AI 中文总结
本研究拓展积分投影模型，构建含多物种、营养循环的模型，以黄石北部动物群数据验证，揭示捕食者对野牛及植被的影响，适用于生态管理与预测。
AI 中文摘要
将个体层面的过程（如存活与繁殖）与生态系统动态关联颇具挑战性，原因在于种群与物种间存在复杂相互作用，这类相互作用依赖于生物的年龄、体型、质量等性状，且受种群结构波动的影响。积分投影模型（IPMs）已深化了我们对连续性状种群结构所驱动的动态的认识，但这些模型仅应用于相对简单的系统，通常包含1至2个物种，仅覆盖自然食物网中部分营养级。我们从四个方面拓展了这类模型：其一，提出通用多物种积分投影模型，可将种群结构纳入初级生产者、初级消费者与次级消费者；其二，依据生物能学原理，将物种间的生物量流映射为生物个体内的分配流，用于维持生命、繁殖或生长，从而将个体层面过程与生态系统功能关联起来；其三，引入营养循环环节，分解者将有机物分解为养分，为植物生长提供支撑；其四，提供高效拟合算法，可结合种群数量时间序列对模型进行校准。我们以黄石国家公园北部的麋鹿、野牛、狼和美洲狮的数量为参数，对模型进行参数化与拟合，探究捕食者的灭绝与恢复所产生的影响。模型预测显示，捕食者移除后野牛数量下降，捕食者恢复后野牛数量回升，表明狼和美洲狮对黄石北部野牛数量的增加具有积极作用；同时，模型再现了捕食者对木本落叶植被更新的间接效应。该方法适用于各类生态系统，可应用于种群管理与生态预测领域。
英文摘要
Linking individual-level processes, such as survival and reproduction, to ecosystem dynamics is challenging due to interactions among populations and species. These interactions depend on organism traits, such as age, body size, and mass, and are influenced by fluctuations in population structure. Integral projection models (IPMs) have advanced our understanding of dynamics arising from population structure in continuous traits. Yet, these models have only been applied to relatively simple systems, featuring one or two species and spanning a fraction of the trophic levels observed in natural food webs. We extend these models in four ways. First, we provide a general multi-species IPM where population structure can be included in primary producers and primary and secondary consumers. Second, we link individual-level processes to ecosystem functioning by mapping fluxes of biomass between species to fluxes within individuals, using bioenergetic principles for allocation to maintenance, reproduction, or growth. Third, we introduce a nutrient recycling loop through which decomposers break down organic matter into nutrients that enable plant growth. Finally, we provide an efficient fitting algorithm to calibrate the model with time series of population sizes. We showcase our approach by parameterising and fitting the model to counts of elk, bison, wolves, and cougars in northern Yellowstone National Park to study the impact of predator extirpation and recovery. Our model predicts that bison decrease following predator removal and recover following predator recovery, suggesting a positive contribution of wolves and cougars to the increase of bison in northern Yellowstone. It also reproduces indirect effects of predators on woody deciduous vegetation regeneration. Our approach is suitable for a broad range of ecosystems, with applications for population management and ecological forecasting.
