Data from: Varying levels of clonality and ploidy create barriers to gene flow and challenges for conservation of an Australian arid-zone ecosystem engineer, Acacia loderi

Acacia loderi, the ecosystem engineer of the endangered Acacia loderi Shrublands in arid eastern Australia, spans a persistent (> 15 000 year) but poorly studied landscape feature, the Darling River. We investigated the genetic structure of 19 stands of eight to > 1000 plants separated by < 300 km to test for variation in life histories between semi-arid and arid stands to the east and west of the Darling River, respectively. Eight of nine stands east of the Darling were exclusively sexual, whereas most of those to the west were clonal. Three western stands were monoclonal, two were polyploid, and one was a diverse mix of diploid and triploid phenotypes. Bayesian analysis revealed a complex genetic structure within the western stands, whereas the eastern stands formed only two genetic clusters. Conservation of small stands may require augmentation of genotypic diversity. However, most genotypic diversity resides within the eastern stands. Although arid zone stands of A. loderi are not always clonal, clonality and polyploidy are more common in the arid west. Clear demarcation of life histories either side of the Darling River may reflect ancient or contemporary effects of physical disturbance associated with the river channel, or cryptic environmental differences, with sexual and asexual reproduction, respectively, at a selective premium in the semi-arid east and arid west. The restricted distribution of clones and variation in clonality and polyploidy suggests that smaller stands may be vulnerable and warrant individual management.洛德勒金合欢（Acacia loderi）是澳大利亚东部干旱地区濒危洛德勒金合欢灌丛（Acacia loderi Shrublands）的生态系统工程师，其分布区域为存在超15000年但研究程度极低的达令河（Darling River）周边持久景观。本研究针对19个样地开展了遗传结构分析，这些样地包含8至1000余株植株，样地间距均小于300公里，旨在检验达令河东西两侧的半干旱与干旱样地在生活史特征上的差异。达令河东侧的9个样地中有8个完全仅进行有性繁殖，而西侧多数样地则以克隆繁殖为主。其中3个西部样地为单克隆种群，2个为多倍体种群，另有1个样地由二倍体与三倍体表型混合构成。贝叶斯分析（Bayesian analysis）结果显示，西部样地存在复杂的遗传结构，而东部样地仅形成两个遗传聚类簇。对小型样地的保育工作可能需要补充其基因型多样性，但绝大多数基因型多样性集中于东部样地。尽管洛德勒金合欢的干旱区种群并非均以克隆繁殖为主，但克隆繁殖与多倍体现象在西部干旱区更为普遍。达令河两岸生活史特征的清晰分界，可能反映了与河道相关的古老或当代物理扰动效应，或是隐性环境差异所导致的结果：半干旱东侧的有性繁殖具备选择优势，而干旱西侧则以无性繁殖占据选择优势。克隆种群的分布范围受限，加之克隆繁殖与多倍体现象存在变异，提示小型样地可能较为脆弱，需开展针对性的个体管理。