The origins and evolutionary history of xerophytic vegetation in Australia

Abstract

The xeromorphic vegetation is a significant component of the Australian flora and phylogenetic and phylogeographic analysis of xeromorphic plants provides a basis for understanding the origins and evolutionary history of the Australian vegetation. Here we expand on previous reviews of the origins and maintenance of the Australian flora with an emphasis on the xeromorphic component. Phylogenetic evidence supports fossil evidence for evolution of sclerophyll and xeromorphic vegetation from the Eocene with lineages becoming more common in the Oligocene and Miocene, a time of major change in climate and vegetation in Australia. Phylogenetic evidence supports the mesic biome as ancestral to the arid zone biome in Australia in phylogenies of key groups. The diversification and radiation of Australian species shows single origins of xeromorphic group mainly at deeper levels in phylogenies as well as multiple origins of arid occurring species at shallower levels. Divergence across the Nullarbor is also evident and speciation rates in south-western Australia were higher than in the south-east in several plant families. Estimates of timing of diversification generally show either constant rates of diversification or increased diversification from the mid to late Miocene. Phylogeographic studies consistently demonstrate high localised genetic diversity and geographic structure in xeromorphic species occupying both mesic and arid biomes.

Abiotic correlates with diversity and distinctiveness in Sunshine Coast heathlands: Moisture, volcanic landscapes and patterned mounds

“…Previous work in rainforests in Queensland found clustering associated with drier Regional Ecosystems, and refugia associated with long‐term moist areas (Kooyman et al., 2013; Shapcott et al., 2015). However in heathy systems, refugial areas have also been associated with mesic areas including in the Mediterranean (Mastrogianni et al., 2019), in the campo rupestre of Brazil (Miazaki et al., 2015) and in Australia (Byrne & Murphy, 2020; Hopper & Gioia, 2004; Reside et al., 2014; Schut et al., 2014), but this is not always so (Moro et al., 2015).…”

A classification of woody communities based on biological dissimilarity

“…Biological dissimilarities have been widely used in multiple areas of forest ecological research, such as examining community assembly mechanisms (Swenson & Enquist, 2009; Kraft & Ackerly, 2010; Spasojevic & Suding, 2012), exploring vegetation evolutionary processes (Bouchenak‐Khelladi et al, 2010; Byrne & Murphy, 2020), and assessing the relationship between biodiversity and ecosystem functioning (Tilman et al, 1997; Paquette & Messier, 2011; Finegan et al, 2015; Hao et al, 2018, 2020; Yue et al, 2020). Some previous studies have attempted to incorporate biological attributes into vegetation classifications.…”

Adapting to extremes: Reconstructing evolution in response to changing climate over time and space in the diverse Australian plant genus Acacia

“…As the arid zone expanded, previously widespread mesic forest habitats contracted to the coastal margins. Plant groups responded in different ways (Byrne & Murphy, 2020; Crisp et al, 2004; Weston & Jordan, 2017). Some (such as Nothofagus ) remained confined to humid forest conditions and contracted with these habitats to small mesic refuges.…”