Survival of Juvenile Giant Kelp: The Effects of Demographic Factors, Competitors, and Grazers
Survival of Juvenile Giant Kelp: The Effects of Demographic Factors, Competitors, and Grazers
复制标题
幼年巨型海带的生存：人口因素、竞争对手和食草动物的影响
DOI：
10.2307/1937552
复制
发表时间：
1989
期刊：
影响因子：
4.8
通讯作者：
Steven L. Lagos
中科院分区：
文献类型：
--
作者：
T. Dean;K. Thies;Steven L. Lagos
研究了巨藻幼体的存活模式与海胆取食、成年海带遮荫、新兵密度、其他藻种密度和底物分布的关系。在白色海胆(Lytechinus Anamesus)丰富的地区或有覆盖着成虫的树冠的地区，生存较差。在其他地点，新兵的密度解释了生存中最大的变异性，存活的幼虫比例与新兵数量呈负相关。潜在的藻类竞争对手(加州翼藻属和月国藻属)、红海胆(Strongyloctrotus Franciscanus)和底物分布对存活率没有显著影响。依赖密度生存的机制类似于解释许多陆地植物种群自我稀疏的“显性和抑制”模型。在新兵密度较高的林分中，出现了扭曲的大小分布，这可能是对光的竞争的结果。高密度林分比低密度林分拥有更多的小植物，在随后的暴风雨中，只有较大的植物存活下来。这导致幸存者的分配比根据招募人数所预期的更为公平。在大多数巨型海带种群中，种内相互作用，无论是成体和幼体之间的相互作用，还是同一队列中的幼体之间的相互作用，似乎都是重要的结构力量。在许多陆地种群中都有相似之处。然而，在其他藻类种群中，几乎没有证据表明死亡依赖于密度或支持优势抑制假说。这些差异可能与对光的竞争有关，这种竞争在大型囊藻森林和许多陆地种群中非常强烈，但在其他底栖藻类的组合中则不那么强烈。
Patterns of survival of juvenile giant kelp (Macrocystis pyrifera) were examined in relation to grazing by sea urchins, shading by adult kelp, density of recruits, densities of other algal species, and substrate distribution. Survival was poorer in areas where white sea urchins (Lytechinus anamesus) were abundant or where there was an overlying canopy of adults. At other sites, the density of recruits explained the greatest proportion of variability in survival, and the proportion of juveniles that survived was negatively correlated with the number of recruits. Potential algal competitors (Pterygophora californica and Cystoseira osmundacea), red sea urchins (Strongylocentrotus franciscanus), and substrate distributions had no significant effect on survival. The mechanisms of density—dependent survival were similar to "dominance and suppression" models that explain self—thinning in many terrestrial plant populations. In stands where densities of recruits were high, skewed size distributions developed, probably as the result of competition for light. High—density stands had proportionally more small plants than low—density stands, and, during subsequent storms, only the larger plants survived. This led to a more equitable distribution of survivors than would be expected based on the number of recruits. Intraspecific interactions, both between adults and juveniles and among juveniles of the same cohort, appear to be important structuring forces in most giant kelp populations. The parallels in many terrestrial populations. However, in other algal populations, there is little evidence for density—dependent mortality or for the dominance—suppression hypothesis. These differences may relate to competition for light, which is intense in Macrocystis forests and many terrestrial populations, but less so in assemblages of other benthic algae.