Theory 15/Community turnover/Environmental DNA

Turnover Is Detectable Before Loss

The claim

Community turnover is set by the ratio of species replacement rate to detection probability, so eDNA detects replacement long before any species is lost.

01Mechanism

DNA persists in water for days; repeated sampling measures presence without capture, and replacement shows up as compositional change.

02Prediction

Turnover should be detectable while richness is unchanged.

03Refutation

Turnover appearing only with richness loss would remove the early-detection claim.

04What makes it checkable

eDNA metabarcoding now gives repeated, cheap, non-invasive composition estimates at sites where traditional surveys were too costly to repeat.

05Why it was not testable before

Repeated conventional surveys were prohibitively expensive; sequencing made repetition routine.