What controls the population dynamics of the invasive thistle Carduus nutans in its native range?
What controls the population dynamics of the invasive thistle Carduus nutans in its native range?
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DOI：
10.1111/j.1365-2664.2006.01228.x
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发表时间：
2006-10-01
影响因子：
5.7
通讯作者：
Shea, Katriona
中科院分区：
文献类型：
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作者：
Jongejans, Eelke;Sheppard, Andy W.;Shea, Katriona
1. 入侵的蓟Carduus nutans在美洲、澳大利亚和新西兰造成了重大经济损失。我们第一次在其原生地欧亚大陆模拟了其种群动态，在那里它很少达到有问题的密度，以便确定在入侵范围内改进这种杂草管理策略的方法。特别是，我们调查了蓟的原生范围内的专业敌人是否抑制了蓟的数量，正如敌人释放假说所预测的那样，如果是这样，这种影响如何与其他可能限制人口增长的因素联系起来。我们用三个法国人口的数据构建了人口转移矩阵模型。一项动态速率弹性分析表明，繁殖决定了33%至61%的种群预计增长率，因此是这种单果短寿多年生植物种群动态的关键驱动因素。所有三个种群的模型都预测了种群大小的减小（lambda < 1）。通过限制因子遗漏分析，我们发现，造成种子损失的本地食草昆虫对种子形成的影响大于绵羊的花环破坏和夏季干旱对种子形成的共同影响。去除食虫动物使本地种群增长率平均提高了166%；从模型中去除羊的伤害和夏季干旱使种群增长增加了51%。特殊食草动物和干旱协同作用影响繁殖。合成与应用。我们表明，在矩阵元素层面上，动态速率弹性分析比弹性分析提供了更多的管理信息，特别是当管理选项仅影响某些动态速率时。例如，它可以用来预测预传播植花动物在控制管理中的有效性。该模型还可以帮助确定通过综合杂草管理（例如通过防止过度放牧）减少幼苗建立概率来增强生物防治的方法。这种方法说明了如何利用入侵物种的本地范围研究来产生对入侵范围内种群管理的见解。
1. The invasive thistle Carduus nutans causes major economic losses in the Americas, Australia and New Zealand. For the first time, we have modelled its population dynamics in its native range, Eurasia, where it rarely reaches problematic densities, in order to identify ways to improve management strategies for this weed in the invaded range.2. In particular, we investigated whether specialist enemies in the thistle's native range suppress thistle populations, as predicted by the enemy-release hypothesis, and, if so, how this effect relates to other factors that may limit population growth.3. We constructed population transition matrix models with data from three French populations. A vital rate elasticity analysis revealed that reproduction determines between 33% and 61% of the projected growth rate of the populations, and thus is a key driver of the population dynamics of this monocarpic short-lived perennial.4. Decreases in population size were predicted by the models for all three populations (lambda < 1). Using limiting factor omission analyses, we showed that the suite of native insect herbivores causing seed losses had a larger impact than the joint effects of rosette damage by sheep and summer drought acting on seedling establishment. Removal of insect herbivores increased the native population growth rate by 166% on average; removal of sheep damage and summer drought from the model increased population growth by 51%. Specialist herbivores and drought interacted synergistically to affect reproduction.5. Synthesis and applications. We show that vital rate elasticity analysis provides more management information than elasticity analysis on the level of matrix elements, particularly when management options affect only certain vital rates. For example, it can be used to make predictions about the effectiveness of predispersal floral herbivores in control management. The model can also help identify ways in which biocontrol can be augmented using integrated weed management that reduces seedling establishment probabilities, for example by preventing overgrazing. This method illustrates how native range studies of invasive species can be used to generate insights into managing populations in the invaded range.