This study explored foraging ecology in a guild of 13 woodpecker species found in the lowland rainforests of peninsular Malaysia. The data collected were used for two purposes: (1) to compare species from temperate and tropical woodpecker assemblages in an attempt to understand patterns of diversity, and (2) to determine the effects of logging on Malaysian woodpeckers.
Ecological and morphological patterns of diversity were investigated in woodpeckers from tropical sites in Malaysia (Pasoh Forest Reserve and Sungai Lalang Forest Reserve) and Guatemala, and two temperate sites in North America. Multivariate analyses separated species into two ecomorphs: “conventional” - species that excavated frequently and had large bills, long bracing tails, and relatively short toes, and “novel” - species that used a variety of microhabitats (bamboo, ant nests) and had relatively short tails, short, flattened bills, and long toes. Both temperate and tropical species were classified as the first ecomorph, but the “novel” ecomorph comprised primarily tropical species. These woodpeckers used tropical resources not readily available year-round in temperate forests, such as arboreal ant and termite nests, bamboo, and leaves. These novel resources may explain the maintenance of high woodpecker diversity in tropical rainforests.
Woodpecker response to logging exhibited some atypical patterns. Overall abundance in recently logged stands (mean = 5 years) is similar to unlogged forest, but drop by half in older stands (mean = 10 years). Numbers rebound in older (25 + years) stands, but species composition differs significantly from that in unlogged forest. The abundance of preferred microhabitats (particularly snags) also follows this pattern and suggests that the effects of logging are delayed for woodpeckers. Rainforests often incur massive damage during logging, and many logs, stumps, and damaged trees are left behind. The result is a spike in necromass available to woodpeckers for foraging and nesting. This supply buffers woodpecker populations in the years immediately following logging, but as the dead wood decays, woodpecker numbers drop. Large, snag-foraging woodpeckers seem most affected in the long term. The importance of snags should be considered in the management of Malaysian forests.