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

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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.