Citizen science is increasingly recognised as one of the most cost-effective means of achieving large-scale and long-term biodiversity monitoring. Here we assess the potential for citizen scientists to contribute to the long-term monitoring of land cover, land use and habitat change through ongoing field data collection.
Land cover monitoring is most commonly carried out via remote sensing or professional surveys but these can be costly, low detail or spatiotemporally limited. We used ongoing habitat data collection by citizen scientists participating in a structured survey of breeding birds to assess whether there is the potential for citizen scientists more broadly to play a role in the long-term monitoring of habitat extent and condition. Categorical habitat data has been collected annually by over 2500 volunteers as part of the UK Breeding Bird Survey since 1994 and we used this to quantify temporal variation in the reporting of different habitats in the British countryside. Where possible we validated our estimates of habitat cover and change using independent estimates from professional surveys and other datasets.
We detected increases in woodland cover, in particular mixed woodland, and declines in farmland cover, particularly livestock farming. Our habitat cover estimates closely matched alternative land cover estimates but there was little correspondence in estimates of change between survey types and we discuss why discrepancies may occur.
Although the data we used were not initially designed for this purpose, our results suggest that there is considerable potential to use citizen science for cost-effective identification of temporal patterns in land use, habitat-type and management in ways that could complement other methods.