Tamarisk Beetle found along Colorado River within Grand Canyon

This was a fascinating read. Biological solutions always seem to have unintended consequences. Someone here (POFR?) mentioned that native species have had trouble reestablishing after the Tammies are gone. Time will tell. Tammies were and are a big problem. lets hope bigger concerns don’t replace them

Grand Canyon National Park News Release Release date: Immediate

Contact(s): Maureen Oltrogge Phone number: 928-638-7779 Date: October 21, 2009

Tamarisk Beetle (Diorhabda spp.) found along Colorado River within Grand Canyon National Park

Grand Canyon, Ariz. —Biologists and ecologists from the National Park

Service and the Tamarisk Coalition, based in Grand Junction, Colorado,

recently found the first tamarisk leaf beetle (Diorhabda spp.) in Grand

Canyon National Park. The tamarisk leaf beetle, which feeds specifically

on tamarisk, was approved for release as a biological control agent in

certain areas of the west in 2001 to help manage tamarisk. Also known as

salt cedar, tamarisk (Tamarix spp.) is a highly invasive plant native to

Eurasia that grows along the Colorado River and in riparian habitats

throughout the southwest. Tamarisk, which is particularly successful in

areas with altered flow regimes, impacts water resources, native plant

diversity, wildlife habitat, and recreation, and poses an increased

wildfire risk where it grows in dense stands.

The National Park Service and numerous partners began a tamarisk management

program in Grand Canyon National Park in 2000. The effort focuses on the

park’s side canyons and tributaries, where a natural flow regime occurs.

To date, approximately 270,000 trees have been removed from over 6,000

acres in the park. Park biologists and volunteers continue to maintain

those areas, and have documented the important recovery of native

vegetation. Lori Makarick, the park’s Vegetation Program Manager, stated,

“We plan on continuing this program, and in fact, have people removing

tamarisk from the park’s backcountry this week.” She added, “Now that the

tamarisk beetle has been found in the park, we also need to make sure we

are prepared to move forward with active native plant restoration efforts

in the Colorado River Corridor in the next few years.”

Tamarisk beetle monitoring along the Colorado River in Grand Canyon

National Park was conducted from August 9-24. During monitoring, small

numbers of beetle larvae were found on tamarisk trees along both sides of

the river corridor beneath Navajo Bridge and on river left at Brown’s

Inscription, twelve miles downstream of Lees Ferry. National Park Service

biologists found adult beetles six miles downstream of Lees Ferry in

September.

Researchers previously thought that this species of the tamarisk leaf

beetle would restrict its range to above the 38th parallel, which is near

the upper end of Lake Powell. The beetles were not approved for release

within 200 miles of southwestern willow flycatcher habitat, an endangered

species which is known to nest in tamarisk – a dominant species in the

Colorado River corridor. Tamarisk leaf beetles are now causing defoliation

of tamarisk trees further south than originally anticipated. According to

Dr. Dan Bean of the Colorado Department of Agriculture, the small

population of beetles recently documented in Grand Canyon National Park is

unlikely to overwinter successfully. However, it appears likely that as

beetle numbers increase a viable reproducing population will be established

in Grand Canyon within the next several years.

The Tamarisk Coalition, whose mission is to provide education and technical

assistance for the restoration of riparian lands in the west, and the

Colorado Department of Agriculture are collaboratively monitoring the

tamarisk beetle in Colorado, Utah and Arizona. They are tracking its

dispersal, establishment, and expansion and providing information on

impacts of the beetle on riparian native and non-native plant ecology and

wildlife habitat. Tim Carlson, Tamarisk Coalition Research and Policy

Director, notes, “Monitoring of beetle movement and vegetative response are

critically important, not only to understand the direct and indirect

impacts of the beetle on riparian ecosystems, but in order to implement

adaptive management activities aimed at re-establishing native vegetation.”

According to Lori Makarick, this will become increasingly important in

areas along the Colorado River corridor that provide critical habitat for

threatened and endangered species.

The continued spread of the tamarisk leaf beetle throughout the Colorado

River in Grand Canyon National Park may have dramatic impacts on the

canyon’s complex riparian ecosystems. Growing infestations of the tamarisk

leaf beetle in Grand Canyon may defoliate and kill tamarisk trees that now

dominate the river corridor. While the demise of this nonnative invader is

welcome, it will pose new management challenges such as: how to remove the

standing dead trees, how to assess rapid changes in wildlife habitat, and

how to successfully restore native plant communities. Park resource

managers are eager to expand and develop new partnerships with other

federal land management agencies and organizations to assist with the

development of long-term plans to restore native ecosystems in the Colorado

River corridor both within and outside park boundaries. Plans will need to

address potential impacts to species of special concern, such as the

southwestern willow flycatcher and the wide array of insects and wildlife

that currently utilize tamarisk. The initiation of the tamarisk beetle

monitoring effort was the first step in a pro-active approach that will

include coordination among stakeholders involved in planning and

implementing riparian restoration projects.

Martha Hahn, Chief of Science and Resource Management, stated, “This is a

situation where there are no boundaries and we will need to work with all

land management agencies within the greater Colorado River watershed that

wildlife habitat and sensitive species planning is integrated into all of

our planning efforts and decisions.

Superintendent Steve Martin said, “Park resource management staff, as well

as staff from other federal land management agencies and partner

organizations has been very successful in controlling tamarisk in the

park’s side canyons. With continued coordination and stakeholder

involvement, we should be successful in actively restoring native plant

communities and wildlife habitat in the river corridor.”

For additional information, please contact Lori Makarick, Vegetation

Program Manager at Grand Canyon National Park at (928) 226-0165 or Tim

Carlson, Research and Policy Director at the Tamarisk Coalition (970)

256-7400 www.tamariskcoalition.org.

-NPS-

Maureen Oltrogge Public Affairs Officer Grand Canyon National Park (928) 638-7779 (928) 638-7609 fax maureen_oltrogge@…