XVI International Botanical Congess

The native flora of this State (140,212 km2) numbers 2,650 species, including 155 endemics. Over 500 native taxa are listed as endangered or threatened. Presently naturalized in Florida are 1,180 nonnative plant species, nearly all introduced via human activities, about 125 of these exotics are considered invasive in Florida natural areas. This paper reviews observational data from government and private agencies to summarize direct effects of invasive nonnative plants on rare native plants through displacement or genetic swamping. Results include documented instances of population loss for 30 of the listed rare natives and observed immediate threats to another 190 listed species. Thus, nonnative plant invasions are adversely affecting nearly half of Florida's rare plants.