## 5 Conclusions
### Short-Term Trend Analysis  
For short-term trend analysis of the GLI, EVI, NDVI, and SAVI vegetation indices, the Mann-Kendall test, modifications, and Sen's slope methods were used. Planet Scope satellite data were taken as a reference due to the high spatial resolution in order to understand the effectiveness of using data from the medium-resolution Landsat and Sentinel satellites for short-term trend analysis. According to Sen's slope results, a well-expressed relationship between Sentinel-2 and Planet Scope is clearly visible, which was expected due to the spatial resolution. Thus, according to the results for Planet Scope and Sentinel-2, the trends are biased to decrease; however, for Landsat 8, it is vice versa. For the short-term assessment of changes in the state of natural mountain grasslands, while high-resolution data from Planet Scope provide detailed information, medium-resolution images from Sentinel are still effective for monitoring grassland conditions. In addition, Sentinel-2 is open-source data, and all these considerations make Sentinel-2 a reliable and effective tool for detailed and accurate monitoring of grassland biomass in mountainous small areas.  
Therefore, it cannot be stated with certainty that the small area under consideration showed an increasing or decreasing trend over a short period of time. In order to have an even clearer picture of the situation, it is necessary to study a wider spatial and temporal series and include climatic data. Moreover, there are several factors that should be considered in our future research, such as human impact on the grasslands, and in situ data that enables us to make a quantitative and qualitative analysis of aboveground biomass should also be included.  
Conceptualization, G.A., V.M., A.M. and S.A.; methodology, G.A., V.M., A.M. and S.A.; validation, G.A., V.M. and A.K.; formal analysis, G.A., V.M. and A.K.; investigation, G.A., V.M., A.M. and S.A.; resources, A.M. and A.K.; data curation, G.A., A.K., A.M. and V.M.; writing--original draft preparation, G.A.; writing--review and editing, S.A. and V.M.; visualization, G.A., A.K. and A.M.; supervision, S.A. and V.M.; project administration, G.A. and S.A.; funding acquisition, G.A. All authors have read and agreed to the published version of the manuscript.  
The work was implemented the frame of the No 22 AA-1E021 project funded by the Science Committee/Higher Education and Science Committee of the Ministry of Education, Science, Culture and Sport of RA.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The research was conducted at the Center for Ecological-Noosphere Studies NAS RA (CENS), and the authors would like to acknowledge the administration for permission to use existing facilities to conduct this research. The authors also acknowledge the Authorities of the Nerkin Sasnashen (Alishan Areyan) rural community for their dedicated support during the field survey. Finally, the research was funded by the Science Committee/Higher Education and Science Committee of the Ministry of Education, Science, Culture and Sport of RA.  
The authors declare no conflicts of interest.