Fletcher W J
Institute of Marine Ecology, School of Biological Sciences, University of Sydney, 2006, N.S.W., Australia.
Oecologia. 1988 Mar;75(2):272-277. doi: 10.1007/BF00378608.
Regular monitoring of populations of the subtidal limpet Patelloida mufria (Hedley), which were at naturally large densities (>1000/m), showed that at the times when there were peaks in juvenile recruitment, the mortality of adults increased greatly. This produced a cyclical pattern in the density of adults, suggesting the juveniles play a partial regulatory role. Experimental manipulations were done to test the influence of overall density and the density of juveniles on the growth and survival of adults. These indicated that an increase in overall density reduced the rate of growth of individuals and increased the rate of adult mortality during the peaks in juvenile recruitment. Similarly, removing these juveniles as they recruited averted this decline in adult abundance. The proposed mechanism to explain these results is that the juveniles have a competitive advantage over adults as they are much smaller and therefore require less energy to survive. It is hypothesisied, therefore, that there will be a threshold of adult size below which the recruits will lose their competitive advantage. Furthermore, if their density became too great, the cover of crustose algae (which is the main food of this species) would be removed resulting in a rapid decline in the numbers of P. mufria. Such an occurrence could be the ultimate regulatory agent for this species.
对潮下笠贝Patelloida mufria（赫德利）种群进行定期监测，这些种群自然密度很大（>1000个/平方米），结果表明，在幼体补充量达到峰值时，成体的死亡率大幅上升。这在成体密度上产生了一种周期性模式，表明幼体起到了部分调节作用。进行了实验操作，以测试总体密度和幼体密度对成体生长和存活的影响。结果表明，总体密度的增加会降低个体的生长速度，并在幼体补充量达到峰值时提高成体死亡率。同样，在幼体补充时将其移除可避免成体数量的这种下降。用来解释这些结果的拟议机制是，幼体比成体具有竞争优势，因为它们体型小得多，因此生存所需能量更少。因此推测，成体大小存在一个阈值，低于这个阈值，新补充个体将失去竞争优势。此外，如果它们的密度变得过大，壳状藻类（该物种的主要食物）的覆盖层将被清除，导致mufria数量迅速下降。这种情况可能是该物种的最终调节因素。
