Spatiotemporal Dynamics and Future Trajectories of Coupling Coordination Between Net Ecosystem Productivity and Human Activity Intensity: A Case Study of the Zhangjiakou–Chengde Region, Northern China

Comments 1: The abstract remains too dense, with technical details. The originality of the study in relation to previous work is not sufficiently highlighted, and the practical implications remain general and lack impact.

Response 1: Agree. Thank you very much for this insightful comment. We have substantially revised the abstract to enhance its clarity, balance, and informativeness. In the new version, technical details were reduced, and the focus was shifted toward explaining the main objectives, findings, and implications. The revised abstract now provides a clearer overview of the spatiotemporal coordination between carbon sequestration capacity and human activity intensity, highlights the key spatial patterns and dominant drivers, and elaborates on how the findings can guide regional ecological restoration and carbon neutrality strategies.The updated abstract (Page 1, Lines 13–30) is highlighted in yellow in the revised manuscript.

Revised text:

“Understanding the coordination between regional carbon sequestration and human activities is essential for achieving ecological sustainability and carbon neutrality. This study explored the spatiotemporal evolution, driving mechanisms, and sustainability of net ecosystem productivity (NEP) and human activity intensity (HAI) in the Zhangjiakou–Chengde region of northern China from 2000 to 2023. NEP and HAI were integrated through a coupling coordination framework to assess their dynamic balance and relative development. Results show that the coordination between carbon sinks and human activities has improved continuously over the past two decades, shifting from human-dominated imbalance to a more synergistic pattern. Spatially, higher coordination levels were concentrated in forested mountain areas, while agricultural and transitional zones exhibited instability or lagging development. Land use regulation, vegetation recovery, and terrain conditions were identified as the primary factors shaping this pattern, with interaction effects amplifying spatial disparities. Trend analysis suggests that northeastern and eastern regions will likely sustain their positive trajectories, whereas the agro-pastoral transition belt remains vulnerable. These findings deepen understanding of carbon–human interactions in fragile ecosystems and provide scientific evidence for differentiated land management, ecological restoration, and carbon neutrality planning in northern China and similar regions worldwide.”

Comments 2: The introduction suffers from certain descriptive lengthy passages that dilute the main thread. The justification for the choice of region remains poor. The research hypotheses are not explicitly formulated.

Response 2: Agree. Thank you very much for your thoughtful and constructive comment. We have substantially revised the Introduction to improve its focus, logical structure, and clarity. Redundant descriptive content was condensed to strengthen the main narrative. To address your suggestions, we expanded the justification for choosing the Zhangjiakou–Chengde (ZC) region by emphasizing its dual ecological and socio-economic roles as both a carbon sink and a development frontier within the Beijing–Tianjin–Hebei ecological barrier. In addition, we incorporated the expected research hypotheses more naturally into the regional context, rather than presenting them separately, to ensure smooth logical continuity. The revised text now highlights how ecological restoration programs and land-use regulation are hypothesized to enhance NEP–HAI coordination, while spatial heterogeneity persists across ecological zones.

These revisions improve the coherence of the introduction and more clearly explain why the ZC region provides an ideal case for exploring the spatiotemporal coordination between carbon sequestration and human activity intensity. The modifications can be found on Pages 2–3, Lines 47–49, Lines 66–71, Lines 72–89, highlighted in yellow in the revised manuscript.

Revised text:

“Numerous studies have investigated NEP as a key indicator of carbon balance at global and regional scales [11]. NEP has been shown to respond strongly to climatic variation, vegetation cover, and land-use change [12, 13].” (Pages 2–3, Lines 47–49)

“However, despite growing interest, comprehensive assessments of NEP–HAI coordination remain limited. Existing studies have often examined natural or anthropogenic factors separately, overlooking their combined and interactive influences. Furthermore, few studies have evaluated the long-term sustainability of coordination trends, leaving uncertainties about whether observed improvements can persist under future environmental or policy changes.” (Pages 2–3, Lines 66–71)

“The Zhangjiakou–Chengde (ZC) region, located in northern Hebei Province, rep-resents a typical agro-pastoral transition zone and a critical ecological barrier for Beijing and Tianjin [27]. It performs multiple ecological functions such as water conservation, wind prevention, and carbon sequestration, yet experiences increasing stress from water scarcity, overgrazing, and rapid socio-economic growth [28]. In recent decades, the re-gion has been the focus of major ecological restoration programs, including the Beijing–Tianjin Sandstorm Source Control Project and the Returning Farmland to Forest Program, which have profoundly altered both land-use patterns and vegetation productivity. These contrasting ecological and socio-economic dynamics make the ZC region an instructive setting for examining how carbon sequestration capacity and human activity intensity interact over space and time. It is expected that ongoing restoration and land-use regulation have progressively enhanced the coordination between NEP and HAI, while spatial heterogeneity remains pronounced, with stronger coordination in forested mountains and weaker balance in the agricultural and transition zones. Understanding these processes in a region that simultaneously serves as a carbon sink and a development frontier provides important insights into the mechanisms driving ecosystem–human linkages and their implications for sustainable regional management.” (Pages 2–3, Lines 72–89)

Comments 3: In the Materials and Methods section, the current maps do not geographically locate the study region, and certain methodological choices are not sufficiently justified, such as the equal weighting of NEP and HAI in the coordination index. The use of data from empirical models is not clearly explained.

Response 3: Agree. Thank you very much for this valuable comment. We have carefully revised the Materials and Methods section to improve methodological clarity and transparency.

(1) To address the reviewer’s first concern, a revised geographical location map (Figure 1) has been added to clearly show the position of the Zhangjiakou–Chengde (ZC) region within northern China. The updated figure now displays administrative boundaries and major topographic features, indicating its ecological importance as a transition zone between the Beijing–Tianjin metropolitan area and the Inner Mongolia Plateau.

(2) Regarding the equal weighting of NEP and HAI (α₁ = α₂ = 0.5), we have added a detailed explanation in the revised text. The equal weighting reflects the conceptual principle that ecological and human systems are of equal importance to regional sustainable development. Assigning equal importance to both avoids bias toward either environmental or socio-economic aspects and ensures that the coordination index represents a balanced evaluation of both dimensions.

(3) To clarify the use of empirical model data, we have added explanatory text specifying that the heterotrophic respiration (Rh) model was derived from previous empirical parameterization studies based on field observations in northern China. The reliability and applicability of this model have been validated in similar temperate ecosystems (referenced in citations [29–30]). This ensures consistency between NEP estimation and the regional climatic conditions of the ZC area.

These revisions strengthen the methodological justification, enhance reproducibility, and improve readers’ understanding of the analytical framework. The modifications can be found on Page 3 Line 119, Page 5, Lines 151–156, Page 6, Lines 194–198, highlighted in yellow in the revised manuscript.

Revised text:

(1)

Figure 1. Study area. (Page 3 Line 119)

(2)” The empirical Rh model applied in this study was derived from parameterized relationships validated in previous field-based research conducted in temperate ecosystems of northern China. These studies demonstrated that the model performs well in regions with similar climatic and vegetation conditions, thereby ensuring the reliability of NEP estimation in the ZC region [29, 30].” (Page 5, Lines 151–156)

(3)” This setting reflects the principle that ecological and human subsystems are equally important in achieving sustainable regional development. Giving them equal importance avoids bias toward either environmental or socio-economic dimensions and ensures that the final coordination degree reflects the balance between ecological performance and human activity intensity.” (Page 6, Lines 194–198)

Comments 4: The results are presented in an overly descriptive manner. Major trends are not always highlighted in a concise manner. Some figures, which are complex and technical, are not explained sufficiently to be accessible to the general public.

Response 4: Agree. Thank you very much for this helpful comment. We have revised the Results section to make it more concise, analytical, and reader-friendly. Specifically:

(1) Key trends and spatial patterns have been highlighted in each subsection by adding summary sentences that synthesize the main findings. For example, we emphasized that NEP increased significantly with a pronounced north–south gradient, while HAI growth was concentrated around urban and agricultural expansion areas.

(2) We added several transitional statements (e.g., “Overall, these results reveal a continuous improvement in the coordination degree from western to eastern subregions”) to strengthen logical flow and ensure that readers can easily grasp the main message without excessive description.

(3) Figure explanations have been refined to improve accessibility. For complex visualizations such as Figure 5 (Sankey diagram) and Figure 6 (spatial coupling maps), we added short interpretive notes clarifying what each color gradient and arrow represents, and how they correspond to shifts in coordination categories.

These modifications enhance clarity and allow both academic and general readers to better understand the key patterns and implications. All revised parts have been highlighted in yellow in the updated manuscript. (Page 10 Lines 310-313, Page 13, Lines 353–355, Pages 10-11, Lines 299–302)

Revised text:

(1)” Overall, NEP exhibited a steady upward trend across the study period, reflecting enhanced ecosystem productivity driven by vegetation recovery, while HAI showed a sharp increase in urban and agricultural zones, indicating intensifying human development pressures.” (Page 10 Lines 310-313)

(2)” These results reveal a clear improvement in the coupling coordination degree from west to east, with the eastern forested areas maintaining stable coordination and the western farming–pastoral zones showing gradual recovery from previous imbalance.”(Page 13, Lines 353–355)

(3) “Figure 5 visualizes the dynamic transitions among coordination types, where arrow width represents the magnitude of change and color intensity indicates the direction of evolution. This helps illustrate how regions shifted between ecological- and hu-man-dominant states over time.”(Pages 10-11, Lines 299–302)

Comments 5: In the discussion, the perspectives remain somewhat superficial at times and do not clearly show what the study adds to existing work on other regions. Methodological limitations are hardly discussed, which is a significant weakness. Finally, practical implications are mentioned, but they remain general and would benefit from being developed into concrete recommendations for management and public policy.

Response 5: Agree. Thank you very much for this valuable comment. We have substantially revised the Discussion section to deepen the interpretation of findings, clarify the study’s novelty compared with previous research, acknowledge methodological limitations, and provide more specific and actionable policy implications.

(1) To address the first point, we added a paragraph emphasizing the unique contribution of this study to understanding NEP–HAI coordination in fragile agro-pastoral regions. We clarified that the integration of NEP and HAI at a fine spatiotemporal scale provides new insights into how ecological restoration and socio-economic development interact, which distinguishes this study from previous regional assessments focused solely on either carbon sinks or human impacts.

(2) To address the reviewer’s concern on methodological limitations, we added a short reflective paragraph outlining potential sources of uncertainty, such as the spatial resolution of interpolated climatic variables, the use of model-derived NEP estimates, and the assumption of equal weights in the coordination index. We also explained how these limitations could be addressed in future research through higher-resolution datasets and dynamic socio-ecological modeling.

(3) Finally, we strengthened the practical and policy recommendations by linking them to differentiated regional management strategies. Specifically, we proposed:

– promoting ecological restoration and vegetation protection in low-coordination zones;

– consolidating achieved gains through eco-compensation and sustainable agriculture in stable coordination areas; and

– encouraging low-carbon development and land-use optimization in transitional zones.

These recommendations make the study more relevant to practical ecological governance and spatial planning.

All modifications are highlighted in yellow in the revised manuscript. (Page 17, Lines 481-486, Page 19, Lines 551–568, Page 18, Lines 509–516)

Revised text:

(1)” This study jointly quantified NEP and HAI dynamics at a fine spatiotemporal resolu-tion, revealing how ecological resilience and human pressure evolve interactively. The findings highlight that the agro-pastoral transition zone exhibits distinctive coordina-tion mechanisms compared with forest or urban ecosystems, contributing new empiri-cal evidence for understanding carbon–human relationships under fragile environ-mental conditions.” (Page 17, Page 18, Lines 537–550)

(2)” 4.4. Limitations and Perspectives

The estimation of NEP relies partly on model-based heterotrophic respiration (Rh) data, which may introduce uncertainties in areas with complex topography or sparse observations. Likewise, the use of interpolated climatic datasets and the equal-weight assumption between NEP and HAI could affect the precision of the coupling coordination index. Moreover, satellite-derived data in rural or low-density regions may contain inherent errors, and socioeconomic indicators such as GDP and population density may not fully reflect informal or seasonal human activities.

In addition, exogenous factors—including regional policy changes, agricultural subsidy adjustments, and extreme weather events such as droughts or floods—may in-fluence both NEP and HAI but were not explicitly considered in this analysis. These sources of uncertainty highlight the need for future research to incorporate high-er-resolution remote sensing products, integrate field-based biophysical and so-cio-economic data, and explore alternative weighting approaches such as principal component analysis (PCA) or the analytic hierarchy process (AHP) to test the robust-ness of the HAI index. Future work could also focus on developing dynamic so-cio-ecological models capable of capturing feedbacks between human and ecological systems, thereby improving the explanatory and predictive capacity of NEP–HAI coor-dination analyses.” (Page 19, Lines 551–568)

(3) “From a management and planning perspective, differentiated strategies are essen-tial to strengthen the coordination between ecological and human systems. In areas with persistent imbalance, ecological restoration and strict land-use regulation should remain the primary focus to prevent further degradation. Regions with stable coordination should consolidate resilience through ecological compensation mechanisms, sustainable agricultural transition, and improved landscape connectivity. Transitional zones, where human pressure remains high, require the promotion of low-carbon industrial transformation and optimized spatial structure to harmonize production, living, and ecological functions. Beyond local management, the NEP–HAI coordination framework provides a scientific basis for integrating ecological assessment into regional and national territorial planning. It can support the delineation of ecological conservation zones, inform land-use intensity thresholds, and guide resilience-oriented policies aligned with global sustainability and carbon neutrality goals. These targeted recommendations enhance the policy relevance and transferability of the study’s findings.” (Page 18, Lines 537–550)

Comments 6: The conclusion lacks conciseness and does not offer sufficiently precise research perspectives to pave the way for future studies. The recommendations are too general and do not fully exploit the potential of the results.

Response 6: Agree. Thank you very much for this valuable suggestion. We have carefully revised the Conclusion section to make it more concise, structured, and forward-looking.

(1) The revised version now summarizes the main findings, dominant drivers, and spatial trends in a clear four-point structure, avoiding redundancy and emphasizing the logical flow from results to implications.

(2) The third conclusion explicitly introduces a research perspective by highlighting future trajectories of NEP–HAI coordination and the need for targeted management in degradation-prone areas. This addition reflects the study’s forward-looking dimension and helps pave the way for future research on dynamic ecosystem–human coupling.

(3) The policy recommendations have been refined and made more actionable by distinguishing between low-, stable-, and high-pressure zones, thereby enhancing the practical value and regional applicability of the findings.

These revisions make the conclusion more concise, precise, and policy-relevant, fully addressing the reviewer’s concerns. All modified content has been highlighted in yellow in the revised manuscript. (Page 19, Lines 569–595)

Revised text:

” This study explored the coupling coordination between NEP and HAI in the ZC region from 2000 to 2023. By integrating multi-source data, spatial analysis, and trend-sustainability modeling, the research provides new insights into how ecological and socio-economic systems co-evolve in fragile agro-pastoral transition zones.The main conclusions are as follows:

 (1) NEP and HAI exhibited a coordinated upward trend, indicating that regional ecological restoration and socio-economic development are gradually achieving mutual reinforcement. The coordination pattern evolved from human-dominated imbalance to ecological–social synergy, with high coordination concentrated in the forested eastern mountains and low coordination persisting in agro-pastoral transition belts.

(2) LUI was identified as the dominant driver of spatial heterogeneity in coupling coordination, while natural factors such as vegetation condition (NDVI), drought stress (SPEI), and topography (ELV, SLP) gained increasing importance over time. Interactive effects between anthropogenic and natural factors.

(3) MK and Hurst analyses revealed that the ZC region will likely continue on a positive trajectory of NEP–HAI coordination, though with pronounced spatial differ-entiation. Strongly improving areas are concentrated in mountainous zones, while degradation-prone areas remain in agro-pastoral transition belts, requiring targeted management.

(4) Targeted management strategies should be adopted according to regional co-ordination levels. Low-coordination zones require vegetation recovery, soil conservation, and strict land-use regulation; stable coordination areas should strengthen resilience through ecological compensation and sustainable agriculture; and high-pressure transi-tion zones should promote low-carbon development and land-use optimization. These differentiated measures can support the realization of carbon neutrality and ecological security goals in northern China, while offering a reference for sustainable development in similar regions worldwide.” (Page 19, Lines 569–595)

Comments 1: The manuscript offers a solid and technically competent study of the interaction between net ecosystem productivity and the intensity of human activities in an agro-pastoral environment in northern China. This is a highly relevant topic for ecological sustainability, as it addresses the challenge of reconciling environmental restoration and socio-economic development in sensitive areas. The article stands out for its orderly structure, appropriate use of quantitative methods, and clear graphical presentation of results. However, its main opportunity for improvement lies in moving from a predominantly descriptive approach to a more interpretative and comparative one, capable of placing the findings within a broader theoretical and geographical framework. It shows potential to contribute significantly to the debate on territorial sustainability and ecological resilience, provided that it reinforces the critical discussion, methodological justification, and international projection of its results. The text could achieve notable academic impact through a more in-depth conceptual review and a more direct connection to public policies and global sustainability agendas.

Response 1: Agree. We sincerely thank the reviewer for this insightful comment. In response, we have strengthened the Discussion section to enhance the interpretative depth and theoretical context of the study. The revised text now emphasizes that the spatiotemporal evolution of NEP–HAI coordination represents a transition from human-dominated imbalance toward more balanced and ecologically favorable states, driven by ecological restoration, land-use regulation, and climatic improvement. This trend is interpreted as part of a broader pathway of harmonizing human development with ecological resilience in fragile transition zones. Moreover, the discussion highlights the unique coordination mechanisms of agro-pastoral regions compared with forest or urban ecosystems, reinforcing the study’s conceptual contribution and policy relevance. The revised sentences have been highlighted in yellow in the manuscript. (Page 17, Lines 477–490)

Revised text:

“The spatiotemporal evolution of NEP–HAI coordination in the ZC region demon-strates a transition from human-dominated imbalance toward more balanced and eco-logically favorable states, driven by the combined effects of ecological restoration, land-use regulation, and gradual climatic improvement. This trend reflects a broader pathway of harmonizing human development with ecological resilience in fragile tran-sition zones. Nevertheless, the persistence of localized imbalances—particularly within agro-pastoral transitional belts—highlights the need for differentiated management strategies that reinforce ecological restoration and balance environmental protection with socio-economic development [45]. This study jointly quantified NEP and HAI dy-namics at a fine spatiotemporal resolution, revealing how ecological resilience and hu-man pressure evolve interactively. The findings highlight that the agro-pastoral transi-tion zone exhibits distinctive coordination mechanisms compared with forest or urban ecosystems, contributing new empirical evidence for understanding carbon–human relationships under fragile environmental conditions.” (Page 17, Lines 477–490)

Comments 2: This article provides an insightful analysis of the relationship between net ecosystem productivity (NEP) and the intensity of human activity (HAI) in a fragile agro-pastoral region of northern China. From the outset, it acknowledges the importance of studying these linkages in the context of sustainability and carbon neutrality. However, while the introduction is comprehensive in terms of the number of citations it contains, it is limited to a descriptive review of the literature. It would have been preferable for the authors to engage more critically with the limitations of previous research, such as the absence of multiscale integration and the omission of complex social factors beyond population density and GDP. Comparing the region in question with other agro-pastoral transition regions worldwide would have strengthened the argument and enhanced the study's global relevance. In this regard, referencing the article 'The Changing Contexts of the Desertification Debate' (Journal of Arid Environments, https://doi.org/10.1016/j.jaridenv.2005.03.003), could be useful as it would enable the authors to demonstrate that pressures on ecosystems in agro-pastoral contexts are not unique to China, but rather global phenomena observed in Africa and other regions. Such a comparison would reinforce the international validity of the study and emphasise the need for a comparative approach to understanding the interactions between human activity and ecosystem productivity. Furthermore, it would be advisable for the authors to provide clearer context for their choice of study area in the introductory section (p. 2), explaining why the Zhangjiakou–Chengde region represents a paradigmatic case of agro-pastoral transition and what its biophysical and socio-economic characteristics are compared to other regions of China. This contextualisation would strengthen the scientific and geographical justification of the work, showing that the selected area is not only a representative example, but also a laboratory for ecological policies for restoration and desertification control.

Response 2: Agree. Thank you very much for this constructive suggestion. We have revised the Introduction to strengthen the international perspective and clarify the representativeness of the study area. Specifically, we added a statement highlighting that similar human–environment tensions and ecological degradation processes occur globally in arid and semi-arid transition zones, emphasizing that the challenges faced in the Zhangjiakou–Chengde region are part of broader global issues. The recommended reference “The Changing Contexts of the Desertification Debate” (Reynolds & Stafford Smith, 2005) has been added to support this point. (Pages 2-3, Lines 72–90, Page 22, Lines 720–721)

Revised text:

“The Zhangjiakou–Chengde (ZC) region, located in northern Hebei Province, represents a typical agro-pastoral transition zone and a critical ecological barrier for Beijing and Tianjin [27]. It performs multiple ecological functions such as water conservation, wind prevention, and carbon sequestration, yet experiences increasing stress from water scarcity, overgrazing, and rapid socio-economic growth [28]. In recent decades, the region has been the focus of major ecological restoration programs, including the Beijing–Tianjin Sandstorm Source Control Project and the Returning Farmland to Forest Program, which have profoundly altered both land-use patterns and vegetation productivity. Similar human–environment tensions and ecological degradation processes are observed globally in arid and semi-arid transition zones [29], suggesting that the ZC region not only represents a typical Chinese case but also reflects broader global challenges of harmonizing ecological restoration and socio-economic development. It is expected that ongoing restoration and land-use regulation have progressively enhanced the coordi-nation between NEP and HAI, while spatial heterogeneity remains pronounced, with stronger coordination in forested mountains and weaker balance in the agricultural and transition zones. Understanding these processes in a region that simultaneously serves as a carbon sink and a development frontier provides important insights into the mechanisms driving ecosystem–human linkages and their implications for sustainable regional management.” (Pages 2-3, Lines 72–90)

“29. Herrmann, S. M.; Hutchinson, C. F., The changing contexts of the desertification debate. Journal of Arid Environments 2005, 63, (3), 538-555.” (Page 22, Lines 720–721)

Comments 3: Methodologically, the article is rigorous and meticulous. The construction of the HAI index using the entropy method together with Geodetector, the Mann–Kendall test and the Hurst exponent demonstrates a robust approach to exploring NEP–HAI dynamics. However, the methodology section lacks reflection on the limitations inherent in the satellite data employed, which often contains errors in rural and low-density areas. Additionally, incorporating a comparison with alternative indicator-weighting methods, such as principal component analysis or the analytic hierarchy process, would have tested the robustness of the human activity index. Integrating field data, both biophysical and socioeconomic, would provide a more concrete improvement, validating the grid-scale results and strengthening the reliability of the analysis. It would also be useful to explain in more detail in Figure 2 how the sub-dimensions of the HAI are operationalised and which specific variables make up each category. For example, in the case of social intensity, it would be useful to justify the choice of demographic indicators, and their relative weighting compared to economic variables. Similarly, in the description of the NEP calculation (p. 5), it is suggested that the explanation of the modelling of heterotrophic respiration (Rh) be expanded, as the article briefly mentions its derivation from temperature and humidity but does not specify the reference coefficients or equations. This omission limits the reproducibility of the analysis. An additional methodological improvement would be to incorporate a sensitivity analysis of the HAI index and NEP with respect to data sources (MODIS, NTL and interpolated meteorological series), which would allow the quantification of possible margins of error. It would also be advisable to include cross-validation of the results through correlations with variables observed in the field or local historical records, thus strengthening the empirical credibility of the model.

Response 3: Agree. We appreciate the reviewer’s insightful comments. We fully agree that these methodological issues deserve careful consideration. In response, the revised manuscript explicitly acknowledges these limitations in the Discussion section (Section 4.3) and provides corresponding explanations. Specifically, we clarified that (1) NEP estimation partially relies on model-based data, which may introduce uncertainties in areas with complex terrain or sparse observations; (2) the use of interpolated climatic datasets and the equal-weight assumption between NEP and HAI may affect the precision of the coordination index; and (3) satellite-derived data in rural and low-density regions may contain inherent errors. These points have been incorporated into the discussion to ensure transparency. Furthermore, we emphasized that future research will address these limitations by integrating higher-resolution datasets, incorporating field-based biophysical and socio-economic observations, and testing alternative weighting approaches (e.g., PCA, AHP) to enhance robustness. In addition, the sub-dimensions of the HAI index and the parameters used in the Rh estimation have been further clarified in Table 2 to improve methodological transparency. (Page 19, Lines 555–572, Page 6, Line 177)

Revised text:

“4.4. Limitations and Perspectives

The estimation of NEP relies partly on model-based heterotrophic respiration (Rh) data, which may introduce uncertainties in areas with complex topography or sparse observations. Likewise, the use of interpolated climatic datasets and the equal-weight assumption between NEP and HAI could affect the precision of the coupling coordination index. Moreover, satellite-derived data in rural or low-density regions may contain inherent errors, and socioeconomic indicators such as GDP and population density may not fully reflect informal or seasonal human activities.

In addition, exogenous factors—including regional policy changes, agricultural subsidy adjustments, and extreme weather events such as droughts or floods—may in-fluence both NEP and HAI but were not explicitly considered in this analysis. These sources of uncertainty highlight the need for future research to incorporate high-er-resolution remote sensing products, integrate field-based biophysical and so-cio-economic data, and explore alternative weighting approaches such as principal component analysis (PCA) or the analytic hierarchy process (AHP) to test the robust-ness of the HAI index. Future work could also focus on developing dynamic so-cio-ecological models capable of capturing feedbacks between human and ecological systems, thereby improving the explanatory and predictive capacity of NEP–HAI coordination analyses.” (Page 19, Lines 555–572)

“Table 2. Composition and relative significance of indicators used to construct the HAI.”

(Page 6, Line 177)

Comments 4: The results clearly show that NEP and HAI have both increased significantly over the past two decades, reflecting both ecological restoration processes and growing development pressures. Figure 5 presents the spatiotemporal transitions of NEP–HAI coupling and uses a Sankey diagram to provide a more interpretative analysis of change flows, highlighting the magnitude, ecological direction (e.g. areas moving from low to high coordination) and political-environmental significance of transitions. It would be interesting to discuss whether these areas coincide with priority areas for state intervention, such as ecological corridors or regions included in 'red line ecological protection' programmes. While spatial representations in the form of maps and flow diagrams enrich interpretation, the discussion remains largely descriptive and does not delve into the social and political mechanisms that explain these trends. For instance, it would be beneficial to analyse the specific restoration programmes or land-use policies that have been instrumental, or the socio-economic changes (e.g. urban migration or agricultural intensification) that have influenced the evolution of HAI. Similarly, including counterfactual scenarios — such as what might have occurred in the absence of ecological restoration — would enable a more critical evaluation of the applied policies and provide a better assessment of the impact of human interventions. Likewise, temporal trend analysis could be enhanced using moving windows or five-year comparison periods to identify breaks or accelerations in NEP–HAI coordination dynamics associated with policies implemented between 2000 and 2020.

Response 4: Agree. Thank you very much for this insightful suggestion. We fully agree that the discussion of driving mechanisms should be expanded to include policy and socio-economic dimensions. Accordingly, we have revised the end of Section 4.2 to interpret the observed spatial differentiation in relation to regional ecological restoration projects and socio-economic restructuring. The revised sentences have been highlighted in yellow in the manuscript. (Page 18, Lines 518–526)

Revised text:

“The spatial differentiation of NEP–HAI coordination reflects not only biophysical drivers but also the influence of regional ecological policies and socio-economic re-structuring. The improvement in coordination in eastern mountain zones corresponds to the implementation of national restoration projects such as the Beijing–Tianjin Sand-storm Source Control Project and the Grain for Green Program, while persistent low-coordination areas in the agro-pastoral transition belts indicate regions where pol-icy enforcement and ecological investment remain insufficient. These findings highlight the coupled effects of ecological restoration and socio-economic transformation on the evolution of human–ecosystem relationships in the ZC region.” (Page 18, Lines 518–526)

Comments 5: During the discussion, the authors appropriately link their findings to existing literature, emphasising the pivotal role of land use as a controlling factor. However, there is a gap in terms of applicability beyond the case study. A meaningful improvement would be to project the results towards territorial governance, demonstrating how the findings could be incorporated into spatial planning, agricultural policies or energy transition strategies. In this regard, the work 'Assessment of Ecological Capacity for Urban Planning and Improving Resilience in the European Framework' (https://doi.org/10.18172/cig.5638) could enrich the analysis, as it provides a robust methodology for integrating ecological assessment into territorial planning at regional and municipal scales. This resilience-based approach incorporates precise environmental information into planning instruments and offers a model that could be applied to NEP–HAI analysis. This would give the study greater practical applicability and stronger links with public management. Incorporating such methodological frameworks would strengthen the connection between ecological analysis and policymaking, and also broaden the international relevance of the work by showing how European experiences can inform the Chinese case in terms of sustainability and integrated planning. In addition, the authors could draw parallels between their NEP–HAI coordination approach and European ecosystem services assessment frameworks (MAES, ESMERALDA or INCA), emphasising that both seek to integrate biophysical and socio-economic data into spatial decision-making. This would open up the possibility of adapting the proposed methodology to other contexts, facilitating its international transferability. Similarly, it is suggested that the discussion incorporate an analysis of territorial resilience, considering whether improvements in NEP–HAI coordination imply a true capacity of the system to withstand future disturbances, or whether it is a temporary balance conditioned by short-term policies.

Response 5: Agree. Thank you very much for this valuable suggestion. We fully agree that the discussion should extend beyond the local context to emphasize the implications of our findings for spatial governance and policy design. Accordingly, we have revised the policy-related discussion to strengthen the connection between the results and territorial planning, ecological management, and resilience-oriented governance. The revised sentences have been highlighted in yellow in the manuscript. (Page 18, Lines 539–552)

Revised text:

“From a management and planning perspective, differentiated strategies are essential to strengthen the coordination between ecological and human systems. In areas with persistent imbalance, ecological restoration and strict land-use regulation should remain the primary focus to prevent further degradation. Regions with stable coordination should consolidate resilience through ecological compensation mechanisms, sustainable agricultural transition, and improved landscape connectivity. Transitional zones, where human pressure remains high, require the promotion of low-carbon industrial transformation and optimized spatial structure to harmonize production, living, and ecological functions. Beyond local management, the NEP–HAI coordination framework provides a scientific basis for integrating ecological assessment into regional and national territorial planning. It can support the delineation of ecological conservation zones, inform land-use intensity thresholds, and guide resilience-oriented policies aligned with global sustainability and carbon neutrality goals. These targeted recommendations enhance the policy relevance and transferability of the study’s findings.” (Page 18, Lines 539–552)

Comments 6: At the same time, the article lacks a critical analysis of the following methodological limitations: uncertainties in heterotrophic respiration models; the spatial resolution of interpolated climate variables; and biases in socioeconomic indicators. Addressing these weaknesses and proposing avenues for future research, such as using high-resolution sensors or developing dynamic socio-ecological models, would make the work more scientifically transparent and lend greater weight to its conclusions. Specifically, authors could include a section entitled 'Limitations and Perspectives' at the end of the manuscript. In this section, they could discuss the possible influence of unconsidered exogenous factors, such as regional political variations, changes in agricultural subsidies or extreme weather events (e.g. droughts or floods), which could affect both NEP and HAI. This addition would provide analytical depth and contextualise the results within the uncertainty inherent in socio-ecological systems.

Response 6: Agree. We sincerely appreciate this valuable suggestion. We fully agree that explicitly addressing methodological uncertainties and outlining directions for future research can improve the scientific transparency and depth of the study. Accordingly, we have added a new section titled “4.4. Limitations and Perspectives” at the end of the manuscript.

This section now discusses the potential uncertainties associated with model-based heterotrophic respiration (Rh) estimation, the spatial resolution of interpolated climatic datasets, and possible biases in socioeconomic indicators. It also acknowledges the influence of unconsidered exogenous factors such as regional policy changes, agricultural subsidy adjustments, and extreme weather events (e.g., droughts or floods). In addition, we have proposed future research directions, including the integration of higher-resolution remote-sensing data, incorporation of field-based biophysical and socio-economic observations, and exploration of alternative weighting methods (PCA or AHP). These additions enhance the analytical depth of the manuscript and provide a clear perspective for further work on NEP–HAI coordination. The revised sentences have been highlighted in yellow in the manuscript. (Page 19, Lines 553–570)

Revised text:

“4.4. Limitations and Perspectives

The estimation of NEP relies partly on model-based heterotrophic respiration (Rh) data, which may introduce uncertainties in areas with complex topography or sparse observations. Likewise, the use of interpolated climatic datasets and the equal-weight assumption between NEP and HAI could affect the precision of the coupling coordina-tion index. Moreover, satellite-derived data in rural or low-density regions may contain inherent errors, and socioeconomic indicators such as GDP and population density may not fully reflect informal or seasonal human activities.

In addition, exogenous factors—including regional policy changes, agricultural subsidy adjustments, and extreme weather events such as droughts or floods—may in-fluence both NEP and HAI but were not explicitly considered in this analysis. These sources of uncertainty highlight the need for future research to incorporate high-er-resolution remote sensing products, integrate field-based biophysical and so-cio-economic data, and explore alternative weighting approaches such as principal component analysis (PCA) or the analytic hierarchy process (AHP) to test the robust-ness of the HAI index. Future work could also focus on developing dynamic so-cio-ecological models capable of capturing feedbacks between human and ecological systems, thereby improving the explanatory and predictive capacity of NEP–HAI coor-dination analyses.” (Page 19, Lines 553–570)

Comments 7: While the conclusions fulfil their purpose of summarising the main results and confirming improvements in NEP–HAI coordination, they are limited to reiterating the findings without providing operational recommendations. It would be an improvement to propose differentiated strategies for the types of regions identified: strengthening restoration and land-use regulation in areas of persistent degradation; consolidating progress in regions showing strong improvement through compensation policies and forest protection; and promoting sustainable agriculture and low-carbon urbanisation in transitional areas where human pressure remains significant. Furthermore, linking the findings to international agendas, such as the Sustainable Development Goals or the Paris Agreement commitments, would increase the research's practical and global relevance.

Response 7: Agree. We sincerely appreciate this valuable comment. In response, we have revised the Conclusion section to include more specific and operational recommendations. The revised text now proposes differentiated strategies for the types of regions identified, including vegetation restoration and strict land-use regulation in low-coordination zones, ecological compensation and sustainable agriculture in stable areas, and low-carbon development and land-use optimization in transitional zones where human pressure remains high. Furthermore, the conclusion now highlights the relevance of these findings to broader sustainability goals, emphasizing their contribution to regional carbon neutrality and ecological security while providing insights applicable to global sustainability contexts. . The revised sentences have been highlighted in yellow in the manuscript. (Page 19, Lines 571–597)

Revised text:

“5. Conclusion

This study explored the coupling coordination between NEP and HAI in the ZC region from 2000 to 2023. By integrating multi-source data, spatial analysis, and trend-sustainability modeling, the research provides new insights into how ecological and socio-economic systems co-evolve in fragile agro-pastoral transition zones.The main conclusions are as follows:

 (1) NEP and HAI exhibited a coordinated upward trend, indicating that regional ecological restoration and socio-economic development are gradually achieving mutual reinforcement. The coordination pattern evolved from human-dominated imbalance to ecological–social synergy, with high coordination concentrated in the forested eastern mountains and low coordination persisting in agro-pastoral transition belts.

(2) LUI was identified as the dominant driver of spatial heterogeneity in coupling coordination, while natural factors such as vegetation condition (NDVI), drought stress (SPEI), and topography (ELV, SLP) gained increasing importance over time. Interactive effects between anthropogenic and natural factors.

(3) MK and Hurst analyses revealed that the ZC region will likely continue on a positive trajectory of NEP–HAI coordination, though with pronounced spatial differ-entiation. Strongly improving areas are concentrated in mountainous zones, while degradation-prone areas remain in agro-pastoral transition belts, requiring targeted management.

(4) Targeted management strategies should be adopted according to regional co-ordination levels. Low-coordination zones require vegetation recovery, soil conservation, and strict land-use regulation; stable coordination areas should strengthen resilience through ecological compensation and sustainable agriculture; and high-pressure transi-tion zones should promote low-carbon development and land-use optimization. These differentiated measures can support the realization of carbon neutrality and ecological security goals in northern China, while offering a reference for sustainable development in similar regions worldwide.” (Page 19, Lines 571–597)

Comments 1: How were the NEP datasets validated against ground-truth or independent data? Please provide validation metrics or references to support the reliability of the estimated values.

Response 1: Agree. We thank the reviewer for this important question regarding data reliability. In response, we have added a clarification in the Methods section (2.3 Estimation of NEP) to explain the validation basis of the NEP datasets. Specifically, we now state that the empirical Rh model used in this study was derived from parameterized relationships validated in previous field-based research conducted in temperate ecosystems of northern China. These studies have demonstrated consistent performance of the model under similar climatic and vegetation conditions, ensuring the reliability of NEP estimation in the ZC region. The revised sentences have been highlighted in yellow in the manuscript. (Page 5, Lines 151–156)

Revised text:

“The empirical Rh model applied in this study was derived from parameterized rela-tionships validated in previous field-based research conducted in temperate ecosystems of northern China. These studies demonstrated that the model performs well in regions with similar climatic and vegetation conditions, thereby ensuring the reliability of NEP estimation in the ZC region [30, 31].” (Page 5, Lines 151–156)

Comments 2: The coupling coordination degree model is applied, but its suitability for this specific ecological-human system is not discussed. Please clarify why this model was chosen over others.

Response 2: Agree. We appreciate the reviewer’s valuable suggestion. To address this concern, we have added a brief explanation in Section 2.5 to clarify the rationale for using the coupling coordination degree model (CCDM). The revised text now states that the CCDM provides a systematic framework for characterizing the interaction and developmental balance between ecological and human systems. In this study, it is applied to jointly evaluate the coupling state of ecosystem carbon sequestration (NEP) and human activity intensity (HAI), revealing the overall level and direction of their co-evolution. Compared with simple correlation or regression analyses, the CCDM emphasizes the coordination and integrated development of interrelated subsystems, offering a more comprehensive representation of the dynamic equilibrium between ecological and socio-economic processes. The revised sentences have been highlighted in yellow in the manuscript. (Page 6, Lines 178–185)

Revised text:

“The coupling coordination degree model (CCDM) provides a systematic framework for characterizing the interaction and developmental balance between ecological and human systems. In this study, it is applied to jointly evaluate the coupling state of NEP and HAI, revealing the overall level and direction of their co-evolution. Compared with simple correlation or regression analyses, the CCDM emphasizes the coordination and integrated development of interrelated subsystems, offering a more comprehensive representation of the dynamic equilibrium between ecological and socio-economic processes [33].” (Page 6, Lines 178–185)

Comments 3: The interaction detector results are presented, but the underlying mechanisms of these interactions (e.g., why LUI and NDVI interact strongly) are not sufficiently explained.

Response 3: Agree. We thank the reviewer for this valuable suggestion. In response, we have added a brief explanation in Section 4.2 to clarify the mechanism underlying the strong interaction between LUI and NDVI. The revised text now notes that this interaction stems from the reciprocal feedback between land-use change and ecosystem productivity, where intensive land conversion alters vegetation structure and carbon uptake, while vegetation conditions, in turn, constrain land-use efficiency and spatial expansion. This addition strengthens the interpretive depth of the interaction detector results and enhances the discussion of human–environment coupling mechanisms. The revised sentences have been highlighted in yellow in the manuscript. (Page 18, Lines 505– 509)

Revised text:

“This strong interaction can be attributed to the reciprocal feedback between land-use change and ecosystem productivity, where intensive human land conversion alters vegetation structure and carbon uptake, while vegetation conditions, in turn, constrain human land-use efficiency and spatial expansion.” (Page 18, Lines 505– 509)

Comments 4: Future Prediction? The study employs the Hurst exponent to "predict" future trajectories of the coupling coordination degree (D). However, this approach essentially measures the long-term memory or persistence of the historical time series (2000-2023). The "future" here is not a true forecast of a specific future state (e.g., for the year 2030), but rather a statistical characterization of whether the observed historical trend is likely to continue or reverse, based solely on its own internal structure. The manuscript should clarify this critical point to avoid misleading readers into thinking a conventional temporal forecast was performed. The authors should explicitly state that this is an assessment of the sustainability of the past trend and discuss the limitations of this approach, particularly the assumption that external drivers (e.g., future policy shocks, extreme climate events) will not disrupt the historical pattern.

Response 4: Agree. We thank the reviewer for this important clarification. We agree that the Hurst exponent does not provide a conventional forecast of future states but rather evaluates the persistence or anti-persistence of a historical trend. Accordingly, we have revised the text in Section 2.7.2 to clearly state that this analysis assesses the sustainability of the past trajectory of the coupling coordination degree (D) rather than predicting specific future values. The revised text also acknowledges that this approach assumes the continuation of existing conditions and does not account for potential external disturbances such as future policy shifts, socioeconomic changes, or extreme climatic events. The revised sentences have been highlighted in yellow in the manuscript. (Page 8, Lines 247–251)

Revised text:

“It should be noted that the Hurst exponent does not predict specific future values but evaluates the persistence or reversal tendency of historical trends. It reflects the sus-tainability of the observed trajectory under similar conditions, assuming that no major external disturbances—such as policy or climate changes—occur.” (Page 8, Lines 247–251)

Comments 5: The policy recommendations are general. Could more specific, actionable strategies be proposed for different coordination types (e.g., carbon-stress vs. synergistic regions)?

Response 5: Agree. We thank the reviewer for this valuable suggestion. In response, we have refined the policy discussion in Section 4.3 to include more specific and actionable strategies tailored to different coordination types. The revised text now highlights that areas with persistent imbalance should prioritize ecological restoration and strict land-use regulation, while regions with stable coordination should enhance resilience through ecological compensation, sustainable agricultural transition, and improved landscape connectivity. Transitional zones, where human pressure remains high, are recommended to promote low-carbon industrial transformation and optimized spatial structure. Furthermore, we emphasized that the NEP–HAI coordination framework can inform ecological zoning, land-use thresholds, and resilience-oriented policies aligned with national and global sustainability goals. These revisions make the policy recommendations more practical, differentiated, and directly applicable to management and planning. The revised sentences have been highlighted in yellow in the manuscript. (Page 18, Lines 537–550)

Revised text:

“From a management and planning perspective, differentiated strategies are essen-tial to strengthen the coordination between ecological and human systems. In areas with persistent imbalance, ecological restoration and strict land-use regulation should remain the primary focus to prevent further degradation. Regions with stable coordi-nation should consolidate resilience through ecological compensation mechanisms, sustainable agricultural transition, and improved landscape connectivity. Transitional zones, where human pressure remains high, require the promotion of low-carbon in-dustrial transformation and optimized spatial structure to harmonize production, liv-ing, and ecological functions. Beyond local management, the NEP–HAI coordination framework provides a scientific basis for integrating ecological assessment into regional and national territorial planning. It can support the delineation of ecological conserva-tion zones, inform land-use intensity thresholds, and guide resilience-oriented policies aligned with global sustainability and carbon neutrality goals. These targeted recom-mendations enhance the policy relevance and transferability of the study’s findings.” (Page 18, Lines 537–550)

Comments 6: How do the findings from the ZC region compare with other agro-pastoral transition zones globally? A brief comparative discussion would strengthen the paper’s contribution.

Response 6: Agree. We appreciate the reviewer’s valuable comment. To address this suggestion, we have incorporated a brief comparative discussion in the Introduction. The revised text now emphasizes that similar human–environment tensions and ecological degradation processes are observed globally in arid and semi-arid transition zones, indicating that the ZC region not only represents a typical Chinese case but also reflects broader global challenges of harmonizing ecological restoration and socio-economic development. This addition highlights the international relevance of the study and situates the findings of the ZC region within a wider global context of agro-pastoral transition zones. The revised sentences have been highlighted in yellow in the manuscript. (Pages 2-3, Lines 79–89)

Revised text:

“Similar human–environment tensions and ecological degradation processes are observed globally in arid and semi-arid transition zones [29], suggesting that the ZC region not only represents a typical Chinese case but also reflects broader global challenges of harmonizing ecological restoration and socio-economic development. It is expected that ongoing restoration and land-use regulation have progressively enhanced the coordi-nation between NEP and HAI, while spatial heterogeneity remains pronounced, with stronger coordination in forested mountains and weaker balance in the agricultural and transition zones. Understanding these processes in a region that simultaneously serves as a carbon sink and a development frontier provides important insights into the mecha-nisms driving ecosystem–human linkages and their implications for sustainable regional management.” (Pages 2-3, Lines 79–89)

Comments 7: The present paper does not address the significant lagged and cumulative effects that climate change may exert on vegetation growth. The following articles are recommended for reading, they may provide valuable additional insights and enhance the content of both the introduction and discussion sections of your paper. Refined assessment of space-time changes, influencing factors and socio-economic impacts of the terrestrial ecosystem quality A case study of the GBA Intra-Annual Cumulative Effects and Mechanisms of Climatic Factors on Global Vegetation Biomes' Growth Cumulative Effects of Climatic Factors on Terrestrial Vegetation Growth.

Response 7: We thank the reviewer for this helpful suggestion. We have incorporated a brief discussion of the lagged and cumulative effects of climate change on vegetation productivity in the Discussion section and cited the references to strengthen the analysis. The revised text notes that the impacts of temperature, precipitation, and drought often occur with temporal delays and gradual accumulation, contributing to spatiotemporal variations in NEP, particularly in areas where vegetation recovery lags behind climatic improvement. This addition enhances the scientific depth of the discussion and acknowledges the importance of delayed climate–vegetation responses in shaping NEP–HAI dynamics. (Page 18, Lines 509–515, Page 24, Lines 769–771, Page 24, Lines 772–773, Page 24, Lines 774–776)

Revised text:

“In addition, the impact of climate change on vegetation productivity shows lagged and cumulative effects [50, 51]. The influences of temperature, precipitation, and drought often occur with temporal delays and gradual accumulation, contributing to spatio-temporal variations in NEP, particularly in areas where vegetation recovery lags be-hind climatic improvement [52]. Future research should further examine these delayed climate–vegetation responses to deepen understanding of NEP–HAI coupling mechanisms.” (Page 18, Lines 509–515, Page 23, Lines 764–766, Page 23, Lines 767–768, Page 23, Lines 769–771)

“50. Wen, Y. Y.; Liu, X. P.; Xin, Q. C.; Wu, J.; Xu, X. C.; Pei, F. S.; Li, X.; Du, G. M.; Cai, Y. L.; Lin, K.; Yang, J.; Wang, Y. P., Cumulative Effects of Climatic Factors on Terrestrial Vegetation Growth. Journal of Geophysical Research-Biogeosciences 2019, 124 , 789-806.” (Page 23, Lines 764–766)

“51. Du, G. M.; Yan, S. H.; Chen, H.; Yang, J.; Wen, Y. Y., Intra-Annual Cumulative Effects and Mechanisms of Climatic Factors on Global Vegetation Biomes' Growth. Remote Sensing 2024, 16, 779.” (Page 23, Lines 767–768)

“52. Wen, Y. Y.; Yang, J.; Liao, W. L.; Xiao, J. N.; Yan, S. H., Refined assessment of space-time changes, influencing factors and socio-economic impacts of the terrestrial ecosystem quality: A case study of the GBA. Journal of Environmental Management 2023, 345.” (Page 23, Lines 769–771)

Comments 1: The first issue is the weakness of the international comparative framework. Despite the expanded introduction and discussion, the authors continue to rely almost exclusively on Chinese literature and general studies on ecological dynamics. The international references recommended in the initial review have not been included. Notably absent is the work by Herrmann and Hutchinson (https://doi.org/10.1016/j.jaridenv.2005.03.003) on the evolving discourse on desertification in Africa, despite its relevance in drawing parallels with other semi-arid regions. This omission reduces both the theoretical richness of the discussion and the transferability of the results. Without demonstrating that the NEP–HAI dynamics observed in China are similar to processes in other regions of the world, the article risks being perceived as an exclusively local case with limited capacity to inform global debates on sustainability in agro-pastoral systems.

Response 1: Agree. We appreciate the reviewer’s valuable suggestion to strengthen the international comparative framework. In the revised version, we have expanded the introduction by incorporating a global perspective that highlights similar ecological–human interaction mechanisms observed in other semi-arid regions, particularly in Africa and Central Asia. This addition emphasizes that the NEP–HAI dynamics identified in the Zhangjiakou–Chengde region are consistent with broader global processes of ecological restoration and socio-economic coordination under fragile environmental conditions. The discussion now provides greater theoretical depth and enhances the international transferability of the study’s findings. In addition, the reference “Herrmann, S. M.; Hutchinson, C. F., The changing contexts of the desertification debate. Journal of Arid Environments 2005, 63(3), 538–555.” has been added as reference [29] to support this global comparative discussion. (Pages 2-2, Lines 79–93, Page 22, Lines 720–721)

Revised text:

“Similar human–environment tensions and ecological degradation processes are observed globally in arid and semi-arid transition zones, particularly in Africa and Central Asia, where vegetation dynamics, climate variability, and human adaptation processes are tightly intertwined[29]. These global parallels indicate that the NEP–HAI relationships identified in the ZC region are not unique to northern China but reflect broader mechanisms of ecological restoration and socio-economic coordination under fragile environmental conditions. This broader comparative perspective enhances the theoretical depth and international transferability of the study. It is expected that ongoing restoration and land-use regulation have progressively enhanced the coordi-nation between NEP and HAI, while spatial heterogeneity remains pronounced, with stronger coordination in forested mountains and weaker balance in the agricultural and transition zones. Understanding these processes in a region that simultaneously serves as a carbon sink and a development frontier provides important insights into the mecha-nisms driving ecosystem–human linkages and their implications for sustainable regional management.” (Pages 2-2, Lines 79–93)

“29. Herrmann, S. M.; Hutchinson, C. F., The changing contexts of the desertification debate. Journal of Arid Environments 2005, 63, (3), 538-555.” (Page 22, Lines 720–721)

Comments 2: Similarly, the absence of international methodological frameworks, such as those used in the 'Assessment of Ecological Capacity for Urban Planning and Improving Resilience in the European Framework' (https://doi.org/10.18172/cig.5638) research project, directly affects the robustness and replicability of the proposed approach. Integrating this research would demonstrate that the developed methodology is compatible with other internationally recognised ecological assessment systems, thereby increasing its potential adoption beyond China. Failing to establish these connections risks making the study appear methodologically isolated and of limited relevance to the global academic community. The study's resilience-based approach incorporates precise environmental information into planning instruments and provides a model for NEP–HAI analysis. This should be considered to give the study greater practical applicability and stronger links with public management. The relevant section should discuss whether these aspects could be incorporated into evaluations in China.

Response 2: Agree. We sincerely thank the reviewer for highlighting the need to align the proposed methodology with internationally recognized ecological assessment frameworks. In response, we have added a paragraph discussing the conceptual consistency between the NEP–HAI coordination framework and resilience-based ecological assessment systems widely applied in European territorial planning. This addition clarifies that our approach not only reflects local conditions but also aligns with global practices integrating environmental indicators, human activity intensity, and spatial planning. The revision strengthens the methodological robustness and demonstrates the potential international applicability of the NEP–HAI framework. (Page 19, Lines 555–563, Page 24, Lines 785–786)

Revised text:

“The NEP–HAI coordination framework proposed in this study is conceptually consistent with internationally recognized resilience-based ecological assessment sys-tems, such as those adopted in European territorial planning frameworks [53]. Both approaches emphasize integrating environmental information, human activity intensity, and spatial regulation into decision-making processes. Incorporating this perspective demonstrates that the NEP–HAI model is not limited to China but can be adapted to other contexts for evaluating ecological capacity and supporting sustainable territo-rial governance. Such alignment enhances the robustness and international relevance of the methodology, facilitating its potential application in global ecological management and policy design.” (Page 19, Lines 555–563)

“53. Córdoba Hernández, R.; Camerin, F., Assessment of ecological capacity for urban planning and improving resilience in the European framework: An approach based on the Spanish case. Cuadernos de Investigación Geográfica 2023, 49, 119–142.” (Page 24, Lines 785–786)

Comments 3: Furthermore, the lack of a counterfactual analysis and critical reflection on implemented policies restricts the article's ability to draw evaluative and operational conclusions. While the findings currently confirm the effectiveness of programmes such as Grain for Green, the manuscript does not explore what might occur in the absence of these interventions or under alternative management scenarios. This omission reduces the practical utility of the work for decision-making in contexts of uncertainty or in countries that have not implemented similar policies, and weakens the recommendations.

Response 3: Agree. We thank the reviewer for this valuable suggestion. We agree that incorporating counterfactual perspectives could further enhance the evaluative capacity of the study. To address this, we have added a paragraph in the discussion acknowledging the absence of explicit counterfactual analysis and highlighting the potential for future research to integrate scenario-based approaches. This addition emphasizes that exploring alternative policy or management pathways—such as the absence or modification of ecological restoration programs—would provide deeper insights into the effectiveness and transferability of interventions under varying socio-ecological contexts. (Page 19, Lines 572–579)

Revised text:

“Although the findings confirm the positive effects of ecological restoration pro-grams such as the Grain for Green Project, this study did not include explicit counter-factual analyses to explore what might occur in the absence of these interventions or under alternative management scenarios. Future research could incorporate scenar-io-based modeling and policy simulations to assess how different land-use and restora-tion strategies influence NEP–HAI coordination under uncertain socio-ecological con-ditions. Such approaches would enhance the evaluative capacity of the framework and extend its applicability to regions that have not implemented similar ecological policies.” (Page 19, Lines 572–579)

Comments 4: Finally, weak links to international agendas such as the Sustainable Development Goals (SDGs) or the Paris Agreement affect the visibility and positioning of the article within global sustainability and climate change debates. In such a competitive research field, explicitly linking the results to these agendas is an effective way for the study to transcend its regional framework and gain international scientific and policy relevance.

Response 4: Agree. We appreciate the reviewer’s suggestion to strengthen the linkage between our findings and global sustainability frameworks. In response, we have added a paragraph in the conclusion section explicitly connecting the NEP–HAI coordination framework with the United Nations Sustainable Development Goals (SDGs) and the Paris Agreement. This addition highlights how the study contributes to global climate mitigation, ecosystem restoration, and low-carbon development goals, enhancing the manuscript’s international relevance. (Page 20, Lines 617–623)

Revised text:

“Moreover, the findings of this study align with international sustainability and climate governance frameworks, particularly the United Nations Sustainable Devel-opment Goals (SDGs) and the Paris Agreement. By providing a regional pathway to-ward carbon neutrality and ecosystem resilience, the NEP–HAI coordination frame-work contributes to SDG 13 (Climate Action) and SDG 15 (Life on Land), and offers a transferable approach for balancing ecological protection with socio-economic devel-opment in other semi-arid regions worldwide..” (Page 20, Lines 617–623)