Phenology of Tropical Birds in Peninsular Malaysia: Effects of Selective Logging and Food Resources

Abstract

AbstractThe increasing prevalence of selective logging in Southeast Asian tropical rainforests compels much-needed studies to examine its effects on the vital life-cycle events of their resident understory birds, which are particularly sensitive to such degradation. Food abundance, which can be an important factor in avian phenology, may be affected by selective logging. Therefore, studies that compare food abundance and breeding and molting occurrence simultaneously at the same sites are important for the ecological monitoring of such logging regimes. Using bimonthly mist netting in two rainforest areas in Peninsular Malaysia, we assessed the breeding and molting occurrence and diets of understory birds and compared the abundance of food resources in unlogged forests and forests that had been selectively logged 30 years before. Our study revealed no differences between forest types in overall understory-resident bird abundance; comparative species richness; feeding-guild composition; breeding and molting occurrence and temporal variation; or arthropod, fruit, and flower abundance. The similarity in food resources could account for the similarity in avian phenological characteristics between forest types. Increased breeding corresponded with increased food abundance at the feeding-guild level, and dietary data supported these findings. Breeding cycles of sensitive indicator groups such as understory resident birds are likely to depend on food abundance and forest structure and, thus, on selective logging. Our observation of undiminished avian breeding and molting occurrence in selectively logged forests is an encouraging indication of their conservation potential. However, we emphasize that differences in selective logging practices could affect the forest structure and avifauna differently. Setting thresholds for extraction and regeneration time and subscribing to minimum-impact methods that reduce collateral damage are essential if selectively logged areas are to maintain most of their initial biodiversity.Fenología de Aves Tropicales en Malasia Peninsular: Efectos de la Tala Selectiva y los Recursos Alimenticios