Soils of the uplands are immature, thin organics of the Canaveral series. In some places they have high salinity because of salt spray and hurricane overtopping. Sanibel's uplands vegetation is largely secondary - or seriously impacted by exotic plants. In places it is desertlike in appearance because of its adaptations to drought. The ragweed-castor bean association is a group of herbaceous annuals which readily invades newly cleared areas.
Cabbage palm is the most ubiquitous plant on the island.
The island's slash pine probably represents a relic community. Its natural habitat is shared with the saw palmetto. More information on current vegetation of the island is presented in the section of this chapter dealing with the condition of the uplands. The mammals of Sanibel's uplands often appear in other ecological zones as well. Both the bobcat and the panther are secretive and seen infrequently.