A review of the methods for studying biotic interactions in phenological analyses

Abstract

Phenological events play a key role modulating ecosystem services; however, the complex and interlinked nature of ecosystems indicates that interactions among different taxa during phenological events can have consequences for the entire ecosystem. Currently, there is a lack of a unified criteria on the methodologies studying phenology and biotic interactions. We performed an extensive integrative review of works evaluating phenology and biotic interactions. We identified four broad categories of studies that have explored biotic interactions within phenology research: (a) spatial and temporal asynchronies, (b) biotic factors as covariates, (c) simulation studies and (d) interaction indices. We found that spring phenology has received much more attention than any other season, while mutualistic and obligated interactions, as well as trophic interactions and networks have been explored more routinely than facilitation or competition. Authors tend to interpret coexistence among species as biotic interactions without any direct measurement, particularly in spatial and temporal asynchrony studies, but this also occurs to a certain extent in all categories. We also found a lack of formal examination in most studies exploring phenological mismatches in response to climate change. We propose a conceptual framework for the inclusion of phenology in the study of biotic interactions that apportions research into the conceptualisation and modelling of biotic interactions. Conceptualisation explores phenological data, types of interactions and the spatiotemporal dimensions, which all determine the representation for biotic interactions within the modelling framework, and the type of models that are applicable. Finally, we identify emerging opportunities to investigate biotic interactions in phenology research, including spatially and temporally explicit species distribution models as proxies for phenological events and the combination of novel technologies (e.g. acoustic recorders, telemetry data) to quantify interactions.