Fire is a major driver of the genetic diversity of two co-occurring Tasmanian palaeo-endemic conifers
Fire is a major driver of the genetic diversity of two co-occurring Tasmanian palaeo-endemic conifers
复制标题
火是两种同时存在的塔斯马尼亚古特有针叶树遗传多样性的主要驱动因素
DOI：
10.1111/jbi.12919
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发表时间：
2016
影响因子：
3.9
通讯作者：
Motomi Ito and David J.M.S Bowman
中科院分区：
文献类型：
--
作者：
James R. P. Worth;Gregory J. Jordan;James R. Marthick;Sakaguchi;S.;Eric A. Colhoun;Grant J. Williamson;Motomi Ito and David J.M.S Bowman
全新世火灾对火不耐受物种遗传结构的影响在很大程度上被忽视了。在这里，我们调查的相对影响，末次冰期气候与全新世火灾的遗传多样性的两个共同发生的，火不耐针叶树使用比较人口genetic study.LocationThe palaeoendogenous plant‐rich montane rain forests and alpine coniferous heath of Tasmania，Australia.MethodsThe Tasmanian endogenous conifersAthrotaxis cupressoidesD. Don（20个居群461个样本）和Diselma archeriHook. f. (576样品来自23个种群，其中16个是为A.分别用8个和9个EST核微卫星进行基因分型。遗传多样性和结构之间进行了比较，并在两个物种的遗传模式的因素进行了研究，通过检查隔离距离，与末次冰期最大模拟分布和化石记录的相关性，以及火灾历史指数的采样stines.ResultsThe广范围的遗传结构的两个物种是相似的（Fst= 0.09和F 'st= 0.21为A。柏属D. archeri; Fst= 0.06和F 'st= 0.24），种群期望杂合度、等位基因丰富度、私有等位基因丰富度和成对遗传分化在物种间存在显著相关。此外，遗传多样性指标显着下降的火灾历史的指数。鉴于化石证据和模型证据表明，这两个物种在末次冰期期间都出现在它们目前的分布范围附近，并且缺乏证据表明这两个物种之间存在距离隔离，对多样性模式的合理解释是重复的全新世火灾导致的遗传衰退。特别是那些没有耐火特性的物种，气候变化导致的火灾增加可能会对这些物种造成重大威胁。在塔斯马尼亚，近年来观察到的干闪电增加，加上异常干燥的条件，可能会进一步降低不耐火的古特有物种的范围和遗传多样性。
AimThe impacts of Holocene fires on the genetic architecture of fire‐intolerant species have largely been overlooked. Here, we investigate the relative impacts of the last glacial climate versus Holocene fires on the genetic diversity of two co‐occurring, fire‐intolerant conifers using a comparative population genetic study.LocationThe palaeoendemic plant‐rich montane rain forests and alpine coniferous heath of Tasmania, Australia.MethodsThe Tasmanian endemic conifersAthrotaxis cupressoidesD. Don (461 samples from 20 populations) andDiselma archeriHook.f. (576 samples from 23 populations, 16 of which were for sites sampled forA. 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.ResultsThe range‐wide genetic structure of the two species was similar (Fst= 0.09 andF’st= 0.21 forA. cupressoidesversusD. archeri;Fst= 0.06 andF’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 conclusionsOur 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.