Wetlands with open water interspersed within areas of emergent vegetation (i.e., interspersion) have greater biodiversity than those within homogenous stands of vegetation. Decreased interspersion because of encroachment by cattail (Typha glauca, Typha angustifolia) and common reed (Phragmites australis americanus and Phragmites australis [hereafter Phragmites]) is common in coastal wetlands of the Great Lakes and occurs through a multitude of mechanisms (e.g., agricultural run-off/sedimentation, colonization/invasion of open areas by non-native Phragmites, decreasing lake levels). Relatively homogenous wetlands, such as those dominated by cattail and Phragmites, may be avoided by waterbirds, frog, turtles, and fish, thereby reducing wetland biodiversity and utility to resource users (i.e, birdwatchers, fisherman, and hunters). At inland and coastal wetlands within the Great Lakes region abundances of waterbirds varies positively with interspersion. For these reasons wetland restoration, creation, and enhancement projects often attempt to increase interspersion by dredging and scraping openings in an irregular pattern where monotypic stands of cattail and Phragmites occur.
At Long Point Provincial Park, Crown Marsh (Crown Marsh) interspersion or the ratio of open water to vegetation has varied substantial from 1955 through present (Figure 1). Presently, large areas of monotypic cattail and invasive Phragmites have colonized much of the Crown Marsh. To increase wetland interspersion and wildlife habitat at Crown Marsh the Long Point Waterfowlers’ Association and the Ministry of Natural Resources restored 15 ponds (range = 1-10 acres in size), 2008 – 2010. Six more ponds ranging from 10-12 acres each are proposed for summer 2011.
Figure 1. Changes in interspersion at Long Point Provincial Park, Crown Marsh 1955 – 1999.
Blue = open water/floating vegetation
Pink = cattail/Phragmites
Green = marsh meadow
Yellow = developed
*Ratios represent water : vegetation
Long Point Waterfowl collected data from the Crown Marsh from May to August 2011. These data were used to evaluate bird, invertebrate, and plant communities at restored ponds, ‘natural’ ponds, and monotypic cattail/Phragmites to monitor influences of restoration efforts within the Crown Marsh.
Project Sponsors and Partners
Long Point Waterfowl
Long Point Waterfowlers’ Association