Browsing Rangeland Ecology & Management, Volume 58, Number 3 (May 2005) by Authors
Cattle and Salmon I: Cattle Distribution and Behavior in a Northeastern Oregon Riparian EcosystemBallard, Teena M.; Krueger, William C. (Society for Range Management, 2005-05-01)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.
Cattle and Salmon II: Interactions Between Cattle and Spawning Spring Chinook Salmon (Oncorhynchus tshawytscha) in a Northeastern Oregon Riparian EcosystemBallard, Teena M.; Krueger, William C. (Society for Range Management, 2005-05-01)The study addressed the interaction between cattle and spawning spring chinook salmon late in the summer, when it is common for cattle to be present in pastures that have streams where spawning occurs. We addressed the occurrence of spawning in the study area and 2 potential impacts of cattle behavior during chinook salmon spawning: 1) disruption of spawning behavior by the presence of cattle near the redd and 2) the frequency of actual cattle contact with redds. Frequency of salmon redds was not significantly different in the stream reaches accessible to cattle compared with excluded reaches. Salmon continued preexisting patterns of behavior while cattle were within visible range of a redd. Cattle were seldom close to a redd and the chance for direct interaction to occur was minimal. When cattle were visibly near the active redd, cattle remained greater than 3.0 m from the active redd 84% of the time. Of the total time redds were observed, cattle contacted the redds <0.01% of the time. Previous studies have shown salmon that are harassed during spawning can retain eggs and even go completely unspawned. All salmon fully spawned in the study area in both years of the study.