Rest-rotation grazing, defined as lack of livestock grazing in a pasture for 15-18 months, is suggested to improve the quality of sagebrush, shrubland, and grassland habitat for a wide range of species. However, little work has been done to evaluate impacts of rest-rotation grazing on migratory avian species which serve as indicators of sagebrush ecosystem integrity. Evaluating the impacts of rest-rotation grazing using indicator species can provide valuable insight into how rest-rotation grazing may affect multiple species in the ecosystem.
Our research is focused on how different grazing systems, rest-rotation and traditional, change songbird community structure (e.g., species abundance and richness). Traditional grazing, in contrast to rest-rotation grazing, is defined as repeated livestock grazing in a pasture over multiple vegetation growing seasons. From 2013-2015 we assessed abundance of the avian communities on lands with traditional grazing and a rest-rotation grazing scheme developed as a conservation strategy with the Sage Grouse Initiative.
Here we describe our findings from the 2013, 2014, and 2015 field seasons. We focused on five species that represent the range of vegetation use within our study area. Brewer’s sparrow (Spizella breweri), a sagebrush obligate, depends on sagebrush for important life history requirements, including foraging and breeding activities. McCown’s longspur (Rhynchophanes mccownii) is a grassland obligate. Horned lark (Eremophila alpestris), vesper sparrow (Pooecetes gramineus), and western meadowlark (Sturnella neglecta) are associated with both sagebrush and grassland vegetation.
General patterns in individual species abundance have been consistent for the three sampling years. Three species, Brewer’s sparrow, horned lark, and vesper sparrow, have shown no significant difference in abundance between traditional and rest-rotation grazing. McCown’s longspur and western meadowlark have shown significant differences in abundance between the traditional and rest-rotation grazing. McCown’s longspur was more than twice as abundant on rest-rotation than traditional grazing. In contrast, western meadowlark was more than twice as abundant on traditional grazing as rest-rotation grazing.
