A late Otiran-Holocene paleoenvironment reconstruction based on cave excavations in northwest Nelson, New Zealand

Excavations of deposits ranging in age from 20 000 years ago, within the Otira glacial maximum, to the commencement of the Holocene 10 000 years ago, from Honeycomb Hill Cave in the Oparara valley, northwest Nelson, New Zealand, have revealed a large fossil avifauna. Faunal and floral analyses indicate that the cave, now in a lowland podocarp/beech forest, was in a subalpine shrub zone with nearby montane forest about 20 000 years ago. From this the existence of substantial forest remnants persisting throughout the Otiran Stage in this region is inferred. The upland moa Megalapteryx didinus (Owen) and crested moa Pachyornis australis Oliver are inferred to have been primarily mhabitants of montane forest and subalpine shrubland. By contrast, the little bush moa Anomalopteryx didiformis (Owen) lived primarily in lowland forests. Other extinct birds inferred to have preferred the open shrubland prevailing in the Oparara dunng the Otiran are Finsch's duck Euryanas finschi Van Beneden, Aptornis otidiformis (Owen), and Harpagornis moorei Haast. Kakapo Strigops habroptilus Gray are only present in younger deposits laid down when forest conditions prevailed, supporting the idea that these were primarily lowland birds.