García C, Jordano P, Godoy J A
Integrative Ecology Group, Estación Biológica de Doñana, CSIC, Pabellón del Perú, Avda. María Luisa, s/n, E-41013 Sevilla, Spain.
Mol Ecol. 2007 May;16(9):1947-55. doi: 10.1111/j.1365-294X.2006.03126.x.
Pollination and seed dispersal determine the spatial pattern of gene flow in plant populations and, for those species relying on pollinators and frugivores as dispersal vectors, animal activity plays a key role in determining this spatial pattern. For these plant species, reported dispersal patterns are dominated by short-distance movements with a significant amount of immigration. However, the contribution of seed and pollen to the overall contemporary gene immigration is still poorly documented for most plant populations. In this study we investigated pollination and seed dispersal at two spatial scales in a local population of Prunus mahaleb (L.), a species pollinated by insects and dispersed by frugivorous vertebrates. First, we dissected the relative contribution of pollen and seed dispersal to gene immigration from other parts of the metapopulation. We found high levels of gene immigration (18.50%), due to frequent long distance seed dispersal events. Second, we assessed the distance and directionality for pollen and seed dispersal events within the local population. Pollen and seed movement patterns were non-random, with skewed distance distributions: pollen tended moved up to 548 m along an axis approaching the N-S direction, and seeds were dispersed up to 990 m, frequently along the SW and SE axes. Animal-mediated dispersal contributed significantly towards gene immigration into the local population and had a markedly nonrandom pattern within the local population. Our data suggest that animals can impose distinct spatial signatures in contemporary gene flow, with the potential to induce significant genetic structure at a local level.
授粉和种子传播决定了植物种群中基因流动的空间格局，对于那些依赖传粉者和食果动物作为传播媒介的物种来说，动物活动在决定这种空间格局中起着关键作用。对于这些植物物种而言，所报道的传播模式以短距离移动为主，且伴有大量的迁入现象。然而，对于大多数植物种群来说，种子和花粉对当代总体基因迁入的贡献仍缺乏充分的记录。在本研究中，我们在一个当地的马哈利樱桃（Prunus mahaleb (L.)）种群中，于两个空间尺度上调查了授粉和种子传播情况，该物种由昆虫授粉并由食果脊椎动物传播种子。首先，我们剖析了花粉和种子传播对来自集合种群其他部分的基因迁入的相对贡献。我们发现由于频繁的长距离种子传播事件，基因迁入水平很高（18.50%）。其次，我们评估了当地种群内花粉和种子传播事件的距离和方向性。花粉和种子的移动模式是非随机的，距离分布呈偏态：花粉倾向于沿接近南北方向的轴移动达548米，种子则传播达990米，且经常沿西南和东南轴传播。动物介导的传播对当地种群的基因迁入有显著贡献，并且在当地种群内具有明显的非随机模式。我们的数据表明动物能够在当代基因流动中施加独特的空间特征，有可能在局部水平上诱导显著的遗传结构。
