Deciphering Phenological Dynamics: Multiscale Geospatial Synthesis of Climate Interactions in the Tropical Dry Deciduous Forest Ecosystem of India

Climate change presents an unmatched challenge to global forest ecosystems and tropical forests serve as important sentinels of ecological transformation. Forest phenology is recognized as an important indicator of ecosystem health and nuanced understandings into the complicated interactions between biological systems and climate variability are offered by it. This study aimed to assess the responses of forest ecosystems using high-resolution PhenoCam images and multi-scale geospatial analysis. We used an integrated method, combining ground-based PhenoCam observations with satellite imagery from AVHRR and Sentinel-2, using ERA-5 Land climate reanalysis data. To produce comprehensive ecological assessments at various geographical and temporal scales, we integrated Normalized Difference Vegetation Index (NDVI) observations with Green Chromatic Coordinate (GCC) analysis. Our finding reveals that the Gir Forest's growth season lasts 203 days and shows a notable upward trend (R² = 0.78, p < 0.01), which is explained by warming temperatures. Interannual variations in Season Start (SOS) and Season End (EOS) were noted, with EOS delaying by 4.2 days each decade and SOS advancing by an average of 3.5 days per decade. This pattern demonstrated the impact of climatic factors by extending the growing season length by roughly 7.7 days every decade. Species-specific responses demonstrated varying susceptibilities to climate variables. Temperature had the strongest correlation with SOS shifts (R² = 0.82), followed by precipitation (R² = 0.68) and soil moisture (R² = 0.55). These findings emphasize the complex interactions between phenological shifts and environmental gradients. By bridging observational scales and methodological techniques, this research offers an important framework for comprehending the dynamics of forest ecosystems. The results highlight the need of using high-resolution remote sensing and sophisticated ecological modelling to track phenological changes and provide crucial information about how climate variability affects tropical dry deciduous forests.

Keywords: Climate change, Phenology, Phenometrics, Remote Sensing, Near surface sensor