title: Pronounced Seasonal Changes in the Movement Ecology of a Highly Gregarious Central-Place Forager, the African Straw-Coloured Fruit Bat (Eidolon helvum).
abstract: BACKGROUND
  Straw-coloured fruit bats (Eidolon helvum) migrate over vast distances across the African continent, probably following seasonal bursts of resource availability. This causes enormous fluctuations in population size, which in turn may influence the bats' impact on local ecosystems. We studied the movement ecology of this central-place forager with state-of-the-art GPS/acceleration loggers and concurrently monitored the seasonal fluctuation of the colony in Accra, Ghana. Habitat use on the landscape scale was assessed with remote sensing data as well as ground-truthing of foraging areas.
  
  
  RESULTS
  During the wet season population low (~ 4000 individuals), bats foraged locally (3.5-36.7 km) in urban areas with low tree cover. Major food sources during this period were fruits of introduced trees. Foraging distances almost tripled (24.1-87.9 km) during the dry season population peak (~ 150,000 individuals), but this was not compensated for by reduced resting periods. Dry season foraging areas were random with regard to urban footprint and tree cover, and food consisted almost exclusively of nectar and pollen of native trees.
  
  
  CONCLUSIONS
  Our study suggests that straw-coloured fruit bats disperse seeds in the range of hundreds of meters up to dozens of kilometres, and pollinate trees for up to 88 km. Straw-coloured fruit bats forage over much larger distances compared to most other Old World fruit bats, thus providing vital ecosystem services across extensive landscapes. We recommend increased efforts aimed at maintaining E. helvum populations throughout Africa since their keystone role in various ecosystems is likely to increase due to the escalating loss of other seed dispersers as well as continued urbanization and habitat fragmentation.
authors.affiliation: Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology (MPIO), Am Obstberg 1, 78315, Radolfzell, Germany; Department of Biology, University of Konstanz, Konstanz, Germany; Zoological Institute, TU Braunschweig, Braunschweig, Germany.
authors.forename: Jakob
authors.initials: J
authors.lastname: Fahr
authors.affiliation: Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology (MPIO), Am Obstberg 1, 78315, Radolfzell, Germany; Department of Biology, University of Konstanz, Konstanz, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Abedi-Lartey
authors.affiliation: German Remote Sensing Data Center (DFD), German Aerospace Center (DLR), Oberpfaffenhofen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Esch
authors.affiliation: Luxembourg Institute of Science and Technology (LIST), Belvaux, Luxembourg.
authors.forename: Miriam
authors.initials: M
authors.lastname: Machwitz
authors.affiliation: Wildlife Division of the Forestry Commission, Accra, Ghana; University of Ghana, Legon, Accra, Ghana.
authors.forename: Richard
authors.initials: R
authors.lastname: Suu-Ire
authors.affiliation: Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology (MPIO), Am Obstberg 1, 78315, Radolfzell, Germany; Department of Biology, University of Konstanz, Konstanz, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wikelski
authors.affiliation: Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology (MPIO), Am Obstberg 1, 78315, Radolfzell, Germany; Department of Biology, University of Konstanz, Konstanz, Germany.
authors.forename: Dina K N
authors.initials: DK
authors.lastname: Dechmann
mesh_terms: D061725:Accelerometry; D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D002685:Chiroptera / Q000502:physiology*; D004032:Diet; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D005426:Flight, Animal / Q000502:physiology*; D020387:Food Chain; D005638:Fruit; D040362:Geographic Information Systems; D005869:Ghana; D006801:Humans; D008297:Male; D063148:Plant Dispersal / Q000502:physiology; D058998:Remote Sensing Technology; D012621:Seasons; D014197:Trees; D014507:Urbanization