What caused extinction of the pleistocene megafauna of sahul?

2016 The Author(s) Published by the Royal Society. All rights reserved. During the Pleistocene, Australia and New Guinea supported a rich assemblage of large vertebrates. Why these animals disappeared has been debated for more than a century and remains controversial. Previous synthetic reviews of this problem have typically focused heavily on particular types of evidence, such as the dating of extinction and human arrival, and have frequently ignored uncertainties and biases that can lead to misinterpretation of this evidence. Here, we review diverse evidence bearing on this issue and conclude that, although many knowledge gaps remain, multiple independent lines of evidence point to direct human impact as the most likely cause of extinction

A comprehensive database of quality-rated fossil ages for Sahul\u27s Quaternary vertebrates

The study of palaeo-chronologies using fossil data provides evidence for past ecological and evolutionary processes, and is therefore useful for predicting patterns and impacts of future environmental change. However, the robustness of inferences made from fossil ages relies heavily on both the quantity and quality of available data. We compiled Quaternary non-human vertebrate fossil ages from Sahul published up to 2013. This, the FosSahul database, includes 9,302 fossil records from 363 deposits, for a total of 478 species within 215 genera, of which 27 are from extinct and extant megafaunal species (2,559 records). We also provide a rating of reliability of individual absolute age based on the dating protocols and association between the dated materials and the fossil remains. Our proposed rating system identified 2,422 records with high-quality ages (i.e., a reduction of 74%). There are many applications of the database, including disentangling the confounding influences of hypothetical extinction drivers, better spatial distribution estimates of species relative to palaeo-climates, and potentially identifying new areas for fossil discovery

Fast and simple procedure for fractionation of zinc in soil using an ultrasound probe and FAAS detection. Validation of the analytical method and evaluation of the uncertainty budget

A new fast method for determination of mobile zinc fractions in soil is proposed in this work. The three-stage modified BCR procedure used for fractionation of zinc in soil was accelerated by using ultrasounds. The working parameters of an ultrasound probe, a power and a time of sonication, were optimized in order to acquire the content of analyte in soil extracts obtained by ultrasound-assisted sequential extraction (USE) consistent with that obtained by conventional modified Community Bureau of Reference (BCR) procedure. The content of zinc in extracts was determined by flame atomic absorption spectrometry. The developed USE procedure allowed for shortening the total extraction time from 48 h to 27 min in comparison to conventional modified BCR procedure. The method was fully validated, and the uncertainty budget was evaluated. The trueness and reproducibility of the developed method was confirmed by analysis of certified reference material of lake sediment BCR-701. The applicability of the procedure for fast, low costs and reliable determination of mobile zinc fraction in soil, which may be useful for assessing of anthropogenic impacts on natural resources and environmental monitoring purposes, was proved by analysis of different types of soil collected from Podlaskie Province (Poland). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10661-015-5020-6) contains supplementary material, which is available to authorized users

Criteria for assessing the quality of Middle Pleistocene to Holocene vertebrate fossil ages

Confidence in fossil ages is a recognized constraint for understanding changes in archaeological and palaeontological records. Poor estimates of age can lead to erroneous inferences-such as timing of species arrival, range expansions and extinctions-preventing robust hypothesis testing of the causes and consequences of past events. Therefore, age reliability must be demonstrated before patterns and mechanisms are inferred. Here we present a generalized quality-rating scheme based on a two-stage set of objective criteria: first, our method assesses the reliability of an age regarding the dating procedure, and second, if the age is based on association, it assesses the confidence in its association with the target vertebrate fossil. We developed this quality rating specifically for Australian applications, but it could be applied to other regions and to longer timescales with some modification. Our method ranks ages in four categories of reliability (A* and A are reliable; B and C are unreliable). In our case study of the late Pleistocene megafauna of Sahul, accounting for reliability (i.e., accepting only reliable ages) reduced the number of useful records within chronologies by 70%; for most species, this greatly affects any inferences regarding the timing and possible drivers of extinction. Our method provides a simple, replicable and general tool for assessing the age quality of dated fossils, as well as provides a guide for selecting useful protocols and samples for dating