Research article2015Peer reviewedOpen access
Biodiversity mediates top-down control in eelgrass ecosystems: a global comparative-experimental approach
Duffy JE, Reynolds PL, Bostrom C, Coyer JA, Cusson M, Donadi S, Douglass JG, Eklof JS, Engelen AH, Eriksson BK, Fredriksen S, Gamfeldt L, Gustafsson C, Hoarau G, Hori M, Hovel K, Iken K, Lefcheck JS, Moksnes PO, Nakaoka M, O'Connor MI, Olsen JL, Richardson JP, Ruesink JL, Sotka EE, Thormar J, Whalen MA, Stachowicz JJ
Abstract
Nutrient pollution and reduced grazing each can stimulate algal blooms as shown by numerous experiments. But because experiments rarely incorporate natural variation in environmental factors and biodiversity, conditions determining the relative strength of bottom-up and top-down forcing remain unresolved. We factorially added nutrients and reduced grazing at 15 sites across the range of the marine foundation species eelgrass (Zostera marina) to quantify how top-down and bottom-up control interact with natural gradients in biodiversity and environmental forcing. Experiments confirmed modest top-down control of algae, whereas fertilisation had no general effect. Unexpectedly, grazer and algal biomass were better predicted by cross-site variation in grazer and eelgrass diversity than by global environmental gradients. Moreover, these large-scale patterns corresponded strikingly with prior small-scale experiments. Our results link global and local evidence that biodiversity and top-down control strongly influence functioning of threatened seagrass ecosystems, and suggest that biodiversity is comparably important to global change stressors.
Keywords
2015,biodiversity-ecosystem functioning,bottom,coordinated experiments,down control,ecology letters,food webs,metabolic ecology,structural equation modelling,top,up control
Published in
Ecology Letters
2015, Volume: 18, number: 7, pages: 696--705
UKÄ Subject classification
Ecology
Publication identifier
DOI: https://doi.org/10.1111/ele.12448
Permanent link to this page (URI)
https://res.slu.se/id/publ/88511