Biogeography and Biome Assembly
Andrew Lowe | Ed Biffin | Gunnar Keppel
Understanding the broad-scale processes of biome assembly is important in interpreting both historical patterns and future responses of ecosystems to global change. We use molecular tools (DNA sequences; AFLPs; microsatellite variation) to reconstruct evolutionary relationships amongst exemplar plant lineages as a basis to explore the timing and patterns of diversification in the context of major environmental change and infer the relationships between floristic regions in Australasia.
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The southern hemisphere conifer families Podocarpaceae and Araucariaceae provide good model systems for these investigations, given their ‘ancient' origins, widespread distributions, extensive fossil records and their relative utility for ‘nearest living relative' comparisons - i.e. using modern species to interpret the response of extinct, close relatives.
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 | The Australasian Floristic Interchange – Craig Costion |
The wet tropics of northeast Queensland have long been regarded as a refuge for "primitive" or basal angiosperm lineages. It received World Heritage Status primarily for having the highest concentration of basal angiosperms of any other biome on earth. The floristic affinities of this region are debated; a primarily Gondwanan relict flora vs. a flora with a strong "intrusive" Asian element; and have not been thoroughly addressed using current molecular methods. Current investigation is focused on the Queensland wet tropic tree flora and its relationship to the flora of SE Asia. In addition, phylogenetic diversity estimations are being incorporated into conservation planning activities.
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Many milestone discoveries in the fields of evolution and ecology have originated from the study of island systems. The Melanesian islands in the SW Pacific provide an ideal natural laboratory for study, as they provide a mosaic of islands of recent geological origin and of different sizes and distances from ancient Gondwanan source continents. In addition, many Melanesian islands still have extensive and intact stands of tropical rain forest (although many are now severly threatened by logging). Despite their suitability for evolutionary and ecological study, the SW Pacific has received little scientific attention. This project examines genetic dynamics and interactions at three different scales; Species within genera, populations within species and spatial genetic structure within population for members of Myristica (Myristicaceae) and Calophyllum (Clusiaceae). | |
Funding:
Lowe AJ, Keppel G (2007-2010) Genetic dynamics of lowland rainforest trees on islands in the tropical Southwest Pacific. Australian and Pacific Science Foundation. ($24.5K)
Lowe AJ, et al. (July 2006) Developing biogeographic know-how: Improving species divergence and dispersal estimations to examine geological and climatic evolutionary drivers. ARC Discovery ($282K).
Relevant publications:
Biffin E, Hill R, Lowe AJ. Did Agathis (Araucariaceae: Coniferales) really survive the Oligocene drowning of New Zealand. Systamtic Biology. Submitted
Keppel G, Lowe A, Possingham H (2009) Changing perspectives on the biogeography of the tropical South Pacific: influences of dispersal, vicariance and extinction. Journal of Biogeography 36: 1035–1054.
Cavers S, Navarro C, Lowe AJ (2003) Chloroplast DNA phylogeography reveals colonisation history of a Neotropical tree, Cedrela odorata L., in Mesoamerica. Molecular Ecology 12: 1451-1460.
