School of Health Sciences
Dickcissel, population modeling, tallgrass prairie
Spahr, Lauren A., "The Interactive Effects of Annual Climatic Variability and Rangeland Management on the Reproductive Success of Dickcissels (Spiza americana)" (2017). Senior Honors Theses. 689.
Grassland songbird populations have declined due to poor rangeland management and habitat fragmentation. Few studies have taken into account variation in climatic conditions in tallgrass prairie systems when determining the factors contributing to songbird reproductive success. During a six year study we measured reproductive success in Dickcissels on five rangeland treatments. We estimated daily survival rates (DSRs) and linked estimates of daily survival to rangeland management type and climate data. DSRs were best predicted by the model including mean temperature, winter season precipitation, and interactions, which had 7.5 times more support than the constant model. Mean annual temperature was negatively correlated with daily survival rates. Thus climate conditions play important roles in the health and stability of grassland songbird populations.