Students as citizen scientists: project-based learning through the iNaturalist platform could provide useful biodiversity data

Abstract

In a time when much of the world has a smartphone, almost everyone can contribute to biodiversity data. The current rate of species loss has been qualified as the sixth mass extinction, and conservation actions, such as protecting important areas for biodiversity and increasing awareness, demand public engagement to advance scientific knowledge. Using smartphone apps to document the location of species and species distribution change through space and time is incredibly useful. In this context, data on species detection represent the most basic evidence to recognize biodiversity patterns and trends. This citizen science data can help support scientific measurements to track anthropogenic effects on species and track ecological processes, such as migration, dispersion, and local extinction in biological communities over time. A central issue when making biodiversity assessments is that many organisms are rare and in many parts of the planet the biota is unknown (Petersen et al. 2021). In cases where species are rare, it is difficult to combat extinction because the data is lacking, creating a geographic or Wallacean shortfall (Whittaker et al. 2005; Oliveira et al. 2016). This gap raises a tricky question: ‘How many ecologists do we need to survey biodiversity globally?’ The answer is: ‘as many as possible’. Then, why not grab some help from the public? Citizen science, which is the involvement of a large community of volunteers in data collection, is the approach that could make this possible (Bonney 2021). While some local citizen science initiatives use structured or semi-structured sampling strategies, others can produce biota observations using sampling that is unstructured temporally (e.g. any hour of the day, any day of the week) and spatially (i.e. anywhere they like) at a global scale (Callaghan et al. 2021). Although there are potential biases, unstructured data in international community science platforms, such as iNaturalist, often form valuable datasets to produce knowledge and eventually to support conservation measures (Pocock et al. 2019). The iNaturalist app, for instance, is a main venue that provides data for the Global Biodiversity Information Facility (GBIF) (Bonney 2021; Callaghan et al. 2021). GBIF, or even iNaturalist, can work like a repository of data to verify where species are present. In fact, presence-only species occurrence data have substantially increased since 2007 (Heberling et al. 2021), in part thanks to citizen science projects. However, the rate of growth of the number of observations is uneven among regions, as many developing countries, especially those in tropical regions, are still vastly under-surveyed (Pocock et al. 2018; Fritz et al. 2019). Brazil is one of the countries where citizen science is still young but shows great potential, especially based on some particular taxa, such as birds and frogs (Forti and Szabo in press; Schubert, Manica, and Guaraldo 2019). Even though the citizen science is promising, more observations are needed for many taxa and regions in Brazil, and some places, such as semiarid areas, are neglected even by professional scientists (de Oliveira et al. 2012). The Brazilian semiarid region is a centre of high endemism (Leal, Tabarelli, and Silva 2003) and hosts spectacular biodiversity (de Queiroz, Rapini, and Giulietti 2006), which is only beginning to be described (Bento, Souza-Silva, and Vasconcellos et al. 2021). This dry region is dominated by xerophytic and deciduous vegetation, which characterize the Caatinga biome (Ab’Saber 1977; Da Costa, de Araújo, and Lima-Verde 2007). As the result of a low historical sampling effort, the Caatinga has been mistakenly considered to have poor biodiversity (de Oliveira et al. 2012). Covering 844,453 km in northeastern Brazil, only 1% of its territory is under full protection (Hauff 2010). Unfortunately, the Caatinga is acutely threatened by fire, and millions of