title: Non-random food-web assembly at habitat edges increases connectivity and functional redundancy.
abstract: Habitat fragmentation dramatically alters the spatial configuration of landscapes, with the creation of artificial edges affecting community structure and dynamics. Despite this, it is not known how the different food webs in adjacent habitats assemble at their boundaries. Here we demonstrate that the composition and structure of herbivore-parasitoid food webs across edges between native and plantation forests are not randomly assembled from those of the adjacent communities. Rather, elevated proportions of abundant, interaction-generalist parasitoid species at habitat edges allowed considerable interaction rewiring, which led to higher linkage density and less modular networks, with higher parasitoid functional redundancy. This was despite high overlap in host composition between edges and interiors. We also provide testable hypotheses for how food webs may assemble between habitats with lower species overlap. In an increasingly fragmented world, non-random assembly of food webs at edges may increasingly affect community dynamics at the landscape level.
authors.affiliation: School of Biological Sciences, University of Canterbury, Christchurch, 8140, New Zealand.|las Zonas Áridas, CONICET, CC 507, 5500, Mendoza, Argentina.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Peralta
authors.affiliation: School of Biological Sciences, University of Canterbury, Christchurch, 8140, New Zealand.|Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Skogsmarksgränd, Umeå, Sweden.
authors.forename: Carol M
authors.initials: CM
authors.lastname: Frost
authors.affiliation: School of Animal Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia.|CSIRO Land & Water, Centre for Environment and Life Sciences, Floreat, Western Australia, 6014, Australia.
authors.forename: Raphael K
authors.initials: RK
authors.lastname: Didham
authors.affiliation: USDA-ARS Northern Plains Agricultural Research Laboratory, Sidney, Montana, 59270, USA.
authors.forename: Tatyana A
authors.initials: TA
authors.lastname: Rand
authors.affiliation: School of Biological Sciences, University of Canterbury, Christchurch, 8140, New Zealand.|Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire, SL5 7PY, UK.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Tylianakis
mesh_terms: D004463:Ecology; D017753:Ecosystem; D020387:Food Chain; D065928:Forests; D060434:Herbivory
keywords: edge effects; food-web structure; generalism; host; native forest; network dissimilarity; parasitoid; plantation forest; rewiring of interactions; species composition