Submitted to: Arid Land Research and Management
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/9/2009
Publication Date: N/A
Citation: Interpretive Summary: Reestablishment of Wyoming big sagebrush on mined lands is required if it is a component of the rangeland plant community prior to disturbance. However, successful long-term establishment and growth of this species has been difficult due to the heavy utilization by wildlife on some mines in Wyoming and other parts of the Great Plains and Great Basin. To fully assess the impacts of wildlife and to assess which species of wildlife are responsible for the excess browse a study was initiated by establishing a wildlife exclosure on an existing sagebrush establishment research plot in Wyoming. We found that exclusion of wildlife greatly enhanced the growth of big sagebrush and significantly reduced the mortality on the big sagebrush plants. Our data indicated that rabbits were the major browser of the big sagebrush and that utilization was greatest during the winter months. Sagebrush utilization was least on the heaviest grass seeding treatments indicating some protection from browse by the dense grass community. These findings will aid the mining industry and regulatory agency assess success of big sagebrush reestablishment and separate out the impacts of wildlife utilization. Wildlife impacts could be reduced by providing fewer rockpiles on reclaimed lands for rabbits and other small mammals, erection of raptor perches, and management of adjacent undisturbed rangelands.
Technical Abstract: Wildlife browsing of Artemisia tridentata (big sagebrush) on reclaimed coal mined land threatens long-term, sustainable reclamation success. A wildlife-proof exclosure was constructed in 2001 on a 10-year old A. tridentata reestablishment research site at North Antelope Coal mine in northeastern Wyoming to assess wildlife browsing impacts. Artemisia tridentata survival, growth, and plant community attributes (species richness, canopy cover, and diversity) were evaluated inside and outside the exclosure, across the original grass seeding rate treatments (0, 16, 32 kg PLS ha-1). Long-term A. tridentata density decreased across all seeding rates from 1994 to 2002. Higher A. tridentata density, leader (shoot) growth, and canopy cover, along with lower mortality, occurred inside the exclosure across all seeding rates. Lower winter use, higher survival, and lower mortality of A. tridentata in the 32 compared to the 0 and 16 kg PLS ha-1 seeding rates suggest a beneficial relationship between A. tridentata survival and higher grass seeding rate. Approximately 33% mortality of marked A. tridentata plants occurred outside the exclosure. Lepus townsendii campanius (white-tailed jackrabbit), L. californicus melanotis (black-tailed jackrabbit), and Sylvilagus audubonii baileyi (cottontail rabbit) were identified as primary browsers of A. tridentata. Plant species richness, cover, and diversity decreased from 2001 to 2002, probably due to below average precipitation during the study. Defoliation of A. tridentata was severe, indicating the magnitude of impact from browsing wildlife. Post mining wildlife management and habitat manipulation on adjacent rangeland is suggested to ensure successful reclamation of coal mined lands.