Testo, Weston , Watkins, James .
Comparative gametophyte ecology of the American hart's-tongue fern and associated fern taxa: evidence for recent population declines in New York State.
The American hart's-tongue fern (Asplenium scolopendrium var. americanum) is a rare fern endemic to eastern North America. In the United States, it is federally protected as a threatened species, and fewer than 4000 individuals exist in small populations in New York, Michigan, Tennessee, and Alabama. More than 90% of these are found in two counties in central New York, however these populations have declined by greater than half in recent years and at least one important population has been extirpated. These drastic declines have yielded considerable concern regarding the fern's conservation status, yet their causes and the taxon's ecology remain poorly understood. This work seeks to contribute to our understanding of the fern's biology through a comprehensive examination of its gametophyte ecology. We studied a wide range of ecological traits in A. scolopendrium var. americanum as well the more common European hart's-tongue fern (A. scolopendrium var. scolopendrium) and four associated fern species. Gametophytes of all taxa were grown at two temperature treatments (20C and 25C) and the following were studied: spore germination rates, gametophyte desiccation and temperature tolerance, and sporophyte recruitment. Compared to all other taxa, A. scolopendrium var. americanum exhibited the lowest rates of germination and sporophyte recruitment. Gametophytes of A. scolopendrium var. americanum were also the most sensitive to drought and increased temperatures out of all taxa studied. These results suggest that low reproductive success and sensitivity to abiotic stress exhibited by A. scolopendrium var. americanum gametophytes may be linked to the fern's recent declines and that the taxon may be in significant peril due to habitat change resulting from climate change and stochastic disturbance events.
Log in to add this item to your schedule
1 - Colgate University, Box Z 5647, Hamilton, NY, 13346, USA
2 - Colgate University, Department Of Botany, 129 Ho Science Center, 13 Oak Drive, Hamilton, NY, 13346-1338, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Union E/Hyatt
Date: Monday, July 9th, 2012
Time: 9:00 AM