Abstract Local and regional species extirpations may become more common as changing climate and disturbance regimes accelerate species’ in situ range contractions. Identifying locations that function as both climate and disturbance refugia is critical for biodiversity conservation. Here, we investigate the persistence of a disjunct, fire-sensitive conifer population, yellow-cedar (Callitropsis nootkatensis), in the historically frequent-fire landscape of the Blue Mountains in eastern Oregon, USA. We used tree rings to reconstruct multi-century fire histories, which were then used to compare historical mean fire return intervals (MFRIs) inside of the cedar grove to the surrounding dry forest matrix, as well as to examine relationships between historical fire occurrence and reconstructed climate. We also examined trends in post-fire yellow-cedar mortality and regeneration between 2006, when the grove burned in a wildfire, through 2017. Results indicated that fire was less frequent in the cedar grove (MFRI = 35.8 years) than in the surrounding dry mixed-conifer forest (MFRI = 14.4 years). Historical fire occurrence was associated with hotter and drier conditions. Following the 2006 fire, cedar mortality was high (>90%), but by 2017 post-fire regeneration was abundant (median = 8125 seedlings ha-1). The eastern Oregon cedar grove appears to occupy a fire refugium historically decoupled from the frequent-fire regime of the broader landscape. The topographic position of the grove suggests it is also a climate refugium. Despite high mortality following fire in 2006, yellow-cedar is regenerating in the grove. Managing for climate and disturbance refugia has been identified as an important option for conservation in the context of rapid global change, and this study provides evidence that locations where climate and disturbance refugia overlap may be disproportionately important for the maintenance of regional biodiversity. However, active management may be required for populations to persist in some of these locations as anthropogenic change is capable of overwhelming the underlying buffering capacity of refugia.

中文翻译：

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分离和分离？对火敏感的针叶树物种在历史上频繁发生火灾的景观中的持久性

摘要 随着气候变化和干扰机制加速物种就地范围收缩，地方和区域物种灭绝可能变得更加普遍。确定兼具气候和干扰避难所功能的地点对于生物多样性保护至关重要。在这里，我们调查了美国俄勒冈州东部蓝山历史上频繁发生火灾的景观中分离的、对火敏感的针叶树种群黄雪松 (Callitropsis nootkatensis) 的持久性。我们使用年轮重建了多世纪的火灾历史，然后将其用于比较雪松林内的历史平均火灾重现间隔 (MFRI) 与周围干燥的森林矩阵，并检查历史火灾发生与重建之间的关系气候。我们还研究了从 2006 年到 2017 年森林火灾后黄雪松死亡和再生的趋势。结果表明，雪松林（MFRI = 35.8 年）的火灾频率低于周围干燥的森林。混交针叶林（MFRI = 14.4 年）。历史上的火灾发生与更热和更干燥的条件有关。2006 年火灾后，雪松死亡率很高（>90%），但到 2017 年火灾后再生很丰富（中位数 = 8125 株幼苗 ha-1）。俄勒冈州东部的雪松林似乎占据了一个历史上与更广泛景观的频繁火灾制度脱钩的防火避难所。小树林的地形位置表明它也是一个气候避难所。尽管 2006 年火灾后死亡率很高，但黄雪松正在树林中再生。在全球快速变化的背景下，管理气候和干扰避难所已被确定为保护的重要选择，这项研究提供的证据表明，气候和干扰避难所重叠的地点可能对维持区域生物多样性非常重要。然而，由于人为变化能够压倒避难所的潜在缓冲能力，因此可能需要积极管理才能使这些地方的种群持续存在。