I came to the comments to say this but knew in my heart of hearts it had already been said

Sadly in the South they were hit extra hard when the invasive Burmese Python who likes similar habitats to the pygmy rattlesnake began to spread a parasitic pentasome that seems to affect pygmy rattlesnakes in particular really badly coupled with the introduction of the Cuban Tree Frog

The likeliest of explanations is that pygmys just don't do well in industrialized areas whether or not they have water sources, so as Florida developed, their populations got isolated into pockets of wetlands and costal flood plains.

Compare it to a few more common snake species like the Southern Black Racer and Eastern Rat Snake where you can see where their populations fluidly connect to eachother

You can see this scattering of populations a bit more clearly on observation maps like iNat.
Most of these areas seem to correlate with water seeming that they like to hunt in and around water but they do seem to be missing from a few vast wetland/swampland areas

Removing green iguanas from the environment and establishing protected areas for the unique island forms that will hopefully all one day get their own species status.
Also hopefully delineating these species will help protect them against the persecutions faced by Iguana iguana.

The best temporary solution is really looking to establish captive breeding groups of iguanas unique to each ISLAND not each species(many of the subspecies may one day gain species status). We don't want another Cyclura lewsi issue happening. With stable captive populations, we can work on -

Unfortunately, that won't be an easy fought battle babies of all the Iguana genus species look nearly identical to the untrained eye and without genetic testing, which can be difficult to get the funding or equipment for, its hard to tell which species you have or worse if they're hybrids

While Green Iguanas have begun to naturalize in Florida, having little impact outside of human disturbed areas, these small fragile island ecosystems just are prepared for a lizard capable of such competitive exclusion of the native island species that many island plants rely on.

Distinguishing these species will also hopefully help us disassociate them from one of their biggest threats.
Hybridization with invasive green iguanas.
While closely related, Green Iguanas didn't evolve on these islands and, therefore, don't share the balanced niche the native iguanas have.

Giving them unique delineation not only helps offer them unique protection status and raise awareness of how critical their population statistics are but also raises awareness about them. I'm certain the vast majority wouldn't even know that there are unique forms of Iguana throughout the Caribbean

While mainland Green Iguanas and their unique island relatives may share a common ancestry, these animals have become ecologically isolated for so long, and the island forms have developed unique ecologies to fill specific niches on their islands that would be under threat from their removal.

This is one of the few rare times you'll find me firmly leaning on the side of splitting. I definitely believe all of the Caribbean Iguana spp need to be split but purely for their own safety. It can often impede conservation efforts when little research is being done on what makes them unique.