The grass is not always greener on the other side: Seasonal reversal of vegetation greenness in aspect-driven semiarid ecosystems
Our current understanding of semiarid ecosystems is that they tend to display higher vegetation greenness on polar-facing slopes (PFS) than on equatorial-facing slopes (EFS). However, recent studies have argued that higher vegetation greenness can occur on EFS during part of the year. To assess whether this seasonal reversal of aspect-driven vegetation is a common occurrence, we conducted a global scale analysis of vegetation greenness on a monthly time scale over an 18-year period (2000-2017). We examined the influence of climate seasonality on the normalised difference vegetation index (NDVI) values of PFS and EFS at 60 different catchments with aspect-controlled vegetation located across all continents except Antarctica. Our results show that an overwhelming majority of sites (70%) display seasonal reversal, associated with transitions from water-limited to energy-limited conditions during wet winters. These findings highlight the need to consider seasonal variations of aspect-driven vegetation patterns in ecohydrology, geomorphology, and earth system models.
Citation Information
Publication Year | 2020 |
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Title | The grass is not always greener on the other side: Seasonal reversal of vegetation greenness in aspect-driven semiarid ecosystems |
DOI | 10.1029/2020GL088918 |
Authors | Nikul Kumari, Patricia M. Saco, Jose F. Rodriguez, Samuel Johnstone, Ankur Srivastava, Kwok P. Chun, Omer Yetemen |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Geophysical Research Letters |
Index ID | 70211323 |
Record Source | USGS Publications Warehouse |
USGS Organization | Geosciences and Environmental Change Science Center |