Vascular epiphytes are a striking feature from tropical forests and they are most diverse in the Neotropics. As a structurally dependent group, they rely on their host for support. Although epiphyte diversity is insufficiently studied, it is predominantly explored at the tree and the site scales. The first evaluation of vertical epiphyte distribution determinants on a tree dates to 1925; forty years later, variables determining local diversity were assessed across forest types for the first time. Studies at these scales characterize the body of literature on epiphyte research, but new approaches have emerged in the last years. Still, we lack a current synthesis to address knowledge gaps and new research directions.

We summarize the current knowledge of epiphyte diversity at the tree and local scale based on scientific literature and our shared experience and understanding, focused mainly on the last ten years. This review uses two modern tools: the ResearchRabbit app, a novel way to search for papers and authors and visualize research landscapes, and a combined text mining approach with a joint cluster-ordination to categorize the current literature into relevant literature research clusters. We focus on the last ten years and elaborate on the most critical research axes of epiphyte diversity at the tree and local scales. There are known patterns at the tree and local scale, and the effects of tree and site on epiphyte diversity are intertwined. With this comparative overview of current studies, we want to show the development in the field and point to future research directions.