A tale of two springs: contrasting forest soundscapes during the COVID-19 lockdown (2020) and after the record snowstorm Filomena (2021) from Central Spain

Abstract

AbstractDuring the COVID-19 pandemic, humanity temporarily retired from the outdoors. The strict lockdown measures in Spain coincided with the onset of the nesting season of birds, thriving in an unusually quiet environment. Here, we have recorded in forests near San Lorenzo de El Escorial (Central Spain) during the lockdown period in 2020, and the closer to normal spring in 2021. We found strong differences in soundscapes by recording year and location, regardless of the effects of meteorology and human mobility. Species altered their behaviour by increasing their calling intensity during 2021 to cope with higher noise levels, however, acoustic activity was generally less diverse and complex. The difference between years was particularly detrimental for the highest-pitched biophony in 2021. We interpret that an extreme snowfall, Filomena, may have caused a mortality event with lasting effects in the community during the 2021 spring. Since extreme climatic events are likely going to keep happening in the area due to climate change, our data is a useful baseline to guide future conservation efforts, and examine how our activity and climate change are changing the soundscapes of Spanish Mediterranean forests.