Ruiz Javier, Boucher Douglas H, Ruiz-Moreno Diego, Ingram-Flóres Cherryl
Department of Ecology and Evolutionary Biology, The University of Michigan, Ann Arbor, MI 48109, USA.
Rev Biol Trop. 2009 Mar-Jun;57(1-2):321-38. doi: 10.15517/rbt.v57i1-2.11324.
Seed production, seed dispersal and recruitment are critical processes in population dynamics, because they are almost never completely successful. We recorded the recruitment dynamics for the population of Dipteryx oleifera in a tropical rainforest in eastern Nicaragua (12 degrees 05' N., 83 degrees 55' W.) from March 2002 to August 2006. Seeds and seedlings had highly clumped distributions, while sapling distributions appeared to be random. Seedling survival increased away from the nearest conspecifc adult tree, where seedling density is lower. Since relative growth rates of seedlings are not correlated with the distance to the nearest conspecific adult, seedling survival appears to be independent of seedling growth. Seedling density is inversely correlated with seedling insect herbivory damage. Seedling survival correlated negatively with the number of saplings per sub-plot (10x10 m), suggesting that insect herbivore may also cue in on saplings rather than only on adult D. oleifera trees in order to locate seedlings. Seedling establishment is significantly clumped with respect to the nearest adult tree. Larger clumps of seedlings seems more ephemeral than isolated smaller clumps located away from the nearest D. oleifera tree. These results support current empirical evidence presented earlier for the Janzen-Connell hypothesis for Dipteryx oleifera at seed and seedling stages and, the Recruitment Limitation hypothesis at the sapling stage, because sapling individuals might have recruited after random light-gap formation.
种子生产、种子传播和更新补充是种群动态中的关键过程，因为它们几乎从未完全成功。我们记录了2002年3月至2006年8月间尼加拉瓜东部（北纬12度05分，西经83度55分）热带雨林中油楠种群的更新补充动态。种子和幼苗分布高度聚集，而幼树分布似乎是随机的。远离最近的同种成年树时，幼苗存活率增加，那里幼苗密度较低。由于幼苗的相对生长率与到最近同种成年树的距离无关，幼苗存活率似乎与幼苗生长无关。幼苗密度与幼苗遭受昆虫食草损害的程度呈负相关。幼苗存活率与每个小区（10×10米）内幼树数量呈负相关，这表明食草昆虫可能也会以幼树为线索，而不仅仅是油楠成年树，以便找到幼苗。幼苗更新补充相对于最近的成年树而言显著聚集。较大的幼苗丛似乎比远离最近油楠树的孤立较小幼苗丛更短暂。这些结果支持了之前提出的关于油楠种子和幼苗阶段的扬森-康奈尔假说以及幼树阶段的更新补充限制假说的现有实证证据，因为幼树个体可能是在随机形成林窗后更新补充的。
