Background/Question/Methods   Alpine plant communities are rare in New England. Arctic species like Diapensia lapponica reach the southern edge of their range here, while endemic populations of Geum peckii grow exclusively in New England and Nova Scotia. The limited alpine zone in New Hampshire may be especially susceptible to climate change. In response to this concern, the Appalachian Mountain Club began monitoring six alpine plant species five years ago. Tracking the reproductive phenology of alpine plants in established plots equipped with air and soil temperature probes, the AMC hopes to model how alpine flowers respond to temperature cues. To supplement the data collected by trained researchers, the AMC has enlisted the help of hikers. The AMC's Mountain Watch program follows a citizen-scientist model, with the organization providing outreach and education to volunteers who monitor alpine plant phenology across the White Mountains. Unlike other citizen science projects that aim to take advantage of local knowledge, Mountain Watch asks people who may not be familiar with the alpine zone to identify plant species that they may never have seen before. An assessment of the reliability of this volunteer-collected data is presented here, five years into the Mountain Watch project.

Results/Conclusions A survey of nineteen sites in the White Mountains revealed that volunteers may be overwhelmed by the program requirements. The AMC asks its citizen scientists to 1) recognize the target species 2) identify the phenological phases present 3) rate their confidence level regarding their identifications and 4) provide a precise written description of their location. A review of the first five years of citizen-science in the Mountain Watch program suggests three main sources of error. Imprecise location descriptions rendered over five hundred volunteer data sheets (of the 1775 total) from the Presidential Range unsuitable for mapping phenological changes. High rates of inaccuracies in species identification (averaging 33% of observations across all species) call into question the reliability of volunteer-collected data. Finally, volunteer bias towards the AMC's “celebrity” species, Diapensia, means that common but lesser known species are being overlooked. This review reiterates the importance of project design in citizen science. We hope to fine-tune the AMC's citizen science model in the alpine zone with the goal of producing more reliable data in the Mountain Watch program and informing the design of other citizen science projects.