In order to make this consideration and offer analysis, it would be useful to define the terms metaphysical, epistemological, and motivational.
Metaphysical is the study of a thought process, for example how a person perceives things, how one reasons, how one communicates. It is a way of dealing with abstract concepts. It is the study of what is real.
Epistemologocal is the justification of the claimed knowledge. Or, simply put, it is the study of knowledge itself. How can you KNOW something, in other words.
Motivational is that which inspires to action or thought.
That having been said, then, the metaphysical notion that morality requires a religious foundation is dependent on the questioner's concept of morality. Once a rubric for morality is determined, then one can claim that morality indicates that a religious foundation produces or gives rise, more often than not, to morality in a group or society.
Epistimologically speaking, the studies would seem to indicate that those areas where religious practices are strong and expected amongst its population, the most commonly considered products of morality are displayed. This is observable, quantifiable, and repeatable.
Motivationally speaking, case studies, eye witness accounts, and testimonies could inspire audiences or readers to follow religious practices as one possible, and potential, way to a moral life.