Partitioning fish communities into guilds for ecological analyses: an overview of current approaches and future directions

A major strength of the guild approach is its ability to simplify community analysis by aggregating species with similar roles or functions into groups. These groups can be used to study a number of important ecological concepts, including functional diversity, community response to disturbance, and food-web dynamics. Despite increased use, guild membership can be based on subjective criteria that are arbitrarily chosen, leading to inconsistencies across studies. Additionally, studies using the guild approach generally ignore ontogenetic changes in diet and habitat use and therefore do not fully capture the complexity of aquatic communities. Although these issues have been discussed in the literature, much has changed since the last review was published a decade ago. In our examination, we discuss data requirements and consequences of data availability and reliability on guild formation. We identify bootstrapping and permutation techniques developed to address limitations through cluster validation and the identification of ontogenetic shifts prior to guild delineation. Lastly, we provide a step-by-step guide to guild analysis, accompanied by a decision tree, to facilitate objective and informed guild creation.