Analysis of Spatiotemporal Evolution Characteristics and Influencing Factors of Vegetation Net Primary Productivity in Shendong Mining Area

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 This manuscript analyzed the spatiotemporal distribution characterisitics data and influencing factors of vegetation Net Primary Productivity (NPP) of the Shendong coal mining area.  In the manuscript, meteorological data, remote sensing images, and land utilization data were selected.  The Shendong coal mining NPP variation has been 0-350 gC/m2 from 2000 to 2023. And the Shendong coal mining average NPP is 0-250gC/m2 in 2024.  The Shendong coal mining NPP was significantly correlated with annual cumlative rainfall, annual mean temperature, annual mean Normalized Vegetation Index, and not significantly correlated with mining factors. The manuscript argues that the annual average NPP after 2011 has been higher than the average level. This phenomenon shows that the ecological environment of the Shendong coal mining area is gradudally improving.  I think this is an interesting and useful topic. However, there are still doubts to be clarified as follows:

(1) The discussion section is too short. I think there is a need to analyzed the impact of coal mining on NPP in the literature compared to this manuscript. Some of the contents of the result section can be reconciled into the discussion section.

(2) Most of the picture in the manuscript are unclear. The authors should have increased the font size and sampled 600 dpi resolution for all pictures.

(3) It is recommended that the relevant statements be revised to make the manuscript consistent. For example, " it (NPP) is not significantly related to mining factors." in abstract and "mining activities have a significant impact on the remaining NPP after excluding meteorological effects." in Conclusions. 

(4) Abbreviations that appear for the first time need to be explained e.g. CASA, RSEI .

Author Response

1. The discussion section is too short. I think there is a need to analyzed the impact of coal mining on NPP in the literature compared to this manuscript. Some of the contents of the result section can be reconciled into the discussion section.

Response: Thanks for your comments, the structure and content has been improved in discussion part:

The study used the BLOME-BGC Model to calculate shendong coal mining’ NPP from year 2000 to 2010. The NPP value and change trend is similar to this article [26]. Niu Hongbo et al used the MOD17A3 database and analyzed the NPP trend from 2000 to 2016 [27]. The result showed the average NPP value were mainly concentrated at 150-200gC/m², which is same as this article. Considering the NPP results in Inner Mongolia, some articles also support the changing results of the NPP, which are similar with those found in this article [28-30]. Thus, the NPP in Inner Mongolia shown a fluctuating rise trend from 2000-2023.

About the correlation results between NPP and meteorological elements, scholar concluded that the annual vegetation NPP in Shendong mining area is significantly positively correlated with precipitation, but not significantly correlated with annual average temperature [26].

About the coal mining factor’s effect, Niu Hongbo et al concluded that the growth of NPP vegetation in mining areas is disturbed by mining activities, and the degraded mines are mainly 7distributed in high-intensity mining areas [27], which can support the result of this article. Xiang Yang et al showed that the growth status of vegetation NPP in different mines of Shendong mining area was deteriorated [31]. Bose of the results are similar to the conclusion of this article.

What is more, increasingly of article are focused on the lag between nature factors and NPP [31-33]. So that, we will select the improved CASA model and nature data to analyze the long-term period NPP at mining area and study the time lag between the NPP and each factor.

There are still some shortcomings in this article that need to be further improved. (1) The changes in the values of different parameters when calculating NPP may affect the research results. (2) Because of the NDVI data, this article only analyzes the working face NPP and mining factors of high-precision remote sensing images from 2018 to 2023. The impact time and scope of mining factors on NPP still need further research. (3) The influencing factors of vegetation NPP are not only environmental factors, but also factors such as vegetation characteristics and human activities should be considered, which affect the changes in vegetation NPP.

2. Most of the picture in the manuscript are unclear. The authors should have increased the font size and sampled 600 dpi resolution for all pictures.

Response: Thanks for your comments, the font size and resolution of the pictures has been increased:

Figure 1.（d）Distribution and topographic map of coal mines of the shendong mining area.

Figure 2.  Annual variation curve of vegetation NPP in Shendong mine area

Figure 3. Trends in vegetation NPP changes in Shendong mining area

Figure 4. Main years and annual spatial distribution characteristics of vegetation NPP in Shendong mining area.

Figure 7. Spatial distributions of the correlation coefficient between annual NPP and annual NDVI

Figure 8. Annual distribution of surface subsidence and NPP in the fourth district of Shangwan coal mine

3. It is recommended that the relevant statements be revised to make the manuscript consistent. For example, " it (NPP) is not significantly related to mining factors." in abstract and "mining activities have a significant impact on the remaining NPP after excluding meteorological effects." in Conclusions;

Response: Thanks for your comments, this article discussed the influence of NPP and NPP_CM. The NPP value indeed is not significantly related to mining factors, in the scale of shendong mining scale. When excluding meteorological effects, however, the NPP_CM has been affected by mining activities strongly. Thus, I rewrote the sentence in conclusion: mining activities have a significant impact on the NPP_CM after excluding meteorological effects.

4. Abbreviations that appear for the first time need to be explained e.g. CASA, RSEI .

Response: Thanks for your comments, the abbreviations has been explained in the article:

At present, most Chinese scholars focus on analyzing the ecological environment of surface mines and western mining areas. Most scholars use the improved Carnegie-Ames-Stanford Approach (CASA) CASA model and Remote Sensing Ecological Inde （RSEI）index model as research methods to measure the ecological environment of mining areas.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The paper highlights the environmental impacts of coal mining in the Shandong mining area (China). The authors show that the annual average NPP of vegetation has been higher than the average

level. According to their estimations, this fact illustrates that the ecological environment of the mining area is gradually improving. The paper is interesting but requires some revisions before being published in Sustainability.

1. The authors should urgently and comprehensively describe the environmental impacts of coal production and consumption. They must emphasize how the coal economy affects and will continue to affect the transition to sustainability.
2. Coal mining activities typically result in significant changes in land cover and soil structure, which directly impact the health and productivity of vegetation. Mining operations may lead to deforestation, soil erosion and habitat fragmentation, all of which contribute to the alteration of NPPs. This paper shows that, despite adverse impacts, NPP levels in Shendong Mining Area, as a whole, are on an upward trend between 2000 and 2023. The manuscript shows that despite the adverse impacts, the average vegetation NPP of the Shendong mining area in 24 years is 0-250gC/m²; after 2011, the annual average vegetation NPP is higher than the average level, which shows that the ecological environment of the mining area is gradually improving. Authors should conduct a thorough literature review, exemplifying all relevant studies that show the relationship between coal mining and NPPs. It is unclear how coal mining cannot significantly impact the overall environment.
3. The authors note that the coal economy is associated with environmental sustainability and sustainable development. They have to add a brief discussion on sustainable development to engage the readers. Moreover, it is highly recommended to include references to the following two papers: 'Broad strokes towards a grand theory in the analysis of sustainable development: a return to the classical political economy', New Political Economy, 27(5), pp. 866-878, and 'History, Knowledge, and Sustainable Economic Development: The Contribution of John Stuart Mill’s Grand Stage Theory', Sustainability, 13 (3).
4. The authors should further discuss their results. The discussion section needs to be longer.
5. What are the theoretical and policy implications of this paper?

Comments on the Quality of English Language

Minor editing of the English language is required.

Author Response

1. The authors should urgently and comprehensively describe the environmental impacts of coal production and consumption. They must emphasize how the coal economy affects and will continue to affect the transition to sustainability.

Response: Thanks for your comments, I have described the environmental and sustainable development impacts of coal production in introduction part:

Coal enterprises have their own unique characteristics in development. Therefore, coal enterprises should pay more attention to implementing sustainable development strategies to prolong their development. After a long period of reckless and extensive development, coal enterprises have developed many problems that seriously affect their subsequent development. These are all challenges that coal enterprises need to face in implementing sustainable development strategies [3].

The environmental problems caused by coal production are seriously threatening human health, natural resources, and ecological environment, and have been widely concerned by the international community. Many scholars have conducted research on coal environmental pollution, including wastewater pollution, air pollution, soil pollution and so on [4]. The water pollution caused by coal mining activities is the main source of water pollution worldwide [5]. Untreated mine water discharged into surface rivers will cause serious water pollution [6]. High intensity coal mine excavation can also cause serious groundwater level drop, resulting in fragile ecological environment in some areas and severe damage [7]. In addition to the environmental impact factors mentioned above, the underground mining of coal can also lead to ground subsidence and the formation of subsidence areas, affecting the growth of surface vegetation and even causing the loss of land resources in mining areas, leading to an imbalance in the ecosystem [8].

2. Coal mining activities typically result in significant changes in land cover and soil structure, which directly impact the health and productivity of vegetation. Mining operations may lead to deforestation, soil erosion and habitat fragmentation, all of which contribute to the alteration of NPPs. This paper shows that, despite adverse impacts, NPP levels in Shendong Mining Area, as a whole, are on an upward trend between 2000 and 2023. The manuscript shows that despite the adverse impacts, the average vegetation NPP of the Shendong mining area in 24 years is 0-250gC/m²; after 2011, the annual average vegetation NPP is higher than the average level, which shows that the ecological environment of the mining area is gradually improving. Authors should conduct a thorough literature review, exemplifying all relevant studies that show the relationship between coal mining and NPPs. It is unclear how coal mining cannot significantly impact the overall environment.

Response: Thanks for your comments, the relationship between coal mining and NPP has been displayed in the introduction part (reference 4-7):

Li Zhixiang et al. used the MOD17A3H dataset to analyze the spatiotemporal changes of vegetation NPP in six major coalfields in Shanxi Province, and the impact of land cover types on vegetation NPP. The results showed that from 2005 to 2015, the vegetation NPP of the six major coalfields in Shanxi Province showed a fluctuating growth trend, and the increase in forest and cultivated land area led to a significant increase in vegetation NPP [4].

Fan Deqin et al. added vegetation NPP as a new indicator to the RSEI index model and summarized the patterns of environmental changes in the Shenfu mining area from 2000 to 2016. The conclusion shows that with coal mining, the ecological quality of the mining area has steadily improved and recovered continuously [5].

Sun Yinglong et al. calculated vegetation NPP by using the carbon flux TEC model. By analyzing the spatial variation of NPP in Lincang City from 2000 to 2018 and the relationship with meteorological factors, the study displayed the characteristics of sustained growth of NPP in Lincang City, and the most significant correlation with rainfall [6].

Zhang Wenkai et al. used an improved CASA model to calculate the distribution characteristics of vegetation NPP in the Shendong mining area from 2005 to 2015. Research has shown that the impact of mining levels at different scales and intensities of coal mines on vegetation NPP in the Shendong mining area is not significant [7].

3. The authors note that the coal economy is associated with environmental sustainability and sustainable development. They have to add a brief discussion on sustainable development to engage the readers. Moreover, it is highly recommended to include references to the following two papers: 'Broad strokes towards a grand theory in the analysis of sustainable development: a return to the classical political economy', New Political Economy, 27(5), pp. 866-878, and 'History, Knowledge, and Sustainable Economic Development: The Contribution of John Stuart Mill’s Grand Stage Theory', Sustainability, 13 (3).

Response: Thanks for your comments, the environmental sustainability and sustainable development has been described in the introduction part:

The concept of sustainable development has been announced after the publication of the Brundtland Commission Report by the World Commission on Environment and Devel-opment [2]. The sustainable development means " .. development that meets the needs of the present without compromising the ability of future generations to meet their own needs". The sustainability economic notion, more specifically, focus on the market oppor-tunities about the welfare level hat each generation inherit to the next one [3].

4. The authors should further discuss their results. The discussion section needs to be longer.

Response: Thanks for your comments, the structure and content has been improved in discussion part:

The study used the BLOME-BGC Model to calculate shendong coal mining’ NPP from year 2000 to 2010. The NPP value and change trend is similar to this article [26]. Niu Hongbo et al used the MOD17A3 database and analyzed the NPP trend from 2000 to 2016 [27]. The result showed the average NPP value were mainly concentrated at 150-200gC/m², which is same as this article. Considering the NPP results in Inner Mongolia, some articles also support the changing results of the NPP, which are similar with those found in this article [28-30]. Thus, the NPP in Inner Mongolia shown a fluctuating rise trend from 2000-2023.

About the correlation results between NPP and meteorological elements, scholar concluded that the annual vegetation NPP in Shendong mining area is significantly positively correlated with precipitation, but not significantly correlated with annual average temperature [26].

About the coal mining factor’s effect, Niu Hongbo et al concluded that the growth of NPP vegetation in mining areas is disturbed by mining activities, and the degraded mines are mainly 7distributed in high-intensity mining areas [27], which can support the result of this article. Xiang Yang et al showed that the growth status of vegetation NPP in different mines of Shendong mining area was deteriorated [31]. Bose of the results are similar to the conclusion of this article.

What is more, increasingly of article are focused on the lag between nature factors and NPP [31-33]. So that, we will select the improved CASA model and nature data to analyze the long-term period NPP at mining area and study the time lag between the NPP and each factor.

There are still some shortcomings in this article that need to be further improved. (1) The changes in the values of different parameters when calculating NPP may affect the research results. (2) Because of the NDVI data, this article only analyzes the working face NPP and mining factors of high-precision remote sensing images from 2018 to 2023. The impact time and scope of mining factors on NPP still need further research. (3) The influencing factors of vegetation NPP are not only environmental factors, but also factors such as vegetation characteristics and human activities should be considered, which affect the changes in vegetation NPP.

5. What are the theoretical and policy implications of this paper?

Response: Thanks for your comments, this article combines spatial econometric methods to analyze the spatial distribution patterns of NPP in various mines based on different characteristics, and analyzes the variation characteristics of meteorological factors at the mining area scale; Fit the relationship between vegetation NPP in mining areas and mining factors. The aim is to extend the general relationship between the net primary productivity of typical coal mine vegetation and its driving factors to the universal relationship in coal mining areas with similar mining conditions, geomorphic features, and vegetation coverage.

In addition, this article results of this article contribute to providing more suitable methods for improving the ecosystem of mining areas, which also have reference significance for vegetation NPP research in mining areas with similar terrain and landforms.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have made significant attempts to address my comments. However, a little more work should be done in:

(a) presenting the relevant literature, as the paper does not include a literature review section.

(b) discussing the notion of sustainable development. The proposed references 'Broad strokes towards a grand theory in the analysis of sustainable development: a return to the classical political economy', New Political Economy, 27(5), pp. 866-878, and 'History, Knowledge, and Sustainable Economic Development: The Contribution of John Stuart Mill’s Grand Stage Theory', Sustainability, 13 (3). should be incorporated to enhance this discussion.     

Comments on the Quality of English Language

Moderate editing of the English language is required

Author Response

1. Presenting the relevant literature, as the paper does not include a literature review section.

Response: Thanks for your comments, I have provided an explanation for this issue:

This article includes 35 references, among which references 1 to 12, 27 are descriptions of policies and concepts; In literature 13 to 21 at “introduction part”, this article described the main methods that scholars used to measure the ecological environment of mining areas, and also displayed the main content and conclusion; In literature 22 to 26 at “Material and Method” part, each formula character has been explained in this article; In literature 28 to 33 at “discussion part”, this article referenced some studies’ content to support the result of analysis. Each reference in this part has been present about the author and specific content which is relevant of this article; References 33 to 35 are descriptions of the parts that can be further improved.

2. discussing the notion of sustainable development. The proposed references 'Broad strokes towards a grand theory in the analysis of sustainable development: a return to the classical political economy', New Political Economy, 27(5), pp. 866-878, and 'History, Knowledge, and Sustainable Economic Development: The Contribution of John Stuart Mill’s Grand Stage Theory', Sustainability, 13 (3). should be incorporated to enhance this discussion.

Response: Thanks for your comments, I have enhanced sustainable development discussion:

The concept of sustainable development has been announced after the publication of the Brundtland Commission Report by the World Commission on Environment and Development [2]. The sustainable development means“. development that meets the needs of the present without compromising the ability of future generations to meet their own needs". The sustainability economic notion, more specifically, focus on the market opportunities about the welfare level hat each generation inherit to the next one [3]. Sustainable development research should include a comprehensive historical background and a broader explanatory framework. More theories have shown a clear stable trend, gradually shifting their attention comprehensively to the context or developmental background. Smith, Mill, and Marx's theory of developmental stages provides a powerful theoretical framework that can integrate multiple, diverse, and medium-sized contemporary clues in development research. Classical political economy provides an analytical foundation for certain elements, including the important role of history, the necessity of interdisciplinary methods, and the priority of analyzing social classes [4]. A major theory in development research, namely John Stuart Mill's Grand Stage Theory, provides the necessary perspective for development research to fully understand the origins of contemporary events. Mueller's theory regards the dialectical relationship between knowledge/innovation (human capital) and nature (natural capital) as an accelerator of economic change. In Mueller's political economy, innovation and nature play a crucial role in achieving sustainable economic development. Contemporary society and development issues require the adoption of alternative research approaches in development studies. There is an urgent need to revive grand theories that can encompass multiple intermediate range theories, provide greater historical depth, and offer necessary interdisciplinary perspectives to better understand and articulate complex and interconnected development dynamics. In this regard, we attempt to demonstrate that Mill's theory of stages provides a dynamic and grand theory that can be expanded and enriched through contact with mid-term theories that address empirical challenges [5].

Author Response File: Author Response.docx

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

The authors addressed my previous comments and improved their manuscript.