Long-Term Impacts of Poaching on Relatedness, Stress Physiology, and Reproductive Output of Adult Female African Elephants
Long-Term Impacts of Poaching on Relatedness, Stress Physiology, and Reproductive Output of Adult Female African Elephants
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DOI：
10.1111/j.1523-1739.2008.01035.x
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发表时间：
2008-12-01
影响因子：
6.3
通讯作者：
Wasser, S. K.
中科院分区：
文献类型：
--
作者：
Gobush, K. S.;Mutayoba, B. M.;Wasser, S. K.
1989年象牙禁令之前的广泛偷猎通过减少老年成年雌性大象的数量，极大地改变了许多种群中母系非洲象(Loxodonta Africana)家庭群体的人口结构。我们通过调查1989年前坦桑尼亚Mikumi国家公园对非洲象种群的大量偷猎导致的混乱的社会结构的遗传、生理和生殖相关性，评估了偷猎的长期影响。我们检测了来自109组成年母象的218头成年母象的粪便糖皮质激素水平和生殖输出，这些母象在2003年至2005年的25个月内在大小、年龄结构和平均遗传亲缘关系上不同。自1989年以来，种群规模的分布几乎没有变化，但有长牙的老年母系家长的家庭数量增加了14.2%。缺乏年长母系长辈、一级成年亲属和较强社会联系的女性的粪便糖皮质激素值显著高于具有这些特征的女性(所有女性R(2)=0.31；多成年组女性R(2)=0.46)。经常去历史上偷猎风险较高的偏远地区的雌性比那些在偷猎低风险地区的女性有更高的粪便糖皮质激素值。弱结合和低群体亲缘关系的雌性生殖输出显著降低(R(2)[U]=0.21)。来自被破坏群体的雌性，被定义为观察到平均群体亲缘关系低于模拟未被偷猎家庭的预期平均值1SD，其生殖产出显著低于来自完整群体的雌性，尽管许多雌性处于生殖高峰期。这些结果表明，在1989年象牙禁令实施1.5年后，偷猎年迈的相关母象的长期负面影响在成年母象中持续存在。
Widespread poaching prior to the 1989 ivory ban greatly altered the demographic structure of matrilineal African elephant (Loxodonta africana) family groups in many populations by decreasing the number of old, adult females. We assessed the long-term impacts of poaching by investigating genetic, physiological, and reproductive correlates of a disturbed social structure resulting from heavy poaching of an African elephant population in Mikumi National Park, Tanzania, prior to 1989. We examined fecal glucocorticoid levels and reproductive output among 218 adult female elephants from 109 groups differing in size, age structure, and average genetic relatedness over 25 months from 2003 to 2005. The distribution in group size has changed little since 1989, but the number of families with tusked old matriarchs has increased by 14.2%. Females from groups that lacked an old matriarch, first-order adult relatives, and strong social bonds had significantly higher fecal glucocorticoid values than those from groups with these features (all females R(2) = 0.31; females in multiadult groups R(2) = 0.46). Females that frequented isolated areas with historically high poaching risk had higher fecal glucocorticoid values than those in low poaching risk areas. Females with weak bonds and low group relatedness had significantly lower reproductive output (R(2)[U] = 0.21). Females from disrupted groups, defined as having observed average group relatedness 1 SD below the expected mean for a simulated unpoached family, had significantly lower reproductive output than females from intact groups, despite many being in their reproductive prime. These results suggest that long-term negative impacts from poaching of old, related matriarchs have persisted among adult female elephants 1.5 decades after the 1989 ivory ban was implemented.