Trashy treasures? The increasing terrestrial invertebrate diversity in small-scale dumps

Abstract

The research on the impact of plastic pollution on biodiversity has primarily focused on aquatic ecosystems, especially marine ones. Therefore, it is vital to assess how plastic pollution affects other environments and organisms, including terrestrial invertebrates. These organisms are widely recognized for their susceptibility to environmental changes and pollution. The objectives of this study were i) to investigate the potential influence (positive or negative) of macroplastic debris (MaP) on invertebrates inhabiting riverine sandy environments, ii) the potential occurrence of the microplastic (MP) adherence phenomenon on the invertebrate's body by entanglement on the body's setae or electrostatic effect (i.e., bioadhesion), and iii) the effects of removal of debris on the colonized diversity. By performing a mesocosm experiment, emulating a “small-scale dump” (also called micro-waste sites), we found that terrestrial invertebrates show a preference for colonizing areas rich in MaP, resulting in higher species richness in these areas (39 taxa in areas containing plastic debris vs. 21 taxa in areas free of plastics). This preference is likely due to the provision of shade, protection, and distinct micro-habitats offered by MaP. Regarding MP, we observed a significant number of invertebrates with MPs attached to their bodies (4.3 ± 0.8 MPs attached per individual), mainly wolf spiders (Lycosidae) and ground beetles (Carabidae), suggesting potential negative ecological implications that are discussed herein.