Introgression between Betula tianshanica and Betula microphylla and its implications for conservation
Introgression between Betula tianshanica and Betula microphylla and its implications for conservation
复制标题
天山桦和小叶桦的渐渗及其保护意义
DOI：
10.1002/ppp3.10182
复制
发表时间：
2021-07-01
影响因子：
5.1
通讯作者：
Wang, Nian
中科院分区：
文献类型：
--
作者：
Ding, Junyi;Hua, Donglai;Wang, Nian
社会影响报告 在快速变化的环境中，物种保护可能会因区分密切相关物种的不确定性而受到阻碍。正在进行的隐秘杂交会增加更多的不确定性，可能是有益的，也可能是破坏性的。在这里，我们发现一种正在衰落的白桦树种正在与中国西北部准噶尔盆地的一种更广泛的亲戚杂交，它们的杂交种以前被命名为稀有亚种。鉴于这种白桦树的数量不断减少，我们建议保护工作的目标应该是减缓该混合区人为栖息地丧失的速度，并保护其纯种群远离混合区。在密切相关的物种相遇的地区，自然资源保护主义者必须考虑到它们杂交的可能性。杂交可能对物种的长期未来产生积极或消极的影响。如果存在，则需要了解其动态。小叶桦是中国西北地区的一种衰退的湿地树种，与它的近亲天山桦形成了叶子形态和地理分布的连续体。我们利用生态位模型来预测小叶双歧杆菌和天山双歧杆菌的分布。我们使用限制性位点相关 DNA 测序和 SSR 来解析其遗传结构和等位基因共享模式。生态位模型预测，自末次盛冰期以来，天山白桦的范围将扩大到小叶白桦的范围，而未来小叶白桦的范围将缩小。遗传数据表明，这两个物种在准噶尔盆地和天山地区发生了杂交，这两个物种在不久前曾同时出现过，而在阿勒泰山区，没有天山B. tianshanica出现的记录。先前被鉴定为小叶双歧杆菌亚种的稀有种群被证明是杂交起源的。需要进一步研究小叶双歧杆菌和天山双歧杆菌杂交在中国西北地区不断变化的环境中的成本和效益。我们目前的数据表明，保护工作的目标应该是减缓准噶尔盆地混合区人为栖息地丧失的速度，并保护远离阿勒泰山混合区的纯种群。
Societal Impact Statement In rapidly changing environments species conservation can be hindered by uncertainties in distinguishing closely related species. Cryptic ongoing hybridization can add further uncertainty and could be beneficial or destructive. Here, we show that a declining birch tree species is hybridizing with a more widespread relative in the Junggar basin, NW China, and their hybrids have been previously named as rare sub-species. Given the declining numbers of this birch tree, we suggest that conservation effort should aim to slow the rate of anthropogenic habitat loss at this hybrid zone and preserve its pure populations away from the hybrid zone. In areas where closely related species meet, the possibility that they may hybridize must be taken into account by conservationists. Hybridization may have positive or negative consequences for the long-term future of species. If present, its dynamics need to be understood. Betula microphylla is a declining wetland tree species in NW China that forms a continuum of leaf morphology and geographic distribution with its relative Betula tianshanica. We use ecological niche models to predict the distribution of B. microphylla and B. tianshanica. We use restriction site-associated DNA sequencing and SSRs to resolve their genetic structure and patterns of allele sharing. Ecological niche models predict an expansion of the range of B. tianshanica into that of B. microphylla since the Last Glacial Maximum and the contraction of B. microphylla's range in the future. Genetic data suggest that the two species have hybridized in the Junggar basin and in the Tianshan Mountains where the two species have co-occurred in the recent past and in the Altay Mountains where there are no records of B. tianshanica occurrence. Rare populations previously identified as sub-species of B. microphylla were shown to be of hybrid origin. Further research is needed on the costs and benefits of hybridization between B. microphylla and B. tianshanica in the changing environment of NW China. Our current data suggest that conservation effort should aim to slow the rate of anthropogenic habitat loss at the hybrid zone in the Junggar basin and preserve pure populations far away from the hybrid zone in the Altay Mountains.