Influences of Precipitation on Bison Weights in the Northern Great Plains

On the Ground
- We evaluated relationships between bison weights and prior precipitation during 1983 to 2015 for Wind Cave and 1998 to 2015 for Badlands National Parks.
- We generally found positive correlations between weights for most sex and age cohorts and precipitation during each of the preceding 7 years. The association was strongest for yearlings.
- We speculate that rainfall several years prior can improve forage, which affects the condition of cows, which affects neonatal weights and subsequent growth of young bison.
- Correlations were stronger for a moving average of previous precipitation, suggesting a cumulative effect.
- Our analysis demonstrates the importance of long-term monitoring for better understanding of grassland ecosystems.