Latitudes and Land Use: Global Biome Shifts in Vegetation Persistence Across Three Decades

Keywords: vegetation persistence, NDVI, land use, biome, AVHRR, greening, seasonality,
Abstract Type: Paper Abstract

Abstract

The dynamics of terrestrial vegetation are shifting globally due to environmental changes, with potential repercussions for the proper functioning of the earth system. However, the response of global vegetation, the study of such changes and the methods used to monitor them, have in of themselves, been found to significantly impact the findings. This study uses a vegetation persistence metric to present a global exploration of vegetation responses to climatic, latitudinal, and land-use changes at a biomes level across three decades (1982-2010) of seasonal vegetation
activity via NDVI. Results demonstrated that positive vegetation persistence was found to be greater in June, July, August, and September, October, November, with an increasing vegetation persistence found in the Northern Hemisphere (NH) over the Southern Hemisphere (SH). While vegetation showed positive persistence overall, this was not constant across all biomes. Overall forested biomes showed positive responses in both the NH and SH. Contrastingly, desert, xeric shrubs, and savannas exhibited no significant patterns, but grassland showed more negative patterns and much higher variability, compared to the other biomes. The main drivers of changes appear to relate to climate, with tropical biomes linking to the availability of seasonal moisture, whereas the northern hemisphere forested biomes are driven more by temperature. Grasslands respond to moisture also, with high precipitation seasonality driving the persistence patterns. The use here of a novel statistical time series analysis of NDVI at a pixel level, and looking historically back in time, highlights the utility and power of such techniques within global change studies.