Johnson Ladd E, Brawley Susan H
Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA, , , , , , US.
School of Marine Science, University of Maine, Orono, ME 04469-5722, USA, , , , , , US.
Oecologia. 1998 Dec;117(4):517-526. doi: 10.1007/s004420050688.
The daily settlement of eggs and zygotes of the monoecious brown alga Pelvetia compressa (J. Agardh) De Toni was measured on artificial substrata in areas inside and outside patches of adults in the high intertidal zone of central California. Settlement was generally 1-2 orders of magnitude higher under the adult canopy. This pattern seems to be due to the synchronous release of gametes during the daytime low tide. The release of gametes also appears periodic over longer time scales (e.g., 3- and 14-day cycles). In spite of the high availability of propagules under the adult canopy, juveniles were most abundant outside patches, where propagule availability was lower. In both areas, juveniles were disproportionately associated with patches of a red algal turf [primarily Endocladia muricata (Postels & Ruprecht) J. Agardh and Masticarpus papillata (C. Agardh) Kützing]. The turf, which is less common under the P. compressa canopy, may offer protection from dislodgment, grazing, and/or desiccation and thus facilitate recruitment at this site. Overall, post-settlement processes appear more important in determining population structure than does the availability of propagules in areas in and around patches of adults. However, the apparent small range of dispersal of P. compressa may make propagule availability an important limitation to the establishment of new populations and may restrict gene flow between populations.
在加利福尼亚中部潮间带高潮区成年藻丛内部和外部区域的人工基质上，对雌雄同体的褐藻扁叶海带（J. 阿加德）德托尼的卵和受精卵的每日沉降情况进行了测量。在成年藻冠层下方，沉降量通常要高1 - 2个数量级。这种模式似乎是由于配子在白天退潮时同步释放所致。配子的释放在更长的时间尺度上（例如3天和14天的周期）似乎也具有周期性。尽管成年藻冠层下方的繁殖体可利用性很高，但幼体在藻丛外部最为丰富，而那里繁殖体的可利用性较低。在这两个区域，幼体都不成比例地与一种红藻草皮斑块（主要是多刺内枝藻（波斯泰尔斯和鲁普雷希特）J. 阿加德和乳头粘皮藻（C. 阿加德）屈茨）相关联。这种草皮在扁叶海带藻冠层下方不太常见，可能提供了防止被冲走、被啃食和/或干燥的保护，从而促进了该地点的幼体补充。总体而言，沉降后过程在决定种群结构方面似乎比成年藻丛及其周围区域繁殖体的可利用性更为重要。然而，扁叶海带明显较小的扩散范围可能使繁殖体的可利用性成为新种群建立的一个重要限制因素，并可能限制种群之间的基因流动。
