Spectral separation of submerged aquatic vegetation using two-meter multispectral digital imagery

This study investigates the capability of two-meter airborne digital multispectral imagery for the spectral separation of five species of SAV sampled within the Bear Lake NWR (National Wildlife Refuge) in Idaho. Sampled brightness values for the Submerged Aquatic Vegetation (SAV) types were tested for differences using a Kruskal-Wallis single factor ANOVA (Analysis of Variance) with tied ranks. It was found that the differences in ranked means were statistically significant. Multiple comparisons tests were used to test which SAV types were different. The Tukey-Kramer tests for the green, red, and near-infrared bands confirmed that the brightness values for Chara vulgaris are different than those of Hippuris vulgaris. The Tukey-Kramer tests were applied to four band ratios: (1) the Simple Ratio (near-infrared/red), (2) NDVI or Normalized Difference Vegetation Index (near-infrared - red/near-infrared + red), (3) near-infrared/green ratio, and (4) red/green ratio. Test results for the Simple Ratio, NDVI and the red/green indicated that there were no significant differences between any of the SAV types. Results of the red/green ratio showed that six statistically significant differences existed and that Potamogeton pectinatus and Ceratophyllum demersum are different from Myriophyllum spicatum, Hippuris vulgaris, and Chara vulgaris.