Citizen science (CS) can foster transformative impact for science, citizen empowerment and socio-political processes. To unleash this impact, a clearer understanding of its current status and challenges for its development is needed. Using quantitative indicators developed in a collaborative stakeholder process, our study provides a comprehensive overview of the current status of CS in Germany, Austria and Switzerland. Our online survey with 340 responses focused on CS impact through (1) scientific practices, (2) participant learning and empowerment, and (3) socio-political processes. With regard to scientific impact, we found that data quality control is an established component of CS practice, while publication of CS data and results has not yet been achieved by all project coordinators (55%). Key benefits for citizen scientists were the experience of collective impact (“making a difference together with others”) as well as gaining new knowledge. For the citizen scientists’ learning outcomes, different forms of social learning, such as systematic feedback or personal mentoring, were essential. While the majority of respondents attributed an important value to CS for decision-making, only few were confident that CS data were indeed utilized as evidence by decision-makers. Based on these results, we recommend (1) that project coordinators and researchers strengthen scientific impact by fostering data management and publications, (2) that project coordinators and citizen scientists enhance participant impact by promoting social learning opportunities and (3) that project initiators and CS networks foster socio-political impact through early engagement with decision-makers and alignment with ongoing policy processes. In this way, CS can evolve its transformative impact.

The functionality available on modern ‘smartphone’ mobile devices, along with mobile application software and access to the mobile web, have opened up a wide range of ways for volunteers to participate in environmental and biodiversity research by contributing wildlife and environmental observations, geospatial information, and other context-specific and time-bound data. This has brought about an increasing number of mobile phone based citizen science projects that are designed to access these device features (such as the camera, the microphone, and GPS location data), as well as to reach different user groups, over different project durations, and with different aims and goals. In this chapter we outline a number of key considerations when designing and developing mobile applications for citizen science, with regard to (1) Interoperability. The factors that influence the usability of the mobile application are covered in both (2) Participant Centred Design and Agile Development, and (3) User Interface and Experience Design. Finally, the factors that influence sustained engagement in the project are covered in (4) Motivational Factors for Participation.

With the boom in urban living has come a boom in urban gardening. In particular, urban community gardening is an increasingly popular form of horticultural production, community involvement and connection to nature. Through the establishment and management of community gardens, biodiversity can flourish, with community gardens as ‘hotspots’ of flora and fauna within the urban matrix. Gardeners can deeply connect with the natural elements of gardens and thus learn about and gain appreciation for the natural world. Such interactions can combat the loss of nature experiences in cities. Despite their benefits for nature and for people, community gardens are threatened ecosystems as often temporary fixtures in city landscapes due to lack of land tenure and policy protection. In this perspective, we recognize community gardens as an important ecosystem in urban conservation and argue for the defence of urban community gardens by city policy. We formalize this activity and the value of these ecosystems with scientific evidence from ecological and social‐ecological research in 39 community gardens in Berlin and Munich, Germany. Although our data reveal that these gardens support large amounts of biodiversity and catalyse human‐nature connections, a lack of comprehensive documentation of social‐ecological benefits at the city level can make community gardens vulnerable to urban planning threats; we have seen losses of multiple research sites in the last 4 years of biodiversity research. Policy implications: To protect community gardens now and for future urban generations, we call for systematic and comprehensive data collection on community gardening activities and policy support for these urban ecosystems. Some cities are starting to do this and this can be scaled out. We argue for the recognition of urban community gardens as a physical land use and also of the gardeners themselves as important habitat managers and stewards of urban biodiversity. Read the free Plain Language Summary for this article on the Journal blog.

The conservation of pollinators requires social understanding to catalyse restoration action. Citizen science (CS) is discussed as a way to promote interest and action for pollinating insects. Yet, the drivers behind pro-pollinator behaviour are largely unclear, especially in urban areas. To better understand public engagement in pollinator conservation, we studied urban community gardeners’ identity, nature-relatedness, emotions, and attitudes toward pollinators and their intentions to get involved in pro-pollinator behaviour in their gardening practice. We surveyed community gardeners in Berlin and Munich, Germany, some of which were participating in a citizen science project. In this scientific study, we created four different sets of generalized linear models to analyse how the gardeners’ pro-pollinator behaviour intentions and behaviour were explained by socio-psychological factors. The responses of 111 gardeners revealed that gardeners that were fascinated by pollinators, held positive attitudes and felt joy about seeing pollinators reported intentions to protect or support pollinators, suggesting that fascination and joy can be harnessed for research and conservation on pollinators. Similarly, joy about seeing pollinators predicted participation in the CS project. We believe that CS may represent a pathway through which urban residents may become key actors in conservation projects within their nearby greenspaces.

Apps for mobile devices and web-based platforms are increasingly used in citizen science projects. While extensive research has been done in multiple areas of studies, from Human-Computer Interaction to public engagement in science, we are not aware of a collection of recommendations specific for citizen science that provides support and advice for planning, design and data management of mobile apps and platforms that will assist learning from best practice and successful implementations. In two workshops, citizen science practitioners with experience in mobile application and web-platform development and implementation came together to analyse, discuss and define recommendations for the initiators of technology based citizen science projects. Many of the recommendations produced during the two workshops are applicable to citizen science project that do not use mobile devices to collect data. Therefore, we propose to closely connect the results presented here with ECSA’s Ten Principles of Citizen Science.