Linking seasonal shifts in the timing of species interactions to the dynamics of temporary pond communities

大多数物种的生命周期可以看作是一个季节性的时间表。生物生命周期中的重要事件，如发芽、开花、孵化和繁殖，都发生在一年中的特定季节和时间。这些事件发生的时间被称为物候学，它很重要，因为它决定了一个物种的个体在什么时候以及在哪个发育阶段与群落的其他成员相互作用。因此，物种之间的相互作用也遵循季节物候。物种物候不是恒定的，而是随着天气模式的变化（例如温度或降雨的变化）而逐年变化。因此，这些环境条件的变化也导致物种相互作用的季节时间的变化。虽然在自然群落中经常观察到物种相互作用物候的变化，但在研究自然生态群落的动态和结构时，它们通常被忽视。然而，物种的相互作用决定了自然群落和生态系统过程的结构和多样性。因此，了解物候变化如何影响物种相互作用对我们预测自然群落动态和功能的能力至关重要。这些知识对于预测环境变化如何影响生态系统服务也至关重要。拟议的项目将建立一个广泛的机制框架，以确定物种物候变化何时以及如何改变物种相互作用及其共存。研究者将在淡水群落中进行实验，并利用实验结果建立数学模型。由于环境变化，物种物候在全球范围内发生了明显的变化；因此，这项研究的结果将有助于预测这些变化的后果。此外，这项研究的发现可以指导在不断变化的世界中保护自然和农业生态系统的计划。该研究还将为本科生、研究生和早期职业科学家提供培训机会，包括来自科学界代表性不足群体的个人。该项目将采用一种综合方法，将在一个研究充分的池塘群落中进行的一系列实验与一般理论模型相结合。实验起着多重作用。他们将测试一种新的机制框架，预测相对物候的变化如何在一年/季节内改变物种的相互作用。（ii）这也将确定物候本身的变化（不仅仅是平均值）何时以及如何改变物种相互作用；（iii）确定物种人均相互作用强度之间的关键功能关系，以及这些关系如何被密度依赖过程和其他物种修改。最后，该实验将用于建立一般数学模型，以确定和预测物种物候的平均值和变化何时以及如何影响平稳和非平稳系统中群落和物种共存的长期动态。

The life cycle of most species can be view as a seasonal time table. Important events during the life cycle of organisms such as germination, flowering, hatching, and reproduction occurs during specific seasons and time of the year. The timing of these events, which is called phenology, is important because it determines when and at which developmental stage individuals of a species interact with other members of the community. Consequently, interactions among species also follow a seasonal phenology. Species phenologies are not constant but instead vary across years with changes in weather patterns (e.g. changes in temperature or rainfall). Thus, these changes in environmental conditions also lead to changes in the seasonal timing of species interactions. Although shifts in the phenology of species interactions are often observed in natural communities, they are typically neglected when studying the dynamics and structure of natural ecological communities. Yet, species interactions determine the structure and diversity of natural communities and ecosystem processes. Thus, understanding how changes in phenology affect species interactions is critical for our ability to predict the dynamics and functioning of natural communities. This knowledge is also essential to predict how environmental changes might affect ecosystems services. The proposed project will develop a broad, mechanistic framework to identify when and how variation in species phenologies will alter species interactions and their coexistence. The investigator will conduct experiments in freshwater communities and use the results to develop mathematical models. Phenologies of species are clearly changing globally as a result of environmental changes; thus, the results from this research will help anticipate the consequences of these changes. Furthermore, the findings of the study could guide plans to conserve natural and agricultural ecosystems in a changing world. The study will also provide training opportunities for undergraduate, graduate students, and an early career scientist, including individuals from underrepresented groups in the sciences.The project will use an integrative approach that combines a series of experiments in a well-studied pond community and general theoretical model. The experiments serve multiple roles. (i) They will test a new mechanistic framework that predicts how shifts in relative phenologies alter species interactions within a year/season. (ii) This will also determine when and how variation in phenologies per se (not just the mean) will alter species interactions and (iii) identify key functional relationship between species per-capita interaction strength, and how these are modified by density-dependent processes and other species. Finally (iv) the experiment will be used to develop general mathematical models which to determine and predict when and how shifts in mean and variation of species' phenologies affect long-term dynamics of communities and species coexistence in stationary and non-stationary systems.