Ward Samuel F, Riggins John J
Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS 39762 USA.
Biol Invasions. 2023 Apr 27:1-15. doi: 10.1007/s10530-023-03069-5.
The rate at which invading organisms disperse into novel habitats is fundamental to their distribution and abundance. Forecasts of spread often assume that invasion speed is constant through time and among directions but, depending on the extent to which this assumption is violated, the efficacy of delimitation surveys and eradication programs could suffer. Knowledge of the mechanisms underlying spatiotemporal variation in spread could help refine forecasts and guide management, particularly in the early stages of invasions. We investigated rates of spread by laurel wilt, one of the most damaging non-native forest pests in North America, using three standard approaches (effective range radius, distance regression, and boundary displacement) and evaluated the strength and drivers of variation in directional spread (i.e., anisotropy). Estimates of mean annual spread varied from 24 to 40 km/yr, but spread was highly anisotropic with invasion speeds reaching approximately 100 km/yr south, 80 km/yr west, and 50 km/yr north, a pattern that we attribute to the abundance of host redbay trees and warmer temperatures fostering rapid southern and western spread. This pattern-quicker spread of laurel wilt from the point of introduction into areas forecasted as highly suitable for its persistence-suggests that establishment location might have a major influence on rates of anisotropy. Our findings underscore the utility of habitat suitability modeling-in which host availability and suitable climate are widely used to forecast establishment risk-for identifying areas into which spread will proceed most rapidly following establishment of a new invader and/or a satellite population via a long-distance dispersal event.
The online version contains supplementary material available at 10.1007/s10530-023-03069-5.
入侵生物扩散到新栖息地的速度对其分布和丰度至关重要。扩散预测通常假定入侵速度在时间和方向上是恒定的，但根据这一假设被违背的程度，划定调查和根除计划的效果可能会受到影响。了解扩散时空变化背后的机制有助于改进预测并指导管理，特别是在入侵的早期阶段。我们使用三种标准方法（有效范围半径、距离回归和边界位移）研究了月桂枯萎病（北美最具破坏性的非本地森林害虫之一）的扩散速度，并评估了方向扩散（即各向异性）变化的强度和驱动因素。年平均扩散估计值在24至40公里/年之间，但扩散具有高度各向异性，向南的入侵速度约为100公里/年，向西为80公里/年，向北为50公里/年，我们将这种模式归因于寄主红海湾树的丰富以及温暖的温度促进了向南和向西的快速扩散。这种模式——月桂枯萎病从引入点更快地扩散到预测非常适合其持续存在的地区——表明建立地点可能对各向异性速率有重大影响。我们的研究结果强调了栖息地适宜性建模的实用性——在该模型中，寄主可用性和适宜气候被广泛用于预测建立风险——用于识别新入侵者和/或卫星种群通过长距离扩散事件建立后扩散将最快进行的区域。
在线版本包含可在10.1007/s10530-023-03069-5获取的补充材料。
