Temporal changes in fecundity and age at sexual maturity of southern elephant seals at Marion Island
Temporal changes in fecundity and age at sexual maturity of southern elephant seals at Marion Island
复制标题
马里恩岛南象海豹繁殖力和性成熟年龄的时间变化
DOI：
10.1007/s003000000217
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发表时间：
2001
期刊：
影响因子：
1.7
通讯作者：
F. Taylor
中科院分区：
文献类型：
--
作者：
P. Pistorius;M. Bester;S. Kirkman;F. Taylor
我们的目的是研究生殖参数的变化对马里恩岛南部象海豹的人口统计学的影响。我们使用特定年龄的捕获概率的繁殖女性在Cormack-Jolly-Seber的背景下，以获得生殖率。我们发现，成熟年龄下降，繁殖率增加，人口下降，表明补偿性反应。3岁儿童的生育率范围为0.03至0.29（平均值=0.16），4岁儿童为0.18至0.50（平均值=0.40），5岁儿童为0.28至0.50（平均值=0.45）。我们认为，相对增加的食物供应，伴随着人口的下降，促进性成熟与更快的增长少年人口丰度较低时，更早。这表明，繁殖力的相对重要性，在大象海豹种群调节被低估。此外，性成熟的开始似乎可能是第一个人口变量的变化，以应对人口密度的变化。
Our objective was to examine the effect of variation in reproductive parameters on the demography of southern elephant seals at Marion Island. We used age-specific capture probabilities of breeding females in a Cormack-Jolly-Seber context to derive reproductive rates. We found that age at maturity declined and fecundity rates increased as the population declined, indicating a compensatory response. Fecundity rates ranged from 0.03 to 0.29 among 3-year-olds (mean=0.16), 0.18 to 0.50 in 4-year-olds (mean=0.40), and 0.28 to 0.50 in 5-year-olds (mean=0.45). We think that a relative increase in food availability, concomitant with the population decline, promoted earlier sexual maturity correlated with more rapid growth of juveniles when population abundance was lower. It is suggested that the relative importance of fecundity in population regulation in elephant seals has been underestimated. Moreover, it appears that the onset of sexual maturity may be the first demographic variable to change in response to a change in population density.