https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:17154 Wed 11 Apr 2018 11:08:50 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:19826 Sat 24 Mar 2018 07:56:55 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:17998 Sat 24 Mar 2018 07:56:35 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:30185 c parameter, is controlled by water–rock interaction, with higher and lower Mg_c during dry and wet phases, respectively. This is thought to reflect incongruent dissolution of Mg-rich phases. Correction of Sr concentrations for contributions from airborne exogenic Sr, based on ⁸⁷Sr/⁸⁶Sr ratios, yields the bedrock-only contribution (Sr_c). Sr_c variation in stalagmite calcite is influenced by speleothem growth rate and by variation of the calcite-water Sr partitioning in wet and dry phases, and only to a minor extent by incongruent dissolution of Mg-rich phases. Concentration profiles for Mg_c and Sr_cg (corrected for growth rate effects) show inverse correlations and are inferred to show hydrological significance which is captured in a hydrological index, HI. We suggest HI provides robust information on water–rock interaction related to hydrological changes and can be utilized in both wet and semi-arid environments, provided the corrections for soil Mg and exogenic Sr can be applied with confidence. Application of the HI index allows correction of Grotta Savi oxygen isotope data, to yield a δ¹⁸O_c time series that shows when changes in moisture sources and atmospheric reorganization, or changes in moisture amount, were significant. This is especially evident during the Younger Dryas (YD). The Savi record supports the concept of a two-phase YD, marked by an increase of moisture and stronger impact of Adriatic and Mediterranean Sea influences over the northern Adriatic region from 12.3 ka onwards. Then, a large-scale atmospheric reorganization and gradual northward shift of the Polar Front caused a progressive reduction of sea influence over the region from 12.1 ka, supporting the concept of a hemispheric change.]]> Sat 24 Mar 2018 07:41:31 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:30556 Athrotaxis cupressoides D. Don (461 samples from 20 populations) and Diselma archeri Hook.f. (576 samples from 23 populations, 16 of which were for sites sampled for A. cupressoides), were genotyped using eight and nine EST nuclear microsatellites respectively. Genetic diversity and structure was compared between the two species and the factors underlying genetic patterns in both species were investigated by examining isolation by distance, correlations with Last Glacial Maximum modelled distributions and the fossil record, and a fire history index of the sampled stands. Results: The range-wide genetic structure of the two species was similar (F_st = 0.09 and F’_st = 0.21 for A. cupressoides versus D. archeri; F_st = 0.06 and F’_st = 0.24), and there were significant correlations between species for population-based expected heterozygosity, allelic richness, private allelic richness and pairwise genetic divergences. Furthermore, genetic diversity metrics decreased significantly with an index of fire history. Given fossil evidence and modelling evidence that both species occurred near their current ranges during the last glaciation and a lack of evidence for isolation by distance in either species, the plausible explanation for the patterns of diversity is genetic decline resulting from repeated Holocene fires. Main conclusions: Our study suggests that fire can have substantial impacts on genetic structure and diversity of plant species, particularly those without fire-tolerant traits, and that any increases in fire resulting from climate change may impose substantial threats to such species. In Tasmania, the observed increase in dry lightning in recent years, combined with periods of abnormally dry conditions, may therefore further degrade the range and genetic diversity of fire-intolerant palaeoendemic species.]]> Sat 24 Mar 2018 07:27:09 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:24116 Sat 24 Mar 2018 07:11:43 AEDT ]]>