The Neglected Role of Intraspecific Variation in Plastic Pollution Research

The predominant focus of initial research endeavours investigating the impacts of ongoing climate change on biodiversity has been on studying the effects on species as the primary unit of measurement. However, over the last decade, numerous studies have taught us that neglecting intraspecific (genetic and/or phenotypic) diversity limits our understanding of the impacts that human activities have on life on Earth. Intraspecific biodiversity is a critical component of ecological systems, providing the foundation for adaptation, stability, productivity, and the long-term persistence of species and ecosystems. Evidence has demonstrated that consideration of variation below the species level is an absolute prerequisite for a comprehensive understanding of the impacts of anthropogenic pressure, the likely consequences for wider ecosystems and efficient management strategies. Plastic litter has rapidly emerged as a worldwide threat to global biodiversity. Critically, to date, akin to the initial phases of climate change research, the main emphasis of studies has primarily been on examining the effects of plastics on species as the principal metric of assessment. Studies investigating how, or to what extent, plastic pollution affects diversity below the species level are lagging. In this perspective piece, we argue that, by overlooking the role of intraspecific variation in plastic pollution research, the consequences of this new, and ever growing, ecological threat may be oversimplified and underestimated.