Fresh Creek Nature Preserve
Fresh Creek Park - Invasive Phragmites
Phragmites are considered to be a "cosmopolitan" species – one that grows throughout the world – but in recent years it has become particularly invasive, taking over other species' habitats. It is not clear why phragmites suddenly began spreading so rapidly. Some ecologists believe that a new strain, genetically different from the native American species, was recently introduced from Europe. Anthropogenic, or human-caused, changes to soils also may have promoted phragmites growth. Increased nutrients and pollutants from fertilizers, sewage discharge, and urban stormwater runoff give phragmites a competitive advantage over other plants. Whatever the reason for phragmites' spread, the population of the reed in the Northeast has skyrocketed in recent years, to the detriment of other plant and animal species.
Young phragmites is good for livestock feed, but local wildlife does not generally consume it. Occasionally, waterfowl may eat its seeds, muskrats its stems and rhizomes; but overall, phragmites provides poorer nutrition than the plant species it replaces. Although the thick strands provide good thermal cover for molting waterfowl, most birds do not nest where there is an abundance of phragmites, leading to dwindling bird populations.
Phragmites adjacent to a salt marsh usually grows above the daily tides, limiting their use as a fish habitat to the rare spring tide that brings them to high elevations. In coastal areas, introducing tidal flow and planting salt marsh cordgrass (Spartina alterniflora), which is very salt-tolerant, can restrict phragmites growth. Other control efforts include herbicide use, which is effective but also leads to eradication of non-target species; cutting, which induces the same problem; and summer burning, which can actually encourage stronger growth by adding nutrients to the soil.
The invasive tendencies of phragmites are not completely negative. Thanks to their aggressive growth patterns, phragmites is able to remove enormous quantities of contaminants from degraded soils and wetlands. In England, where the plant is used to make thatched roofs, mats, and other weavings, phragmites is endangered, and ecologists there are exploring restoration methods.
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- Fresh Creek Park
- Fresh Creek Park - Invasive Phragmites
- Fresh Creek Park - Salt Marshes In New York City Parks