title: Detailed monitoring of a small but recovering population reveals sublethal effects of disease and unexpected interactions with supplemental feeding.
abstract: Infectious diseases are widely recognized to have substantial impact on wildlife populations. These impacts are sometimes exacerbated in small endangered populations, and therefore, the success of conservation reintroductions to aid the recovery of such species can be seriously threatened by outbreaks of infectious disease. Intensive management strategies associated with conservation reintroductions can further compound these negative effects in such populations. Exploring the sublethal effects of disease outbreaks among natural populations is challenging and requires longitudinal, individual life-history data on patterns of reproductive success and other indicators of individual fitness. Long-term monitoring data concerning detailed reproductive information of the reintroduced Mauritius parakeet (Psittacula echo) population collected before, during and after a disease outbreak was investigated. Deleterious effects of an outbreak of beak and feather disease virus (BFDV) were revealed on hatch success, but these effects were remarkably short-lived and disproportionately associated with breeding pairs which took supplemental food. Individual BFDV infection status was not predicted by any genetic, environmental or conservation management factors and was not associated with any of our measures of immune function, perhaps suggesting immunological impairment. Experimental immunostimulation using the PHA (phytohaemagglutinin assay) challenge technique did, however, provoke a significant cellular immune response. We illustrate the resilience of this bottlenecked and once critically endangered, island-endemic species to an epidemic outbreak of BFDV and highlight the value of systematic monitoring in revealing inconspicuous but nonetheless substantial ecological interactions. Our study demonstrates that the emergence of such an infectious disease in a population ordinarily associated with increased susceptibility does not necessarily lead to deleterious impacts on population growth and that negative effects on reproductive fitness can be short-lived.
authors.affiliation: Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, CT2 7NZ, UK.|Mauritian Wildlife Foundation, Grannum Road, Vacoas, Mauritius.
authors.forename: Simon
authors.initials: S
authors.lastname: Tollington
authors.affiliation: International Zoo Veterinary Group, Station House, Parkwood Street, Keighley, West Yorkshire, BD21 4NQ, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Greenwood
authors.affiliation: Mauritian Wildlife Foundation, Grannum Road, Vacoas, Mauritius.|Durrell Wildlife Conservation Trust, Les Augres Manor, Trinity, Jersey, JE3 5BP, UK.
authors.forename: Carl G
authors.initials: CG
authors.lastname: Jones
authors.affiliation: Institute for Conservation Research, San Diego Zoo Global, 15600 San Pasqual Valley Road, Escondido, CA, USA.
authors.forename: Paquita
authors.initials: P
authors.lastname: Hoeck
authors.affiliation: Mauritian Wildlife Foundation, Grannum Road, Vacoas, Mauritius.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Chowrimootoo
authors.affiliation: Mauritian Wildlife Foundation, Grannum Road, Vacoas, Mauritius.
authors.forename: Donal
authors.initials: D
authors.lastname: Smith
authors.affiliation: Mauritian Wildlife Foundation, Grannum Road, Vacoas, Mauritius.
authors.forename: Heather
authors.initials: H
authors.lastname: Richards
authors.affiliation: Mauritian Wildlife Foundation, Grannum Road, Vacoas, Mauritius.
authors.forename: Vikash
authors.initials: V
authors.lastname: Tatayah
authors.affiliation: Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, CT2 7NZ, UK.
authors.forename: Jim J
authors.initials: JJ
authors.lastname: Groombridge
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology* / Q000821:virology; D018173:Circoviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D017925:Circovirus; D003247:Conservation of Natural Resources; D004032:Diet / Q000662:veterinary; D056727:Endangered Species; D056084:Genetic Fitness; D008436:Mauritius; D046409:Psittacula / Q000276:immunology / Q000502:physiology / Q000821:virology*; D012098:Reproduction / Q000502:physiology*
keywords: disease ecology; ecological immunology; generalized linear mixed models; psittacine beak and feather disease; reproductive success; supplementary feeding