Diversification and Biogeography of Lasiopetaleae [Malvaceae] and the History of the Southwestern Australian Flora

University Of Miami, Coral Gables FL

Investigators

Abstract

The southwestern corner of Australia is designated a biodiversity hotspot because of its diverse and unique flora. Over 5400 species of plants grow in an area the size of New Mexico; 79% of these species are found only in southwestern Australia. Despite this botanical importance, the origins and history of this unique flora have not been studied intensively. In this project by Dr. Barbara Whitlock and Dr. Carolyn Wilkins, one group of plants, the velvet bushes or Lasiopetaleae, is used as a model to understand the origins, history, and diversity of the southwestern Australian flora. Lasiopetaleae include ten genera and about 180 species of shrubs and trees, placed in the mallow or cotton family Malvaceae. They are found throughout Australia but are especially diverse in the southwest. The first step is to determine how all the species of Lasiopetaleae are related to each other using information from DNA sequences, morphology, and anatomy. These relationships are portrayed as an evolutionary tree, or phylogeny. This involves extensive fieldwork throughout Australia to find and collect specimens from 100+ species of Lasiopetaleae. Once the phylogeny is known, it will be used to understand where the group originated and how geologic events have shaped evolution within the group. It will also be used to determine if the southwestern flora is so diverse because evolution occurs more rapidly there. Three measures will be used to examine the rate of evolution: (1) speciation, or the formation of new species; (2) DNA mutations; and (3) morphology and anatomy. Once these rates are calculated, they can be compared to Lasiopetaleae growing in other regions of Australia and to other groups of plants elsewhere in the world. Together, these measures will shed light on the underlying evolutionary processes that led to the high diversity in southwestern Australia. This study will generate hypotheses that will later be used as a framework for future studies of other groups of southwestern Australian plants, leading to a fuller understanding of the origin of a biodiversity hotspot. The new specimens that will be collected for this project will likely result in the recognition of new species and expand knowledge of the biodiversity of Australia significantly. They will allow for the status of rare species to be determined, resulting in more informed conservation decisions. To insure that discoveries and results are shared as widely as possible, information on specimens including digital photographs will be entered into an online database. This will help disseminate results to the nonscientific community and lead to a greater appreciation of the Western Australian flora. In addition, this project will strengthen communication and intellectual exchange among American and Australian scientists. It will promote education in systematic biology by training students in field methods in Australia, and a graduate student in molecular biology techniques at the University of Miami. This project will also broaden the participation in systematic biology of two women who are at early stages in their careers.