Nutrient identity modifies the destabilising effects of eutrophication in grasslands.
Oliver CarrollEvan BatzerSiddharth BharathElizabeth T BorerSofía CampanaEllen EschYann HautierTimothy OhlertEric W SeabloomPeter B AdlerJonathan D BakkerLori BiedermanMiguel N BugalhoMaria CaldeiraQingqing ChenKendi F DaviesPhilip A FayJohannes M H KnopsKimberly KomatsuJason P MartinaKevin S McCannJoslin L MooreJohn W MorganTaofeek O MurainaBrooke OsborneAnita C RischCarly StevensPeter A WilfahrtLaura YahdjianAndrew S MacDougallPublished in: Ecology letters (2021)
Nutrient enrichment can simultaneously increase and destabilise plant biomass production, with co-limitation by multiple nutrients potentially intensifying these effects. Here, we test how factorial additions of nitrogen (N), phosphorus (P) and potassium with essential nutrients (K+) affect the stability (mean/standard deviation) of aboveground biomass in 34 grasslands over 7 years. Destabilisation with fertilisation was prevalent but was driven by single nutrients, not synergistic nutrient interactions. On average, N-based treatments increased mean biomass production by 21-51% but increased its standard deviation by 40-68% and so consistently reduced stability. Adding P increased interannual variability and reduced stability without altering mean biomass, while K+ had no general effects. Declines in stability were largest in the most nutrient-limited grasslands, or where nutrients reduced species richness or intensified species synchrony. We show that nutrients can differentially impact the stability of biomass production, with N and P in particular disproportionately increasing its interannual variability.