Mapping Plant Growth Index (PGI) over Australia from 1990 to 2024

Abstract. Australia spans nearly the full spectrum of global bioclimatic zones, from tropical savannas to arid deserts and alpine environments. Understanding how climate constrains vegetation growth across this gradient is essential for interpreting ecosystem dynamics and informing land-management decisions. We introduce a Plant Growth Index (PGI), a continental-scale metric derived from meteorological data from the Bureau of Meteorology Atmospheric high-resolution Regional Reanalysis for Australia (BARRA-R), European Space Agency (ESA) Plant Functional Type (PFT) layers, and C₃/C₄ grass fractions estimated from NASA Moderate Resolution Imaging Spectroradiometer (MODIS) enhanced vegetation index (EVI). The Plant Growth Index captures year-to-year variation in vegetation status, water availability, and climatic conditions. Spatially, values of the PGI are highest in tropical and subtropical regions and lowest in arid deserts. Benchmarking against gross primary productivity (GPP) from the Terrestrial Ecosystem Research Network (TERN) OzFlux network, the Normalised Difference Vegetation Index (NDVI), the Standardised Precipitation-Evapotranspiration Index (SPEI), and Australian Grassland and Rangeland Assessment by Spatial Simulation (Aussie-GRASS) indicates that PGI broadly reflects regional vegetation productivity patterns. The PGI provides a reproducible, continental-scale tool for ecological modelling, rangeland monitoring, and climate-impact studies and can be accessed at https://doi.org/10.5281/zenodo.18762343  (Retkute et al., 2026).