Latitudinal Trends in Genetic Diversity and Distinctiveness of Quercus robur Rear Edge Forest Remnants Call for New Conservation Priorities

IF 4.6 2区环境科学与生态学 Q1 BIODIVERSITY CONSERVATION

Diversity and Distributions Pub Date : 2025-04-25 DOI:10.1111/ddi.70018

Camilla Avanzi, Francesca Bagnoli, Edoardo Romiti, Ilaria Spanu, Yoshiaki Tsuda, Elia Vajana, Giovanni Giuseppe Vendramin, Andrea Piotti

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引用次数: 0

Abstract

Aim

Knowledge of the spatial distribution of intraspecific genetic variation is essential for planning conservation actions, designing networks of protected areas, and informing possible assisted migration strategies. Although the Italian peninsula harbours unique genetic variation as a legacy of Quaternary migrations, only sporadic genetic information is available for forest tree species. Here, we present the first geographically comprehensive genetic characterisation of Quercus robur, an iconic broadleaved species of European floodplain forests, in an area which acted as a primary glacial refugium for the species.

Location

Italy.

Methods

745 individuals from 25 populations were sampled and genotyped with 16 nuclear microsatellite markers. Their genetic structure was assessed through various metrics of diversity and distinctiveness, as well as by Bayesian clustering and multivariate methods. The demographic history of inferred gene pools was evaluated through Approximate Bayesian Computation analysis.

Results

Genetic distinctiveness showed a decline with increasing latitude, while allelic richness reached its peak in central Italy. A south-to-north trend in the complexity of the genetic structure was observed, with peninsular Italy being characterised by intermingled gene pools in contrast to the relative homogeneity exhibited by northern populations. Demographic inference indicated that the southern gene pool has been genetically isolated since the penultimate interglacial, whereas populations from central Italy persisted locally in a mosaic of small refugia during the last glaciation.

Main Conclusions

Our results brought out the complexity of the genetic structure of forest trees' populations in southern Europe. At least three Q. robur refugia contributed to the genetic layout of extant populations after the last glacial period, but refugial areas were probably even more numerous in central Italy. Such a detailed characterisation sheds new light on the priorities to be established for the conservation of highly fragmented Q. robur populations in an area rich in diversified genetic lineages.

Abstract Image

查看原文本刊更多论文

栎树后缘林遗存遗传多样性和独特性的纬度变化趋势要求新的保护重点

目的了解种内遗传变异的空间分布对规划保护行动、设计保护区网络和提供可能的辅助迁移策略至关重要。虽然意大利半岛拥有独特的遗传变异作为第四纪迁徙的遗产，但只有零星的遗传信息可用于森林树种。在这里，我们首次对欧洲洪泛区森林的标志性阔叶物种栎木（Quercus robur）进行了地理上全面的遗传表征，该地区曾是该物种的主要冰川避难所。位置意大利。方法从25个群体中抽取745个个体，用16个核微卫星标记进行基因分型。利用贝叶斯聚类和多变量分析方法，对其遗传结构进行了多样性和独特性评价。通过近似贝叶斯计算分析对推断基因库的人口统计学历史进行评估。结果遗传独特性随纬度的增加而下降，等位基因丰富度在意大利中部达到峰值。在遗传结构的复杂性上观察到一种从南到北的趋势，意大利半岛的特征是混杂的基因库，与北方种群表现出的相对同质性形成对比。人口统计学推断表明，自倒数第二个间冰期以来，南部的基因库在基因上就被隔离了，而意大利中部的人口在最后一个冰期期间在当地持续存在于一个小避难所的马赛克中。本研究结果揭示了南欧森林树木种群遗传结构的复杂性。在最后一个冰川期之后，至少有三个Q. robur的避难所对现存种群的遗传布局做出了贡献，但在意大利中部，避难所的数量可能更多。这种详细的特征揭示了在一个具有丰富多样遗传谱系的地区，为保护高度分散的刺柏种群而建立的优先事项。

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来源期刊

Diversity and Distributions 环境科学-生态学

CiteScore

8.90

自引率

4.30%

发文量

195

审稿时长

8-16 weeks

期刊介绍： Diversity and Distributions is a journal of conservation biogeography. We publish papers that deal with the application of biogeographical principles, theories, and analyses (being those concerned with the distributional dynamics of taxa and assemblages) to problems concerning the conservation of biodiversity. We no longer consider papers the sole aim of which is to describe or analyze patterns of biodiversity or to elucidate processes that generate biodiversity.