Temporal dimension of indirect effects: Linking the order and spacing of phenologies to indirect interactions in seasonal communities.

The timing of seasonal life cycle events, such as when plants bloom or animals migrate, plays a vital role in shaping natural ecosystems. Changes in these seasonal patterns, whether due to natural variation or human influence, raise important questions about their effects on the relationships among species and the stability of natural communities. This project investigates how the timing of seasonal life cycles influences interactions among multiple species, especially those involving indirect effects, such as when one species impacts another through a shared predator or resource. Understanding these dynamics is crucial as ecosystems worldwide face rapid environmental changes. This project will also help predict the effects of shifting seasonal patterns on biodiversity, ecosystem stability, and services that benefit society. Members of the public will be engaged in the research through a citizen science initiative, and research training will be provided to undergraduate, graduate, and postdoctoral students. The proposed study will integrate experiments in amphibian pond communities with theoretical models to determine how variation in the sequence and spacing of phenologies of communities is linked to the dynamics of indirect interactions. First, the team will use a pair of complementary experiments that manipulate the sequence and spacing of phenologies of three amphibian species representing a classic one-predator two-prey interaction module. These experiments are designed to test competing hypotheses of how these critical aspects of temporal community structure are linked to the strength and direction of indirect interactions, and to identify the underlying mechanisms. Results from these experiments will guide the development of a temporally explicit community ecology model that incorporates seasonal variation in species’ presence, timing, density, and traits. This model will evaluate what factors can amplify or diminish the influence of indirect interactions and examine the short- and long-term consequences of these patterns across different systems. By linking empirical data with theoretical predictions, the research aims to provide a general framework for understanding how temporal structures shape the dynamics and stability of natural communities under changing environmental conditions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.