New South Wales Department of Primary Industries, National Marine Science Centre, Coffs Harbour, NSW, Australia.
National Marine Science Centre, Southern Cross University, Coffs Harbour, NSW, Australia.
Sci Rep. 2023 Jan 23;13(1):1248. doi: 10.1038/s41598-023-28301-z.
Climate change has driven contemporary decline and loss of kelp forests globally with an accompanying loss of their ecological and economic values. Kelp populations at equatorward-range edges are particularly vulnerable to climate change as these locations are undergoing warming at or beyond thermal tolerance thresholds. Concerningly, these range-edge populations may contain unique adaptive or evolutionary genetic diversity that is vulnerable to warming. We explore haplotype diversity by generating a Templeton-Crandall-Sing (TCS) network analysis of 119 Cytochrome C Oxidase (COI) sequences among four major population groupings for extant and putatively extinct populations only known from herbarium specimens of the dominant Laminarian kelp Ecklonia radiata in the south-western Pacific, a region warming at 2-4 times the global average. Six haplotypes occurred across the region with one being widespread across most populations. Three unique haplotypes were found in a deep-water range-edge population off Moreton Island, Queensland, which likely represents both a contemporary and historic refuge during periods of climatic change. Hindcasting E. radiata cover estimates using extant data, we reveal that this region likely supported the highest kelp cover in eastern Australia during the last glacial maximum. The equatorward range edge, deep-water kelp populations off Moreton Island represent a genetically diverse evolutionary refuge that is currently threatened by warming and requires prompt ex-situ conservation measures.
气候变化导致了全球范围内的大型海藻森林的衰退和消失，随之丧失了它们的生态和经济价值。赤道边缘地区的大型海藻种群特别容易受到气候变化的影响，因为这些地区的升温速度已经达到或超过了它们的热耐受阈值。令人担忧的是，这些边缘种群可能含有独特的适应性或进化遗传多样性，而这些多样性很容易受到变暖的影响。我们通过对来自南太平洋西南部的主要大型海藻巨藻属的 119 个细胞色素 C 氧化酶（COI）序列进行坦普尔顿-克朗德尔-辛格（Templeton-Crandall-Sing，TCS）网络分析，来研究单倍型多样性，这些序列仅来自于现生物种和推测已灭绝的标本。该地区的变暖速度是全球平均水平的 2-4 倍。在该地区发现了六个单倍型，其中一个单倍型广泛分布于大多数种群中。在昆士兰州莫尔顿岛的深水边缘种群中发现了三个独特的单倍型，它们可能代表了气候变化时期的当代和历史避难所。根据现有的数据对巨藻的覆盖范围进行回溯预测，我们发现，在末次冰盛期，该地区可能是澳大利亚东部最大的巨藻覆盖区。莫尔顿岛深水边缘的赤道边缘大型海藻种群是一个具有丰富遗传多样性的进化避难所，目前正受到变暖的威胁，需要采取紧急的异地保护措施。
