نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشیار علوم جنگل، دانشکده منابع طبیعی، دانشگاه محقق اردبیلی، اردبیل، ایران.
2 عضو هیات علمی دانشکده کشاورزی و منابع طبیعی ، دانشگاه محقق اردیبیلی،اردبیل
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction: Natural ecosystems in Iran are under the influence of unprecedented disturbances, including climate changes such as drought, pests and diseases, invasive species, and as a result, vegetation changes. Trend analysis of vegetation and ecosystem health monitoring on a regional scale is necessary to evaluate the changing status of ecosystems and inform the management of environmental disturbance factors. However, these analyses and monitoring are difficult only based on field investigations. Remote sensing provides the possibility of comprehensive evaluations of ecosystems in large areas, and their changes can be observed over time using vegetation indicators in multi-temporal satellite images.
Materials and Methods: This research is based on the time series of Landsat-7 ETM+ and Landsat 8 OLI/TIRS images related to the years 2003 to 2023 and Geographic Information Systems used for analyzing vegetation trends and monitoring the health of the ecosystems in the Fandoghlo region (farthest end of the western Hyrcanian region located in the east of Ardabil). The non-parametric Mann-Kendall (M-K) trend test was used to analyze the spatial-temporal changes of vegetation in the study area.
Results: Based on the results of land cover changes in the study area, the reduction of vegetation cover were found in all natural ecosystems, including forests (-8.5 %), rangeland (-16.5 %), and water bodies (-17.2 %). On the other hand, agriculture (14.7 %) and built-up (30.9 %) areas showed an increase during the study period. Furthermore, the results of the changes in health index (NDVI) during the period 2003-2023 indicate a trend of vegetation browning (decrease) in the Fandoghlo region. In addition, the results of the M-K trend test show that NDVI had a significant linear increasing trend from 2003 to 2011, a non-significant linear increasing trend from 2011 to 2016, and a non-significant linear decreasing trend from 2016 to 2023.
Conclusion: In this study, the analysis of the trend of vegetation cover and health index based on NDVI can provide valuable indications about some processes that are relevant for ecological assessments such as the simplification and destruction of ecosystems or the intensification of agricultural activities. Considering the declining trend of natural ecosystems and the threat to health, it is recommended to implement conservation programs in line with nature to increase the vegetation cover and its health.
کلیدواژه‌ها [English]
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