Large mammal species richness and late Quaternary precipitation change in south‐western Australia

Abstract

The precipitation history of south‐west Australia since the Last Glacial Maximum (LGM) has important implications for understanding southern hemisphere climate dynamics. Previously reported environmental records indicating more open vegetation during the LGM have been interpreted in terms of aridity, but such changes can be explained by alternative mechanisms. To provide new evidence concerning the region's Quaternary precipitation history, we examine temporal changes in large mammal richness at four south‐west Australian fossil sites: Devil's Lair, Tunnel Cave, Witchcliffe Rock Shelter and Rainbow Cave. Large mammal richness is correlated strongly with mean annual precipitation across 53 modern Australian communities. Extending this relationship to the fossil record, a steady increase in richness from the LGM to the onset of the Holocene at both Devil's Lair and Tunnel Cave is consistent with increased precipitation through time. This supports previous interpretations of a more arid LGM and implies regional heterogeneity in the position of the southern hemisphere westerlies. A reduction in richness during the last ∼1000 years is unlikely to be the result of precipitation change and may be related to more frequent burning of the landscape by hunter‐gatherers in an effort to increase availability of large prey.

Climate‐driven ecological stability as a globally shared cause of Late Quaternary megafaunal extinctions: the Plaids and Stripes Hypothesis

“…In Africa today, the number of ungulate species declines as mean annual precipitation decreases (Faith, ). Similarly in Australia today, a significant positive correlation exists between the number of mammal taxa living in an area and the mean annual precipitation there (Faith et al ., ). Australia is exceptional because during the ice age it experienced aridity bottlenecks that reduced its overall carrying capacity for megafauna to low levels.…”

Vegetation and Climate Change in Southwestern Australia During the Last Glacial Maximum

“…The Late Pleistocene environmental and climate history of southwestern Western Australia is little known. Previously published evidence of its biota and climate are confined to relatively coarsely dated fossil wood (Burke, 2004;Dortch, 2004) and vertebrate assemblages (Faith et al, 2017) recovered during archeological cave excavations, and a marine sediment pollen record offshore of the south coast of Western Australia (van der Kaars et al, 2017), which provides a spatially generalized picture of vegetation change throughout the last glacial cycle but includes no samples within the 30-to 20-ka window. Aspects of the vegetation and climate history of the southwest have been documented through Holocene lacustrine pollen records (e.g., Dodson & Lu, 2000;Gouramanis et al, 2012;Itzstein-Davey, 2004), but none of these records have extended into the Pleistocene.…”

Time‐calibrated phylogeny and ecological niche models indicate Pliocene aridification drove intraspecific diversification of brushtail possums in Australia

“…The model suggested that regions of Western and Central Australia may have been suitable for brushtail possums before European settlements (Abbott, 2012;Kerle, 2002). During the Last Glacial Maximum (LGM), precipitation was lower than today (Faith et al, 2017;Sniderman et al, 2019), but we inferred extension of available niche space for T. vulpecula due to the global reduction in sea level that exposed low elevation land around Australia (Figure 2b). The distribution of D-loop haplotypes confirms that Tasmanian T. v. fuliginosus is nested within the mtDNA diversity of T. v. vulpecula across the Bass Strait in Southeast Australia.…”