Rare, Threatened, and Endangered Plant Species of Southwestern Florida and Potential OCS Activity Impacts

Document Type

Technical Report

Publication Date



This report assembles information on the rare, threatened, and endangered plants of southwest Florida (Pinellas, Hillsborough, Manatee, Sarasota, Charlotte, Lee, Collier, and Monroe Counties) and describes the potential impacts of Outer Continental Shelf (OCS) exploration and production upon them.

The introduction describes the extent of OCS oil activities in the eastern Gulf of Mexico and enumerates the contents of the report.

The section “Rare, Threatened, and Endangered Plants of the Eight Southwest Florida Counties and their Habitats” provides a complete tabulation of 274 plant species and a description of their ecological and geographical distributions.

“Causes of Rareness Among the Plants of the Eight Southwest Florida Counties” discusses three reasons for rareness: natural causes, plant destruction or removal, and habitat alteration. It concludes that habitat alteration is a severe and pervasive problem that is likely to worsen.

“Potential Impacts of OCS Development” lists some demographic and land use trends anticipated in the study area and integrates future OCS oil activities with them. Three aspects of oil exploration and production are considered: onshore development, pipeline construction, and oil spills. It is concluded that most of the direct adverse effects of OCS oil activities on plants will be minimal, especially if Port Manatee is chosen as the base of operations. Nearshore spills may cause severe local effects, however, and spills at the drilling rigs, under certain unfavorable conditions, could adversely affect the high concentrations of coastal plant species in predicted areas of landfall.

This report and a companion report on rare, threatened, and endangered vertebrates reach the same conclusions: coastal habitats in southwest Florida are important and sensitive, and great care must be exercised in avoiding even small spills from OCS exploration and petroleum development.

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Citation / Publisher Attribution

U.S. Fish and Wildlife Service, 83 p.