The role of parasites in the dynamics of a reindeer population
The role of parasites in the dynamics of a reindeer population
复制标题
DOI：
10.1098/rspb.2002.2064
复制
发表时间：
2002-08-07
影响因子：
4.7
通讯作者：
Halvorsen, O
中科院分区：
文献类型：
--
作者：
Albon, SD;Stien, A;Halvorsen, O
尽管理论模型表明寄生虫可能调节宿主种群密度，但很少有实证研究支持这一假设。我们提出了宿主-寄生虫相互作用的实验和观察证据，其中寄生虫对宿主种群动态的调节有足够的影响。在对斯瓦尔巴驯鹿及其胃肠道寄生线虫格鲁纳氏线虫的六年研究中，我们发现，与未经治疗的对照组相比，在4月至5月进行的驱虫治疗增加了驯鹿第二年生小牛的可能性。然而，治疗并没有影响驯鹿的越冬生存。寄生虫抑制繁殖力程度的年度变化与前一个10月的格鲁氏弧菌感染丰度呈正相关，而后者又与前两年的寄主密度相关。除了治疗效果外，冬季降水对母驯鹿生育小牛的概率也有很强的负影响。一个简单的矩阵模型参数化使用估计从我们的实验和观测数据。该模型表明，寄生物对繁殖力的影响足以调节驯鹿密度。
Even though theoretical models show that parasites may regulate host population densities, few empirical studies have given support to this hypothesis. We present experimental and observational evidence for a host-parasite interaction where the parasite has sufficient impact on host population dynamics for regulation to occur. During a six year study of the Svalbard reindeer and its parasitic gastrointestinal nematode Ostertagia gruehneri we found that anthelminthic treatment in April-May increased the probability of a reindeer having a calf in the next year, compared with untreated controls. However, treatment did not influence the over-winter survival of the reindeer. The annual variation in the degree to which parasites depressed fecundity was positively related to the abundance of O. gruehneri infection the previous October, which in turn was related to host density two years earlier. In addition to the treatment effect, there was a strong negative effect of winter precipitation on the probability of female reindeer having a calf. A simple matrix model was parameterized using estimates from our experimental and observational data. This model shows that the parasite-mediated effect on fecundity was sufficient to regulate reindeer densities around observed host densities.