Abstract

Eucalyptus benthamii is a threatened species with a restricted range to the southwest of Sydney, Australia. One extant subpopulation is relatively secure within a closed water catchment in the Kedumba Valley. However, the other main subpopulation, which once probably had a more-extensive distribution along the Nepean River, is now fragmented due to clearing for agriculture and urban development. This has impacted on reproductive success and recruitment. Planting of trees in urbanised areas and other locations along the Nepean River has been ongoing for over 20 years and is an important circa situm conservation measure. Government policy has been to plant trees that are of local provenance, however it is difficult to know whether this policy has been properly implemented: it is possible that planting stock may have been sourced from the Kedumba subpopulation. Microsatellite markers were used to examine the probable origins and kinship of 133 planted trees from 15 planted sites around Camden, NSW. Population assignment confirmed that the majority of planted trees are probably from the local Nepean River subpopulation, although some were identified that are very likely to have originated from the Kedumba Valley. While the overall diversity of the planted trees is high, kinship within individual planted stands is often elevated, increasing the potential for inbreeding and limiting their usefulness as seed sources. This probably reflects seed sourced from a narrow genetic base. We discuss the findings and their implications in the context of the species’ management and conservation strategy.

中文翻译：

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新南威尔士州卡姆登（Carden NSW）种植的桉树本生树的起源：使用分子标记检查大约情景保存措施的有效性

摘要

桉树benthhamii是一种受威胁物种，范围在澳大利亚悉尼西南部。在肯杜巴河谷的一个封闭集水区中，一个现存的亚种群相对安全。但是，其他主要的子种群曾经可能在Nepean河沿岸分布更广泛，但现在由于农业和城市发展的清理而分散了。这影响了生殖的成功和招聘。在城市化地区和Nepean河沿岸其他地区植树已经进行了20多年，这是一个重要的时代保护措施。政府的政策一直是种植当地出产的树木，但是，很难知道这项政策是否得到了适当实施：种植种群可能来自肯敦巴亚群。微卫星标记用于检查来自新南威尔士州卡姆登市附近15个种植地点的133棵树木的可能起源和亲缘关系。人口分配证实，大部分植树可能来自当地的Nepean河子种群，尽管已确定其中一些很可能起源于Kedumba谷地。尽管植树的总体多样性很高，但各个植株中的亲缘关系常常得到提高，增加了近交的可能性，并限制了其作为种子来源的用途。这可能反映了来自狭窄遗传基础的种子。我们在物种的管理和保护策略的背景下讨论了发现及其含义。