Also;
Although primarily herbivores, researchers found the remains of tree snails in the stomachs of green iguanas in Bill Baggs Cape Florida State Park, suggesting that iguanas could present a threat to native and endangered species of tree snails.
from Florida Fish and Wildlife website:
green iguanas have consumed nickerbean, which is a host plant of the endangered Miami Blue butterfly. As is the case with other reptiles, green iguanas can also transmit the infectious bacterium Salmonella to humans through contact with water or surfaces...