Scottish Oceans Institute & Centre for Research into Environmental and Ecological Modelling, University of St Andrews, St Andrews, United Kingdom.
PLoS One. 2010 May 27;5(5):e10761. doi: 10.1371/journal.pone.0010761.
Predators can have profound impacts on the dynamics of their prey that depend on how predator consumption is affected by prey density (the predator's functional response). Consumption by a generalist predator is expected to depend on the densities of all its major prey species (its multispecies functional response, or MSFR), but most studies of generalists have focussed on their functional response to only one prey species.
Using Bayesian methods, we fit an MSFR to field data from an avian predator (the hen harrier Circus cyaneus) feeding on three different prey species. We use a simple graphical approach to show that ignoring the effects of alternative prey can give a misleading impression of the predator's effect on the prey of interest. For example, in our system, a "predator pit" for one prey species only occurs when the availability of other prey species is low.
The Bayesian approach is effective in fitting the MSFR model to field data. It allows flexibility in modelling over-dispersion, incorporates additional biological information into the parameter priors, and generates estimates of uncertainty in the model's predictions. These features of robustness and data efficiency make our approach ideal for the study of long-lived predators, for which data may be sparse and management/conservation priorities pressing.
捕食者对猎物的动态有深远的影响，这取决于捕食者的消耗如何受到猎物密度（捕食者的功能反应）的影响。一般捕食者的消耗预计取决于其所有主要猎物物种的密度（其多物种功能反应或 MSFR），但大多数对一般捕食者的研究都集中在它们对一种猎物物种的功能反应上。
使用贝叶斯方法，我们根据在野外捕食三种不同猎物物种的鸟类捕食者（环颈雉 Circus cyaneus）的数据拟合了 MSFR。我们使用一种简单的图形方法来表明，忽略替代猎物的影响可能会对捕食者对感兴趣猎物的影响产生误导性的印象。例如，在我们的系统中，只有当其他猎物物种的供应不足时，一种猎物物种的“捕食者陷阱”才会出现。
贝叶斯方法有效地将 MSFR 模型拟合到野外数据中。它允许在模型中对过分散进行灵活建模，将额外的生物学信息纳入参数先验，并生成模型预测不确定性的估计。稳健性和数据效率这些特点使我们的方法非常适合研究寿命长的捕食者，因为这些捕食者的数据可能稀少，管理/保护重点紧迫。
