Botella Christophe, Bonnet Pierre, Hui Cang, Joly Alexis, Richardson David M
Centre for Invasion Biology (CIB), Department of Botany & Zoology, Stellenbosch University, Stellenbosch 7602, South Africa.
Botany and Modeling of Plant Architecture and Vegetation (AMAP), CIRAD, CNRS, INRAE, IRD, University of Montpellier, 34398 Montpellier, France.
Biology (Basel). 2022 Aug 30;11(9):1293. doi: 10.3390/biology11091293.
Plant invasions generate massive ecological and economic costs worldwide. Predicting their spatial dynamics is crucial to the design of effective management strategies and the prevention of invasions. Earlier studies highlighted the crucial role of long-distance dispersal in explaining the speed of many invasions. In addition, invasion speed depends highly on the duration of its lag phase, which may depend on the scaling of fecundity with age, especially for woody plants, even though empirical proof is still rare. Bayesian dynamic species distribution models enable the fitting of process-based models to partial and heterogeneous observations using a state-space modeling approach, thus offering a tool to test such hypotheses on past invasions over large spatial scales. We use such a model to explore the roles of long-distance dispersal and age-structured fecundity in the transient invasion dynamics of a woody plant invader in South Africa. Our lattice-based model accounts for both short and human-mediated long-distance dispersal, as well as age-structured fecundity. We fitted our model on opportunistic occurrences, accounting for the spatio-temporal variations of the sampling effort and the variable detection rates across datasets. The Bayesian framework enables us to integrate a priori knowledge on demographic parameters and control identifiability issues. The model revealed a massive wave of spatial spread driven by human-mediated long-distance dispersal during the first decade and a subsequent drastic population growth, leading to a global equilibrium in the mid-1990s. Without long-distance dispersal, the maximum population would have been equivalent to 30% of the current equilibrium population. We further identified the reproductive maturity at three years old, which contributed to the lag phase before the final wave of population growth. Our results highlighted the importance of the early eradication of weedy horticultural alien plants around urban areas to hamper and delay the invasive spread.
植物入侵在全球范围内造成了巨大的生态和经济损失。预测其空间动态对于制定有效的管理策略和预防入侵至关重要。早期研究强调了长距离扩散在解释许多入侵速度方面的关键作用。此外，入侵速度高度依赖于其滞后期的持续时间，这可能取决于繁殖力随年龄的缩放比例，特别是对于木本植物，尽管实证证据仍然很少。贝叶斯动态物种分布模型能够使用状态空间建模方法将基于过程的模型与部分和异质观测数据进行拟合，从而提供了一种工具来检验关于过去在大空间尺度上入侵的此类假设。我们使用这样一个模型来探讨长距离扩散和年龄结构繁殖力在南非一种木本植物入侵者的瞬态入侵动态中的作用。我们基于格网的模型考虑了短距离和人为介导的长距离扩散，以及年龄结构繁殖力。我们将模型拟合到机会性出现的数据上，考虑了采样努力的时空变化以及各数据集之间可变的检测率。贝叶斯框架使我们能够整合关于人口统计参数的先验知识并控制可识别性问题。该模型揭示了在第一个十年中由人为介导的长距离扩散驱动的大规模空间扩散浪潮以及随后的急剧种群增长，导致在20世纪90年代中期达到全球平衡。如果没有长距离扩散，最大种群数量将相当于当前平衡种群数量的30%。我们进一步确定了三岁时的生殖成熟度，这导致了在最终种群增长浪潮之前的滞后期。我们的结果强调了早期根除城市周边杂草丛生的园艺外来植物以阻碍和延缓入侵扩散的重要性。
