PARENT SESSION
Oral Session #59: Conservation Ecology: Terrestrial Biodiversity. Presiding: K. Schulz.
Thursday, August 9, 2001. 8:00 AM to 12:15 PM. Madison Ballroom D.
Multiple limits to seedling recruitment for an endangered carnivorous plant of Appalachian Mountain sphagnum bogs.
WALLY, ALAA1, 1
ABSTRACT- Sarracenia jonesii failed to recruit seedlings from 1993-2000 in the 3 remaining North Carolina (USA) populations. Artificial canopy gaps may revitalize ramets and restore demographic structure. I investigated effects of canopy, herb cover, litter and soil disturbance on fecundity and recruitment. I collected seeds from gap and shade conditions to assess canopy effects on seed production and pre-dispersal viability. I also sowed seeds in nested split plots to assess seedling emergence, survivorship, vigor and microsite associations across 3 scales: 1) site location (edge vs. core habitat), 2) gap vs. canopy cover (plot effects), 3) removal of herb, sphagnum/litter, and soil (subplot effects). Seeds per capsule averaged 15% of maximum possible regardless of canopy and pre-dispersal viability was significantly lower under canopy (27% vs. 57%). The combination of treatments best enhancing recruitment from sown seed varied among site locations. More seedlings emerged in edge habitat and variability among core blocks was high. Removal of herbs, litter and soil enhanced emergence but the best treatment differed by site location and canopy condition. Canopy removal alone did not promote emergence. Survivorship over the first season was <18% under canopy versus >70% in gaps, and no seedlings survived two years. Herb cover was advantageous or deleterious to recruitment depending upon treatment and census date. Small-scale treatments and site location chiefly influenced establishment success whereas canopy condition influenced proximate seed viability and ultimate mortality.
KEY WORDS: Sarracenia jonesii, seed viability, seedling recruitment, habitat management