Bryophytes as indicators of water level and salinity change along the northeast Cape Fear River

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Dawn M. Carroll (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/

Abstract: The focus of this study was to identify and describe bryophyte-environment relationships in wetland swamp forests of the Northeast Cape Fear River, southeastern North Carolina. A total of 44 genera consisting of 39 moss species and 21 liverwort species were identified. There was one new liverwort recorded not previously described from North Carolina, Cololejeunea setiloba. The diversity of bryophytes in the swamps of the Northeast Cape Fear River was higher than expected observations. Bryophyte densities and species richness were compared to flood depth relative to the swamp surface, salinity, and elevation of the swamp surface for three sites each with six substations within a transect from riverbank to upland edge. There was a general trend of an increase in bryophyte density and species richness as flood depth and salinity decreased from river to upland. Principal component analysis used 13 environmental variables, ranging from transect distance upriver, substation distance from river’s edge to base of upland, hydrology, elevation, duration of flooding, and salinity. These environmental variables accounted for much of the variation in the abundance of bryophyte species. A principal component biplot showed clustering between species of bryophytes with correlation between certain species and their tolerance for specific stress-related environmental variables. The majority of the bryophytes sampled were not common in the study system and have narrow habitat specificity. Although bryophytes may form a major part of several vegetation types and ecosystems, in this study, relatively few bryophyte species were ecologically abundant or dominant. Isopterygium tenerum is one occurring commonly and over a wide range of habitats. Fontinalis sullivantii, a facultative aquatic bryophyte, in the Northeast Cape Fear River can clearly tolerate low salinity water. It occurs along exposed roots and bases of trees, such as bald cypress. It is submerged at rising and high tide and partially exposed at low tide therefore exposing it to varying salinity as well as desiccation. High salinity, in the range between 5 and 15 ppt, significantly reduced photosynthetic efficiency of the moss species, Fontinalis sullivantii, on the short time scale, followed by some recovery. Desiccation after approximately 3 hours also reduced photosynthetic efficiency. However, observed physical changes in the disappearance of Fontinalis sullivantii due to a major drought suggests a strong relationship between increasing salinity and disappearance of this species. Long term implications of the current study are that bryophyte data will be used to assess future impacts due to current dredging projects in the Cape Fear River estuary.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina Wilmington in Partial Fulfillment of the Requirements for the Degree of Master of Science
Language: English
Date: 2009
Keywords
Bryophytes--North Carolina--Northeast Cape Fear River, Water levels--North Carolina--Northeast Cape Fear River, Water salinization--North Carolina--Northeast Cape Fear River
Subjects
Water salinization -- North Carolina -- Northeast Cape Fear River
Bryophytes -- North Carolina -- Northeast Cape Fear River
Water levels -- North Carolina -- Northeast Cape Fear River