Species that almost always occur in in the same place in the same environmental conditions. Flora and fauna can be obligate species. For example, there are Obligate wetland plants. There are two categories of wetland plants. Obligate wetland plants which are found in wetlands 99% of the time. Then there are Facultative wetland plants which are found in wetlands 67-99% of the time.
Air plants are obligate wetland species and can be found in the Everglades.