TY - JOUR
T1 - Dry season mapping of savanna forage quality, using the hyperspectral Carnegie Airborne Observatory sensor
AU - Knox, Nichola M.
AU - Skidmore, Andrew K.
AU - Prins, Herbert H. T.
AU - Asner, Gregory P.
AU - van der Werff, Harald M. A.
AU - de Boer, Willem F.
AU - van der Waal, Cornelis
AU - de Knegt, Hendrik J.
AU - Kohi, Edward M.
AU - Slotow, Rob
AU - Grant, Rina C.
PY - 2011
Y1 - 2011
N2 - Forage quality within an African savanna depends upon limiting nutrients (nitrogen and phosphorus) and nutrients that constrain the intake rates (non-digestible fibre) of herbivores. These forage quality nutrients are particularly crucial in the dry season when concentrations of limiting nutrients decline and non-digestible fibres increase. Using artificial neural networks we test the ability of a new imaging spectrometer (CAO Alpha sensor), both alone and in combination with ancillary data, to map quantities of grass forage nutrients in the early dry season within an African savanna. Respectively 65%, 57% and 41%, of the variance in fibre, phosphorus and nitrogen concentrations were explained. We found that all grass forage nutrients show response to fire and soil. Principal component analysis, not only reduced image dimensionality, but was a useful method for removing cross-track illumination effects in the CAO imagery. To further improve the mapping of forage nutrients in the dry season we suggest that spectra within the shortwave infrared (SWIR) region, or additional relevant ancillary data, are required.
AB - Forage quality within an African savanna depends upon limiting nutrients (nitrogen and phosphorus) and nutrients that constrain the intake rates (non-digestible fibre) of herbivores. These forage quality nutrients are particularly crucial in the dry season when concentrations of limiting nutrients decline and non-digestible fibres increase. Using artificial neural networks we test the ability of a new imaging spectrometer (CAO Alpha sensor), both alone and in combination with ancillary data, to map quantities of grass forage nutrients in the early dry season within an African savanna. Respectively 65%, 57% and 41%, of the variance in fibre, phosphorus and nitrogen concentrations were explained. We found that all grass forage nutrients show response to fire and soil. Principal component analysis, not only reduced image dimensionality, but was a useful method for removing cross-track illumination effects in the CAO imagery. To further improve the mapping of forage nutrients in the dry season we suggest that spectra within the shortwave infrared (SWIR) region, or additional relevant ancillary data, are required.
KW - Kruger National Park
KW - Savannah
KW - Carnegie Airborne Observatory
KW - Forage quality
KW - ANN
KW - Hyperspectral
UR - http://www.scopus.com/inward/record.url?scp=79953173545&partnerID=8YFLogxK
U2 - 10.1016/j.rse.2011.02.007
DO - 10.1016/j.rse.2011.02.007
M3 - Article
AN - SCOPUS:79953173545
VL - 115
SP - 1478
EP - 1488
JO - Remote Sensing of Environment
JF - Remote Sensing of Environment
SN - 0034-4257
IS - 6
ER -