Species are being lost at unprecedented rates. Evidence is accumulating that biodiversity loss can heavily impact on the functioning of ecosystems, and improving our understanding of how ecosystems will respond to biodiversity decline is among the main challenges in ecology. However, several important aspects of the longer-term effects of biodiversity loss on ecosystems remain unresolved, including how these effects depend on environmental context. This is despite growing evidence that the strength of the relationship between plant diversity and productivity can be strongly context-dependent and altered by changes in environmental conditions, such as soil resource availability. Here, we analyzed data from the world’s longest running across-ecosystem biodiversity manipulation experiment, which has been set up on 30 lake islands in northern Sweden that vary greatly in productivity and soil fertility due to differences in fire history. We tested the effects of environmental context on how plant species loss affects two fundamental community attributes over 20 years: community biomass and stability.
Results/Conclusions
Most available experimental evidence for effects of biodiversity loss on ecosystem functioning is from studies under highly controlled conditions where plant diversity has been varied through random draws from species pools, but our results show that different patterns may occur when species are removed from natural ecosystems. We found that the effects of species loss on community biomass decreased over time and that this decrease was strongest on the least productive and fertile islands. Species loss generally also decreased community stability and these effects were greatest on the most productive and fertile islands. The effects of species loss on biomass and stability depended not only on environmental context but also on species identity. The loss of biodiversity in natural ecosystems under global change is not a random process, and we show that it does not only matter which species are lost and to what extent the remaining species are able to exploit the available resources but also which ecosystems they are lost from. In conclusion, our study indicates that the ecosystem-level consequences of biodiversity loss is not constant across ecosystems and that understanding and forecasting these consequences necessitates taking into account how environmental context moderates effects of biodiversity loss.