The effect of experimentally simulated climate warming on the microbiome of carnivorous plants – A microcosm experiment

Abstract

Climate change models predict a potential increase in air temperature ranging from 2 °C to 4 °C. Global warming will therefore significantly influence the functioning of various organisms and ecosystems. However, the effect of the temperature increase on the functioning of the microbiome of carnivorous plants is as yet unknown. The aim of the study was to assess the effect of experimentally simulated climate warming on the microbiome of the traps of Utricularia vulgaris L. - plant included on the red list in the NT (near-threatened) category. We used ‘microcosm’ experiments (a control treatment and treatments with temperature increases of +2 and +4 °C) to determine the reaction of the microbiome of Utricularia traps and the microbes present in the water inhabited by Utricularia to simulated temperature changes in the temperate climate zone. The temperature increase caused an increase in the species richness of ciliates and in the abundance of bacteria, flagellates, and ciliates. On the other hand, there was a decrease in the abundance of testate amoebae, rotifers, and nematodes, i.e. top predators, in both the traps and the peatbog water. At the same time, warming altered the size structure of microbes towards dominance of small forms. Ordination analyses showed that most important factors determining the occurrence of microbes and small Metazoa are temperature, organic matter, and biogenic compounds. A better understanding of what regulates microbial populations and activity in traps and in water in peatbogs and unraveling of these fundamental mechanisms are particularly critical in order to more accurately predict how peatbogs will respond to climate disturbances.