Acorn dispersal estimated by radio-tracking
Acorn dispersal estimated by radio-tracking
复制标题
DOI：
10.1007/s00442-007-0788-x
复制
发表时间：
2007-07
期刊：
影响因子：
2.7
通讯作者：
J. Pons;J. Pausas
中科院分区：
文献类型：
--
作者：
J. Pons;J. Pausas
鸟类传播的种子很难追踪，特别是在远距离传播的情况下。为了估计橡树的传播距离和欧洲松鸦（Garrulus glandarius）产生的种子阴影，我们在239橡子中插入无线电发射器，将它们放置在鸟类喂食器中，然后通过无线电跟踪定位它们。使用这种方法，我们找到了确切的缓存站点94 Quercus ilexand 54 Q。并确定了贮藏生境特征（植被类型、距离、空间分布）。结果表明：（1）不同种类或大小的橡子在扩散距离分布上没有差异，（2）扩散距离范围从大约3 m到大约550 m（平均值= 68.6 m;中值= 49.2米），（3）最近废弃的田野和森林轨道是松鸦储存橡子的首选地点，而避免了田地和灌木丛，以及（4）种子阴影显示了接近饲养者的橡子聚集区（即，贮藏的集群）以及较长距离处的孤立贮藏。研究结果还表明，无线电发射器是一种廉价和可靠的方式来确定种子阴影和量化种子传播和传播后的种子捕食中到大的种子。
Bird-dispersed seeds are difficult to track, especially in the case of long-distance dispersal events. To estimate the oak dispersal distance and the seed shadow generated by the European jay (Garrulus glandarius), we inserted radio-transmitters in 239 acorns, placed them in bird-feeders and then located them by radio-tracking. Using this methodology we located the exact caching site of 94Quercus ilexand 54Q. suberacorns and determined the caching habitat characteristics (vegetation type, distance, spatial distribution). The results show that: (1) there is no differences in the dispersal distance distribution between the different acorn species or sizes, (2) dispersal distances range from approximately 3 m up to approximately 550 m (mean = 68.6 m; median = 49.2 m), (3) recently abandoned fields and forest tracks were the sites preferred by jays to cache acorns, whereas fields and shrublands were avoided and (4) seed shadows showed acorn aggregation zones (i.e. clusters of caches) close to the feeder as well as isolated caches at longer distances. The results also suggest that radio-transmitters are a cheap and reliable way to determine seed shadows and quantify both seed dispersal and post-dispersal seed predation for medium to large seeds.