Citizen science data can contribute to species distribution modelling
Citizen science programmes can be a useful tool to increase data acquisition and geographical coverage when assessing invasive alien plant species. In addition, citizen science programmes can encourage communication between scientific and non-scientific audiences. In Portugal, approximately 18 % of the mainland flora are alien species with most of them being introduced over the last few decades. The citizen science platform Invasoras.pt was created in 2013 and raises awareness about invasive alien plants in Portugal. The platform allows citizen scientists to report invasive plant occurrences and over a 3-year period, 11 000 occurrences were recorded for 56 plant species. Combining these data with data collected by researchers could improve the accuracy of species distribution models. To test this, three tree species alien to Portugal were modelled using occurrence data collected from two data sources (1) scientific sampling (4 630 occurrences), and (2) citizen science data (2 663 occurrences) collected from Invasoras.pt and which had been verified by experts. Three species were used in the study, all native to Southeast Australia and widespread and well documented in Portugal: Acacia dealbata (Fabaceae: EPPO List of Invasive Alien Plants), A. longifolia and A. melanoxylon. For each species the model was run with the scientific sampled dataset, the citizen science dataset and again combining both datasets. The potential distribution of the species was modelled using biomod2 (R package). All species distribution models delivered a high level of accuracy for predicting the area of invasion with the highest accuracy from the researchers’ data. However, models using citizen science data, or the models using a combination of datasets, predicted an increase in the total area for all species. For A. dealbata, including citizen science data increased the model’s prediction for distribution southwards which better reflected the widespread nature of the species. These results highlight the value of verified citizen science data and its utilization in modelling invasive alien plant distributions.
César de Sá, Marchante H, Marchante E, Cabral JA, Pradinho J, Vicente JR (2019) Can citizen science data guide the surveillance of invasive plants? A model-based test with acacia trees in Portugal, Biological Invasions 21, 2127-2141.