Costs and benefits of masting: economies of scale are not reduced by negative density-dependence in seedling survival in Sorbus aucuparia.
Costs and benefits of masting: economies of scale are not reduced by negative density-dependence in seedling survival in Sorbus aucuparia.
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肥育的成本和效益：花梨幼苗存活的负密度依赖性不会降低规模经济。
作者：
Barbara Seget;M. Bogdziewicz;J. Holeksa;Mateusz Ledwoń;Fiona Milne;Łukasz Piechnik;Alicja Rzepczak;M. Żywiec
授粉是一种在植物中广泛使用的繁殖策略，有助于减少种子捕食和增加授粉。然而，肥大可能涉及成本，特别是负密度依赖(NDD)苗木存活，这是由于在间歇性事件中集中繁殖造成的。桅杆的益处得到了广泛的关注，但其成本还没有得到充分的研究，这使得人们无法理解为什么一些植物物种进化出密集的桅杆，而另一些植物则定期繁殖。我们跟踪观察了花椒的种子生产、种子捕食(均为13年)以及幼苗的招募和存活(11年)。我们测试了在壮年后幼苗存活的NDD是否会减少通过捕食者饱足而产生的脉冲繁殖的好处。在我们的种群中，种子捕食率是极端的(平均为75%)，但被母鱼减少了。普遍接受但未经检验的断言，即脉冲招募与强大的新城疫有关，这一断言没有得到支持。因此，幼苗存活第一年的比例随着水果产量的增加而增加。这为超越种子期的规模经济提供了一次罕见的考验。我们的结果提供了对桅杆播种成本的估计，并表明这些成本可能低于预期。较低的制桩成本，如果普遍的话，可能有助于解释为什么制桩在整个植物界是一种如此广泛的繁殖策略。
Masting is a widespread reproductive strategy in plants that helps to reduce seed predation and increase pollination. However, masting can involve costs, notably negative density-dependent (NDD) seedling survival caused by concentrating reproduction in intermittent events. Masting benefits have received widespread attention, but the costs are understudied, which precludes understanding why some plant species have evolved intense masting, while others reproduce regularly. We followed seed production, seed predation (both 13 years), and seedling recruitment and survival (11 years) in Sorbus aucuparia. We tested whether NDD in seedling survival after mast years can reduce the benefits of pulsed reproduction that come through predator satiation. Seed predation rates were extreme in our population (mean = 75%), but were reduced by masting. The commonly accepted, but untested, assertion that pulsed recruitment is associated with strong NDD was unsupported. Consequently, the proportion of seedlings that survived their first year increased with fruit production. This provides a rare test of economies of scale beyond the seed stage. Our results provide estimation of the costs of mast seeding, and indicate that these may be lower than expected. Low masting costs, if common, may help explain why masting is such a widespread reproductive strategy throughout the plant kingdom.