Greater Yellowstone Area Cooperative Sand and Gravel Pit Weed Survey

Craig McClure,
USDI National Park Service,
Yellowstone National Park,
307.733.8419

Spotted knapweed is still controllable in this WMA

With several million dollars of county, state and federal money being spent each year in the Greater Yellowstone Area (GYA) on locating and controlling noxious weeds, one of the major sources of new weed infestations continues to be the distribution of weed seed infested sand and gravel from contaminated borrow pits. Sand and gravel borrow pits are a challenge from a weed management standpoint due to the constant soil disturbance and volume of equipment coming and going which could be transporting weed seeds into and out of the pit.

In 2003, the Greater Yellowstone Coordinating Committee, comprised of federal land managers in the GYA, funded a cooperative pilot project working with private pit operators, county, state and federal weed managers in Montana, Wyoming and Idaho to assess noxious weed infestations at various active pits in the GYA. Systematic survey methods were developed to record weed species, their location and relative numbers. Weed locations were identified on a map of the pit and representative photographs were taken. Working with county weed supervisors, a biological technician from Yellowstone National Park (YNP) surveyed twenty-six pits between July 16 and July 24 in Montana (13 pits), Wyoming (7 pits) and Idaho (6 pits). The surveyor used a variation of a ranking protocol that has been used in YNP since 1995. Pits were scored by types of weeds present, relative number of weeds, weed locations and history of past weed management efforts (ie do pits have a weed management plan, is it being implemented). Pits were arranged by total scores for use as a comparative tool and potential certification.

Comparisons showed that weeds in many pits were being actively managed with good control. However, some pits were not being effectively managed and had serious weed infestations whose material could potentially spread new weeds through road projects and new subdevelopments throughout the GYA.

Although this cooperative pilot project involved surveying only a portion of the pits being used in the GYA, it was helpful in increasing communication with pit operators regarding weed concerns. Many pit operators were very supportive of the program and are working to eliminate the noxious weed infestations on their property. With minimum costs of several treatments per year, most pits surveyed, particularly the newer pits, and those with smaller acreages have the potential of becoming noxious weed free pits within several years. In 2005, GYA county weed supervisors in Fremont County, ID; Teton and Park Counties, WY; and Gallatin and Park Counties, MT will be expanding and coordinating annual pit survey efforts with assistance from state and federal weed managers. Weed information obtained through these annual surveys will assist pit operators with weed control and public and private users with prevention efforts.

Through this cooperative effort, availability of material from weed-free pits would provide land managers, including transportation departments and private property owners, with a cost effective tool to reduce future weed management expenses and help protect our ranches and wildlands in the GYA. We will all benefit by having pits that help prevent new introductions, thereby saving everyone the long term costs associated with locating and controlling weeds spread by use of weed seed contaminated sand and gravel.