CGRG Bibliography of Canadian Geomorphology
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Author : Hanson, A.R.; Berube, D.; Forbes, D.L.; O’Carroll, S.; Ollerhead, J. and Olsen, L.
Date : 2005.
Title : Impacts of sea-level rise and residential development on salt marsh area in southeastern New Brunswick 1944-2001.
Publication : Proceedings of the 12th Canadian Coastal Conference. Dartmouth, Nova Scotia. November 6-9, 2005.
Issue :
Page(s) :
Abstract
This paper presents preliminary data from a study designed to quantify change in the amount of salt marsh along the Northumberland Strait in southeastern New Brunswick during the time period 1944-2001. Two study sites (Cape Jourimain and Shemogue) currently have large areas of salt marsh present, whereas the other three study sites (Shediac, Aboiteau, and Cocagne) currently have a large amount of residential development. This region has experienced apparent sea-level rise of up to 32 cm during the last century, with predictions that this could increase to 65 cm/century due to climate change. Whereas there are limited data on vertical accretion rates for salt marshes along the Northumberland Strait this retrospective analysis provides insight on how marshes may respond to future sea-level rise. The second important aspect of this study was to document change in salt marshes due to human activities such as drainage and infilling. Aerial photographs from 1944, 1953, 1963, 1971, 1973, 1982, 1996 and 2001 were scanned, control points established and ortho-rectified digital maps created using GIS. Features such as salt marsh (Spartina alterniflora, Spartina patens), open water ponds, brackish transition marsh (Spartina pectinata), as well as residential developments, were identified and digitized on screen. In both undeveloped study sites there was less salt marsh present in 2001 compared to earlier time periods. For Cape Jourimain there was 20% less vegetated salt marsh in 2001 compared to 1963. This change was partially due to the construction of a roadbed through the marsh in 1966 which physically destroyed some marsh area as well as changed hydrology. For Shemogue there was 5% less (15 ha) vegetated salt marsh in 2001 compared to 1944, and open water increased by 18% (9 ha). The amount of vegetated salt marsh area decreased by 31% (17.4 ha) for Aboiteau with visible evidence that 18 ha of coastal wetland had been infilled between 1944 and 2001. For Shediac the amount of vegetated salt marsh also decreased during 1963 – 2001. Between 1973 and 2001 there was a decrease of 16% in vegetated salt marsh in Cocagne (7.4 ha) and infilling of 8.8 ha of coastal wetland. These results indicate that our ability to understand and manage the impacts of climate change on coastal ecosystems will be confounded by human activities in the coastal zone and that rising sea-levels have the potential to further reduce salt marsh habitat in areas that have already lost a substantial amount due to human activities.
Bibliography of Canadian Geomorphology