Landscape Ecology

, Volume 27, Issue 10, pp 1451–1463

Edge and area effects on avian assemblages and insectivory in fragmented native forests

  • Luc Barbaro
  • Eckehard G. Brockerhoff
  • Brice Giffard
  • Inge van Halder
Research Article

DOI: 10.1007/s10980-012-9800-x

Cite this article as:
Barbaro, L., Brockerhoff, E.G., Giffard, B. et al. Landscape Ecol (2012) 27: 1451. doi:10.1007/s10980-012-9800-x
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Abstract

Disentangling the confounded effects of edge and area in fragmented landscapes is a recurrent challenge for landscape ecologists, requiring the use of appropriate study designs. Here, we examined the effects of forest fragment area and plot location at forest edges versus interiors on native and exotic bird assemblages on Banks Peninsula (South Island, New Zealand). We also experimentally measured with plasticine models how forest fragment area and edge versus interior location influenced the intensity of avian insectivory. Bird assemblages were sampled by conducting 15 min point-counts at paired edge and interior plots in 13 forest fragments of increasing size (0.5–141 ha). Avian insectivory was measured as the rate of insectivorous bird attacks on plasticine models mimicking larvae of a native polyphagous moth. We found significant effects of edge, but not of forest patch area, on species richness, abundance and composition of bird assemblages. Exotic birds were more abundant at forest edges, while neither edge nor area effects were noticeable for native bird richness and abundance. Model predation rates increased with forest fragmentation, both because of higher insectivory in smaller forest patches and at forest edges. Avian predation significantly increased with insectivorous bird richness and foraging bird abundance. We suggest that the coexistence of native and exotic birds in New Zealand mosaic landscapes enhances functional diversity and trait complementation within predatory bird assemblages. This coexistence results in increased avian insectivory in small forest fragments through additive edge and area effects.

Keywords

Area effects Avian insectivory Edge effects Exotic birds Forest fragmentation Mosaic landscapes Native birds New Zealand Plasticine models 

Supplementary material

10980_2012_9800_MOESM1_ESM.doc (32 kb)
Supplementary material 1 (DOC 31 kb)

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Luc Barbaro
    • 1
    • 2
  • Eckehard G. Brockerhoff
    • 3
  • Brice Giffard
    • 1
    • 2
  • Inge van Halder
    • 1
    • 2
  1. 1.INRA, BIOGECO, UMR1202CestasFrance
  2. 2.Univ. Bordeaux, BIOGECO, UMR1202TalenceFrance
  3. 3.SCION, New Zealand Forest Research InstituteChristchurchNew Zealand

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