Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
School of Bioscience, University of Skövde, Skövde, Sweden.
J Anim Ecol. 2019 Feb;88(2):196-210. doi: 10.1111/1365-2656.12892. Epub 2018 Sep 7.
Most ecosystem functions and related services involve species interactions across trophic levels, for example, pollination and biological pest control. Despite this, our understanding of ecosystem function in multitrophic communities is poor, and research has been limited to either manipulation in small communities or statistical descriptions in larger ones. Recent advances in food web ecology may allow us to overcome the trade-off between mechanistic insight and ecological realism. Molecular tools now simplify the detection of feeding interactions, and trait-based approaches allow the application of dynamic food web models to real ecosystems. We performed the first test of an allometric food web model's ability to replicate temporally nonaggregated abundance data from the field and to provide mechanistic insight into the function of predation. We aimed to reproduce and explore the drivers of the population dynamics of the aphid herbivore Rhopalosiphum padi observed in ten Swedish barley fields. We used a dynamic food web model, taking observed interactions and abundances of predators and alternative prey as input data, allowing us to examine the role of predation in aphid population control. The inverse problem methods were used for simultaneous model fit optimization and model parameterization. The model captured >70% of the variation in aphid abundance in five of ten fields, supporting the model-embodied hypothesis that body size can be an important determinant of predation in the arthropod community. We further demonstrate how in-depth model analysis can disentangle the likely drivers of function, such as the community's abundance and trait composition. Analysing the variability in model performance revealed knowledge gaps, such as the source of episodic aphid mortality, and general method development needs that, if addressed, would further increase model success and enable stronger inference about ecosystem function. The results demonstrate that confronting dynamic food web models with abundance data from the field is a viable approach to evaluate ecological theory and to aid our understanding of function in real ecosystems. However, to realize the full potential of food web models, in ecosystem function research and beyond, trait-based parameterization must be refined and extended to include more traits than body size.
大多数生态系统功能和相关服务都涉及营养层次上的物种相互作用，例如传粉和生物防治害虫。尽管如此，我们对多营养层次群落中的生态系统功能的理解还很有限，研究也仅限于小群落的操作或大群落的统计描述。食物网生态学的最新进展可能使我们能够克服机制理解和生态现实之间的权衡。分子工具现在简化了对摄食相互作用的检测，基于特征的方法允许将动态食物网模型应用于真实生态系统。我们首次测试了一种基于比例的食物网模型复制现场时间非聚集丰度数据的能力，并提供了对捕食作用功能的机制理解。我们旨在复制并探索在瑞典十个大麦田中观察到的麦长管蚜这种蚜虫食草动物的种群动态的驱动因素。我们使用了一个动态食物网模型，将观察到的捕食者和替代猎物的相互作用和丰度作为输入数据，使我们能够研究捕食作用在蚜虫种群控制中的作用。逆问题方法用于同时进行模型拟合优化和模型参数化。该模型在十个大麦田中五个的麦长管蚜丰度中捕获了超过 70%的变化，支持了模型所体现的假设，即身体大小可以成为节肢动物群落中捕食的一个重要决定因素。我们进一步展示了深入的模型分析如何能够分解功能的可能驱动因素，例如群落的丰度和特征组成。分析模型性能的可变性揭示了知识空白，例如偶发性蚜虫死亡率的来源，以及一般方法开发的需求，如果得到解决，将进一步提高模型的成功率，并使我们能够对生态系统功能进行更有力的推断。研究结果表明，用现场丰度数据来对抗动态食物网模型是一种可行的方法，可以评估生态理论，并帮助我们理解真实生态系统中的功能。然而，为了充分发挥食物网模型在生态系统功能研究及其他方面的潜力，基于特征的参数化必须得到完善和扩展，以包括比身体大小更多的特征。
