The Use of Satellite Imagery in Estimating Aboveground and Belowground Biomass of Aquatic Vegetation, The Food Source of Waterfowl

Abstract

In this research we studied the possibilities to estimate the biomass of aquatic vegetation in a shallow lake using IKONOS image. IKONOS-2 image, with one infrared and three visible bands, was obtained on the 19th of August 2005. The study was carried out in the Lauwersmeer (The Netherlands) that Bewick’s swans use as an autumn staging site to forage on the belowground biomass of fennel pondweed. This research gave the following results; (i) biomass map and biomass estimated from satellite image (ii) relationship between measured above ground biomass and measured below ground biomass, (iii) relationship between measured biomass and remote sensing estimated biomass in nine creeks of the study area. The ILWIS, ArcMap and ERDAS IMAGINE software packages were used for image processing and spatial analysis. Biomass estimation or prediction from IKONOS image was carried out using six combinations of multispectral band ratios and NDVI. The spectral indices were extracted and predictive equations for biomass generated using simple linear and quadratic regression models. There was significant positive correlation (r=0.67, p=0.001) between measured above ground biomass and measured below ground biomass found in sandy and clayey soils. The ratio of band 1/band 3 gave the strongest relationship (r=0.67, p=0.001). Testing the simple linear (r2=0.45, p=0.001) and quadratic models (r2=0.53, p=0.001) this band ratio also gave the best fit and it was used for biomass prediction. The quadratic model predicted more biomass and yielded slightly higher prediction error (RMSE=2.32) than the linear model (RMSE=2.28). About 90% of the predicted biomass of both models gave approximately 10% higher biomass as compared to the measured biomass.

Keywords: Remote sensing/GIS, biomass estimation, aquatic vegetation, Potamogeton pectinatus, above and belowground biomass

Cite this Article

Takem E.A. Delphine and Ekani M.T. Aloys, The Use of Satellite Imagery in Estimating Aboveground and Belowground Biomass of Aquatic Vegetation, the Food Source of Waterfowl. Journal of Remote Sensing & GIS. 2015; 6(2): 33–40P.