Non-native bugs threatening habitat for endangered songbirds
By Summit Voice
FRISCO — Conservation advocates say non-native tamarisk-eating bugs have gone haywire, destroying habitat needed by endangered southwestern willow flycatchers, native songbirds that need thick riparian vegetation to survive.
The exotic beetles were imported from Asia to destroy invasive tamarisk plants seen as a threat to water resources, but now the bugs have invaded the nesting areas of southwestern willow flycatchers in southern Utah, Nevada, and northern and western Arizona. If the beetle spreads farther without mitigation, it could seriously threaten the flycatcher’s survival, according to Dr. Robin Silver, with the Center for Biological Diversity.
Efforts to eradicate tamarisk are costly and labor-intensive, and some recent research by the U.S. Geological Survey indicates that exotics (including Russian Olive) use about the same amount of water as native willows and cottonwoods.
In June 2010, the U.S. Department of Agriculture temporarily restricted release of the insects based on concerns about impacts to flycatcher habitat. The decision is outlined in this USDA memo.
Along with Maricopa Audubon, the CBD last week filed a notice of intent to sue the U.S. Department of Agriculture and APHIS, the USDA’s Animal and Plant Health Inspection Service, over their failure to safeguard flycatchers.
APHIS promised mitigation if its release of the beetles went awry, but has not taken the steps necessary — including planting native willows and cottonwoods to replace dying tamarisk — to help the endangered flycatchers.
“APHIS refuses to clean up its own mess now that its introduction of an exotic, invasive biocontrol agent has gone haywire,” Silver said.
The U.S. Fish and Wildlife Service was also included in the notice of intent to sue for failing to protect the flycatcher as required by the Endangered Species Act; another federal agency, the Bureau of Reclamation, was included because its plans to protect the flycatcher in western Arizona are no longer sufficient due to the spread of the beetles. Today’s notice clears the way for litigation against these agencies if they fail to initiate protective actions within 60 days.
Flycatchers frequently nest where tamarisk has displaced native cottonwood and willow trees. A quarter of the birds’ territories are found in areas dominated by tamarisk, and about half are found in areas of mixed tamarisk and native trees.
“APHIS needs to consult with the Fish and Wildlife Service to develop and pay for an emergent plan to ensure that native species provide alternative habitat for the highly endangered flycatcher,” said Maricopa Audubon President Mark Larson.
APHIS released the tamarisk-defoliating leaf beetle with an agreement that no beetles would be released within 200 miles of flycatcher habitat or within 300 miles of documented flycatcher breeding areas, and that the beetles could not become established within the range of the flycatcher. Both of these agreements were broken.
In July 2006 APHIS introduced the beetles directly into flycatcher-nesting areas along the Virgin River in southern Utah.