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Abstract: The radiocarbon (14C) content of ambient air particulate matter (PM) collected in Launceston (Australia) through routine state government PM10 sampling has been measured by accelerator mass spectrometry (AMS) to determine the contribution of woodsmoke to wintertime air pollution. For AMS sample preparation a modified combustion method was required for determination of the non-carbonate carbon fraction of PM collected on borosilicate filter media to minimise the effects of the filter melting during combustion to CO2. Negligible differences in the radiocarbon content of atmospheric aerosols were observed for samples using different filter media, particle-size fraction, sample storage, and sample combustion conditions. 14C analyses revealed that contemporary carbon sources contribute 97–99% of the total non-carbonate carbon mass of wintertime ambient PM, supporting the conclusion that woodsmoke is the main contributor to Launceston air pollution. Conversely, fossil carbon sources were found to contribute a relatively constant 1.0±0.7μgCm−3 throughout the year, characteristic of transport-related emissions. [Copyright &y& Elsevier]

Climate change is affecting the distribution of species and the functioning of ecosystems. For species that are slow growing and poorly dispersed, climate change can force a lag between the distributions of species and the geographic distributions of their climatic envelopes, exposing species to the risk of extinction. Climate also governs the resilience of species and ecosystems to disturbance, such as wildfire. Here we use species distribution modelling and palaeoecology to assess and test the impact of vegetation-climate disequilibrium on the resilience of an endangered fire-sensitive rainforest community to fires. First, we modelled the probability of occurrence of Athrotaxis spp. and Nothofagus gunnii rainforest in Tasmania (hereon "montane rainforest") as a function of climate. We then analysed three pollen and charcoal records spanning the last 7,500 cal year BP from within both high (n = 1) and low (n = 2) probability of occurrence areas. Our study indicates that climatic change between 3,000 and 4,000 cal year bp induced a disequilibrium between montane rainforests and climate that drove a loss of resilience of these communities. Current and future climate change are likely to shift the geographic distribution of the climatic envelopes of this plant community further, suggesting that current high-resilience locations will face a reduction in resilience. Coupled with the forecast of increasing fire activity in southern temperate regions, this heralds a significant threat to this and other slow growing, poorly dispersed and fire sensitive forest systems that are common in the southern mid to high latitudes., (© 2019 John Wiley & Sons Ltd.)