Biodiversity loss can heavily affect the functioning of ecosystems, and improving our understanding of how ecosystems respond to biodiversity decline is one of the main challenges in ecology1,2,3,4. Several important aspects of the longer-term effects of biodiversity loss on ecosystems remain unresolved, including how these effects depend on environmental context5,6,7. Here we analyse data from an across-ecosystem biodiversity manipulation experiment that, to our knowledge, represents the world’s longest-running experiment of this type. This experiment has been set up on 30 lake islands in Sweden that vary considerably in productivity and soil fertility owing to differences in fire history8,9. We tested the effects of environmental context on how plant species loss affected two fundamental community attributes—plant community biomass and temporal variability—over 20 years. In contrast to findings from artificially assembled communities10,11,12, we found that the effects of species loss on community biomass decreased over time; this decrease was strongest on the least productive and least fertile islands. Species loss generally also increased temporal variability, and these effects were greatest on the most productive and most fertile islands. Our findings highlight that the ecosystem-level consequences of biodiversity loss are not constant across ecosystems and that understanding and forecasting these consequences necessitates taking into account the overarching role of environmental context.
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We thank numerous assistants for help in the field. This work was supported by grants to D.A.W. from the Swedish Research Council (Vetenskapsrådet) and a Wallenberg Scholars award.Reviewer information
Nature thanks Y. Hautier, P. Morin and F. van der Plas for their contribution to the peer review of this work.
Extended data figures and tables
Extended Data Fig. 1 Effects of plant species removal on temporal biomass patterns (1999–2016, years 3–20) of individual species biomass.
a–i, Data show individual species biomass (g per m2) for V. myrtillus (a–c), V. vitis-idaea (d–f) and E. hermaphroditum (g–i) for large, medium and small islands. Species codes (M, V, E) refer to the plant species remaining after removal. Thick dark-coloured lines show mean values per treatment (n = 10 islands per size class, except for E treatments on large islands (n = 8), E treatments on medium islands (n = 5), M + E treatments on medium islands (n = 8), E treatments on small islands (n = 9), M treatments on small islands (n = 8) and M + E treatments on small islands (n = 9). Thin light-coloured lines show values for individual plots. Within island size classes, removal treatments with the same letters are not significantly different across years through the duration of the study. Treatment effects were tested using linear mixed models fitted by a restricted maximum likelihood method, and we used contrast analyses to test across-year differences between removal treatments (see Methods for details).
Extended Data Fig. 2 Temporal patterns (1999–2016; years 3–20) of the proportion of variance in total plant biomass explained by the species-removal treatment for large, medium and small islands.
The proportion of variance explained (also called the effect size) was calculated using marginal R2 values (R2GLMM(m)) for linear mixed models (n = 10 islands per size class). Linear regressions were fit for each island size class (dotted lines). We used linear mixed models to test how R2GLMM(m) changed over time with island size class and year as fixed factors and year as a continuous variable. Contrasts on the interaction between island size class and year were used to test if the slopes of regressions between year and R2GLMM(m) differed between island size classes. Significant differences in slopes among island size classes at α = 0.05 are indicated in the panel.
This file contains 10 tables, 12 figures, and supplementary discussion. Together, these items provide essential background information and additional analyses further exploring the role of plant species identity, relative yield total and transgressive over-yielding, and non-linear patterns of effects of species loss