Regional demographic trends from long-term studies of saguaro (Carnegiea gigantea) across the northern Sonoran Desert

► Ten Sonoran Desert saguaro populations were monitored and aged from 1959 to 2005. ► Age structure and regeneration rates vary widely across census dates and sites. ► Saguaro regeneration was highest in 1780-1860, similar to ponderosa pine in highlands. ► Predicting saguaro dynamics will be confounded by grass invasions and climate change.