Tamarisk biocontrol using tamarisk beetles: Potential consequences for riparian birds in the southwestern United States

The Condor
By: , and 



The tamarisk beetle (Diorhabda spp.), a non-native biocontrol agent, has been introduced to eradicate tamarisk (Tamarix spp.), a genus of non-native tree that has become a dominant component of riparian woodlands in the southwestern United States. Tamarisk beetles have the potential to spread widely and defoliate large expanses of tamarisk habitat, but the effects of such a widespread loss of riparian vegetation on birds remains unknown. We reviewed literature on the effects of other defoliating insects on birds to investigate the potential for tamarisk beetles to affect birds positively or negatively by changing food abundance and vegetation structure. We then combined data on the temporal patterns of tamarisk defoliation by beetles with nest productivity of a well-studied riparian obligate, the Southwestern Willow Flycatcher (Empidonax traillii extimus), to simulate the potential demographic consequences of beetle defoliation on breeding riparian birds in both the short and long term. Our results highlight that the effects of tamarisk biocontrol on birds will likely vary by species and population, depending upon its sensitivity to seasonal defoliation by beetles and net loss of riparian habitat due to tamarisk mortality. Species with restricted distributions that include areas dominated by tamarisk may be negatively affected both in the short and long term. The rate of regeneration and/or restoration of native cottonwoods (Populus spp.) and willows (Salix spp.) relative to the rate of tamarisk loss will be critical in determining the long-term effect of this large-scale ecological experiment.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Tamarisk biocontrol using tamarisk beetles: Potential consequences for riparian birds in the southwestern United States
Series title The Condor
Volume 113
Issue 2
Year Published 2011
Language English
Publisher University of California Press
Publisher location Berkeley, CA
Contributing office(s) Pacific Island Ecosystems Research Center, Southwest Biological Science Center
Description 11 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title The Condor
First page 255
Last page 265
Country United States
Online Only (Y/N) N
Additional Online Files (Y/N) N
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