Butterfly response to severe ENSO-induced forest fires in Borneo

1. Little is known about animal community response to severe El Nino Southern Oscillation (ENSO)-induced fire events. Here the response of butterflies to the 1997/98 ENSO-induced fire event in East Kalimantan (Indonesian Borneo) is assessed. In addition to the community-wide study, a detailed assessment of the lycaenid Jamides celeno is made. 2. Species richness declined significantly from 211 species pre-ENSO to 39 species post-ENSO and community composition changed significantly. Along with the decline in species richness there was a marked increase in dominance. Jamides celeno, for example, increased from 3% of the pre-ENSO assemblage to 58% of the post-ENSO assemblage. Like J. celeno, most of the species in the post-ENSO assemblage were generalists; most of the specialist species having disappeared from pre- to post-ENSO. 3. The major host plant used by J. celeno was the abundant resprouting Fordia splendidissima. Furthermore, significantly more eggs were laid on plants with the crazy ant, Anoplolepis gracilipes, present than on plants with other ants or no ant attendance. Caterpillar presence was significantly higher on plants tended by ants than on untended plants. 4. The median distance moved by J. celeno was 30 m with a maximum recorded distance of 290 m. 5. The abundance of J. celeno and other generalists in the post-ENSO assemblage at Wanariset was probably related to their ability to utilise the few available resources after the fire (e.g. F. splendidissima resprouts), their presence in degraded habitats surrounding the Wanariset forest, and their ability to disperse successfully, by either being strong fliers (e.g. Euploea spp.) or being able to attain very high population sizes and thereby produce a surplus of dispersers (e.g. J. celeno).