Citizen science projects involve people who are not professional scientists in scientific research. A growing number of citizen science programs engage the public in observing nature using defined protocols, with projects ranging from monitoring the abundance of targeted species, to more detailed observations of organisms and their environments. I will use a case study approach to illustrate the scientific, science education and conservation value to public engagement in scientific research. In the Monarch Larva Monitoring Project (MLMP), scientists and citizen scientists work together to measure the distribution and abundance of monarch butterflies throughout the US. From 1997 to 2007, volunteers and participating scientists have monitored over 600 natural area, garden, roadside and agricultural sites in the US and Canada. These citizen scientists provide information that helps to conserve monarchs and their threatened migratory phenomenon, and advance our understanding of butterfly ecology, thus contributing to basic biological and conservation knowledge. For example, their data have helped us to understand interactions between monarchs and a tachinid fly parasitoid and basic details of monarch migration and breeding cycles.
Citizen science is not solely focused on obtaining answers to questions; it often combines research, education, community development and conservation outcomes. Citizen science programs provide venues in which non-scientists can engage in the processes of inquiry and discovery used by scientists to understand natural phenomena. This engagement helps to develop a more scientifically-literate public, thus increasing public support for science and, potentially, the number of individuals choosing careers in ecology. Citizen science may also provide broad conservation benefits by helping to develop a concerned and educated public that takes an active stewardship role in conservation. MLMP volunteers learn about the value and characteristics of monarch habitat, and work to preserve habitat at many levels, from advocating for more environmentally-friendly mowing regimes and insect-friendly pest control, to challenging development projects that threaten monarch habitat. Additionally, the MLMP and other citizen monitoring programs produce data with applied conservation value. Because so many conservation programs depend on understanding how human activities affect particular species, species assemblages, or populations, we often use monitoring data to assess the need for and success of conservation efforts.