What does hark a Stark Bark in the Park mean?

Hark = Listen to

stark = severe or bare in appearance

bark = the sharp explosive cry of certain animals

park = a large public green area in a town

As a sentence, it doesn't mean much of anything since "stark" (referring to appearance) isn't a modifier one would use with "bark" (referring to sound).

The original sentence: "Hark, a Stark Bark in the Park!" remarks Patriarch Quark is part of a lesson in Words on the Vine about mother/father vocabulary Words and targets "patriarch" -- the male head of a family or tribe. It could also be used as an example of consonance of sound -- the internal rhyming Words. I suspect its main function is to show how clever the writer thinks he or she is.