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Submitted to: Journal of Wildlife Management
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/19/2011 Publication Date: 5/1/2012 Citation: Augustine, D.J., Derner, J.D. 2012. Disturbance regimes and mountain plover habitat in shorgrass steppe: Large herbivore grazing does not substitute for prairie dog grazing or fire. Journal of Wildlife Management. 76(4):721-728. Interpretive Summary: The presence of prairie dogs and the use of prescribed fire in grasslands of the western Great Plains can conflict with livestock production goals. However, conditions created by burning or prairie dog grazing can potentially be important for some native grassland birds. We studied habitat for the mountain plover, a grassland bird that breeds in the western Great Plains, in relation to prescribed fire, grazing by cattle, and grazing by black-tailed prairie dogs. Studies were conducted on the Pawnee National Grassland and the Central Plains Experimental Range in Weld County, Colorado. Breeding mountain plovers primarily occurred on black-tailed prairie dog colonies or areas burned during the previous dormant season. Vegetation surrounding mountain plover nests and foraging locations was characterized by small clusters of short vegetation interspersed with high amounts of bare soil. Mountain plovers rarely occupied grassland lacking prairie dogs or recent fire, but those that did selected sites with similar vegetation height and bare soil exposure as sites on burns and prairie dog colonies. Vegetation structure at mountain plover-occupied sites was also similar to randomly located sites on burns and prairie dog colonies, but differed from sites managed only with cattle. Very heavy cattle grazing (2x recommended stocking rate) in spring (March–May) or summer (May–October) for six years produced less bare soil than burns and prairie dog colonies, particularly following years with average or above-average precipitation. These findings indicate that very heavy cattle grazing does not serve as a substitute for prairie dog grazing or fire in terms of effects on vegetation structure and mountain plover habitat. Both prescribed burning and management to increase the size and distribution of black-tailed prairie dog colonies appear to be important and complementary means to manage for mountain plover breeding habitat in shortgrass steppe. Provision of mountain plover habitat has tradeoffs with traditional management for livestock production in shortgrass steppe, highlighting the need for land managers to clearly define management goals on lands managed for multiple outcomes. Technical Abstract: Restoring historic disturbance regimes in North American grasslands can conflict with livestock production goals and has been controversial due to uncertainty in the importance and pattern of different disturbances prior to European settlement. Understanding responses of native fauna to disturbance regimes can provide insight to their historic role in grasslands. We studied nesting habitat for the mountain plover (Charadrius montanus) in relation to prescribed fire, grazing by large herbivores (cattle), and grazing by black-tailed prairie dogs (Cynomys ludovicianus) in the shortgrass steppe of northeastern Colorado. Breeding mountain plovers primarily occurred on black-tailed prairie dog colonies or areas burned during the previous dormant season. Vegetation surrounding mountain plover nests and foraging locations was characterized by a fine-scale mosaic of prostrate (<4 cm tall) vegetated patches interspersed with high levels of bare soil (>35%) within 1-m2 plots. This fine-scale pattern was distributed homogenously over a broad (> 100 m radius) area. Mountain plovers rarely occupied grassland lacking prairie dogs or recent fire, but those that did selected sites with similar vegetation height and bare soil exposure as sites on burns and prairie dog colonies. Vegetation structure at mountain plover-occupied sites was also similar to randomly located sites on burns and prairie dog colonies, but differed substantially from sites managed only with cattle. Very heavy cattle grazing (2x recommended stocking rate) implemented in spring (March–May) or summer (May–October) for six years produced significantly less bare soil than burns and prairie dog colonies, particularly following years with average or above-average precipitation. These findings indicate that very heavy cattle grazing does not serve as a substitute for prairie dog grazing or fire in terms of effects on vegetation structure and mountain plover habitat. Both prescribed burning and management to increase the size and distribution of black-tailed prairie dog colonies appear to be important and complementary means to manage for mountain plover breeding habitat in shortgrass steppe. Provision of mountain plover habitat has tradeoffs with traditional management for livestock production in shortgrass steppe, highlighting the need for land managers to clearly define desired outcomes for management to provide multiple ecosystem goods and services. |
