title: Habitat diversity and ecosystem multifunctionality-The importance of direct and indirect effects.
abstract: Ecosystems worldwide are facing habitat homogenization due to human activities. Although it is commonly proposed that such habitat homogenization can have negative repercussions for ecosystem functioning, this question has yet to receive explicit scientific attention. We expand on the framework for evaluating the functional consequences of biodiversity loss by scaling up from the level of species to the level of the entire habitats. Just as species diversity generally fosters ecosystem functioning through positive interspecies interactions, we hypothesize that different habitats within ecosystems can facilitate each other through structural complementarity and through exchange of material and energy across habitats. We show that experimental ecosystems comprised of a diversity of habitats show higher levels of multiple ecosystem functions than ecosystems with low habitat diversity. Our results demonstrate that the effect of habitat diversity on multifunctionality varies with season; it has direct effects on ecosystem functioning in summer and indirect effects, via changes in species diversity, in autumn, but no effect in spring. We propose that joint consideration of habitat diversity and species diversity will prove valuable for both environmental management and basic research.
authors.affiliation: Department of Marine Sciences, University of Gothenburg, 405 30 Göteborg, Sweden.
authors.forename: Christian
authors.initials: C
authors.lastname: Alsterberg
authors.affiliation: Department of Marine Sciences, University of Gothenburg, 405 30 Göteborg, Sweden.
authors.forename: Fabian
authors.initials: F
authors.lastname: Roger
authors.affiliation: Department of Marine Sciences, University of Gothenburg, 405 30 Göteborg, Sweden.
authors.forename: Kristina
authors.initials: K
authors.lastname: Sundbäck
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden.
authors.forename: Jaanis
authors.initials: J
authors.lastname: Juhanson
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg, 412 96 Göteborg, Sweden.
authors.forename: Stefan
authors.identifier: 0000-0001-6409-7444
authors.initials: S
authors.lastname: Hulth
authors.affiliation: Department of Forest Mycology and Plant Pathology, Uppsala, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden.
authors.forename: Sara
authors.initials: S
authors.lastname: Hallin
authors.affiliation: Department of Marine Sciences, University of Gothenburg, 405 30 Göteborg, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Gamfeldt
mesh_terms: D000818:Animals; D001419:Bacteria / Q000254:growth & development; D044822:Biodiversity; D017753:Ecosystem; D016014:Linear Models; D058086:Microalgae / Q000254:growth & development; D009586:Nitrogen Fixation; D012621:Seasons
keywords: Habitat diversity; Marine; SEM; Sediment; direct and indirect effects; microbial diversity; multifunctionality