pinch point, and ecological barrier point, collectively referred to as ecological nodes.” (lines 147).
Comment #6: Line 102: “strategies to optimize regional ecological space and enhance ecosystem services”. But this study is not about Ecosystem Services at all, is it? Omit this.
Response #6: Thank you for your summary and comment. We dropped this part.
Comment #7: Lines 141 and further: overlaps with what is stated in the introduction.
Response #7: Thank you for your summary and comment. We dropped this part.
Comment #8: Line 141 and further: the method does not take into account the requirements that different species impose on the size and quality of the sources and corridors. So now it is mainly a theoretical exercise that has no relation to the actual needs of species. Working with target species that represent a type of animal (or plant) is now very well established in landscape ecology. By not doing this, it is unclear what the true value of this study is.
Response #8: Thank you for your summary and comment. This study seeks to examine the spatio-temporal development of landscape patterns in Wanning City, elucidate the features of changes in ecological network structure within the city, and suggest strategies for optimizing the regional ecological space.
Comment #9: Line 181: this refers to a target area; what is that? An animal has no deliberate goal in mind when it migrates. This could be another source area, but then the word is not quite well chosen.
Line 181: what does an ecological corridor look like? Does this have a minimum width? According to standard ecological theory, certain animal species also require a certain width of the corridor? In addition, images of the corridors could be very helpful in getting an idea of what we are talking about.
Response #9: Thank you for your summary and comment. The Minimum Cumulative Resistance model (MCR) is a technique utilized for the creation of ecological corridors and nodes. It considers the factors of source area, resistance surface, and distance, with the objective of minimizing cumulative resistance between connecting regions. Additionally, it takes into account the connection relationship between nodes and has the capability to group nodes or regions with strong correlation into the same partition, resulting in more meaningful partition outcomes. In this investigation, the cost path module within ArcGIS was employed to compute the cumulative resistance value from each ecological source patch to other patches, using the core ecological source as the input source and the comprehensive resistance surface as the input resistance. This process yielded the minimum cumulative resistance surface of the source. Subsequently, on the minimum cumulative resistance surface, the minimum resistance path between each pair of ecological source patches is generated, thus forming the ecological corridor.
Comment #10: Line 277: Is it the case that the western part of Wanning is a large source area? Or does this just say that the quality of the area is high? Where are the ecological sources within this area?
Response #10: Thank you for your summary and comment. Previous research has primarily identified ecological source areas using two main approaches: Firstly, by directly designating nature reserves or areas marked for ecological protection as ecological source areas; and secondly, by establishing a minimum area threshold for ecological source areas based on existing references, and identifying ecological patches larger than this threshold as the final ecological source areas. However, these methods are predominantly subjective and do not account for the scale effect of the landscape. This study takes into consideration various factors such as land use/land cover type, roads, landform, distance from water sources, and distance from main traffic arteries to develop an evaluation index system (Table 1) for assessing habitat suitability on a scale of 0-1. Based on this, an area threshold ranging from 2 to 40 hectares, with intervals of 2 hectares, was set to analyze the changes in the number of ecological patches, total area, and habitat suitability in order to determine the minimum area of ecological source. Figure 1 illustrates that as the threshold value increases, the number and total area of ecological patches decrease rapidly. When the threshold was raised to 32 hectares, the decline in the number and total area of ecological patches began to level off. Conversely, the mean value of habitat suitability showed a gradual increase with the rise in threshold value, stabilizing at around 0.9. Consequently, 32 hectares was identified as the minimum area threshold for the ecological source area of Wanning City.
Comment #11: Line 287: “Wannings ecological corridors are primarily situated in the central and eastern parts of the city”. Where do those corridors lead to, if the sources are only in the west (and almost nothing in the east?). Here too I find it difficult to imagine. Line 342: the identification of the obstacle points is a strong point of this study. The title of this paragraph also promises restoration countermeasures. However, I don't see that in the story and that is a shame. Show what the obstacle points actually look like (not just a color), and explain what you can or should do to solve them. Be specific. Line 360: the same applies to the restoration plan: one belt, four sources, etc. I do not yet see what this means, but I would like you to elaborate more specifically, because it is now unclear why this is the result of the research. This is reflected in line 439 where it speaks cryptically about “optimizing ecological spaces”. What do you mean? Line 375: a distinction is made in importance of the ecological corridors on the basis of their geographical distribution. In some districts they are more important than in others. Why is it like that? It seems to me that you want to have a strong network everywhere. This is reflected in line 448, perhaps a map would be helpful to explain this principle? Line 393: current theory, what does that mean?
Response #11: Thank you for your summary and comment. The eastern region of the map contains ecological source patches, necessitating the distribution of ecological corridors in this area. This is due to the central and western parts being predominantly comprised of large ecological source areas (line 297). We are not implementing a particular design scheme; rather, we are simply indicating the spatial coordinates of the obstacle points. "One Belt, Four Sources, Eight Districts, Multiple Corridors, and Multiple Points. "Referring to an abstract concept, we designed a coastal ecological landscape zone (easternmost) in Figure 5. Four ecological source areas are designed in the west and south .For additional inquiries, adjustments have been implemented in the relevant sections of the text.
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsI just respond to the comments that are – in my opinion - not yet satisfactory answered. If you do not agree with me, please say so (do not beat around the bush). Thank you for the other alterations.
Comment #2: Line 59: thereby overcoming limitations arising from incomplete information. Explain how you did that (in the method).
Response #2: Thank you for your summary and comment. The following is an analysis of existing literature and research conducted by other scholars. Currently, there is a growing interest in the application of landscape ecology and graph theory to investigate ecological networks. The research approach, which integrates landscape ecology and ecological network analysis, enables the spatial assessment of landscapes using available data, such as land use change data. This method addresses challenges associated with the limited availability of information on species predation, reproduction, and migration, and facilitates the long-term monitoring of habitat changes in terms of both quantity and quality.
Reference:
- Cao, Z.; Sun, Y.; Xie, G.; Qiu, P. Study on the evolution of the ecological network in the Haikou coastal zone. Sheng Tai Xue Bao. 2020, 40, 1044–1054.
- Yang, J.; Zeng, C.; Cheng, Y. Spatial influence of ecological networks on land use intensity. Sci. Total Environ. 2020, 717, 137151. doi: 10.1016/j.scitotenv.2020.137151
- He, J.; Pan, Y.; Liu, D. Analysis of the wetland ecological pattern in Wuhan City from the perspective of ecological network. Sheng Tai Xue Bao. 2020, 40, 3590–3601. doi: 10.5846/stxb201903250562
Thank you for your explanation. However, you did not add this to the text, so maybe I may understand this now, but the readers don’t.
Comment #3: Line 72: The criticism of others working with ecological network theory is that it “may exclude small but ecological crucial patches.” But 2.3.1 explains that this study only includes patches larger than 32 hectares. How can this be reconciled?
Response #3: Thank you for your summary and comment. As depicted in Figure 1, there is a noticeable decrease in both the quantity and overall size of ecological patches as the threshold value increases. Once the threshold reached 32 hectares, the decline in these parameters appeared to stabilize. Conversely, the average habitat suitability value exhibited a gradual increase with the rising threshold value, ultimately stabilizing at approximately 0.9. Consequently, the threshold of 32 hectares was determined to be the minimum area requirement for the ecological source area of Wanning City.
32 hectares is huge, especially in urban areas. Your method may say that 32 is a threshold, this is not wat literature says about it. For instance: https://www.makingnaturescity.org/urban-biodiversity-framework/patch-size/ Here patches with a minimum size of 0,8 hectares are considered. So my point is that you say that your work takes into account small patches, but according to international literature, they are huge, missing smaller but (for some species) important patches. Please reflect on that.
Comment #8: Line 141 and further: the method does not take into account the requirements that different species impose on the size and quality of the sources and corridors. So now it is mainly a theoretical exercise that has no relation to the actual needs of species. Working with target species that represent a type of animal (or plant) is now very well established in landscape ecology. By not doing this, it is unclear what the true value of this study is.
Response #8: Thank you for your summary and comment. This study seeks to examine the spatio-temporal development of landscape patterns in Wanning City, elucidate the features of changes in ecological network structure within the city, and suggest strategies for optimizing the regional ecological space.
You do not respond to my question. What is the practical value of your study? Does it have real world relevance, or is it just a mathematical exercise? Please explain.
Comment #9: Line 181: this refers to a target area; what is that? An animal has no deliberate goal in mind when it migrates. This could be another source area, but then the word is not quite well chosen.
Line 181: what does an ecological corridor look like? Does this have a minimum width? According to standard ecological theory, certain animal species also require a certain width of the corridor? In addition, images of the corridors could be very helpful in getting an idea of what we are talking about.
Response #9: Thank you for your summary and comment. The Minimum Cumulative Resistance model (MCR) is a technique utilized for the creation of ecological corridors and nodes. It considers the factors of source area, resistance surface, and distance, with the objective of minimizing cumulative resistance between connecting regions. Additionally, it takes into account the connection relationship between nodes and has the capability to group nodes or regions with strong correlation into the same partition, resulting in more meaningful partition outcomes. In this investigation, the cost path module within ArcGIS was employed to compute the cumulative resistance value from each ecological source patch to other patches, using the core ecological source as the input source and the comprehensive resistance surface as the input resistance. This process yielded the minimum cumulative resistance surface of the source. Subsequently, on the minimum cumulative resistance surface, the minimum resistance path between each pair of ecological source patches is generated, thus forming the ecological corridor.
You do not answer my question. Maybe the width of the corridor is not part of your model, but I presume that your model calculates sizes of space between building blocks or other non-permeable elements – will not put a corridor in a space of e.g. half a meter wide. In order to better understand what your model is doing, this kind of information is vital.
Comment #10: Line 277: Is it the case that the western part of Wanning is a large source area? Or does this just say that the quality of the area is high? Where are the ecological sources within this area?
Response #10: Thank you for your summary and comment. Previous research has primarily identified ecological source areas using two main approaches: Firstly, by directly designating nature reserves or areas marked for ecological protection as ecological source areas; and secondly, by establishing a minimum area threshold for ecological source areas based on existing references, and identifying ecological patches larger than this threshold as the final ecological source areas. However, these methods are predominantly subjective and do not account for the scale effect of the landscape. This study takes into consideration various factors such as land use/land cover type, roads, landform, distance from water sources, and distance from main traffic arteries to develop an evaluation index system (Table 1) for assessing habitat suitability on a scale of 0-1. Based on this, an area threshold ranging from 2 to 40 hectares, with intervals of 2 hectares, was set to analyze the changes in the number of ecological patches, total area, and habitat suitability in order to determine the minimum area of ecological source. Figure 1 illustrates that as the threshold value increases, the number and total area of ecological patches decrease rapidly. When the threshold was raised to 32 hectares, the decline in the number and total area of ecological patches began to level off. Conversely, the mean value of habitat suitability showed a gradual increase with the rise in threshold value, stabilizing at around 0.9. Consequently, 32 hectares was identified as the minimum area threshold for the ecological source area of Wanning City.
I think part of the confusion is that in section 3.1.2 you speak about the ecological source areas (plural) while in 3.2.1 you speak about ‘the number of patches in Wanning city ecological source area (singular) increased…” there is a mix up between patches en source area. Please be more secure in defining your key elements.
Comment #11: Line 287: “Wannings ecological corridors are primarily situated in the central and eastern parts of the city”. Where do those corridors lead to, if the sources are only in the west (and almost nothing in the east?). Here too I find it difficult to imagine. Line 342: the identification of the obstacle points is a strong point of this study. The title of this paragraph also promises restoration countermeasures. However, I don't see that in the story and that is a shame. Show what the obstacle points actually look like (not just a color), and explain what you can or should do to solve them. Be specific. Line 360: the same applies to the restoration plan: one belt, four sources, etc. I do not yet see what this means, but I would like you to elaborate more specifically, because it is now unclear why this is the result of the research. This is reflected in line 439 where it speaks cryptically about “optimizing ecological spaces”. What do you mean? Line 375: a distinction is made in importance of the ecological corridors on the basis of their geographical distribution. In some districts they are more important than in others. Why is it like that? It seems to me that you want to have a strong network everywhere. This is reflected in line 448, perhaps a map would be helpful to explain this principle? Line 393: current theory, what does that mean?
Response #11: Thank you for your summary and comment. The eastern region of the map contains ecological source patches, necessitating the distribution of ecological corridors in this area. This is due to the central and western parts being predominantly comprised of large ecological source areas (line 297). We are not implementing a particular design scheme; rather, we are simply indicating the spatial coordinates of the obstacle points. "One Belt, Four Sources, Eight Districts, Multiple Corridors, and Multiple Points. "Referring to an abstract concept, we designed a coastal ecological landscape zone (easternmost) in Figure 5. Four ecological source areas are designed in the west and south .For additional inquiries, adjustments have been implemented in the relevant sections of the text.
Thank you for your answer, but most of my questions are not yet answered.
Author Response
I just respond to the comments that are – in my opinion - not yet satisfactory answered. If you do not agree with me, please say so (do not beat around the bush). Thank you for the other alterations.
The authors would like to thank the Editors and Reviewers for reviewing this manuscript and providing their professional opinions/comments/suggestions, upon which the manuscript has been revised. In the following, our responses are set in bold blue characters, and text added to the manuscript is set in red characters both in this report and the revised manuscript itself.
Comment #2: Line 59: thereby overcoming limitations arising from incomplete information. Explain how you did that (in the method).
Response #2: Thank you for your summary and comment. The following is an analysis of existing literature and research conducted by other scholars. Currently, there is a growing interest in the application of landscape ecology and graph theory to investigate ecological networks. The research approach, which integrates landscape ecology and ecological network analysis, enables the spatial assessment of landscapes using available data, such as land use change data. This method addresses challenges associated with the limited availability of information on species predation, reproduction, and migration, and facilitates the long-term monitoring of habitat changes in terms of both quantity and quality.
Reference:
- Cao, Z.; Sun, Y.; Xie, G.; Qiu, P. Study on the evolution of the ecological network in the Haikou coastal zone. Sheng Tai Xue Bao. 2020, 40, 1044–1054.
- Yang, J.; Zeng, C.; Cheng, Y. Spatial influence of ecological networks on land use intensity. Sci. Total Environ. 2020, 717, 137151. doi: 10.1016/j.scitotenv.2020.137151
- He, J.; Pan, Y.; Liu, D. Analysis of the wetland ecological pattern in Wuhan City from the perspective of ecological network. Sheng Tai Xue Bao. 2020, 40, 3590–3601. doi: 10.5846/stxb201903250562
Thank you for your explanation. However, you did not add this to the text, so maybe I may understand this now, but the readers don’t.
Response: The revised literature review (see lines 61-67) clearly indicates the issue.
Comment #3: Line 72: The criticism of others working with ecological network theory is that it “may exclude small but ecological crucial patches.” But 2.3.1 explains that this study only includes patches larger than 32 hectares. How can this be reconciled?
Response #3: Thank you for your summary and comment. As depicted in Figure 1, there is a noticeable decrease in both the quantity and overall size of ecological patches as the threshold value increases. Once the threshold reached 32 hectares, the decline in these parameters appeared to stabilize. Conversely, the average habitat suitability value exhibited a gradual increase with the rising threshold value, ultimately stabilizing at approximately 0.9. Consequently, the threshold of 32 hectares was determined to be the minimum area requirement for the ecological source area of Wanning City.
32 hectares is huge, especially in urban areas. Your method may say that 32 is a threshold, this is not wat literature says about it. For instance: https://www.makingnaturescity.org/urban-biodiversity-framework/patch-size/ Here patches with a minimum size of 0,8 hectares are considered. So my point is that you say that your work takes into account small patches, but according to international literature, they are huge, missing smaller but (for some species) important patches. Please reflect on that.
Response: The revised literature review (see lines 78) indicates the issue. We have revised the description of the literature review, and we believe that the selection of ecological sources in the existing studies is rather arbitrary and lacks a scientific basis. For the identification of ecological source areas, most methods either directly select nature reserves or ecological protection areas as ecological sources or base their choices on morphological spatial pattern analysis, We propose a selection of 32 thresholds, which we think is reasonable and effective on the study area scale. If we study the micro aspects of parks and blocks, a minimum size of 0,8 hectares will be considered.
Comment #8: Line 141 and further: the method does not take into account the requirements that different species impose on the size and quality of the sources and corridors. So now it is mainly a theoretical exercise that has no relation to the actual needs of species. Working with target species that represent a type of animal (or plant) is now very well established in landscape ecology. By not doing this, it is unclear what the true value of this study is.
Response #8: Thank you for your summary and comment. This study seeks to examine the spatio-temporal development of landscape patterns in Wanning City, elucidate the features of changes in ecological network structure within the city, and suggest strategies for optimizing the regional ecological space.
You do not respond to my question. What is the practical value of your study? Does it have real world relevance, or is it just a mathematical exercise? Please explain.
Response: Wanning City, located in the southeast of Hainan Island, is an important node city in the territorial spatial planning of Hainan Province, and is one of the important growth poles for the future urban development of Hainan Province. In recent years, under the influence of development, construction, and human activities, the land use and landscape pattern of Wanning City have changed significantly, which has an impact on the function and stability of the regional ecosystem. At the same time, under the background of regional coordinated and integrated development in the future, many policies and plans will certainly have a far-reaching impact on the land use layout of Wanning City. The true value of this study is to analyze the spatiotemporal evolution of landscape patterns in Wanning City, reveal the change characteristics of the ecological network structure in Wanning City, propose countermeasures and suggestions for optimizing regional ecological space and improving ecosystem services, and provide the scientific basis for ecological protection and restoration in the territorial spatial planning of Wanning City.
Comment #9: Line 181: this refers to a target area; what is that? An animal has no deliberate goal in mind when it migrates. This could be another source area, but then the word is not quite well chosen.
Line 181: what does an ecological corridor look like? Does this have a minimum width? According to standard ecological theory, certain animal species also require a certain width of the corridor? In addition, images of the corridors could be very helpful in getting an idea of what we are talking about.
Response #9: Thank you for your summary and comment. The Minimum Cumulative Resistance model (MCR) is a technique utilized for the creation of ecological corridors and nodes. It considers the factors of source area, resistance surface, and distance, with the objective of minimizing cumulative resistance between connecting regions. Additionally, it takes into account the connection relationship between nodes and has the capability to group nodes or regions with strong correlation into the same partition, resulting in more meaningful partition outcomes. In this investigation, the cost path module within ArcGIS was employed to compute the cumulative resistance value from each ecological source patch to other patches, using the core ecological source as the input source and the comprehensive resistance surface as the input resistance. This process yielded the minimum cumulative resistance surface of the source. Subsequently, on the minimum cumulative resistance surface, the minimum resistance path between each pair of ecological source patches is generated, thus forming the ecological corridor.
You do not answer my question. Maybe the width of the corridor is not part of your model, but I presume that your model calculates sizes of space between building blocks or other non-permeable elements – will not put a corridor in a space of e.g. half a meter wide. In order to better understand what your model is doing, this kind of information is vital.
Response: See 2.3.3. Ecological Corridor Identification and lines 201-214. We used formula 1 to calculate the ecological corridor.
Five landscape indicators, namely, the number of ecological source areas (PN), total area (TA), largest patch index (LPI), area-weighted mean proximity index (AWMPI), and degree of landscape division (DIVISION), were selected to assess the changes in landscape patterns within the habitat patches (refer to Table 2). Sustaining adequate habitat quantity and quality forms the foundation for supporting population reproduction and ecological flow, thereby playing a key role in maintaining biodiversity. The PN and TA indices, directly related to habitat loss and fragmentation, were chosen to depict the abundance of ecological source areas. The LPI serves as a measure of the dominance of a particular landscape type, indirectly reflecting the direction and intensity of human activity. The AWMPI gauges the concentration of regional landscape patterns concerning landscape fragmentation. As the AWMPI decreases with increased patch dispersion, the DIVISION focuses on measuring the degree of dispersion of individual distributions of different patches in a specific landscape type. A smaller mean proximity index (MPI) value indicates a higher degree of dispersion among patches of the same type, reflecting an increased level of landscape fragmentation.
Comment #10: Line 277: Is it the case that the western part of Wanning is a large source area? Or does this just say that the quality of the area is high? Where are the ecological sources within this area?
Response #10: Thank you for your summary and comment. Previous research has primarily identified ecological source areas using two main approaches: Firstly, by directly designating nature reserves or areas marked for ecological protection as ecological source areas; and secondly, by establishing a minimum area threshold for ecological source areas based on existing references, and identifying ecological patches larger than this threshold as the final ecological source areas. However, these methods are predominantly subjective and do not account for the scale effect of the landscape. This study takes into consideration various factors such as land use/land cover type, roads, landform, distance from water sources, and distance from main traffic arteries to develop an evaluation index system (Table 1) for assessing habitat suitability on a scale of 0-1. Based on this, an area threshold ranging from 2 to 40 hectares, with intervals of 2 hectares, was set to analyze the changes in the number of ecological patches, total area, and habitat suitability in order to determine the minimum area of ecological source. Figure 1 illustrates that as the threshold value increases, the number and total area of ecological patches decrease rapidly. When the threshold was raised to 32 hectares, the decline in the number and total area of ecological patches began to level off. Conversely, the mean value of habitat suitability showed a gradual increase with the rise in threshold value, stabilizing at around 0.9. Consequently, 32 hectares was identified as the minimum area threshold for the ecological source area of Wanning City.
I think part of the confusion is that in section 3.1.2 you speak about the ecological source areas (plural) while in 3.2.1 you speak about ‘the number of patches in Wanning city ecological source area (singular) increased…” there is a mix up between patches en source area. Please be more secure in defining your key elements.
Response: Thank you very much for pointing out this small and important issue. See lines 292 clearly indicates the issue.
Comment #11: Line 287: “Wannings ecological corridors are primarily situated in the central and eastern parts of the city”. Where do those corridors lead to, if the sources are only in the west (and almost nothing in the east?). Here too I find it difficult to imagine. Line 342: the identification of the obstacle points is a strong point of this study. The title of this paragraph also promises restoration countermeasures. However, I don't see that in the story and that is a shame. Show what the obstacle points actually look like (not just a color), and explain what you can or should do to solve them. Be specific. Line 360: the same applies to the restoration plan: one belt, four sources, etc. I do not yet see what this means, but I would like you to elaborate more specifically, because it is now unclear why this is the result of the research. This is reflected in line 439 where it speaks cryptically about “optimizing ecological spaces”. What do you mean? Line 375: a distinction is made in importance of the ecological corridors on the basis of their geographical distribution. In some districts they are more important than in others. Why is it like that? It seems to me that you want to have a strong network everywhere. This is reflected in line 448, perhaps a map would be helpful to explain this principle? Line 393: current theory, what does that mean?
Response #11: Thank you for your summary and comment. The eastern region of the map contains ecological source patches, necessitating the distribution of ecological corridors in this area. This is due to the central and western parts being predominantly comprised of large ecological source areas (line 297). We are not implementing a particular design scheme; rather, we are simply indicating the spatial coordinates of the obstacle points. "One Belt, Four Sources, Eight Districts, Multiple Corridors, and Multiple Points. "Referring to an abstract concept, we designed a coastal ecological landscape zone (easternmost) in Figure 5. Four ecological source areas are designed in the west and south .For additional inquiries, adjustments have been implemented in the relevant sections of the text.
Thank you for your answer, but most of my questions are not yet answered.
Line 287: “Wannings ecological corridors are primarily situated in the central and eastern parts of the city”. Where do those corridors lead to, if the sources are only in the west (and almost nothing in the east?). Here too I find it difficult to imagine.
Response: The eastern region of the map contains ecological source patches, necessitating the distribution of ecological corridors in this area. This is due to the central and western parts being predominantly comprised of large ecological source areas
Line 342: the identification of the obstacle points is a strong point of this study. The title of this paragraph also promises restoration countermeasures. However, I don't see that in the story and that is a shame. Show what the obstacle points actually look like (not just a color), and explain what you can or should do to solve them. Be specific.
Response: We are not implementing a particular design scheme; rather, we are simply indicating the spatial coordinates of the obstacle points.
Line 360: the same applies to the restoration plan: one belt, four sources, etc. I do not yet see what this means, but I would like you to elaborate more specifically, because it is now unclear why this is the result of the research.
Response: See the lines 369-381.
Based on the identification of ecological pinch points and obstacles, coupled with the prioritization of ecological network elements, we introduce an ecological network protec-tion and restoration plan known as "One Belt, Four Sources, Eight Districts, Multiple Cor-ridors, and Multiple Points" (Figure 5a). "One Belt" alludes to the coastal ecological land-scape belt, safeguarding coastal resources, defense forests, and sandy beaches. "Four sources" pertains to the four primary ecological source areas encompassing Shangxi–Jianling, Liulianling, Nanlin, and Jiaxin nature reserves, national forest parks, mountains, and inland seas. These areas hold great significance for soil and water conservation, bio-diversity preservation, and soil and water conservation within Wanning City. The "eight districts" encompass ecological restoration zones concentrated in the towns of Houan, Damao, Changfeng, and Liji. "Multi-corridor and multi-point" refer to the establishment of numerous ecological corridors and crucial ecological nodes, relying on reservoirs, wet-lands, islands, and mountains to preserve regional landscape connectivity.
This is reflected in line 439 where it speaks cryptically about “optimizing ecological spaces”. What do you mean?
Response: Thank you very much for pointing out this small and important issue. See line 449, we deleted it.
Line 375: a distinction is made in importance of the ecological corridors on the basis of their geographical distribution. In some districts they are more important than in others. Why is it like that? It seems to me that you want to have a strong network everywhere. This is reflected in line 448, perhaps a map would be helpful to explain this principle?
Response: See the linse 251-260.
In this paper, the importance of ecological source patches was classified according to the importance value dPC and the current centrality value of ecological corridor, and the protection of ecological network elements (ecological source and ecological corridor) was classified into four levels: extremely important, relatively important, important and generally important.
Line 393: current theory, what does that mean?
Response: Thank you very much for pointing out this small and important issue. we deleted it.
