A major challenge faced by ecologists in the 21st century is to understand how biodiversity could be affected by global environmental change. This research requires large quantities of data on how the genetic, taxonomic and functional composition of communities is changing over space and time. For example, accurately observing and understanding climate change-induced latitudinal shifts in species distributions may require collecting data across thousands of kilometers. Citizen science has been proposed as a mechanism to gather large volumes of spatio-temporally extensive biodiversity data while simultaneously integrating public outreach into research. Consequently, there has been a proliferation of citizen science programs and similar partnerships between scientists and non-scientists; however, the efficacy of these programs in quantifying biodiversity has not been evaluated. To address this issue, we examined hundreds of citizen science programs that collect biodiversity data to ask: Are citizen science programs collecting biodiversity data across the world’s ecosystems and taxa, at scales relevant to address issues of environmental change?
Results/Conclusions
Our data suggest biases in environmental and taxonomic sampling of biodiversity: a major proportion of citizen science programs are collecting exclusively taxonomic diversity data (81%) in terrestrial environments (76%). Most citizen science programs operate at small scales (57% at less than 1,000 km) and most have started relatively recently (36% within the last 5 years). However, a number of programs collect data at larger space and time scales (8% collect at 10,000 km or greater; 9% have been around for longer than 15 years), allowing examination of biodiversity trends in response to larger scale problems, including biological invasions, pollution, land use change, and global climate change. For programs which report participation, 53,000 people have collected data (on average more than 1,000 people per program), suggesting that citizen science can result in data on scales simply unattainable by professionals. Citizen science data do not often result in peer-reviewed scientific papers (9% of sampled programs), suggesting underuse by the scientific community; although most citizen science programs make their data available online, and a substantial fraction have some method of data verification (57%), and standardized sampling effort (60%). It is clear that we must embrace and capitalize on the effort and expertise of citizen scientists to monitor, anticipate, and understand accelerating global change before it is too late. Our rapidly changing world calls for change in the way we address scientific and environmental problems.