Associate Professor The University of British Columbia Vancouver, British Columbia, Canada
Background/Question/Methods
Phenological mismatch—the consequences of shifts in the timing of species interactions (i.e. asynchrony)—is a rapidly expanding area of research critical to predicting the consequences of climate change for communities and ecosystems. These mismatches—if present—are expected to have wide-reaching implications for ecosystem structure and functioning. However, after decades of theoretical and empirical studies, from single systems, we still have no general ability to predict the outcomes of phenological asynchrony due to climate change. We, along with others, have argued this failure is due to a disconnect between the underlying ecological theory (i.e., match-mismatch hypothesis) and the phenological responses to climate change currently documented. Despite these claims, no study has quantitatively assessed the evidence for the match-mismatch hypothesis. Here, we present the first meta-analysis of pair-wise trophic species interactions in terrestrial systems to evaluate evidence for the prevalence of negative fitness impacts of asynchrony. We also examine whether studies that meet the assumptions of the match-mismatch hypothesis are more likely to find a mismatch
Results/Conclusions
Our synthesis included 687 study-site-years from 20 studies, representing 26 interactions from 1960 and 2016.Despite a large range of synchrony to asynchrony to test the match-mismatch hypothesis within studies, we did not find general support for it. Across all interactions, the relationship between fitness and relative timing was linear rather than quadratic and we only found support for the hypothesis in 15% of the interactions. Our results suggest that this hypothesis is unlikely to be a widely applicable theory. Further, assumptions of the hypothesis were not always met. While a closer examination of studies suggests that some major assumptions appear more critical to finding evidence of mismatch than others, our results show that this hypothesis does not explain the key factors underlying the structure of pair-wise trophic interactions across many terrestrial systems. Given the complexity of ecological systems and the need to make accurate predictions about the impacts of climate change on biotic interactions, a greater mechanistic understanding of these factors is needed.
