ABSTRACT
In recent years, significant efforts have been made to restore palila’s habitat and population, for example, by reducing the number of ungulates and trapping rats (Banko 2002; Banko and Farmer 2006). Despite these efforts, a steady decline in palila population has happened, especially during the last 5 years (Leonard et al. 2008). The latest survey showed that there are only approximately 1200 birds left, down from approximately 4400 in 2003 (DLNR 2010). What is particularly perplexing is that no clear causes can be identified for the population decline, making it difficult to take effective measures for palila conservation. Mamane and naio (Myoporum sandwicense) are the two tree species in this habitat. However, mamane is more critical for palila’s survival since palila almost exclusively eats immature mamane seeds. Therefore, it is important to separate mamane and naio trees so that the abundance of mamane trees and their spatial distribution can be derived to understand the palila population dynamics. Since the crowns of mamane and naio are relatively small (with an average crown diameter of 4-5 m) and they can grow next to each other in the habitat, it is very difficult, if not impossible, to classify these two species using conventional medium spatial resolution satellite imagery such as Landsat.
