Abstract Detail

Pacific Biogeography

Potter, Benjamin [1], Newcomb, Richard [2], Drummond, Alexei [3], Lee, William [4].

Origins of the endemic New Zealand tree lineages.

Insular floras that contain high levels of endemism provide fascinating case studies of colonisation history. Assemblages of historically accumulated indigenous diversity, containing a variety of lineages with different immigration ages and richness values, offer unique insights into biogeography and diversification. The trees of New Zealand – a species rich flora consisting of ca. 270 endemic species spread across a broad spectrum of plant diversity (ca. 150 asterids, 80 rosids, 20 conifers, 10 magnoliids, 6 ferns, and 5 monocots) – represents such a group. Here, we set out to characterise the pre-NZ origins and colonisation history of these taxa, and assemble this into a single timeline spanning from the Late Cretaceous to present. Towards this densely sampled molecular dating analyses were conducted using a combination of publicly available and newly generated DNA sequence data. Bayesian relaxed clocks were used to date the NZ vs. overseas floristic disjunctions, and place the NZ immigration events along a timeline. The primary aims were to: (1) build a time-calibrated framework for tree diversification, phylogeography and community assembly research, and (2) contrast the historical arrivals with significant geological and climatological events. Results suggest that although the Zealandia continental fragment has been geographically isolated for ca. 80 million years, over 85% of the tree colonisations can be attributed to dispersal events in the Early Miocene or later (mean ages).  Broadly, most of these dates are in line with a ‘fly-paper of the Pacific’ hypothesis for the NZ tree flora, although some lineages do appear to have genuinely ancient NZ endemnicity, representing possible examples of continuous post-Gondwanan presence.

1 - University of Auckland, School of Biological Sciences, Thomas Building, 3a Symonds Street, Auckland, 1010, New Zealand
2 - New Zealand Institute for Plant & Food Research Ltd., 120 Mt Albert Road, Auckland, 1142, New Zealand
3 - University of Auckland, Centre for Computational Evolution, 303/38 Princes Street, 1010, New Zealand
4 - Landcare Research, 764 Cumberland Street, Dunedin, 9016, New Zealand

New Zealand
molecular phylogenetics

Presentation Type: Colloquium Presentations
Abstract ID:653
Candidate for Awards:None

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