We have faced a number of recurring ontology-related challenges in our ongoing work aimed at extracting structured data from taxonomic treatments and other sources; representing this data in RDF; providing and curating ontological infrastructure for reasoning over this data; and integrating this data into an open biodiversity knowledge graph. We will describe some of the challenges that we have overcome, and some that we continue to struggle with. These include issues with representing and integrating data about phenotypes, habitats, phenology, and establishment means (native vs. introduced). We will also describe the structure of our biodiversity knowledge graph, and invite collaboration in its continued construction.

RDF = Resource Description Framework