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Trading Ecosystems: the ecological implications of marsh conversion
Graham R. Daborn
Symposium on the Protection of Agricultural Heritage
Acadia University17 April 2010
““Henceforth thou art the Genius of the shore,Henceforth thou art the Genius of the shore,In thy large recompense, and shalt be goodIn thy large recompense, and shalt be goodTo all that wander in that perilous flood.”To all that wander in that perilous flood.”
John Milton John Milton Lycidas (1638) L. 182-185.
Sherman Bleakney
The Bay of Fundy is continually changing
Pre-1604• > 100,000
acres of marsh
Morris Map 1724
Arrival of the Acadians
• First dykes constructed at Port Royal 1635-1640
Acadian Conversions to1755
• By 1755 many thousands of acres of alt marsh had been dyked in the areas of Annapolis, Grand Pré, Truro, Beaubassin, Missiguash, Shepody, Tantramar etc.
Acadian uses of dyked lands
• A great variety of crops were raised:hay, wheat, peas, oats, barley, corn, carrots, beets, parsnips, onions, chives, cabbage, turnips etc.
Post-1755 history• With the Expulsion, marsh conversion did not
stop; the Planters took over.• NS 1760 “Act for Appointing Commissioners of
Sewers” included
“Whereas great quantities of marsh, meadows and low ground…are spoiled by overflowing of the sea…the new settlers…be encouraged…to raise dykes and remove such obstructions as prevent these lands from being immediately useful;..”
19th & 20th centuries• Wellington Dyke #1 1816-1823• Aulac 1825• Saxby Gale 1869• Maritime Dykeland Rehabilitation Committee
1943• Habitant Aboiteau 1944• Wellington Dyke #2 • Maritime Marshlands Rehabilitation Act 1949
Does it matter?
Fundy Marshes• A rich, low diversity
plant association dominated by Spartina patens (marsh hay),
• Spartina alterniflora (marsh cord grass), Juncus spp., Limonium spp. (sea lavender) etc.
Animals of the marsh
Animals of the marsh
Fundy Marshes in Summer
Fundy in Winter
Are Fundy salt marshes stable?
Fort Anne• Shoreline
erosion exposed timbers laid down in 1740s
1955Limit of marsh
1992
1996
2003
Windsor Causeway
(1970)
Grande Pre
Windsor
1200
Annual production of S. alterniflora marshes in North America
Fundy Salt Marshes
Conclusion• Fundy salt marshes are among the most
productive in North America.• Fundy salt marshes act as ‘soft’ shoreline
defenses, constantly adjusting to sea level rise.• If ‘let out to sea’, dyked lands will take a long
time to recover their original function: therefore, if they are used productively, there may be no net benefit to removing the dykes.
• If not used productively, why not return them?
“…..take heed lest passion swayThy judgement to do aught which else free-willWould not admit;….”
John Milton ‘Paradise Lost’ VIII:635-637.
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