title: Niche width collapse in a resilient top predator following ecosystem fragmentation.
abstract: Much research has focused on identifying species that are susceptible to extinction following ecosystem fragmentation, yet even those species that persist in fragmented habitats may have fundamentally different ecological roles than conspecifics in unimpacted areas. Shifts in trophic role induced by fragmentation, especially of abundant top predators, could have transcendent impacts on food web architecture and stability, as well as ecosystem function. Here we use a novel measure of trophic niche width, based on stable isotope ratios, to assess effects of aquatic ecosystem fragmentation on trophic ecology of a resilient, dominant, top predator. We demonstrate collapse in trophic niche width of the predator in fragmented systems, a phenomenon related to significant reductions in diversity of potential prey taxa. Collapsed niche width reflects a homogenization of energy flow pathways to top predators, likely serving to destabilize remnant food webs and render apparently resilient top predators more susceptible to extinction through time.
authors.affiliation: Marine Sciences Program, Department of Biological Sciences, Florida International University, 3000 NE 151st St, North Miami, FL 33181, USA. cal1634@yahoo.com
authors.forename: Craig A
authors.initials: CA
authors.lastname: Layman
authors.forename: John P
authors.initials: JP
authors.lastname: Quattrochi
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Peyer
authors.forename: Jacob E
authors.initials: JE
authors.lastname: Allgeier
mesh_terms: D000818:Animals; D001444:Bahamas; D044822:Biodiversity; D002247:Carbon Isotopes; D017753:Ecosystem; D005399:Fishes; D020387:Food Chain; D005766:Gastrointestinal Contents; D007448:Invertebrates; D009587:Nitrogen Isotopes; D010473:Perciformes; D045483:Rivers
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes