In 2019, this comparative study takes up the protocol set up in 1989 during the biodiversity inventory and the description of the functioning of the Bois-Vieux forest pond (Geneva). The rate of decomposition of dead leaves of Quercus robur L. indicates similar functioning in 1989 and 2019. The aquatic macroinvertebrates sampled on two substrates (dead leaves of Quercus robur and immersed stems of Typha latifolia L.) showed an increased overall taxonomic richness of 34 to 40 taxa. Total macroinvertebrate abundance is much lower in 2019, particularly on Quercus (-83%), due to the sharp drop in density of Chironomids (Diptera) and Oligochaetes. The abundance of Insects has declined overall (-49.3% of Insects without Chironomids on Quercus). There has been a significant substitution in the composition of the macroinvertebrate community. Macroinvertebrate biomass is expected to be higher in 2019.