Are butterfly species useful indicators of ecosystem health in Bali Barat National Park?

Abstract

In 2015, Bali Barat National Park was chosen for a Rainforest Standard (RFS) demonstration project. As part of the requirement for the Protected Area Credit of the RFS, species or a group of species that can act as indicators of ecosystem health in Bali Barat National Park (BBNP) have to be identified. Butterflies was one of the taxa assessed for this purpose. A biological survey was conducted in Bali Barat National Park during August-September 2015. Butterfly species were surveyed using a modification of Pollard walk methods by recording species while walking along transects. A total of 82 butterfly species were recoded representing the families Papilionidae, Nymphalidae, Pieridae, Lycaenidae and Riodinidae. Forty-one species, 50 %, were from the family Nymphalidae and 21, 25 % from Pieridae. Nymphalidae and Pieridae was found to be correlated to vegetation structures. The selection process for indicator species was based on Indicator Value (IV) developed by Dufrene and Legendre (1997). Indicator Value uses both abundance and frequency to identify species that may be effective as indicators of ecosystem health. Most of the species with high IV values were associated with savanna vegetation, which is more open and often disturbed. The only Lycaenidae found with a high IV was Tarucus waterstradti, which may be considered as a potential indicator species. However, caution is needed in assessing the potential for butterflies to be used as indicator species because they are small and may be difficult to identify and there is a lack of trained observers in many parts of the tropics.