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Abstract Detail



Biogeography

Moody, Michael [1].

Phylogeography of vulnerable ephemeral pool endemic plant taxa among the southwest Australian granites: dispersal, vicariance and a mosaic of cryptic diversity.

The granite inselbergs of southwest Western Australia are known for high levels of endemism and taxonomic diversity, considered “islands” in a landscape that has grown increasingly more arid over the past 20 m.y. These islands have retained remnants of a flora when this part of Australia had a wetter climate as well as harboring many endemics adapted for the unique mosaic of habitats available. Within these islands are ephemeral pools that fill for weeks or months primarily dependent on winter rains and act as microhabitats with a unique and still poorly understood short-lived flora and fauna. The plants endemic to these pools are small annuals of taxonomically distantly related plant lineages. This research will examines phylogeography of two of the most widespread of these species (Glossostigma drummondii and Isoetes australis) and the priority threatened endemic Myriophyllum petraeum (20 known populations) that all occur in often highly disjunct populations ranging 10s -100s of kilometers apart. Given physical distance, limited dispersal potential and the expectation of little historic habitat variation since the Miocene, these species are hypothesized to show a high level of regional cryptic diversity. If the changing climate has led to isolation and the species have similar dispersal mechanisms, phylogeographic analyses should reveal similar timing and patterns of vicariance across the range for each species. Sequence data from cpDNA introns and the nrDNA ITS region was collected from accessions across the range of each species as well as rare closely related taxa in the same habitats. Results from Bayesian phylogeographic analyses as well as dispersal-vicariance analysis reveal that all three species have similar patterns of cryptic diversity through local endemic haplotypes. Patterns of divergence were shown to correspond with mid- to late Miocene aridity. Also evidence for likely expansion and contraction of genotype range leading to isolation among some populations within species corresponds with Pleistocene fluctuations in aridity. There has also been more recent dispersal among some previously isolated taxa evidenced by recent hybridization among Glossostigma genotypes.

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1 - University of Texas at El Paso, Biological Sciences, 500 W. University Ave., El Paso, TX, 79968, USA

Keywords:
Phylogeography
Western Australia
ephemeral pool
granite inselberg
vicariance
genetic diversity.

Presentation Type: Oral Paper:Papers for Topics
Session: 50
Location: Magnolia/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 2:15 PM
Number: 50004
Abstract ID:791
Candidate for Awards:None


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