Revealing receiver bias in the communication of mapped biodiversity patterns

Researchers often communicate knowledge about biodiversity, especially information about where species are likely to be found, through maps. However, readers do not necessarily interpret such maps in the way the authors intend. We assessed undergraduate students' interpretations of mapped biodiversity data with a mixed-method approach: a survey instrument was developed using writing and focus groups, then delivered to students enrolled in introductory biology courses at the University of Florida in the United States. Surveyed participants (N = 195) were presented with sets of maps for the Palamedes Swallowtail butterfly, Papilio palamedes, with three data visualization methods: point occurrences, expert-assessed range, and correlative distribution model results (distributional models were shown at high and low resolutions). Map interpretations were assessed by asking participants to rate the likelihood of finding a Palamedes Swallowtail at various point on each map and how confident they were in the information the map presented. They were also asked which map type they would most likely use to find a Palamedes Swallowtail. For distributional model maps, the effect of resolution on interpretation was assessed by asking participants to rate the perceived accuracy of each map, as well as their confidence in the data being presented. Participants most trusted in data provided via point maps compared to range and distributional model maps, and trusted point maps most among the three map types. For distribution maps, participants felt more certain in data presented to them via higher-resolution maps and interpreted them as being more accurate. This preference was especially pronounced for participants studying Science, Technology, Engineering, and Mathematics (STEM) fields compared to their non-STEM peers. Our findings suggest biodiversity researchers need to carefully consider symbol choice and resolution when transmitting information about species distributions.