Birds are among the widely-studied group of vertebrates. However, ever since 1999, there are only five or six new species described per year. Recently, ornithologists from a joint research team from the National University of Singapore and the Indonesian Institute of Sciences made a discovery of rather cryptic diversity in birds by discovering five bird species and five new subspecies.
The new species of birds are found by the team led by Associate Professor Frank Rheindt of the Department of Biological Science at the NUS in three small island groups situated in the Wallacea Region of Indonesia. To those who are not familiar, Wallacea is an archipelago in between the Oriental and Australian biogeographical realms and named after Sir Alfred Wallace whose career was mostly spent in these areas. The results of the study were able to provide evidence that mankind's understanding of the species diversity in areas such as Wallacea is still incomplete -- even for a widely-studied group like birds. The study, which was published in Science, suggests that exploration to find undescribed species diversity in this age is promising.
DISCOVERING NEW TAXA
To determine an island's distinct terrestrial communities, one must consider the sea depth. Unfortunately, this important matter is always neglected. As the planet undergoes periods of glacial and interglacial cycles which led to the formation of land bridges during the ice ages, animals from different islands started to interbreed. Creatures on deep-sea and high-elevation islands, on the other hand, did not have the means to travel to and fro and that led to higher endemism rates. With this in mind, professor Rheindt and his team concentrated all research efforts on the islands located off the northeastern Sulawesi: Taliabu and Peleng. Bathymetric data had indicated that deep-sea is present between these two islands and Sulawesi.
It is important as well to compare notes with previous research of the island that is why the research team examined the accounts of collectors such as Sir Alfred Wallace and focused on the places which received little attention and coverage from researchers and collectors. Fortunately, the Sula group -- Taliabu, and small neighboring islands -- perfectly fall under the category. The Sula group was underdocumented because it has only been briefly visited by eight historic collecting expeditions that all focused on coastal areas. On the other hand, Peleng and the islands of the Banggai group were visited three times but only along the coastline.
Professor Rheindt and his team did extensive fieldwork in these remote islands for six weeks starting from November of 2013 until January of 2014 and were able to successfully collect 10 new and long-overlooked avian forms. The team was able to describe five new species and five new subspecies of a songbird through the integration of genomic and phenotypic research methodologies. On the island of Taliabu, the team was able to discover three new species of birds: the Taliabu Grasshopper-Warbler, the Taliabu Myzomela, and the Taliabu Leaf-Warbler. Three new subspecies were also discovered in the area: the Taliabu Snowy-browed Flycatcher, Taliabu Island Thrush, and Sula Mountain Leaftoiler.
There were two new species of birds discovered by the team on Peleng: the Peleng Fantail and the Peleng Leaf-Warbler. There was also a newly-discovered subspecies: the Banggai Mountain Leaftoiler. On the island of Togian, a new subspecies of bird was also discovered, the Togian Jungle-Flycatcher.
According to Rheindt, studying the routes and operations of historic collecting expeditions and identifying gaps is a productive approach to pinpoint focal areas. "The description of this many bird species from such a geographically limited area is a rarity," he said.
IMPLICATIONS FOR CONSERVATION
The research team discovered that both the islands of Taliabu and Peleng suffered from rampant forest destruction to the point that there is no primary lowland forest on both island and its highland forests have been impacted by logging or forest fires. As of the moment, the newly discovered avian species tolerate these activities although Rheindt explained that this should still be a cause for alarm. "As such, urgent and long-lasting conservation action is needed for some of the new forms to survive longer than a couple of decades."