The influence of meteorological fluctuations on vegetation dynamics: trends and modeling

Climate fluctuations can influence the density, health, and vulnerability of vegetation, highlighting the need to evaluate their combined impacts on vegetation dynamics. This study analyzed the trends of changes in precipitation and temperature in West and East Azerbaijan provinces, Iran, to clarify complex interactions of both climatic variables and indices with vegetation cover. The trend of precipitation, temperature, Standardized Precipitation Index (SPI), and Rainfall Anomaly Index (RAI) were analyzed and their impacts on vegetation dynamics were modeled from 1987 to 2022. The maps of Enhanced Vegetation Index (EVI) derived from Landsat 5 (TM + MSS), Landsat 7 (TM + ETM) and Landsat 8 OLI were adopted to examine the effect of climate fluctuations on vegetation cover. The results indicated a decreasing trend in precipitation and an increasing trend in temperature. A negative correlation was found between precipitation and temperature (r=-0.88) (p<0.01). Additionally, there were positive correlations between EVI and precipitation (r=0.53), EVI and SPI (r=0.57) and between EVI and RAI (r=0.61) while there was no significant correlation between EVI and temperature. Moreover, the findings showed that the SPI was a reliable index in estimating vegetation conditions. The findings of this study can enhance the understanding of ecosystem responses to climate fluctuations in the study area.