The role of C3 and C4 grasses to interannual variability in remotely sensed ecosystem performance over the US Great Plains

Time integrated normalized difference vegetation index (SNDVI)derived from National Oceanic and Atmospheric Administration (NOAA)Advanced Very High Resolution Radiometer (AVHRR) multi-temporal imageryover a 10-year period (1989–1998) was used as a surrogate for primary productionto investigate the impact of interannual climate variability on grasslandperformance for central and northern US Great Plains. First, the contribution ofC3 and C4 species abundance to the major grassland ecosystems of the US GreatPlains is described. Next, the relation between mean SNDVI and the SNDVIcoefficient of variation (CV SNDVI) used as a proxy for interannual climatevariability is analysed. Results suggest that the differences in the long-termclimatic control over ecosystem performance approximately coincide withchanges between C3- and C4-dominant grassland classes. Variation in remotelysensed net primary production over time is higher for the southern and westernplains grasslands (primarily C4 grasslands), whereas the C3-dominated classes inthe northern and eastern portion of the US Great Plains, generally show lower CV SNDVI values.