Citizen scientists play a pivotal role in providing necessary biodiversity data. To ensure the continued involvement of a strong volunteer base, insight into the concerns and motivations of voluntary recorders is crucial. This paper presents the findings of a largescale survey (N = 2193) among Dutch volunteer biodiversity recorders of diverse taxa, and focuses on three questions: what are the characteristics of these citizen scientists regarding their activities and socio-demographic background, what are their motivations for recording biodiversity, and what are their views on data sharing and ownership? Our findings show that a connection to, interest in and concern for nature are the most important motivations for biodiversity recorders. Volunteer recorders have high expectations regarding the impact of their data, both for their own learning as well as for science and management. Almost half the volunteers consider their data to be public goods, but this does not mean they support unconditional data sharing. Instead, the acceptability of data sharing with third parties seems strongly linked to the goals of the user. We discuss the implications of our findings for practitioners, such as the role of biology curricula and the importance of learning opportunities to redress the lack of younger volunteers. We argue that conceptualising volunteer recorders as data custodians rather than owners helps to Communicated by Peter Bridgewater.This article belongs to the Topical Collection: Biodiversity appreciation and engagement.Electronic supplementary material The online version of this article

a b s t r a c tWe calculated a Living Planet Index (LPI) for the Netherlands, based on 361 animal species from seven taxonomic groups occurring in terrestrial and freshwater habitats. Our assessment is basically similar to the global LPI, but the latter includes vertebrate species and trends in population abundance only. To achieve inferences on trends in biodiversity more generally, we added two insect groups (butterflies and dragonflies) and added occupancy trends for species for which we had no abundance trends available. According to the LPI, the state of biodiversity has slightly increased from 1990 to 2014. However, large differences exist between habitat types. We found a considerable increase in freshwater animal populations, probably because of improvement of chemical water quality and rehabilitation of marshland habitats. We found no trend in the LPI for woodland populations. In contrast, populations in farmland and open semi-natural habitats (coastal dunes, heathland and semi-natural grassland) declined, which we attribute to intensive agricultural practices and nitrogen deposition, respectively. The LPI shows that, even in a densely populated western European country, ongoing loss of animal biodiversity is not inevitable and may even be reversed if adequate measures are taken. Our approach enabled us to produce summary statistics beyond the level of species groups to monitor the state of biodiversity in a clear and consistent way.

Palabras Clave: aficionados, control de calidad, referencia en circulación, registro de la biodiversidad, validación de datos

Wildlife field guide books present salient features of species, from colour and form to behaviour, and give their readers a vocabulary to express what these features look like. Such structures for observation, or observational grids, allow users to identify wildlife species through what Law and Lynch have called ‘the difference that makes the difference’. In this article, we show how these grids, and the characteristics that distinguish species, change over time in response to wider concerns in the community that use and make the field guides. We use the development of Dutch field guides for dragonflies to show how the ethics of observing wildlife, the recreational value of dragonfly observation, the affordances of observational tools, and biodiversity monitoring and conservation goals all have repercussions for how dragonflies are to be identified. Ultimately, this affects not only how dragonflies are to be observed and identified, but also what is taken to be ‘out there’. The article is based on a transdisciplinary cooperation between a dragonfly enthusiast with emic knowledge and access, and an STS researcher. We hope the articulation of our approach might inspire analyses of other observational practices and communities.

Citizen science can be understood as an approach to scientific research in which volunteer contributors undertake work in one or more phases of the research process. Citizen science projects can be initiated by volunteers or institutional actors (e.g., scientists in academia), and volunteers often work together with professional researchers. In citizen science, participants are not just objects of research (e.g., interviewee or survey respondent) but also research subjects—that is, taking an active role in collecting data, analyzing data sets, contributing to study design, or disseminating results (or combinations of these tasks). Participants may have little background knowledge on the topic under study, or they might be amateur enthusiasts with a great deal of existing expertise. Citizen science projects aim for genuine science outcomes, which can include scientific data sets and publications, new discoveries, or policy or management action. Although citizen science projects are currently being developed and carried out in a wide variety of scientific fields, including medical biology (e.g., self-monitoring of disease symptoms), environmental science (e.g., monitoring air or water quality), history (e.g., archive transcription), and “citizen social science,” the field of biology especially has a long history of amateur involvement in research. Citizen science in this field often takes the form of collecting data on the natural world and submitting these data to biodiversity databases (e.g., reporting bird observations). In addition to collecting data, citizen scientists take up a large part of taxonomy, describing new species and rearranging, merging, and splitting species groups. Furthermore, citizen scientists are heavily involved in the verification process, checking on observations done by other citizen scientists and giving feedback, acting not only as gatekeepers toward data quality but also as authorities, educating the community. Biodiversity citizen science projects may involve monitoring of the natural world initiated by communities of natural history enthusiasts, but research institutes in the field of biology and ecology also increasingly mobilize volunteers to collect data about the natural environment. Compared to many other domains in which citizen science is being applied, biodiversity monitoring especially stands out for its long history of amateur involvement in natural history. Because initiating biodiversity citizen science projects will thus often mean that research and policy actors engage with volunteer-driven networks, understanding these networks aids effective and just design of biodiversity citizen science. Although engaging with these long-standing networks of natural history offers many opportunities, perspectives of professional ecological research and communities of practice can differ markedly. In the current state of affairs, scientific literature shows tensions between volunteers operating in their communities of practice and scientists operating in theirs. Among others, these differences involve the meaning of observations: Whereas in research these are given meaning by gathering them up and statistically analyzing the resulting data sets, within a community of practice observations predominantly reflect human–nature relationships and are shared with expectations of respectful use for the protection of nature. Not only can the meaning of observations differ but also the act of validation can refer to very different activities as well as to different aspects of quality of information. In the community of practice of observers in the field, validation plays an important role in establishing relations of trust and authority within the network, with a strong emphasis on correct observations and volunteers’ motivation for learning and belonging. Conversely, validation in the scientific practice of research concerns the structure of the monitoring protocol and the statistical demands placed on the data. For scientists and policymakers, respectful cooperation with networks of amateur biodiversity recorders requires taking their perspectives seriously and respecting their way of working and the communities they have built. It also requires citizen science organizers to think carefully about whose questions are being answered. For citizen scientists, understanding the (statistical) needs of scientists and the relevance for policy allows their network to grow through funding and training.