title: Phylogenetic diversity and co-evolutionary signals among trophic levels change across a habitat edge.
abstract: Incorporating the evolutionary history of species into community ecology enhances understanding of community composition, ecosystem functioning and responses to environmental changes. Phylogenetic history might partly explain the impact of fragmentation and land-use change on assemblages of interacting organisms and even determine potential cascading effects across trophic levels. However, it remains unclear whether phylogenetic diversity of basal resources is reflected at higher trophic levels in the food web. In particular, phylogenetic determinants of community structure have never been incorporated into habitat edge studies, even though edges are recognized as key factors affecting communities in fragmented landscapes. Here, we test whether phylogenetic diversity at different trophic levels (plants, herbivores and parasitoids) and signals of co-evolution (i.e. phylogenetic congruence) among interacting trophic levels change across an edge gradient between native and plantation forests. To ascertain whether there is a signal of co-evolution across trophic levels, we test whether related consumer species generally feed on related resource species. We found differences across trophic levels in how their phylogenetic diversity responded to the habitat edge gradient. Plant and native parasitoid phylogenetic diversity changed markedly across habitats, while phylogenetic variability of herbivores (which were predominantly native) did not change across habitats, though phylogenetic evenness declined in plantation interiors. Related herbivore species did not appear to feed disproportionately on related plant species (i.e. there was no signal of co-evolution) even when considering only native species, potentially due to the high trophic generality of herbivores. However, related native parasitoid species tended to feed on related herbivore species, suggesting the presence of a co-evolutionary signal at higher trophic levels. Moreover, this signal was stronger in plantation forests, indicating that this habitat may impose stresses on parasitoids that constrain them to attack only host species for which they are best adapted. Overall, changes in land use across native to plantation forest edges differentially affected phylogenetic diversity across trophic levels, and may also exert a strong selective pressure for particular co-evolved herbivore-parasitoid interactions.
authors.affiliation: School of Biological Sciences, University of Canterbury, Private bag 4800, Christchurch, 8140, New Zealand.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Peralta
authors.affiliation: School of Biological Sciences, University of Canterbury, Private bag 4800, Christchurch, 8140, New Zealand.
authors.forename: Carol M
authors.initials: CM
authors.lastname: Frost
authors.affiliation: School of Animal Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.|CSIRO Ecosystem Sciences, Centre for Environment and Life Sciences, Underwood Ave, Floreat, WA, 6014, Australia.
authors.forename: Raphael K
authors.initials: RK
authors.lastname: Didham
authors.affiliation: School of Biological Sciences, University of Canterbury, Private bag 4800, Christchurch, 8140, New Zealand.|Biomolecular Interaction Centre, University of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand.|Electron Microscope Unit, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa.|Department of Plant Pathology and Emerging Pathogens Institute, University of Florida, PO Box 110680, Gainesville, FL 32611-0680, USA.
authors.forename: Arvind
authors.initials: A
authors.lastname: Varsani
authors.affiliation: School of Biological Sciences, University of Canterbury, Private bag 4800, Christchurch, 8140, New Zealand.|Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK.|Allan Wilson Centre for Molecular Ecology and Evolution, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Tylianakis
mesh_terms: D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D017753:Ecosystem; D020387:Food Chain; D060434:Herbivory / Q000145:classification; D007814:Larva / Q000469:parasitology; D007915:Lepidoptera / Q000145:classification / Q000469:parasitology; D009520:New Zealand; D010271:Parasites / Q000145:classification; D010802:Phylogeny; D010944:Plants / Q000145:classification / Q000469:parasitology
keywords: ParaFit; co‐evolution; food web; habitat fragmentation; phylogeny; phylomatic edge effects