Guest blog post by Melanie Werner
Researchers studying the distribution of species need information about where the plant or animal species in question occurs. This usually requires a field study, which is costly, time-consuming and often CO2-intensive. In addition, not all locations where species occur are accessible to humans, such as high mountain areas. As a result, the full range of species is often not covered and the availability of species information is a major challenge for ecological research.
Social media and citizen science projects offer a great potential to increase this availability. Citizen science refers to the involvement of non-experts in scientific projects. In the case of ecological studies, for example, this is the sampling of species occurrences. Thanks to smartphones – capable of capturing high-quality photos and recording precise locations – the ability to gather and share species information has grown significantly. It’s quite simple: take a photo, save the coordinates, upload it, and researchers can use this data to map species distributions. User-friendly platforms or Apps like iNaturalist have become invaluable for this purpose, enabling researchers and citizen scientists to share and utilize occurrence data to advance ecological understanding.
Although some people are interested in and help with such projects, they do not yet reach a broad mass of people. In our study, we explore the potential of the social media platform Instagram, which is one of the largest social media platforms with 2 billion users worldwide and millions of daily uploads. We hypothesize that even more species occurrence data is being generated on this platform, often without users realising its scientific value.
We searched for Instagram posts from 2021 to 2022 in which the tree species Nothofagus pumilio and the location of the photo can be identified. The deciduous species N. pumilio occurs at the treeline in the southern Andes. The species’ vibrant orange-red autumn colouring, in combination to spectacular landscapes, makes it a popular photo motif for tourists, hikers, and locals alike resulting in numerous Instagram posts. Because treelines are often sensitive to climate change, studying the distribution and dynamics of this species is of particular interest.
Our study began by searching Instagram for specific hashtags related to the species (#nothofaguspumilio and #lenga), as well as for locations through location tags, hashtags, and descriptions within posts. This approach allowed us to identify as many images with N. pumilio as possible, even if the users were unaware of its presence.
To select suitable posts, we focused on those where the species could be clearly identified, the location was described, and landscape elements (e.g. mountains, waterbodies, glaciers, urban and tourist area) are visible in the image, that could also be recognised in satellite imagery. For each post, we mapped at least one point at the location where the photo was taken. Additionally, we included occurrences of N. pumilio visible in the background, such as autumn-coloured treelines. This approach ensured a more comprehensive and evenly distributed sampling of the species’ range. The next image illustrates the sampling process of a post captured at Laguna Capri with Mount Fitz Roy in the background.
In this way, we were able to generate 1238 Instagram ground truthing points. These points can be directly used in ecological studies. However, it is important to note that our Instagram ground truthing points, like most citizen science data, is spatially biased. This means that locations can only be captured where people have access, leaving remote or high-altitude areas unrepresented.
For this reason, we added a remote sensing method to our study. As this deciduous species forms mono-species forests at the treeline, it can also be identified in satellite imagery. The occurrence data obtained through supervised classification was then validated using the Instagram ground truthing points. This approach allows us to generate less-biased occurrence data for the species across its entire 2000 km latitudinal range.
Participating in citizen science projects is an essential contribution to research. We encourage you to explore citizen science platforms such as iNaturalist, eBird, or naturgucker, and to include hashtags and detailed location descriptions – ideally with coordinates – when posting your holiday or everyday photos on Instagram. Every contribution helps!
Research article:
Werner M, Weidinger J, Böhner J, Schickhoff U, Bobrowski M (2024) Instagram data for validating Nothofagus pumilio distribution mapping in the Southern Andes: A novel ground truthing approach. Frontiers of Biogeography 17: e140606. https://doi.org/10.21425/fob.17.140606
