Biological invasions are a major threat to biodiversity and have particularly devastating impacts on island ecosystems. The New Caledonia archipelago is considered a biodiversity hotspot due to its diverse native flora. Javan rusa deer (Rusa timorensis) were introduced to New Caledonia in 1870 and the population consists of several hundred thousand individuals today. They directly threaten rare endemic species and affect the composition and structure of the vegetation. While a rusa deer management plan has identified ten priority areas for deer control operations, removing deer could be offset by the dispersal of animals back into the control areas. Here, we genotyped 628 rusa deer using 16 microsatellite markers to analyse the genetic structure of the animals in New Caledonia. We aimed to assess fine-scale genetic structure, to identify natural barriers to deer movement and to assess functional connectivity by optimising individual-based landscape resistance models. Our results suggested that rusa deer formed a single genetic population on the main New Caledonian island. The isolation-by-distance pattern suggested that female dispersal was limited, whereas males had larger dispersal distances. We assessed functional connectivity using different genetic distance metrics and all models performed poorly (mR² ≤ 0.0043). Landscape features thus hardly affected deer movement. The characteristics of our results suggested that they were not an artefact of the colonisation history of the species. Achieving an effective reduction of deer population sizes in specific management areas will be difficult because of the deer’s high dispersal capabilities and impossible without very substantial financial investment.

生物入侵是对生物多样性的主要威胁，对岛屿生态系统的影响尤其严重。新喀里多尼亚群岛因其多样化的本土植物群而被认为是生物多样性热点。爪哇鲁萨鹿 (Rusa timorensis) 于 1870 年被引入新喀里多尼亚，如今其种群数量已达数十万头。它们直接威胁稀有特有物种并影响植被的组成和结构。虽然鲁萨鹿管理计划确定了鹿控制行动的十个优先领域，但将动物驱散回控制区域可能会抵消鹿的消失。在这里，我们使用 16 个微卫星标记对 628 只鲁萨鹿进行了基因分型，以分析新喀里多尼亚动物的遗传结构。我们的目的是评估精细的遗传结构，识别鹿运动的自然障碍，并通过优化基于个体的景观阻力模型来评估功能连接。我们的研究结果表明，鲁萨鹿在新喀里多尼亚主岛上形成了单一的遗传种群。距离隔离模式表明雌性的扩散是有限的，而雄性的扩散距离较大。我们使用不同的遗传距离指标评估功能连接，所有模型都表现不佳（mR ² ≤ 0.0043）。因此，景观特征几乎不影响鹿的活动。我们的研究结果的特征表明它们不是该物种殖民历史的产物。由于鹿的高度分散能力，在特定管理区域内实现鹿群数量的有效减少是很困难的，而且如果没有大量的财政投入就不可能实现。