Asst. Professor of Biology St. Mary's College of California, California, United States
Abstract: Bioblitzes are biodiversity inventories of a focal area conducted during a short period of time and often involve substantial participation by non-scientists. If bioblitzes cause participants to observe nature more closely than they otherwise would, these events could increase both scientific and public knowledge of small organisms (e.g. invertebrates, nonvascular plants and fungi). We ask: do bioblitzes increase observations of lichens in ways that could enhance scientific knowledge of their distribution and abundance? Do bioblitzes increase participants’ awareness of these organisms and positively impact future observations? We addressed these questions using data from the City Nature Challenge (CNC), an annual global event in which “cities” compete to document biodiversity and increase public participation on iNaturalist, an online biodiversity observation platform. We analyzed 556 distinct CNC events from 2018-2022 to determine (1) how the CNC affected the observation of lichens on iNaturalist, (2) whether geographic region or length of time that a city has participated in the CNC affects lichen observation rates, and (3) whether CNC participants were more likely to observe lichens after the event. By comparing iNaturalist observations from participating CNC localities during each event to equivalent time periods two weeks before and after each event, we found that the number of lichen observations increased nearly ten-fold during CNC events relative to time periods before and after. This increased sampling resulted in three times more lichen-forming fungal taxa being recorded during CNC events. The fraction of iNaturalist observations that were of lichens was 21% higher during CNC events, suggesting that bioblitz participants may focus on these smaller organisms which they would otherwise not observe. This increased the total number of high-quality “research grade” observations nearly 10-fold during this time period, due to 6.7 times more users observing lichens during CNC events and a 19% increase in the fraction of lichen observations which were research grade. These preliminary results suggest that bioblitzes can significantly increase observation rates of small organisms in scientifically meaningful ways, but may not cause longer-term changes in participants’ behavior, as lichen observation rates were similar before and after CNC events. Forthcoming analyses of individual CNC participant behavior will further elucidate whether these events effectively increased public awareness and observation of lichens. Participation in the CNC by cities in regions where lichens are understudied has the greatest potential to positively impact scientific knowledge of these species’ distributions.
