22. Threats: The site, at present, is conspicuously threatened with 

 invasion by woody species, especially red maple ( Acer rubrum ) . In 

 June, 1981 the 30 acre remnant was occupied by small patches of open 

 marsh with scattered clumps of maple. These were present in numbers 

 sufficient to have divided the marsh into a mosaic of small openings 

 of perhaps 0.1 hectare in size. As maple continues to close the 

 canopy, marsh grasses and other hydrophytic herbs will be unable to 

 tolerate the increasing shade and will disappear. Unless management 

 steps are quickly taken to restore previous environmental conditions, 

 the site will succeed to red maple, the ubiquitous disturbance 

 vegetation of the Dismal. 



23. Management and preservation recommendations: Regardless 

 of the historical origin of the marsh, the only reasonable manag- 

 ment alternative for the site is maintenance of this community, for 

 vegetation study and for the habitat diversity that it lends to the 

 otherwise forested swamp. While other portions of the refuge might 

 be managed for conservation of disturbance forest types, there is 

 no compelling reason why the goal for this area should not be 

 restoration of the 18th century marsh. 



The immediate aim should be stabilization of the 30 acre remnant, 

 with the long range goal of slowly expanding the marsh to at least 

 300 acres, the minimal area that can be historically documented. 

 Any decision on further expansion, to the size suggested by George 

 Washington, could be based on the relative success of initial 

 efforts. 



Cross Canal should be closed at some point east of the marsh 

 with a variable water control structure. The best approximation to 

 original conditions would be to raise the water in the canal to a 

 level which causes the water table of the surrounding land to be 

 at or above the surface during the wetter seasons of the year. The 

 height should be sufficient to cause the outflow from Corapeake 

 Swamp to spread over the marsh as it would have done during 

 wet seasons before artificial drainage. This would restore 

 periodic nutrient and base input to the marsh. 



Increasing hydroperiod and height of the water table will 

 probably not eliminate established red maple, since it is 

 highly tolerant of fluctuating moisture regimes. It will be 

 necessary to burn periodically as proposed by Gammon and Garrett 

 (1981) to eliminate this species. Once fire has eliminated the 

 maple, it should be possible to prevent encroachment by woody 



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