Valuing the mental health and well-being benefits of nature engagement through measures of soundscape complexity

There is growing recognition of the value and benefits of spending time in nature for human health and well-being, with governments and organisations around the world now developing green prescribing programmes to treat mental health issues and support mental well-being through contact with nature. The COVID-19 pandemic has served to highlight the value of such contact, both in terms of the detrimental impacts of local and national lockdowns on mental health and the widespread appreciation of the benefits of nature engagement during this period. The health and well-being benefits derived from nature represent globally important cultural ecosystem services (CES). However, whilst we know that the quantity of natural space available can influence these CES, the importance of the quality of this space remains largely unknown. We also have only a limited understanding of the role and impact that different elements of biodiversity play in driving nature-health relationships. These knowledge gaps have limited the systematic integration of these CES into wider ecosystem service frameworks, conservation and sustainable development policies, and landscape and urban green-space management.

Sound plays a key role in our experience of nature, with bird song in particular providing the soundtrack to time spent outdoors. Indeed, from Vaughan William's "The Lark Ascending", to Rachel Carson's "Silent Spring", bird song has long been a defining component of our relationship with nature and our assessment of environmental quality. The acoustic characteristics of these soundtracks, or natural soundscapes, can be readily measured. Birds are frequently used as an indicator of wider biodiversity and the composition of bird communities is driven by many factors, such as habitat availability and landscape structure, that are also known to influence the quality of nature experiences. The acoustic characteristics of soundscapes provided by birds can therefore indicate the state of landscape biodiversity more generally. As such, soundscapes have the potential to provide an objective measure of the contribution of biodiversity to mental health and well-being benefits though nature engagement and to enable fuller integration of these CES into the ecosystem service framework and into natural capital policy and management decisions. In this project, our team of academic researchers and key stakeholders from conservation, mental health, industry, planning and policy arenas will develop the mechanistic understanding of the pathways linking landscape structure, soundscape complexity, perceptions of soundscape quality, derived mental health and well-being benefits, and economic values required to achieve this.

Rather than relying on recordings of actual soundscapes, we will use a novel approach that combines bird monitoring data with existing recordings of individual species to construct simulated natural soundscapes across the UK and relate their acoustic properties to local habitat and landscape characteristics. Using both laboratory and online experiments, we will also explore short-term responses to and long-term implications of exposure to soundscapes with varying acoustic characteristics, examining the contextual and individual factors which drive variation in the strengths of these relationships. We will examine the psychological mechanisms that underpin these relationships and investigate whether human noise reduces the benefits of natural soundscapes. We will also relate spatial patterns in soundscape characteristics to indicators of mental well-being and antidepressant prescriptions rates, and quantify people's willingness to pay for improvements in natural soundscape quality. Taken together, these advances will allow us to measure, monitor and predict temporal and spatial patterns in natural soundscape stocks and the flows of derived benefits.