Distribution, Habitat Characteristics, and Population Trends of the Rare Southeastern Endemic Rudbeckia auriculata (Perdue) Kral (Asteraceae)

Abstract

Rudbeckia auriculata is a rare wetland-associated species endemic to three southeastern states: Alabama, Florida, and Georgia. This study includes eight censuses of flowering individuals of the species during the ten-year period from 1992 to 2002. Although the number of known populations has increased during this time, the total number of flowering stems has remained relatively constant. Population size ranged from a single flowering stem to populations with over 1,000 flowering stems. Information on soils and associated species of vascular plants was collected at 20 of the 32 known sites during 1999, 2000, and 2001. Typical sites for the plant are located on wet soils along roadsides, power line right-of-ways or other disturbed sites. Associated species are those characteristic of disturbed open wetland sites. Although some large colonies of R. auriculata still exist, only two populations, both in the northern portion of the species' range, have been protected.