Environment: Feds face lawsuit over tamarisk-killing beetle

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Southwestern willow flycatcher. Photo courtesy USFWS.

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. (more…)

Environment: Tamarisk biocontrol may work after all

Imported leaf-eating beetles slowly adapting to local ecosystems

Tamarisk along the Colorado River near Moab. Photo courtesy Tom Dudley.

By Summit Voice

SUMMIT COUNTY — Efforts to control invasive tamarisk plants along the Arkansas River are looking up, thanks to a boost from some unexpected evolutionary adaptations. A small imported but that eats and kills the water-sucking plants has been expanding its range and reproducing more efficiently after adapting to regional cycles of darkness and light.

“This is one of the clearest cases of rapid evolution,” said Tom Dudley, who has been involved in the tamarisk control efforts at UC Santa Barbara’s Marine Science Institute Riparian Invasive Research Laboratory.

The tamarisk leaf beetle has managed to delay its entry into hibernation to adapt to the shorter days of the southern region of the United States. That adaptation enables the beetle to survive until spring and prolongs the time it has to reproduce. (more…)

Feds nix bugs for tamarisk control on Colorado River

A nest of southwestern willow flycatchers nesting in saltcedar. PHOTO COURTESY U.S. GEOLOGICAL SURVEY.

Impacts to endangered birds at issue; latest studies show the non-native plants don’t use as much water as previously believed

SUMMIT COUNTY — Land managers looking for ways to control invasive tamarisk trees in the Colorado River Basin may have to search for a new tool.

The U.S. Department of Agriculture has terminated the use of a non-native insect used to destroy tamarisk after concluding that the bug was destroying critical habitat used by the southwestern willow flycatcher, listed as endangered by the federal government. The decision, announced in a June 15 memo, affects biological control efforts in 13 states.

Tamarisk, also called saltcellar, is native to the Mediterranean and central Asian region. It was brought to the U.S. to be used as a windbreak and for ornamental purposes. It quickly spread across at least 1.5 million acres in the arid climate and alkaline soils of the Southwest. In an ironic twist, the endangered flycatcher has taken to nesting in tamarisk.

In the past 10 years, various public agencies launched a costly and labor-intensive effort to prevent the stubborn shrub from spreading farther, and to eradicate it in areas where it’s already established. Initial estimates of tamarisk water use were alarming, which created a sense of urgency.  (more…)

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