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

Pollination Biology, Seed Dispersal, and Recruitment in Rudbeckia auriculata (Perdue) Kral, a Rare Southeastern Endemic

“…Thirty-two populations of R. auriculata have been reported in three southeastern states: Alabama (30), Florida (1), and Georgia (1) (Diamond and Boyd 2004). Of this number, six have been extirpated (Diamond and Boyd 2004).…”

“…Of this number, six have been extirpated (Diamond and Boyd 2004). Although a few sites support over 1,000 flowering stems, 19 support 50 or fewer flowering stems (Schotz 2000, Diamond andBoyd 2004). Eight Alabama populations that represent diverse sizes as well as geographic locations within the range of the species were chosen as study sites (Table 1).…”

“…However, for R. auriculata secondary dispersal by water (hydrochory) may be significant. All known populations of this species occur in wetland habitats, often near flowing water and are frequently subjected to flooding (Diamond and Boyd 2004). Secondary hydrochory may be the primary means of long distance dispersal in this species.…”

“…Extensive surveys by several individuals conducted over a 20-year period have failed to document substantial numbers of new populations of R. auriculata (McDaniel 1981, Kral 1983, Schotz 2000, Diamond and Boyd 2004. Sites apparently appropriate for R. auriculata (i.e., wet, sunny, disturbed areas such as roadsides, power line corridors and the edges of beaver ponds) occur between known populations, and often support commonly associated species (Diamond and Boyd 2004).…”

“…Sites apparently appropriate for R. auriculata (i.e., wet, sunny, disturbed areas such as roadsides, power line corridors and the edges of beaver ponds) occur between known populations, and often support commonly associated species (Diamond and Boyd 2004). Rudbeckia auriculata occurs on a wide range of soils and does not seem to be restricted by this factor (Diamond and Boyd 2004). The general rarity of R. auriculata, but local abundance at certain sites, suggests that one or more factors limit population size and dispersal of this species.…”