Abstract ID: 579

Relationship between litterfall and MODIS vegetative index in a transitional forest of Mato Grosso (Sinop LBA test site)

Litterfall is an important component of seasonal rainforests CO2 cycle, guaranteeing nutrients and energy fluxes to the soil. Remotely sensed Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), were already shown to be a good measure of ground-based measurements of forest tree productivity in temperate forest and evergreen rainforest, but we know just a few about relationships in the transitional semi-deciduous forests of the southern Amazon. In this paper we compare seasonal variations of litterfall ground measured at the LBA Sinop test site, with 250m resolution 16-day MODIS NDVI and EVI composites (Land Products, Collection 5, C5_MOD13Q1), obtained from the Oak Ridge National Laboratory (ORNL DAAC). Evaluated time series comprises a seven-year experiment (2001-2007) of monthly sampled litterfall (n: 55), averaged from 20 randomly spaced litter traps, distributed in an area of about 1 ha. Data field were compared with the timely most corresponding NDVI and EVI datasets, averaged for the three MODIS pixels partially covering the field experiment. Litterfall has not a significant correlation with NDVI and EVI values through all the year period. It occurs because, unlike the litterfall, which has well-defined seasonality, with averages ranging from 76 g/m2 to 80.6 g/m2, from wet to dry season, the vegetative index does not have significant seasonal variations from the transitional forest area, that presented average values of 0.874 and 0.875 for NDVI and 0.511 and 0.508 for the EVI, in the wet and dry seasons respectively. When divided in two hydrologic seasons (dry and wet), better correlations were obtained in the dry season (December through May), negative for NDVI and positive for EVI. Future work pretend to include correlation studies between further ground measures (efflux, leaf area index) and additional MODIS products (original bands, fPar, LAI, NPP, GPP).

Session:  Biogeochemistry - Nutrient cycling in forest and savanna ecosystems and agroecosystems.

Presentation Type:  Oral