Date of Award

12-2005

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Botany and Plant Pathology

Advisor

Christopher S. Campbell

Second Committee Member

Christa R. Schwintzer

Third Committee Member

Alison C. Dibble

Abstract

Carex Vphina, the cattail sedge, is listed as rare, threatened, or endangered throughout much of the eastern portion of its range in North America. In Maine, the one known location of C. typhina is the Dead River delta, a floodplain forest where modification of a dam system could reduce spring flooding. I sought to identify potential adverse effects on C. typhina due to change in flood regime. A survey was conducted in 2003 to establish the status of the Maine population. I determined its breeding system, reproductive output, germination requirements, and presence in the seed bank in 2004. The size of 753 tagged individuals ranged fiom 1 cm to 83 cm in circumference with intermediate sizes being most common. Although this species is capable of self-fertilization and out-crossing, it appears to be primarily self-fertilized. Fifty-nine plants produced large numbers of viable seeds (375 k 44). Mean seed weight and percent of perigynia with ripe seeds did not differ significantly between habitats at the study site. Light was required for germination, but germination was greatly reduced when light was filtered through leaves. Seeds germinated readily in standing water. The soil seed bank contained viable C. typhina seeds. The Maine population of C. typhina is currently robust in terms of number and is reproducing at the site. However, competition from woody plants and the negative effects of leaf litter may inhibit C. typhina germination under a reduction in flooding. The altered hydrology may also prevent dispersal of seeds. Conservation efforts, which should focus on maintaining the flood plain hydrology of the Dead River delta, are in conflict with efforts to improve water quality in adjacent Androscoggin Lake. The population should be carefully monitored for changes in number of individuals, recruitment, presence of invasive species, and encroachment of woody competition. If it becomes necessary, woody vegetation shading the population and burying the seeds with litter should be removed and seeds should be dispersed manually.

Download

Share