Response of Western Thatching Ant (Formica obscuripes) Colonies to Mechanical Shrub Crushing and Livestock Exclusion in a Wyoming Big Sagebrush (Artemisia tridentata wyomingensis) Community. Technical Bulletin 2009-1

摘要

Western thatching ants are common to sagebrush steppe ecosystems, building conspicuous mounds of twigs and other vegetation (thatch) to establish and protect their colonies. Thatching ants are important predators of many insects, such as grasshoppers and beetles, and aggressively defend aphids against other predators. Aphid secretions (honeydew) are an important energy source for the ants. Thatching ants and other insects are essential in the diets of greater sage-grouse (Centrocercus urophasianus) chicks as well as other passerine birds, small mammals, and lizards. The sagebrush steppe ecosystem has experienced substantial alterations across its range over the past 150 years with about 75% of the area considered irretrievably altered as a result of agricultural and rural development, wildfire and subsequent dominance by invasive annual grasses and forbs, and historical overgrazing. Greater sage-grouse as well as other sagebrush steppe dependent species (e.g., Brewers sparrow, sage thrasher, and sage sparrow) have experienced substantial population declines in recent decades. Land managers are anxious to develop methods to restore rangelands to healthy communities of sagebrush and herbs.