Ecology. 2014 Apr;95(4):952-62. doi: 10.1890/13-0580.1.
Long-distance seed dispersal (LDD) is considered a crucial determinant of tree distributions, but its effects depend on demographic processes that enable seeds to establish into adults and that remain poorly understood at large spatial scales. We estimated rates of seed arrival, germination, and survival and growth for a canopy tree species (Miliusa horsfieldii), in a landscape ranging from evergreen forest, where the species' abundance is high, to deciduous forest, where it is extremely low. We then used an individual-based model (IBM) to predict sapling establishment and to compare the relative importance of seed arrival and establishment in explaining the observed distribution of seedlings. Individuals in deciduous forest, far from the source population, experienced multiple benefits (e.g., increased germination rate and seedling survival and growth) from being in a habitat where conspecifics were almost absent. The net effect of these spatial differences in demographic processes was significantly higher estimated sapling establishment probabilities for seeds dispersed long distances into deciduous forest. Despite the high rate of establishment in this habitat, Miliusa is rare in the deciduous forest because the arrival of seeds at long distances from the source population is extremely low. Across the entire landscape, the spatial pattern of seed arrival is much more important than the spatial pattern of establishment for explaining observed seedling distributions. By using dynamic models to link demographic data to spatial patterns, we show that LDD plays a pivotal role in the distribution of this tree in its native habitat.
长距离种子扩散（LDD）被认为是树木分布的关键决定因素，但它的影响取决于使种子能够成功发育成成体的种群动态过程，而这些过程在大的空间尺度上仍了解甚少。我们在一个从常绿森林（该物种丰度高）到落叶林（该物种极其稀少）的景观中，对一种树冠树种（Miliusa horsfieldii）的种子到达率、萌发率、存活率和生长率进行了估计。然后，我们使用个体基础模型（IBM）来预测幼树的建立，并比较种子到达和建立在解释观察到的幼苗分布中的相对重要性。远离源种群的落叶林中的个体由于在同种几乎不存在的生境中，经历了多种好处（例如，萌发率提高，幼苗存活率和生长率提高）。这些种群动态过程在空间上的差异的净效应显著提高了远距离散布到落叶林中的种子的幼树建立概率。尽管在这种生境中的建立率很高，但由于从源种群远距离到达的种子数量极低，Miliusa 在落叶林中仍然很少见。在整个景观中，种子到达的空间格局对于解释观察到的幼苗分布比建立的空间格局更为重要。通过使用动态模型将种群动态数据与空间格局联系起来，我们表明 LDD 在该树种在其原生栖息地的分布中起着关键作用。
