Watershed land cover predicts the abundance of macroplastic and other anthropogenic litter in streams

Abstract

Macroplastic and other types of macroscopic anthropogenic litter (AL; trash, particles > 5 mm) are pervasive across ecosystems, persistent in the environment, increasing in abundance, and can degrade into microplastics (particles 2 and 0.011–87.482 g/m 2 . Watershed impervious surface area and urban cover were significant predictors of AL by count (pseudo R 2 = 0.418), likely due to greater numbers of AL sources and enhanced connectivity between terrestrial landscapes and urban streams. However, relationships between land cover and AL mass were weaker (pseudo R 2 = 0.19–0.29), suggesting strong reach‐scale influences on AL mass. Habitat type influenced AL assemblages: floating and overhanging zones showed higher proportions of lightweight materials, while benthic zones contained more dense materials. Our results show watershed urbanization and habitat‐specific retention processes structure AL abundance and assemblage in rivers, improving predictions of AL distribution at larger spatial scales and informing AL prevention and mitigation strategies.

Bibliographic Information