Protist as ideal models to study soil biodiversity-ecosystem functioning

Activity: Talk or presentationOral presentationAcademic

Description

Biodiversity and ecosystem functioning (BEF) are often positively related. This BEF relationship has been mainly shown for plants where a higher diversity of plants is related to higher plant biomass among other ecosystem functions. However, this BEF relationship is poorly studied for one of the most diverse ecosystems in the world (soils), hosting potentially millions of species, including protists. Even more striking is the lack of knowledge on the effect of (interactive) global change drivers (GCDs) on this sBEF relationship, as for aboveground studies it has been shown that higher biodiversity might reduce the negative impacts of (interactive) GCDs on ecosystem functioning. Here I show the results obtained in 2 greenhouse experiments that investigated the soil BEF (sBEF) relationship with a focus on predatory protists under both biotic and abiotic GCDs. I tried to uncover sBEF by manipulating the species richness from 0 to 30 protist species in non-treated controls, under abiotic stress (fertilization or drought), biotic stress (nematodes dominated by root-feeders), and a combination of biotic and abiotic. Then we tested plant biomass (tomato and Cannabis sativa) and biochemical soil parameters related to nutrient cycling (such as soil organic carbon (SOC) or Microbial Biomass Carbon and Nitrogen) as ecosystem functions. Increasing biodiversity showed a wide range of impacts on plant biomass and nutrient cycling, not only positively as mentioned in the literature (here under nematode infection or fertilization) but also negatively as shown under drought. Two stressors combined led to additive patterns canceling out the negative drought effects and positive nematode effects. I conclude that protists are great models to study sBEF relationships in soils, which we show to not generally follow those of plants as ranging from positive to negative, necessitating fundamental changes in claims on (s)BEF. These results are a starting point to uncover the sBEF relationship under ongoing and future climate change and that protists should be part of new endeavours.
Period9 Jul 2023
Event titleIX European Congress of Protistology & Annual Congress of the International Society of Protistologists: "The Century of Protists"
Event typeConference
LocationVienna, AustriaShow on map