Study shows that financial rewards boost quantity, while donations bring out rare species in biodiversity apps.

Osaka, Japan - Voluntary contributions from citizens are increasingly used to monitor biodiversity—but what motivates people to participate, and how do incentives influence the kind of data they provide? A new study led by The University of Osaka and the National Institute for Environmental Studies offers answers. Using a popular nature app, the researchers showed how different incentives influence user behavior—revealing new ways to support biodiversity conservation through citizen science.

The team analyzed the behavior of 830 users who agreed to participate in a randomized field experiment using Biome, a widely used Japanese smartphone app that allows users to post wildlife photos and automatically identifies species using AI.. Participants were divided into three groups: one received a small cash coupon for each post, another triggered a donation to an environmental organization, and the third received no reward. The experiment lasted up to one week per user. Results showed that cash incentives significantly increased the number of posts, while donation incentives led users to share less commonly observed species.

Users were randomly assigned to one of three groups:
(1) A financial group that earned 10 yen per post,
(2) A donation group (prosocial incentive) that triggered a 10-yen charitable contribution per post, and
(3) A control group with no incentive.

The researchers tracked the number of photos and the types of species submitted. “Rare” species were defined based on how infrequently they had been reported by other users on the app.

Results showed that cash incentives led to a significant increase in user activity, boosting the number of submitted posts by approximately 57% compared to the control group. In contrast, donation incentives did not increase the number of posts, but led users to share a higher proportion of rarely submitted species.

Accurate biodiversity monitoring requires both large amounts of data and coverage of less common species. With smartphones now in most people’s hands, citizen science platforms like Biome can crowdsource environmental data—if users stay engaged. This study is one of the first in the world to show, through real-world experimentation, how specific types of incentives affect both the quantity and quality of ecological data collection.

“Different incentives influence not just how much people post, but what they choose to post,” said lead author Shusaku Sasaki. “This insight can help design smarter citizen science programs that truly support biodiversity.”

These findings provide a roadmap for policymakers and organizations designing environmental campaigns. For example, cash incentives may work best when coverage volume is needed, while donation-based incentives can attract users who seek meaning and contribute rarer data. Companies could even use such schemes as part of their sustainability initiatives.

The study was published in Ecological Economics in April 2025 under the title “Prosocial and Financial Incentives for Biodiversity Conservation: A Field Experiment Using a Smartphone App” at DOI: https://doi.org/10.1016/j.ecolecon.2024.108506.