INTRA-SPECIFIC COMPETITION AND DENSITY DEPENDENT JUVENILE GROWTH
INTRA-SPECIFIC COMPETITION AND DENSITY DEPENDENT JUVENILE GROWTH
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DOI：
10.1007/bf02459632
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发表时间：
1992-07-01
影响因子：
3.5
通讯作者：
JIA, L
中科院分区：
文献类型：
--
作者：
CUSHING, JM;JIA, L
推导和研究了一个由幼体和成体组成的半生型大小结构物种动力学的差分方程模型。成虫种群由两个大小类组成，一个较小的类和一个较大的更能生育的类。负反馈是由于幼虫在发育期间总的种群水平增加，从而导致成虫在成熟时变小，从而减缓了幼虫的生长。种内竞争系数是大小相关的，衡量青少年和成年人之间种内竞争的强度。结果表明，成虫和幼虫同时出现的平衡状态通常会因幼虫与成虫竞争的显著增加而不稳定，结果出现了稳定的周期循环，世代在时间上交替，从而避免了竞争。这一结果支持了这样一个原则，即青少年和成年人之间的种内竞争会破坏稳定。然而，这种不稳定原理的例外情况是，表现出非平衡、非周期性动态的种群可以通过增加幼虫和成虫之间的竞争来平衡。例如，当成虫的繁殖力和竞争系数明显依赖于大小类别时，就会发生这种情况。
A difference equation model for the dynamics of a semelparous size-structured species consisting of juvenile and adult individuals is derived and studied. The adult population consists of two size classes, a smaller class and a larger more fertile class. Negative feedback occurs through slowed juvenile growth due to increased total population levels during the developmental period and consequently a smaller adult size at maturation. Intra-specific competition coefficients are size dependent and measure the strength of intra-specific competition between juveniles and adults. It is shown that equilibrium states in which adults and juveniles occur together at all times are in general destabilized by significantly increased juvenile vs adults competition with the result that stable periodic cycles appear, in which the generations alternate in time and hence avoid competition. This result supports the tenet that intra-specific competition between juveniles and adults is destabilizing. Exceptions to this destabilization principle are found, however, in which populations exhibiting non-equilibrium, aperiodic dynamics can be equilibrated by increase competition between juveniles and adults. This occurs, for example, when adult fertility and competition coefficients are significantly size class dependent.