Abstract
Higher biodiversity can stabilize the productivity and functioning of grassland communities when subjected to extreme climatic events. The positive biodiversity-stability relationship emerges via increased resistance and/or recovery to these events. However, invader presence might disrupt this diversity-stability relationship by altering biotic interactions. Investigating such disruptions is important given that invasion by non-native species and extreme climatic events are expected to increase in the future due to anthropogenic pressure. Here we present one of the first multisite invader×biodiversity×drought manipulation experiment to examine combined effects of biodiversity and invasion on drought resistance and recovery at three semi-natural grassland sites across Europe. The stability of biomass production to an extreme drought manipulation (100% rainfall reduction; BE: 88days, BG: 85days, DE: 76days) was quantified in field mesocosms with a richness gradient of 1, 3, and 6 species and three invasion treatments (no invader, Lupinus polyphyllus, Senecio inaequidens). Our results suggest that biodiversity stabilized community productivity by increasing the ability of native species to recover from extreme drought events. However, invader presence turned the positive and stabilizing effects of diversity on native species recovery into a neutral relationship. This effect was independent of the two invader's own capacity to recover from an extreme drought event. In summary, we found that invader presence may disrupt how native community interactions lead to stability of ecosystems in response to extreme climatic events. Consequently, the interaction of three global change drivers, climate extremes, diversity decline, and invasive species, may exacerbate their effects on ecosystem functioning.
Highlights
Loss of biodiversity tends to affect ecosystem functioning and stability of grasslands negatively and is likely to affect human society (Cardinale et al, 2012; Hautier et al, 2015, 2018; Tilman, Isbell, & Cowles, 2014)
Global change drivers lead to exogenous changes in resource availability and the introduction of non-native species, leading to uncertainty as to whether the diversity–stability relationship persists in the face of extreme climatic events (De Boeck et al, 2018) and invasion (Pinto & Ortega, 2016)
We quantified the effects on community productivity of two invasive species in Europe, the legume L. polyphyllus Lindl. and the non-legume forb S. inaequidens DC. We further studied their impacts on community resistance and recovery of biomass production to an extreme climatic event in field mesocosms differing in diversity (1, 3, 6 species) at three sites across Europe (Germany, Belgium, Bulgaria)
Summary
Loss of biodiversity tends to affect ecosystem functioning and stability of grasslands negatively and is likely to affect human society (Cardinale et al, 2012; Hautier et al, 2015, 2018; Tilman, Isbell, & Cowles, 2014). Invasives like Lupinus polyphyllus and Senecio inaequidens increasingly colonize seminatural grasslands while the former tends to form dominance stands, changing the vegetation structure and species diversity drastically (Hejda, Pyšek, & Jarošík, 2009; Lachmuth, Durka, & Schurr, 2010; Scherber, Crawley, & Porembski, 2003; Thiele, Isermann, Otte, & Kollmann, 2010; Volz & Otte, 2001) Those changes will likely affect biotic interactions, abiotic processes and ecosystem stability of the invaded habitats (Sousa, Morais, Dias, & Antunes, 2011; Strayer, 2012). We further studied their impacts on community resistance and recovery of biomass production to an extreme climatic event (ambient conditions, extreme drought manipulation) in field mesocosms differing in diversity (1, 3, 6 species) at three sites across Europe (Germany, Belgium, Bulgaria). These investigate the diversity–stability effect across large spatial and temporal scales, taking into account different disturbances yet generally not including issues related to invasive species (Anderson et al, 2018; but see Flores-Moreno et al, 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
