Data from: Animals alter precipitation legacies: trophic and ecosystem engineering effects on plant community temporal dynamics

1. Multi-year precipitation ‘legacies’ can have stronger effects on plant community composition than rainfall in the current growing season, but variation in the magnitude of these effects is not fully understood. Direct interactions between plants and animals, such as herbivory, and indirect interactions, such as ecosystem engineering (via changes in the physical environment), may influence precipitation legacies by altering mechanisms of lagged effects. However, the role of direct and indirect plant-animal interactions in determining the strength of precipitation legacies remains largely unexplored. 2. Here, we investigated effects of current growing season rainfall and precipitation legacies on grassland composition, and the influence of herbivory and ecosystem engineering interactions on these temporal dynamics. From 2009 to 2014, a period spanning high and low rainfall, we recorded plant cover in kangaroo rat exclosures and paired control plots that included both burrow and inter-burrow areas. We used linear mixed effects modeling and analysis of community dissimilarities to evaluate plant composition responses to current and previous growing season rainfall and kangaroo rat herbivory (presence of seed foraging) and ecosystem engineering (burrowing). 3. We found that community composition was more strongly affected by precipitation legacies than by current growing season rainfall. Greater precipitation in the previous growing season enhanced grass cover and reduced forb and legume cover. Kangaroo rat trophic and engineering interactions had counteracting effects on these legacies. While burrowing increased grass cover and thereby amplified the effects of previous growing season rainfall on community composition, legacies were suppressed by the presence of kangaroo rat foraging, which decreased grass cover. Further analysis revealed that kangaroo rat foraging and burrowing had conflicting effects on residual plant biomass prior to the growing season, suggesting that precipitation legacies were influenced by altered litter dynamics. 4. Synthesis. Our study demonstrates that animals can impact the strength of precipitation legacies through direct and indirect interactions with the plant species that drive lag effects. The influence of multiple types of plant-animal interactions on precipitation legacies may be important to consider for ecosystem management and when generating predictions of community composition and productivity in future ecosystems.

1. 多年尺度的降水遗留效应（precipitation legacies）对植物群落组成的影响往往强于当前生长季的降雨，但这类效应的强度变异尚未得到充分阐明。植物与动物间的直接相互作用（如植食作用）以及间接相互作用（如通过改变物理环境的生态系统工程（ecosystem engineering）），可通过调控滞后效应的作用机制影响降水遗留效应。然而，直接与间接的动植物相互作用在决定降水遗留效应强度中的作用，仍基本未被探索。
2. 本研究探讨了当前生长季降雨与降水遗留效应对草原群落组成的影响，以及植食作用与生态系统工程相互作用对这类时间动态的调控效应。2009年至2014年（涵盖高降雨与低降雨年份），我们在更格卢鼠排除区及配对对照样地（包含洞穴区与洞穴间区域）中记录了植物盖度。我们采用线性混合效应模型与群落相异性分析，评估了植物群落组成对当前及既往生长季降雨、更格卢鼠植食作用（即种子觅食行为存在与否）与生态系统工程（即掘洞行为）的响应。
3. 研究结果表明，植物群落组成受降水遗留效应的影响强度显著高于当前生长季降雨。既往生长季降雨量越高，禾本科植物盖度越高，而非禾本科草本与豆科植物盖度则越低。更格卢鼠的营养级与工程学相互作用对这类降水遗留效应产生了拮抗调控：掘洞行为可提升禾本科植物盖度，从而放大既往生长季降雨对群落组成的影响；而更格卢鼠的种子觅食行为则通过降低禾本科植物盖度，抑制了降水遗留效应。进一步分析显示，更格卢鼠的觅食与掘洞行为对生长季前的残留植物生物量产生了相反的调控作用，这表明降水遗留效应受到枯落物动态改变的影响。
4. 研究总结：本研究证实，动物可通过与介导滞后效应的植物物种产生直接与间接相互作用，进而调控降水遗留效应的强度。在生态系统管理实践，以及预测未来生态系统的群落组成与生产力时，多类型动植物相互作用对降水遗留效应的影响值得重点关注。