Many researchers hypothesize that climate change will lead to phenological mismatches—where the timing of critical life history events between interacting species becomes de-synchronized. Mismatches may lead to negative consequences for the interacting species and their ecological communities. Yet, evidence documenting negative impacts on fitness is mixed. The most common ecological hypothesis that underlies these studies, the Cushing match-mismatch hypothesis, offers testable assumptions and predictions. Combined with a system’s pre-climate change baseline, the hypothesis can predict the consequences of desynchronized phenology due to climate change. Yet to date, there are few robust predictions. Using a systematic literature review, here we explore whether the difficulty in predicting the consequences of climate change-driven shifts in synchrony is due to a disconnect between ecological theory and current empirical approaches.
Results/Conclusions
Our search yielded 43 observational phenological mismatch studies that encompassed terrestrial, marine and freshwater ecosystems as well as a wide latitudinal gradient. We found that none of the studies collected the data required to provide strong tests of this major hypothesis, making it difficult to assess support for it. Further, 74% of studies fail to define pre-climate change baselines in their study system, making predictions about climate change impacts on consumer fitness difficult. We outline how new research that relates empirical observations to underlying mechanisms can provide improved tests of this hypothesis. We highlight how improved approaches—including experiments that clearly link timing to fitness and test extremes, integration across approaches, and null models—could rapidly advance our mechanistic understanding and thus allow robust predictions of shifts with continuing climate change.