That sounds extremely iffy to me. The "disturbance" may be short lived, and the space they take up may be a small portion of the island, but I find it hard to believe that the degree of disturbance caused by a rocket launch can be canceled out by its brevity.
Why not? The latest statistics I could find say that about 22 launches per year happen there. At each launch pad there are probably only a fraction of those. But even if the disturbance is approximately 2 minutes long (a slowly rising rocket), that's less than 1 hour per year. I find it hard to believe that wildlife cannot cope with that.
My understanding is that the noise from a rocket launch is so loud, even 10 miles away, that you have to shout over it to be heard. One mile from the launchpad, it's loud enough to damage your ears.
If it wasn't a launch area it would probably not be a wildlife refuge, especially since there is already an existing refuge, Assateague Island, right next door.
It would most likely be packed with vacation homes, just like the rest of the Mid-Atlantic shoreline.
Disclaimer: I saw this launch from Assateague and it was awesome. I was too far away to see any flying frogs, but the mosquitos and bats did not seem too upset where I was.