Hydrilla

Plants of the wetlands are generally known to be highly dependent upon specific conditions, such as salinity, proximity to water, and vegetation type.
While some plants are able to adapt to condition alterations, other species do not overcome change as well. However, a major threat to all wetland vegetation is hydrilla.

Hydrilla is a non-native, invasive aquatic plant that has staked its claim by out-competing native plants and obstructing waterways. Hydrilla is a submerged, perennial plant that prefers freshwater, but can tolerate up to 7% salinity. This aggressive plant is known for clogging waterways, impeding natural flow, affecting human use such as fishing and seafood harvest, and clogging intakes and municipal drinking water supplies. Hydrilla can take over an area quickly as a result of its ability to multiply rapidly using four different strategies. Regrowth of stem fragments containing at least one node into a new plant, tubers on rhizomes producing new tubers, leaf turions that settle into sediment and form a new plant, and seed dispersal are all methods of reproduction for hydrilla. Hydrilla can out-compete native plants by its ability to tolerate low and high nutrient conditions in addition to growing in low light environments. Hydrilla is also successful in out-competing other plants by growing at a rate of one inch per day until reaching the water’s surface, followed by branching out to form a mat of vegetation which blocks light to other plants.

In order to control the growth of hydrilla, salvinia weevils have been released into severely affected areas. The salvinia weevil lives exclusively on hydrilla as a food source, thus reducing growth rates to allow control of the plant. The Coastal Wetlands Planning, Protection, and Restoration Act is currently researching the best, most beneficial method of controlling and eradicating invasive plant species.

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Invasive Species

Wetlands are natural ecosystems that provide an abundance of wealth to not only it’s inhabitants, but also to surrounding communities. Wetlands provide benefits ranging from water filtration to storm surge protection; however, wetlands have become vulnerable to invasive species. Invasive species are plants, animals, or pathogens that are non-native to the ecosystem and whose introduction causes or is likely to cause damage. Known as major contributors to wetland and coastal habitat loss, invasive species also threaten native species, as well as endangered species who rely exclusively on the wetlands for survival.

The foreign animals that have been recognized as invasive to coastal wetlands include Asian carp, wild boar, island applesnails, and nutria. The invasive plant species include Chinese tallow, common reed, and purple loosestrife. Invasive animal and plant species have altered the health of wetlands in some way; CWPPRA strives to protect the wetlands by constructing methods to diminish the invasive threat and restore native species dominance and health within the wetlands.