Hyperspectral assesments of condition and species composition of Australian grasslands

Temperate grasslands in Australia show dynamic responses to climate, which renders them difficult to study using conventional remote sensing tools. However, the need to adequately describe native grassland variables is critical in maintaining ecological and agricultural values. We used a spectroradiometer to measure leaf-and canopy-level spectra from grassland plots in a controlled environment and compared results to fractional cover and species type. We found that the target species, Themeda australis and Poa labillardierei were separable at canopy and leaf level for both healthy and senescent foliage. In particular, we found differences in the 470-510 nm and 660-700 nm spectral regions. Comparison of narrow band vegetation indices for different combinations of photosynthetic and non-photosynthetic material showed strong relationships across a range of fractional cover values which was co-linear for both species. This method demonstrates the potential for remote sensing to identify Australian grasslands of different quality and composition.