INTRODUCTION

Sybil Creek Baseline Sampling Report
Over the last few thousand years, the area today known as Sybil Creek marsh (Fig. 1, Map of Study Site) system supported a mature tidal salt marsh community dominated by a saltmeadow cordgrass (Spartina patens) in the high marsh and salt marsh cordgrass (Spartina alterniflora) in the low marsh areas (dates are extrapolated from know rates of development in other systems). Within the last few hundred years human activity has changed the face of the system culminating with the construction of tide gates and the placement of fill on the marsh surface during the earlier part of this century. The combined impacts of development, agriculture and hydrological manipulations both on-site and within the watershed has changed portions of the habitat above Rt 146 from a tidal salt marsh to a brackish to freshwater marsh/upland complex within a relatively short period of time (it is within the last 100 years that the system has become brackish). As the system changed from a salt marsh to this brackish marsh complex, its function as a salt marsh declined accordingly.

Once tides were eliminated from the system, the changes in hydrology favored the colonization of common reed (Phragmites australis) to the area. Common reed is a native plant typically found along the high marsh upper border (Orson et al. 1987). In the past this plant was often found in association with cattail (Typha spp.) and switchgrass (Panicum virgatum) and rarely formed the monocultures that we see today (Orson 1999). Common reed is generally not tolerant of sea water and grows best in salinities between 0 ppt and 18 ppt (Bjork 1967, Haslam 1973), although recent investigations have found it inhabiting areas with salinities over 22 ppt (it has been suggested that a genetic variant may be present; Basitka 1998). Common reed has a worldwide distribution and can grow from a few feet below sea level to over ten thousand feet above sea level (Haslam 1973). It is colonial and rarely spreads by seed. Reed is an aggressive colonizer that has been known to expand laterally as much as three meters within a single growing season (Haslam 1973) and because its vegetative reproductive structures are highly lignified, they are strong enough to be able to break through asphalt paving. The combination of the strength of the rhizomes, the height of the culms and its aggressive nature, makes common reed a difficult plant species to remove once it has been established.

Although native to the area, the recent surge of common reed across the State has been cause for concern. In tidal marshes where the tides have been interrupted and/or the soils have been disturbed, this plant has displaced many of the more common species and formed dense monocultures, sometimes covering hundreds of square hectares. Indeed, by 1974, this plant was estimated to have covered over 10% of Connecticut's coastal salt marshes (Niering and Warren 1974). The impacts of monocultures of common reed on the environment are still being debated.

 

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