智利安第斯山脉中部种子扩散后捕食情况的多物种评估。
A multi-species assessment of post-dispersal seed predation in the central Chilean Andes.
作者信息
Muñoz Alejandro A, Cavieres Lohengrin A
机构信息
Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
出版信息
Ann Bot. 2006 Jul;98(1):193-201. doi: 10.1093/aob/mcl087. Epub 2006 May 10.
BACKGROUND AND AIMS
Post-dispersal seed predation in alpine communities has received little attention despite evidence that seeds removed by granivores can decrease plant recruitment into ecosystems. Moreover, few studies have assessed the effects of removal of seeds of a range of species after dispersal on the seeds remaining in ecosystems. A comparison was made of the magnitude of seed removal by ants and birds of nine different shrubby-, herbaceous- and cushion-plant species in the central Chilean Andes in order to assess the interactions between birds, ants and wind, and the types of seeds.
METHODS
A total of 324 soil-covered plates, each containing 50 seeds of one species, were placed in the field at an altitude of 2700 m and assigned to one of four treatments: control, exclusion of ants, birds, and both. The design also allowed the effects of wind to be assessed. Seed removal from plates was monitored over 20 d.
KEY RESULTS
Mean accumulative seed removal by granivores averaged over all nine species combined was 25%. However, large differences between species were evident, with limited seed removal (3-11%) in three herbaceous species (Alstroemeria pallida, Sisyrinchium arenarium, Pozoa coriacea), moderate (18-33%) in five species, including a shrub (Chuquiraga oppositifolia), two herbs (Taraxacum officinale, Rhodophiala rhodolirion), and two cushion-plants (Laretia acaulis, Azorella monantha), and substantial (78%) in the shrub Anarthrophyllum cumingii. The magnitudes of losses caused by birds compared with ants did not differ for the majority of species, although removal by birds was greater than by ants in A. cumingii, and smaller for C. oppositifolia.
CONCLUSIONS
Post-dispersal seed removal is shown to be an important cause of decreased potential plant species recruitment into alpine ecosystems. The substantial differences in the magnitude of seed losses to ants and birds demonstrate the need for evaluation of seed removal on a wide range of species in any given ecosystem.
背景与目的
尽管有证据表明食谷动物带走种子会减少植物在生态系统中的更新，但高山群落种子传播后的捕食情况鲜受关注。此外，很少有研究评估种子传播后多种物种种子被移除对生态系统中剩余种子的影响。对智利安第斯山脉中部9种不同的灌木、草本和垫状植物种子被蚂蚁和鸟类移除的程度进行了比较，以评估鸟类、蚂蚁和风以及种子类型之间的相互作用。
方法
在海拔2700米的野外放置了324个覆盖土壤的盘子，每个盘子装有50粒一种植物的种子，并分为四种处理之一：对照、排除蚂蚁、排除鸟类以及同时排除蚂蚁和鸟类。该设计还能评估风的影响。在20天内监测盘子中种子的移除情况。
主要结果
所有9种植物种子被食谷动物平均累计移除率为25%。然而，不同物种间差异明显，三种草本植物（白花六出花、砂生庭菖蒲、革质波佐花）种子移除率较低（3%-11%），五种植物（包括一种灌木逆叶楚葵、两种草本植物药用蒲公英、红杯仙茅，以及两种垫状植物无茎拉瑞阿、单花亚菊）种子移除率中等（18%-33%），灌木卡明无叶豆种子移除率较高（78%）。大多数物种中，鸟类和蚂蚁造成的种子损失程度没有差异，尽管卡明无叶豆中鸟类移除的种子比蚂蚁多，而逆叶楚葵中鸟类移除的种子比蚂蚁少。
结论
种子传播后被移除是高山生态系统中潜在植物物种更新减少的一个重要原因。蚂蚁和鸟类造成的种子损失程度存在显著差异，这表明在任何给定的生态系统中，都需要对多种物种的种子移除情况进行评估。
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