What kind of glue for spanish cedar?

You may also want to ask around to see if anyone you know has a biscuit cutter. Slapping two to three biscuits between each piece of wood will dramatically improve the tensile strength as well as torsional strength of the end shelf.

If you lived near me I would have you come over and we could have those biscuit holes cut in less than 5 minutes for all of them.

Give it a thought. Maybe get a toolstore to "demonstrate" one of their biscuit joiners on your shelf wood.

Then use what ever glue you want from the above suggestions....I am none to clever when it comes to all those big city folk with their new fangled high tech glues