Creese R G
Department of Zoology, School of Biological Sciences, University of Sydney, 2006, N.S.W., Australia.
Oecologia. 1980 May;45(2):252-260. doi: 10.1007/BF00346466.
Notoacmea petterdi occurs only on vertical surfaces at the highest levels on the shore. On a given surface, density of limpets decreases with increasing height. Mean and maximum sizes of limpets increase with increasing height, due to faster rates of growth at higher levels where densities are lower. Rates of mortality are also negatively correlated with height on the shore, and are therefore generally less at higher levels. Both adult and juvenile limpets exhibit well-developed homing behaviour. There is no evidence of seasonal migrations, density-dependent migrations, nor gradual upward migrations as limpets grow older.Hypotheses are formed on the basis of these preliminary observations and measurements. Results of subsequent experimental manipulations of densities support the hypothesis that density-dependent mortality, due to intraspecific competition, plays a major role in regulating population densities of this limpet. It is also suggested that the pattern of settlement of juvenile limpets is the major factor that determines the limits to the vertical distribution of this species.
彼得氏背石鳖仅出现在海岸最高处的垂直表面。在给定的表面上，帽贝的密度随高度增加而降低。帽贝的平均大小和最大大小随高度增加而增大，这是因为在密度较低的较高位置生长速度更快。死亡率也与海岸上的高度呈负相关，因此通常在较高位置较低。成年和幼年帽贝都表现出发达的归巢行为。没有证据表明存在季节性洄游、密度依赖性洄游，也没有证据表明帽贝随着年龄增长会逐渐向上洄游。基于这些初步观察和测量结果形成了假设。随后对密度进行实验操作的结果支持了这样的假设，即由于种内竞争导致的密度依赖性死亡率在调节这种帽贝的种群密度中起主要作用。还表明，幼年帽贝的定居模式是决定该物种垂直分布范围的主要因素。
