The Sulawesi region of Indonesia is a unique yet understudied biodiversity hotspot. East of Borneo and north of Java, this large starfish-shaped island is home to the Grey-sided Flowerpecker (Dicaeum celebicum). These little birds have a double-tubed, brush-tipped tongue, and they flit about trees and shrubs looking for small fruits.
Populations living on a small chain of islands off the southeastern Sulawesi peninsula -- called the Wakatobi archipelago -- were originally described as a separate species from those on the nearby mainland of Sulawesi. But for reasons unknown, they were reclassified as a subspecies (Dicaeum celebicum kuehni) of the mainland form.
To see if a reassessment is in order, an international team led by Seán Kelly from Trinity College Dublin took a multi-disciplinary approach -- combining genetic, diversification, and morphological data of the Wakatobi populations from seven sites off the southeastern peninsula of Sulawesi. Using mist nets, they captured and released 58 of the flowerpeckers from Buton and Wakatobi Islands during summer months between 1999 and 2012.
Their estimates of genetic divergence and phylogenetic and phenotypic analyses show that the offshore Wakatobi population is a separate species than those on the mainland. Because the birds are reproductively isolated and genetically and morphologically distinct, the team recommends reclassifying these populations to their original status of Wakatobi Flowerpecker, Dicaeum kuehni.
These newly described birds are significantly larger, and the genetic data reveal that the two flowerpecker species don’t mix or interbreed, nor do they cross the 27 kilometer stretch of ocean between them.
Here are more pictures for comparison. The left column are flowerpeckers from mainland Sulawesi, the right column are flowerpeckers from the Wakatobi archipelago. Males are in the top row, females are in the bottom row.
“Accurate data on the distribution and status of bird species are regularly used to inform conservation practices and industrial development,” Kelly says in a news release. “As humans are changing the natural environments of Sulawesi at an incredibly fast rate, the discovery and description of species in the region is of major importance.”
He adds: “We run the risk of losing evolutionarily distinct species before we can even discover or enjoy them.”
The findings were published in PLOS One this week.
Images: 2014 Kelly et al., PLOS One