Do freshwater insect assemblages in exotic plantations resemble those from native forest? Evidence from environmental DNA

Abstract

Widespread deforestation has impacted biodiversity patterns globally, but the potential for forest plantations to restore biodiversity remains unclear. Here we used environmental DNA (eDNA) analysis to compare freshwater insect assemblages between native and exotic forests in New Zealand, a region that has experienced heavy deforestation over recent centuries. Our analysis of mayfly, stonefly, and caddisfly (Ephemeroptera, Plecoptera, and Trichoptera [EPT]) eDNA assemblages from 15 native forest and 15 exotic plantation streams in southern New Zealand yielded 85 taxa, most of which were shared across these habitat types. Assemblages were structured primarily by region rather than habitat type. Although the taxonomic diversity of EPT eDNA assemblages was lower in exotic plantation relative to native forest, most exotic plantation streams yielded assemblages highly similar to those of native forest streams. These findings suggest that exotic plantations can broadly restore previously deforested aquatic communities to resemble those of native forest.