Journal of Insect Conservation

, Volume 19, Issue 1, pp 175–179 | Cite as

Effects of fragmentation on a distinctive coastal sage scrub bee fauna revealed through incidental captures by pitfall traps

  • Keng-Lou James HungEmail author
  • John S. Ascher
  • Jason Gibbs
  • Rebecca E. Irwin
  • Douglas T. Bolger


Recent reports of pollinator declines have revealed a need to better document how anthropogenic disturbances and biogeography jointly influence wild pollinator communities. Here, we examine the effects of urbanization-induced habitat fragmentation on the native bee fauna inhabiting coastal sage scrub habitats of San Diego County, California, USA, a hotspot of bee biodiversity. Pitfall trapping in natural reserves and scrub habitat fragments yielded 70 native bee species or morphospecies, and revealed that bee species richness was lower in fragments than in reserves. However, fragments and reserves harbored bee assemblages similar in relative abundance, evenness, and community composition. Our samples yielded multiple species that are poorly represented in four of the leading institutions with collections of native bees from the southwestern United States, as well as 16 species represented only by specimen records from outside of San Diego County. Our results highlight the importance of continued efforts to document bee assemblages in under-studied regions with respect to their faunal distribution and basic taxonomy, as well as how they are impacted by anthropogenic disturbances such as habitat fragmentation. We also discuss the value of analyzing vouchered pitfall samples for non-target taxa captured incidentally.


Anthophila Pollinators By-catch Habitat fragmentation Museum records 



We gratefully acknowledge the late G. I. Stage for identifying Hesperapis. We thank E. Glassberg for laboratory assistance. We are also grateful for the helpful comments of two anonymous reviewers. This project was funded by National Science Foundation (NSF) award DEB-9981758 to D. T. Bolger and an REU supplement to NSF award DEB-0743535 to R. E. Irwin. Bee specimen records consulted were captured with funding from Robert G. Goelet, NSF award DBI-0956388 to J. S. Ascher, and NSF award DBI-0956340 to D. Yanega. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

Conflict of interest

The authors declare no conflicts of interest.

Supplementary material

10841_2015_9763_MOESM1_ESM.docx (105 kb)
Supplementary material 1 (DOCX 105 kb)


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Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  • Keng-Lou James Hung
    • 1
    • 2
    Email author
  • John S. Ascher
    • 3
  • Jason Gibbs
    • 4
  • Rebecca E. Irwin
    • 1
  • Douglas T. Bolger
    • 5
  1. 1.Department of Biological SciencesDartmouth CollegeHanoverUSA
  2. 2.Division of Biological Sciences, Section of Ecology, Behavior, and EvolutionUniversity of CaliforniaSan Diego, La JollaUSA
  3. 3.Department of Biological SciencesNational University of SingaporeSingaporeSingapore
  4. 4.Department of EntomologyMichigan State UniversityEast LansingUSA
  5. 5.Environmental Studies ProgramDartmouth CollegeHanoverUSA

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