Cattle and Salmon I: Cattle Distribution and Behavior in a Northeastern Oregon Riparian Ecosystem

Abstract

This 2-year study was designed to quantify the influence of terrestrial and stream habitats on cattle distribution and behavior in a riparian pasture with access to active chinook salmon (Oncorhynchus tshawytscha) spawning. The active salmon redds accessible to cattle were at a density of 4.6 redds per km in 1996 and 6.1 redds per km in 1997. The stocking rate was maintained at 0.82 ha AUM-1 for 28 days. Cattle spent approximately 94% of their time in the terrestrial habitats (meadow, disturbance, low shrub, tall shrub, and trees) that supported herbivory-type activities (travel, graze, and rest), the remaining time was spent in stream habitats, which consisted of gravel bar (5%) and in aquatic (, 1%) habitats. Cattle spent approximately 88% of their time on nonherbivory-type activities while in the aquatic habitat. Individual cows were observed during the daylight hours for 18 of 28 days each year they were in the pasture and were never observed in direct contact with a redd. Cattle spent over half of their time drinking and < 0.01% of their time defecating while they were in the aquatic habitat. Defecation was proportional to time spent in each habitat; so about 2% of the manure was directly deposited in the stream.