title: Investigating the long-term legacy of drought and warming on the soil microbial community across five European shrubland ecosystems.
abstract: We investigated how the legacy of warming and summer drought affected microbial communities in five different replicated long-term (>10 years) field experiments across Europe (EU-FP7 INCREASE infrastructure). To focus explicitly on legacy effects (i.e., indirect rather than direct effects of the environmental factors), we measured microbial variables under the same moisture and temperature in a brief screening, and following a pre-incubation at stable conditions. Specifically, we investigated the size and composition of the soil microbial community (PLFA) alongside measurements of bacterial (leucine incorporation) and fungal (acetate in ergosterol incorporation) growth rates, previously shown to be highly responsive to changes in environmental factors, and microbial respiration. We found no legacy effects on the microbial community size, composition, growth rates, or basal respiration rates at the effect sizes used in our experimental setup (0.6 °C, about 30% precipitation reduction). Our findings support previous reports from single short-term ecosystem studies thereby providing a clear evidence base to allow long-term, broad-scale generalizations to be made. The implication of our study is that warming and summer drought will not result in legacy effects on the microbial community and their processes within the effect sizes here studied. While legacy effects on microbial processes during perturbation cycles, such as drying-rewetting, and on tolerance to drought and warming remain to be studied, our results suggest that any effects on overall ecosystem processes will be rather limited. Thus, the legacies of warming and drought should not be prioritized factors to consider when modeling contemporary rates of biogeochemical processes in soil.
authors.affiliation: Section of Microbial Ecology, Department of Biology, Lund University, Ecology Building, 223 62, Lund, Sweden.
authors.forename: Johannes
authors.initials: J
authors.lastname: Rousk
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Smith
authors.forename: Davey L
authors.initials: DL
authors.lastname: Jones
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D001419:Bacteria / Q000254:growth & development; D057231:Climate Change; D055864:Droughts; D017753:Ecosystem; D005060:Europe; D005658:Fungi / Q000254:growth & development; D006358:Hot Temperature; D007930:Leucine / Q000378:metabolism; D012621:Seasons; D012988:Soil Microbiology
chemical_list: D007930:Leucine; D019342:Acetic Acid
keywords: carbon sequestration; decomposition; ecosystem service; global climate change; mineralization; soil C cycle; temperature acclimation; warming adaptation