Using bioacoustics to assess the impact of evergreen invasive plants on bird communities in Wales, United Kingdom

Invasive alien species are one of the major drivers of biodiversity loss, with birds amongst the most vulnerable taxa affected by their impacts. However, potential impacts on bird communities have rarely been investigated, particularly through bioacoustic monitoring and citizen-science approaches. Here, we present a pilot study testing the feasibility of using bioacoustic monitoring, supported by citizen scientists, to explore how the formation of an evergreen shrub layer of invasive alien plants (Rhododendron ponticum and Prunus laurocerasus) may influence bird communities in broadleaved woodlands in Wales, United Kingdom. We trained volunteer citizen scientists on how to use passive acoustic monitoring devices (AudioMoths) to record bird calls. We then used the BirdNET software to identify bird species from 480 hours of audio recordings. A total of 28 bird species from 17 families were identified from the recordings. Overall, the frequency of bird calls did not differ between the control and invaded plots. However, there was significant difference in the frequency of bird calls based on their trophic niches, suggesting that birds respond in different ways to the presence of invasive alien plants. This pilot study shows that bioacoustic monitoring is an effective tool for investigating invasive species impacts and that it can be integrated with citizen science to assess how invasive evergreen shrubs influence bird communities.