Eastern lilaeopsis (Lilaeopsis chinensis) COSEWIC assessment and status report: chapter 8

Limiting Factors and Threats

L. chinensis appears to be an adaptable species able to withstand considerable natural disturbance. This species shares the same habitat as, and is associated with, Spartina alterniflora and other species, but its tolerance to interspecific competition is largely unclear. L. chinensis is able to grow well in controlled freshwater environments so its absence from natural freshwater environments may be due to an unmeasured inability to compete with species other than those with which it is associated, poor ability to disperse, physical barriers preventing dispersal (Affolter 1985), or unmeasured physiological or reproductive constraints.

Modification of the shoreline through human activity has been noted to destroy L. chinensis habitat and probably individual L. chinensis (Keddy 1987). Dumping of bricks at one site along the shoreline of the Tusket River estuary presumably destroyed plants and altered the habitat (from mud to an artificial rocky shore), making recolonization impossible (Keddy 1987). Highway construction was also thought to have destroyed small areas of habitat elsewhere in the estuary (Keddy 1987).

The U.S. Environmental Protection Agency states that sea levels have risen 15-20 cm over the last 100 years. Along the Atlantic coast of the U.S., and into the Canadian Maritimes, sea levels are increasing between 1 mm and 4 mm per year (US EPA 2003). Many factors have contributed to this sea level rise, including the melting of mountain glaciers and polar ice caps, and the increase in ocean water temperatures. Not all factors are connected to greenhouse gases, but global warming appears to be a major cause of rising sea levels seen across the world. What this means to L. chinensis is largely unknown, but one can expect that change in the intertidal zone brought about by changing sea levels may be a threat to this intertidal species over the long term.

Anthropogenic changes in water flow or salinity may have an adverse effect on L. chinensis. However, it has survived the construction of a dam along the Tusket River and withstood the resulting alteration of water flow and salinity (Keddy 1987). Despite its apparent resilience, further shoreline development that has the potential to destroy habitat and alter salinity, water flow and exchange of fresh and saltwater must be planned with consideration for its potential effect on L. chinensis populations. Presently, no threats are imminent.

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