Timing of Cattle Graze as a Management Tool for Plant and Invertebrate Communities in the Centnenial Valley, Montnana

Scientific Disciplines
Biological Sciences - Terrestrial
Montana State University
Centennial Valley
climate variability
invertebrate communities
wateraddition treatment
plant invertebrate communities
graze timing
ecological heterogeneity
biological diversity,
Volume 18, No. 1-4

Timing of cattle graze as a management tool 
For plant and invertebrate communities in the 
Centnenial valley, Montnana
Stacy C. Davis*, Laura Burkle, and Wyatt Cross, Ecology Department, Montana State University, 
Bozeman, Montana 59717
Kyle Cutting, US Fish and Wildlife Service, Red Rock Lakes NWR, Lima, Montana 59739
Grazing is an important natural disturbance in the western US. While many studies 
have focused on the effects of grazing intensity and frequency, little is known about the 
importance of graze timing and how it can affect plant and invertebrate community structure 
and productivity. Timing may be a critical factor for promoting ecological heterogeneity, 

biological diversity, and abundance of food resources for native birds. Our primary goal 
is to understand how timing of graze and climate variability interact to influence plant and 
invertebrate communities throughout the growing season in wet meadows and grasslands 
in the Centennial Valley of southwest Montana. In 2011, control (no graze), early graze 
(beginning June 15), and traditional late graze (beginning July 15) treatments were established 
and replicated in a heterogeneous, irrigated, wet meadow habitat. From June-September, plant 
and invertebrate communities were quantitatively sampled to examine dynamics of biomass 
and diversity. In 2012, a similar experimental design will be implemented in a less-disturbed 
and drier native grassland. A new component will examine interactions between climate 
variability and timing by incorporating a water-addition treatment to simulate the extra 
moisture resulting from a wet year. We predict that increased climate variability will likely 
impact wet meadow and grassland habitat plant and insect phenology, with timing of graze 
becoming particularly critical during dry years. We will discuss results from 2011 and where 
we plan to go in 2012 with the water-addition treatment.