Biodiversity citizen science projects are growing in number, size, and scope, and are gaining recognition as valuable data sources that build public engagement. Yet publication rates indicate that citizen science is still infrequently used as a primary tool for conservation research and the causes of this apparent disconnect have not been quantitatively evaluated. To uncover the barriers to the use of citizen science as a research tool, we surveyed professional biodiversity scientists (n = 423) and citizen science project managers (n = 125). We conducted three analyses using non-parametric recursive modeling (random forest), using questions that addressed: scientists' perceptions and preferences regarding citizen science, scientists' requirements for their own data, and the actual practices of citizen science projects. For all three analyses we identified the most important factors that influence the probability of publication using citizen science data. Four general barriers emerged: a narrow awareness among scientists of citizen science projects that match their needs; the fact that not all biodiversity science is well-suited for citizen science; inconsistency in data quality across citizen science projects; and bias among scientists for certain data sources (institutions and ages/education levels of data collectors). Notably, we find limited evidence to suggest a relationship between citizen science projects that satisfy scientists' biases and data quality or probability of publication. These results illuminate the need for greater visibility of citizen science practices with respect to the requirements of biodiversity science and show that addressing bias among scientists could improve application of citizen science in conservation.

Results from surveys to biodiversity scientists about research methods, preferences, and opinions about citizen science:Results of an online survey targeting biodiversity scientists (IRB approval 43438) to assess: (1) the extent to which citizen science data are presently used in their research, (2) perceptions of citizen science and its resultant data, and (3) requirements for methods and data (e.g. standardization, procedures, measure of error) when conducting their own biodiversity research. This survey contained 25 multi-part questions with binomial (yes/no), multiple choice (inclusive and exclusive), and Likert scale (e.g., strongly agree to strongly disagree) answers, as well as free responses to select prompts. We identified publishing biodiversity scientists using a Web of Science search, restricted to natural science, of corresponding authors of papers containing the word "biodiversity" in the title, abstract, or keywords; this yielded a pool of 3,148 scientists as potential survey respondents. We contacted the corresponding author of each publication by email; 423 scientists completed the survey.Results from surveys to biodiversity citizen science project managers:Results of an online survey targeting citizen science project managers (IRB approval 43438) regarding (1) project goals and details of project administration, (2) data collection protocols, and (3) participant demographics. This survey contained 32 multi-part questions (binomial, multiple choice, Likert scale, and free response); where applicable, we asked identical questions of both scientists (another dataset) and citizen science projects. We identified potential respondents from a database of biodiversity citizen science projects that aggregates projects from seven publicly available databases (see Theobald and Ettinger et al. 2015 for database details). Of these 388 projects, 329 were extant and had contact information 152 that enabled our communication with project managers via email at the time of survey administration. We received a total of 125 responses.

Supplement to: Burgess, Hillary K; DeBey, Lauren B; Froehlich, Halley E; Schmidt, Natalie; Theobald, Elinore J; Ettinger, Ailene K; HilleRisLambers, Janneke; Tewksbury, Josh; Parrish, Julia K (2016): The science of citizen science: Exploring barriers to use as a primary research tool. Biological Conservation, 208, 113-120