Abstract Detail

Biogeography

Cantley, Jason T. [1], Keeley, Sterling [2].

Repeated dispersals of Coprosma (Rubiaceae) out of New Zealand indicate a under recognized source of colonists to other Pacific islands.

Major source areas of colonizing species to Pacific islands have been identified in Australia, Asia, the Indo-Pacific and the Americas. Although Australia has been identified as a major source area, its close geographic neighbor, New Zealand, has not been considered of equal importance for dispersals into the Pacific. Although New Zealand has a rich flora today, this was not always the case, as the Oligocene Marine Transgression (OMT) apparently eliminated most of the floristic diversity approximately 30-28 mya. For this reason, New Zealand is often viewed as a recipient rather than a source of colonists following the continent's reemergence. However, a number of important Pacific wide genera have strong floristic affinities with New Zealand taxa, many of which are not well understood. For example, the genus Coprosma with ~120 species has a center of diversity in New Zealand and many species throughout the Pacific. Our work indicates that Coprosma originated inNew Zealand 10-15 mya. Since that time, over 16 independent lineages have dispersed from New Zealand to other Pacific islands, more than in any other genus. The divergence of Coprosma from its sister genus Nertera and the recent dispersals of Coprosma to other Pacific floras is estimated to have occurred ~10-15 mya and >5 mya, respectively, a time well after the OMT. Furthermore, molecular evidence indicates Coprosma shares this dispersal pattern with at least five other genera including Metrosideros (Myrtaceae), one of the most ecologically important species of Polynesia. These patterns suggest that the role of New Zealand as an important source of colonists needs to be reconsidered despite the negative effects of the OMT on New Zealand's floristic diversity.

Broader Impacts:

1 - University of Hawaii at Manoa, Botany, 3190 Maile Way, St John 101, Honolulu, HI, 96822, USA
2 - University Of Hawaii, DEPT. BOTANY, 3190 MAILE WAY, ROOM 101, Honolulu, HI, 96822-2279, USA

Keywords:
Coprosma
Pacific islands
New Zealand
Rubiaceae
Oligocene Marine Transgression
long distance dispersal.

Presentation Type: Oral Paper:Papers for Topics
Session: 34
Location: Franklin A/Hyatt
Date: Tuesday, July 10th, 2012
Time: 10:30 AM
Number: 34003
Abstract ID:686