Reol: R interface to the Encyclopedia of Life

The Encyclopedia of Life is a website that hosts information about life on Earth. Its mission is to increase awareness and understanding of living nature through a freely accessible digital source. Information is publicly available through graphical webpages (browser interface) or through an application programming interface (API). We developed Reol, an open-source package for the R environment, which downloads data from the EOL API, searches for and extracts specific information, and builds tables with quantitative data and/or hierarchical classifications. We provide a detailed description how Reol can be used as a bridge between the R environment and the EOL API to extract quantitative or hierarchical content. It will be particularly useful for researchers who want information about taxonomic groups of interest (for example: how much information is known about flatworm species? What are the taxonomic synonyms for bird species?) or construct a taxonomic tree. Reol is a tool for researchers who wish to download and gather data from EOL or its provider pages. We provide numerous functions within R for downloading, gathering data in different forms, creating taxonomic trees, and plotting data, which work with functions already available through various packages. It joins a growing body of R packages that interact with web-based APIs to streamline data acquisition, thereby easing the analysis of large publicly available datasets.