Biological Invasions

, Volume 16, Issue 8, pp 1675–1687

Declines in a ground-dwelling arthropod community during an invasion by Sahara mustard (Brassica tournefortii) in aeolian sand habitats

  • Heather L. Hulton VanTassel
  • Anne M. Hansen
  • Cameron W. Barrows
  • Quresh Latif
  • Margaret W. Simon
  • Kurt E. Anderson
Original Paper

DOI: 10.1007/s10530-013-0616-7

Cite this article as:
Hulton VanTassel, H.L., Hansen, A.M., Barrows, C.W. et al. Biol Invasions (2014) 16: 1675. doi:10.1007/s10530-013-0616-7
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Abstract

Sahara Mustard (Brassica tournefortii; hereafter mustard), an exotic plant species, has invaded habitats throughout the arid southwestern United States. Mustard has reached high densities across aeolian sand habitats of southwestern deserts, including five distinct sand habitats in the eastern Coachella Valley, California. We examined trends in ground-dwelling arthropod community structure concurrent with mustard invasion in 90 plots within those habitats from 2003 to 2011 (n = 773 plot·years). We expected arthropod communities to respond negatively to mustard invasion because previous work documented significant negative impacts of mustard on diversity and biomass of native plants, the primary resource base for many of the arthropods. Arthropod abundance and species richness declined during the study period while mustard cover increased, and arthropod metrics were negatively related to mustard cover across all plots. When controlling for non-target environmental correlates (e.g. perennial frequency and precipitation) and for potential factors that we suspected of mediating mustard effects (e.g. native cover and sand compaction), negative relationships with mustard remained statistically supported. Nevertheless, arthropod richness’s relationship decreased slightly in strength and significance suggesting that mechanistic pathways may be both direct (via habitat structure) and indirect (via native cover suppression and sand compaction). However, mechanistic pathways for mustard effects, particularly on arthropod abundance, remain unclear. Most arthropod taxa, including most detritivores, decreased through time and were negatively related to mustard cover. In contrast, many predators were positively related to mustard. In total, our study provides substantial evidence for a negative effect of Sahara mustard on the structure of a ground-dwelling arthropod community.

Keywords

Community structure Arid environments Invasive species impacts Bottom-up effects Aeolian sand dunes 

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Heather L. Hulton VanTassel
    • 1
  • Anne M. Hansen
    • 2
  • Cameron W. Barrows
    • 3
  • Quresh Latif
    • 3
    • 4
  • Margaret W. Simon
    • 5
  • Kurt E. Anderson
    • 1
  1. 1.Department of BiologyUniversity of California, RiversideRiversideUSA
  2. 2.Department of StatisticsUniversity of California, RiversideRiversideUSA
  3. 3.Center for Conservation BiologyUniversity of California, RiversideRiversideUSA
  4. 4.Rocky Mountain Research StationU.S. Forest ServiceBozemanUSA
  5. 5.Department of BiologyUniversity of California, Los AngelesLos AngelesUSA

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