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Abstract：
The alpine area of the Australian mainland is highly sensitive to climate and environmental change, and potentially vulnerable to ecosystem tipping points. Over the next two decades the Australian alpine region is predicted to experience temperature increases of at least 1 °C, coupled with a substantial decrease in snow cover. Extending the short instrumental record in these regions is imperative to put future change into context, and potentially provide analogues of warming. We reconstructed past temperatures, using a lipid biomarker palaeothermometer technique and mercury flux changes for the past 3500 years from the sediments of Club Lake, a high-altitude alpine tarn in the Snowy Mountains, southeastern Australia. Using a multi-proxy framework, including pollen and charcoal analyses, high-resolution geochemistry, and ancient microbial community composition, supported by high-resolution 210Pb and AMS 14C dating, we investigated local and regional ecological and environmental changes occurring in response to changes in temperature. We find the region experienced a general warming trend over the last 3500 years, with a pronounced climate anomaly occurring between 1000 and 1600 cal yrs. BP. Shifts in vegetation took place during this warm period, characterised by a decline in alpine species and an increase in open woodland taxa which co-occurred with an increase in regional fire activity. Given the narrow altitudinal band of Australian alpine vegetation, any future warming has the potential to result in the extinction of alpine species, including several endemic to the area, as treelines are driven to higher elevations. These findings suggest ongoing conservation efforts will be needed to protect the vulnerable alpine environments from the combined threats of climate changes, fire and invasive species.
摘要：
澳大利亚大陆的高山地区对气候和环境变化高度敏感,并且可能容易受到生态系统临界点的影响。在接下来的二十年中，澳大利亚高山地区预计将经历至少1°C的温度升高，再加上积雪的大量减少。在这些地区扩展简短的工具记录对于将未来的变化纳入背景至关重要，并可能提供变暖的类似物。我们重建了过去的温度，使用脂质生物标志物古温度计技术和过去3500年来自ClubLake沉积物的汞通量变化，雪山中的高海拔高山塔恩，澳大利亚东南部。使用多代理框架，包括花粉和木炭分析，高分辨率地球化学，和古老的微生物群落组成，由高分辨率210Pb和AMS14C测年支持，我们调查了响应温度变化而发生的局部和区域生态和环境变化。我们发现该地区在过去的3500年中经历了普遍的变暖趋势，在1000至1600年之间发生了明显的气候异常。BP。在这个温暖的时期，植被发生了变化，其特征是高山物种的减少和开阔林地分类群的增加，这与区域火灾活动的增加同时发生。鉴于澳大利亚高山植被的狭窄海拔带，任何未来的变暖都有可能导致高山物种灭绝，包括该地区的一些地方病，当树线被驱动到更高的海拔时。这些发现表明，需要持续的保护努力来保护脆弱的高山环境免受气候变化的综合威胁。火灾和入侵物种。
