Publications

Macek, M; Prosek, J; Dolezal, J; Wild, J; Jezek, V; Kopecky, M (2025). Elevation-dependent sensitivity of spectral greening to temperature and precipitation in the Western Himalayas. ENVIRONMENTAL RESEARCH LETTERS, 20(5), 54078.

Abstract
Mountain ecosystems are experiencing significant changes due to climate change. Globally, a prevailing greening trend has been observed over the past decades using remote-sensing normalized difference vegetation index (NDVI), suggesting increasing vegetation cover and primary productivity. However, NDVI responses to warming differ across regions. Cold, energy-limited alpine and tundra ecosystems tend to respond positively to warming, while arid, water-limited ecosystems may experience reduced NDVI due to higher transpiration rates limiting plant growth. Additionally, CO2 fertilization effect enhances vegetation productivity by improving plant water use efficiency. This study investigates the drivers of temporal trends in annual maximum NDVI (NDVImax) along an elevational gradient in the arid Western Himalaya (Ladakh, India). We hypothesize that NDVImax will be more sensitive to precipitation anomalies at lower elevations, whereas at higher elevations it will be more sensitive to temperature anomalies. Using Landsat satellite data from 2001 to 2022, we related NDVImax temporal anomalies to temperature and precipitation obtained from the ERA5-Land reanalysis dataset, and local snow cover from MODIS. Our results show complex interactions between climate and elevation that influence NDVImax. Contrary to our expectations, precipitation exhibited a strong positive effect on NDVImax across all elevations and seasons, except for autumn at higher elevations. Temperature effects were weaker and varied across seasons and elevations. Higher summer temperatures increased NDVImax at higher elevations but decreased it at lower elevations. We observed a multidecadal greening trend independent of temperature and precipitation, with this greening being more pronounced at lower elevations. This study highlights the importance of context dependency in understanding vegetation dynamics in fragile, low-productivity mountain ecosystems.

DOI:
10.1088/1748-9326/adc9c7

ISSN: