## 5 Conclusions  
In this study, satellite images were used to examine spatiotemporal variations in Iran's NPP in light of ecosystem boundaries. Findings showed that the share of carbon sequestration in Iran constitutes 1.38 kg*C/m\({}^{2}\)/year and follows a clustered spatial pattern. Larger NPP rates were recorded for ecosystems located in the north and northwest of Iran. Furthermore, spatiotemporal variations were not aligned with the ecosystem boundaries; in fact, a decreasing rate of spatial variations was observed in the southward direction. The highest negative trend was detected in the north of Iran, especially in the Caspian Hyncanian mixed forest ecosystem. Substantially negative carbon sequestration trends were observed in ecosystems with rich vegetation, which supports the idea that measures taken to curb deforestation and natural plant destruction are ineffective. The highest positive trend was spotted in the Azerbaijan shrub desert and steppe ecosystem. This indicates that ecosystems frequently used by humans experience positive trends in carbon sequestration due to agricultural activities. The findings also suggest that NPP rate and agricultural drought have a strong correlation in the Zagros Mountains forest steppe and a weak association in the Registan-North Pakistan sandy desert. However, a significant positive correlation between NPP and agricultural drought was observed. Various correlation coefficients obtained in this study indicate that, besides rainfall and temperature fluctuations, other factors within the ecosystem influence NPP rates. Given the extreme dynamics of climatic factors, it is suggested that future researchers use nonlinear methods (e.g., cross-spectrum analysis of correlations) to identify the degree to which climatic and non-climatic factors influence NPP variations. The findings of this study showed that using remote sensing to monitor carbon sequestration in vast areas, which are influenced by numerous factors, saves a lot of money and time. As such, remote sensing can be used in environmental planning to implement constructive measures. Providing precise information for decision-makers planning in order to balance between society's needs and the exploitation of ecosystems' natural resources during drought periods could contribute to help PNN decreasing. Local non-governmental organizations (NGOs) and their participation in decision-making process, as well as information sharing via social media during drought periods play vital roles in this respect.  
Conceptualization, M.K., O.K. and M.M.; methodology, M.K. and M.M.; software, M.K. and M.M.; formal analysis, M.K., O.K. and M.M.; investigation, M.K. and O.K.; resources, M.K.; data curation, M.K.; writing--review and editing, M.K., O.K. and M.M.; visualization, M.K.; project administration, M.M. All authors have read and agreed to the published version of the manuscript.  
Ferdowsi University of Mashhad, Grant Number: FUM25143.  
[[https://github.com/poyan2021/Carbon-sequestration-.git](https://github.com/poyan2021/Carbon-sequestration-.git)]([https://github.com/poyan2021/Carbon-sequestration-.git](https://github.com/poyan2021/Carbon-sequestration-.git)), accessed on 4 February 2023.  
The authors would like to acknowledge the (LP DAAC) science team to freely provide the data sets used in this study. We acknowledge the Ferdowsi University of Mashhad for support and also thank the Academic Editor for his comments and the anonymous reviewers for their insight.  
All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript.