Journal of Insect Conservation

, Volume 13, Issue 3, pp 329–345

Loss of genetic connectivity and diversity in urban microreserves in a southern California endemic Jerusalem cricket (Orthoptera: Stenopelmatidae: Stenopelmatus n. sp. “santa monica”)

  • Amy G. Vandergast
  • Eric A. Lewallen
  • Joseph Deas
  • Andrew J. Bohonak
  • David B. Weissman
  • Robert N. Fisher
Original Paper

DOI: 10.1007/s10841-008-9176-z

Cite this article as:
Vandergast, A.G., Lewallen, E.A., Deas, J. et al. J Insect Conserv (2009) 13: 329. doi:10.1007/s10841-008-9176-z

Abstract

Microreserves may be useful in protecting native arthropod diversity in urbanized landscapes. However, species that do not disperse through the urban matrix may eventually be lost from these fragments. Population extinctions may be precipitated by an increase in genetic differentiation among fragments and loss of genetic diversity within fragments, and these effects should become stronger with time. We analyzed population genetic structure in the dispersal limited Jerusalem cricket Stenopelmatus n. sp. “santa monica” in the Santa Monica Mountains and Simi Hills north of Los Angeles, California (CA), to determine the impacts of fragmentation over the past 70 years. MtDNA divergence was greater among urban fragments than within contiguous habitat and was positively correlated with fragment age. MtDNA genetic diversity within fragments increased with fragment size and decreased with fragment age. Genetic divergence across 38 anonymous nuclear Inter-Simple Sequence Repeat (ISSR) loci was influenced by the presence of major highways and highway age, but there was no effect of additional urban fragmentation. ISSR diversity was not correlated with fragment size or age. Differing results between markers may be due to male-biased dispersal, or different effective population sizes, sorting rates, or mutation rates among sampled genes. Results suggest that genetic connectivity among populations has been disrupted by highways and urban development, prior to declines in local population sizes. We emphasize that genetic connectivity can rapidly erode in fragmented landscapes and that flightless arthropods can serve as sensitive indicators for these effects.

Keywords

Habitat fragmentation Insects ISSR loci mtDNA sequences Population genetic structure 

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Amy G. Vandergast
    • 1
  • Eric A. Lewallen
    • 1
    • 2
  • Joseph Deas
    • 1
    • 3
  • Andrew J. Bohonak
    • 4
  • David B. Weissman
    • 5
  • Robert N. Fisher
    • 1
  1. 1.U.S. Geological SurveyWestern Ecological Research CenterSan DiegoUSA
  2. 2.Department of Biological SciencesUniversity of Toronto at ScarboroughTorontoCanada
  3. 3.Insect ScienceThe University of ArizonaTucsonUSA
  4. 4.Department of BiologySan Diego State UniversitySan DiegoUSA
  5. 5.Department of EntomologyCalifornia Academy of SciencesSan FranciscoUSA

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