Invasive Plant Survey

The east side of Antelope Creek Habitat Development Area (ACHDA) has been heavily impacted by industrial activities such as oil and gas lease sites, pipelines, roads, irrigation and power lines. These activities have provided an opportunity for exploitation by non-native grass species and other weed species. Vehicle traffic is an excellent carrier for weed seed as some vehicles are traveling many hundreds of miles a day and all the seeds on the undercarriage are not cleaned off before entering the property. Other modes of introduction are through the irrigation canals, as well as on wildlife and domestic livestock. These seeds are then able to get a good start in the disturbance areas where there is no competition and eventually they spread into the surrounding prairie.

Due to the Oil and Gas industries reclamation practices of the past ACHDA has been left with many patches of crested wheat grass (Agropyron pectiniforme) (CWG) associated with the native prairie fields. These fields are typically grazed in the late summer and early fall using our deferred rest rotation. The combination of these old reclamation practices combined with this grazing regime has resulted in some very healthy CWG stands in the native prairie which have now become invasive and are moving into the native pastures due to the fact that the CWG has hardened off and is unpalatable to the cattle by the time they reach these areas.

With these points in mind we are developed a three (3) year study to determine the extent of CWG and disturbance allowed weed invasion on the ACHDA, and then to try a combination of grazing, mowing and spraying to control the CWG and invasive weeds.

Year One

The first year of the study (2007) consisted of data collection on the location of CWG and invasive weeds by searching on quad and foot following existing roads, pipelines, wells and irrigation canals and then tracking these areas with GPS. It is estimated that half of the sites have were located by the end of the field season. This data will be entered into a database and can be used as a layer in the cumulative effects database that is being developed. It will also be used in implementing control measures in the second and third years as well. The option of opening up the CWG canopy using a mower in the fall of the year should be explored as the old CWG growth may act as a grazing barrier to the cattle in year two and three of the study.

Year Two

Data collection of CWG and invasive weeds will continue.

The second year will see control measures implemented on noxious and restricted weeds that had been found during, along with eradication measures of nuisance weeds using a combination of mowing and herbicides on the areas identified in the first year.

As well in the second year the cattle will be brought into the fields while the native pasture is still dormant but the CWG is starting to grow. Five to ten cows will be fitted with GPS tracking collars so that herd movements and grazing patterns can be established (dependent on the availability of collars). This will prove or disprove our theory that the cattle will graze the CWG while it is young and tender instead of the dormant native grasses. Understanding the timing of grazing and utilization of CWG will allow us to choose appropriate control measures. Due to the unavailability of collars, this portion of the Year Two project will be put off indefinitely.

Year Three

Year three of the study will consist of analyzing the information gained from the second year and then modifying the grazing accordingly. There will also be a follow up on the weeds from the years before to see how effective the control measures have been, and to continue treatments if needed in order to insure adequate control.