One of the interesting aspects is that the islands are right on the Wallace Line. The islands which were the focus of the expedition are separated from the main islands of Indonesia by deep-sea channels, meaning that even during the height of the ice ages and the greatest extent of Sundaland these islands were always isolated and surrounded by water. One of the islands having never been connected to Sulawesi despite being less than 15km away! This separation has led to higher rates of endemism which is why they were good places to look for new species. The researchers also looked at past expeditions to the region to determine which locations had been understudied.
As always these days, you can't discover a new species without worrying that it is about to go extinct and these birds are no different. The authors note that,
One species, the Taliabu grasshopper warbler, is of particular concern as its habitat has been reduced to a few square kilometres which was burned in the 1980s and logged in the 1990s. The paper ends (p170) with a lament,virtually no primary lowland forest remains [on the islands were the birds were found], and most highland forests have been affected by some form of logging and/or forest fires, the latter presumably caused by recent climate change (p170)
Urgent, long-lasting conservation action is needed for some of the new forms to survive longer than a couple of decades beyond their date of description.