title: Predicting the consequences of species loss using size-structured biodiversity approaches.
abstract: Understanding the consequences of species loss in complex ecological communities is one of the great challenges in current biodiversity research. For a long time, this topic has been addressed by traditional biodiversity experiments. Most of these approaches treat species as trait-free, taxonomic units characterizing communities only by species number without accounting for species traits. However, extinctions do not occur at random as there is a clear correlation between extinction risk and species traits. In this review, we assume that large species will be most threatened by extinction and use novel allometric and size-spectrum concepts that include body mass as a primary species trait at the levels of populations and individuals, respectively, to re-assess three classic debates on the relationships between biodiversity and (i) food-web structural complexity, (ii) community dynamic stability, and (iii) ecosystem functioning. Contrasting current expectations, size-structured approaches suggest that the loss of large species, that typically exploit most resource species, may lead to future food webs that are less interwoven and more structured by chains of interactions and compartments. The disruption of natural body-mass distributions maintaining food-web stability may trigger avalanches of secondary extinctions and strong trophic cascades with expected knock-on effects on the functionality of the ecosystems. Therefore, we argue that it is crucial to take into account body size as a species trait when analysing the consequences of biodiversity loss for natural ecosystems. Applying size-structured approaches provides an integrative ecological concept that enables a better understanding of each species' unique role across communities and the causes and consequences of biodiversity loss.
authors.affiliation: German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103, Leipzig, Germany.|Faculty of Biology and Pharmacy, Institute of Ecology, Friedrich Schiller University Jena, 07743, Jena, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Brose
authors.affiliation: Institute for Marine and Antarctic Studies and Centre for Marine Socioecology, University of Tasmania, 20 Castray Esplanade, Battery Point TAS 7004, Australia.
authors.forename: Julia L
authors.initials: JL
authors.lastname: Blanchard
authors.affiliation: Theoretical Biology, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Eklöf
authors.affiliation: Ecological Networks and Global Change Group, Experimental Ecology Station, Centre National de la Recherche Scientifique, 09200, Moulis, France.
authors.forename: Nuria
authors.initials: N
authors.lastname: Galiana
authors.affiliation: Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, DK-2100, Copenhagen, Denmark.|National Institute of Aquatic Resources, Technical University of Denmark, DK-2920, Charlottenlund, Denmark.|Systemic Conservation Biology Group, J.F. Blumenbach Institute of Zoology and Anthropology, Georg-August University of Göttingen, 37073, Göttingen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Hartvig
authors.affiliation: German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103, Leipzig, Germany.|Faculty of Biology and Pharmacy, Institute of Ecology, Friedrich Schiller University Jena, 07743, Jena, Germany.
authors.forename: Myriam
authors.initials: M
authors.lastname: R Hirt
authors.affiliation: Department of Biology and Ecology of Fishes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, 12587, Berlin, Germany.|Department of Fish Ecology and Evolution, Eawag, 6047, Kastanienbaum, Switzerland.
authors.forename: Gregor
authors.initials: G
authors.lastname: Kalinkat
authors.affiliation: Environmental and Marine Biology, Åbo Akademi University, FI-20520, Åbo, Finland.
authors.forename: Marie C
authors.initials: MC
authors.lastname: Nordström
authors.affiliation: Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK.
authors.forename: Eoin J
authors.initials: EJ
authors.lastname: O'Gorman
authors.affiliation: German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103, Leipzig, Germany.|Faculty of Biology and Pharmacy, Institute of Ecology, Friedrich Schiller University Jena, 07743, Jena, Germany.
authors.forename: Björn C
authors.initials: BC
authors.lastname: Rall
authors.affiliation: Institut des Sciences de l'Evolution, Université Montpellier, CNRS, IRD, EPHE, CC065, 34095, Montpellier Cedex 05, France.
authors.forename: Florian D
authors.initials: FD
authors.lastname: Schneider
authors.affiliation: Institute of Ecology and Environmental Sciences - Paris, UMR 7618 (UPMC, CNRS, IRD, INRA, UPEC, Paris Diderot), Université Pierre et Marie Curie, 75005, Paris, France.
authors.forename: Elisa
authors.initials: E
authors.lastname: Thébault
authors.affiliation: Department of Biology, Institute for Hydrobiology and Fisheries Science, Center for Earth System Research and Sustainability (CEN), KlimaCampus, University of Hamburg, 22767, Hamburg, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Jacob
mesh_terms: D044822:Biodiversity; D017753:Ecosystem; D053476:Extinction, Biological; D020387:Food Chain
keywords: allometric scaling; biodiversity; complexity; ecosystem functioning; extinctions; food webs; global change; size spectrum; stability