A Historical Floristic Inventory of Pine Rockland Fabaceae (Leguminosae)

Abstract

The pine rocklands of southern Florida are an imperiled habitat as the higher, drier areas of land have been steadily developed over the last century. Little of the original extent of this unique ecosystem remains today, with much of it in remnant fragments affected by surrounding development. With this study, we sought to investigate temporal changes in diversity of pine rockland Fabaceae induced by anthropogenic factors. We provide a status update for Fabaceae taxa, a diverse and important group of plants in pine rocklands. Herbarium collections (1339 records) spanning 175 y (from 1830 to 2015) were used to analyze the species frequency and richness of plants collected. The results indicated temporal fluctuations in collection diversity with frequency of native species highest prior to the year 1920, and nonnative legume richness increasing with the decades. The accompanying species list resulting from the inventory included 119 Fabaceae species, in 52 genera, with an additional 18 species not previously listed for pine rocklands. Many other studies have documented the change in pine rockland cover and its extreme extent of habitat loss and fragmentation as the result of human development and population growth. The results of this study document the indirect effects of human habitation on remnant natural areas, as evidenced by collections from Miami-Dade County, with exotic invasives increasingly represented over time. The results also document the historical distributions of collections of Fabaceae species, helpful to conservation and restoration efforts in the globally imperiled pine rocklands of southern Florida.