Twenty-first-century ecology requires statistical fluency. Ecological observations now include diverse types of data collected across spatial scales ranging from the microscopic to the global, and at temporal scales ranging from nanoseconds to millennia. Ecological experiments now use designs that account for multiple linear and non-linear interactions, and ecological theories incorporate both predictable and random processes. Ecological debates often revolve around issues of fundamental statistical theory and require the development of novel statistical methods. In short, if we want to test hypotheses, model data, and forecast future environmental conditions in the 21st century, we must move beyond basic statistical literacy and attain statistical fluency: the ability to apply statistical principles and adapt statistical methods to non-standard questions. Our prescription for attaining statistical fluency includes two semesters of standard calculus, calculus-based statistics courses, and, most importantly, a commitment to using calculus and post-calculus statistics in ecology and environmental science courses.