title: A continuum of specialists and generalists in empirical communities.
abstract: Understanding the persistence of specialists and generalists within ecological communities is a topical research question, with far-reaching consequences for the maintenance of functional diversity. Although theoretical studies indicate that restricted conditions may be necessary to achieve co-occurrence of specialists and generalists, analyses of larger empirical (and species-rich) communities reveal the pervasiveness of coexistence. In this paper, we analyze 175 ecological bipartite networks of three interaction types (animal hosts-parasite, plant-herbivore and plant-pollinator), and measure the extent to which these communities are composed of species with different levels of specificity in their biotic interactions. We find a continuum from specialism to generalism. Furthermore, we demonstrate that diversity tends to be greatest in networks with intermediate connectance, and argue this is because of physical constraints in the filling of networks.
authors.affiliation: Département de sciences biologiques, Université de Montréal, Pavillon Marie-Victorin, C.P. 6128, succ. Centre-ville, Montréal (Québec) H3C 3J7, Canada; Québec Centre for Biodiversity Sciences, Montréal QC, Canada.
authors.forename: Timothée
authors.initials: T
authors.lastname: Poisot
authors.affiliation: Institut des Sciences de l'Évolution, Université Montpellier 2, CNRS, IRD, CC 065, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.
authors.forename: Sonia
authors.initials: S
authors.lastname: Kéfi
authors.affiliation: CNRS-CIRAD AGIRs, Centre d'Infectiologie Christophe Mérieux du Laos, Vientiane, Lao PDR.
authors.forename: Serge
authors.initials: S
authors.lastname: Morand
authors.affiliation: Institute of Zoology and Institute of Parasitology, Slovak Academy of Sciences, Lofflerova 10, 04001 Kosice, Slovakia.
authors.forename: Michal
authors.initials: M
authors.lastname: Stanko
authors.affiliation: Departamento de Ecologia, Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile; Instituto de Ecologia y Biodiversidad, Casilla 653, Santiago, Chile; Santa Fe Institute, 1399 Hyde Park Road Santa Fe, New Mexico 87501 USA; Laboratorio Internacional en Cambio Global (LINCGlobal) Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile.
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Marquet
authors.affiliation: Institut des Sciences de l'Évolution, Université Montpellier 2, CNRS, IRD, CC 065, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France; Santa Fe Institute, 1399 Hyde Park Road Santa Fe, New Mexico 87501 USA; Wissenschaftskolleg zu Berlin, 14193 Berlin, Germany.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Hochberg
mesh_terms: D000818:Animals; D058448:Biota; D060434:Herbivory / Q000502:physiology*; D006790:Host-Parasite Interactions; D008962:Models, Theoretical; D010944:Plants / Q000469:parasitology*; D054817:Pollination; D011157:Population Dynamics; D013038:Specialization; D013045:Species Specificity