Spatial and Seasonal Patterns of Seed Dissemination of Cornus Controversa in a Temperate Forest
Spatial and Seasonal Patterns of Seed Dissemination of Cornus Controversa in a Temperate Forest
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温带森林中山茱萸种子传播的时空格局
DOI：
10.2307/1941595
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发表时间：
1994
期刊：
影响因子：
4.8
通讯作者：
T. Nakashizuka
中科院分区：
文献类型：
--
作者：
T. Masaki;Y. Kominami;T. Nakashizuka
在日本温带落叶林的两个结果季节中，研究了冠层树 Cornus controversa 种子传播的季节和空间模式。每两周在分布于 1 公顷研究地块（包括 12 颗成熟山茱萸）的种子收集器（N = 221）中监测种子掉落情况。预计年种子产量为 1.57 x 106 粒种子/公顷。这两年，在候鸟食果鸟类进入该地区之前，果实成熟高峰已经结束，只有17%的种子是由鸟类传播的。直接落下的种子放置在靠近母树的地方（通常在 10 m 以内，很少达到 35 m）。相比之下，鸟类传播的种子则表现出明显的分散分布；鸟类所吃的种子有一半以上是在距离树冠边缘>5 m处沉积的，鸟类传播的种子密度超过了距离>15 m处直接落下的种子的密度，有些距离最近的成熟山茱萸>40 m。此外，鸟类似乎选择性地吃含有可存活种子的水果。随着距果树距离的增加，鸟类传播种子的密度显着降低，无论是同种还是异种。距树冠间隙最近边缘的距离（已有数年历史）对鸟类传播种子的空间格局几乎没有影响。这意味着 C. conversa 的种子没有被鸟类定向传播到树冠间隙中。
Seasonal and spatial patterns of seed dissemination of a canopy tree Cornus controversa were studied over two fruiting seasons in a temperate deciduous forest in Japan. Seedfall was monitored every 2 wk in seed traps (N = 221) distributed over a 1—ha study plot that include 12 mature Cornus. Estimated annual seed production was 1.57 x 106 seeds/ha. In both years, the peak of fruit ripening had already ended before migratory frugivorous birds entered the area and only 17% of the seeds were disseminated by birds. Directly fallen seeds were deposited close to the parent trees (usually within 10 m, infrequently as far as 35 m from parent trees). In contrast, bird—disseminated seeds showed a markedly scattered distribution; the birds deposited more than half of the seeds they ate >5 m from the crown edge, and density of bird—disseminated seeds exceeded that of directly fallen seeds at distances >15 m, with some found >40 m from the nearest mature Cornus. In addition, birds seemed to selectively eat fruits that contained viable seeds. The density of bird—disseminated seed decreased significantly with increasing distance from fruiting trees, both conspecific and heterospecific. Distance to the nearest edge of canopy gaps that were several years old had little effect on the spatial pattern of bird—disseminated seeds. This means that seeds of C. controversa were not directionally dispersed into canopy gaps by birds.