Ecology Distribution Management Info Impact Info References and Links Contacts

General Impact ERDC (Undated) reports that, "The dense floating mats of P. repens may impede water flow in ditches and canals and restrict recreational use of shoreline areas of lakes and ponds." The Florida Exotic Pest Plant Council (FLEPPC, 2003) states that, "P. repens has been reported as a weed of 17 crops in 27 countries, and is considered one of the most serious grass weeds." The authors go on to state that, "P. repens quickly forms monocultures that displace native vegetation, particularly in or near shallow waters." Avid (1999) reports that, "P. repens formed dense monotypic stands in response to increased hydroperiod (depth and duration of flooding)." Brecke et al. (2001) states that in Florida, "P. repens is very competitive and has reduced common bermudagrass (Cynodon dactylon (L.) Pers.) growth by nearly 40% after 2 yr (Wilcut et al. 1988). Tillage will not control P. repens, and may in fact serve to spread the weed to previously un-infested areas (Holm et al. 1977 )." Williamset al. (2003) states that, "Because of the lack of apical dominance, every node along the entire rhizome may sprout nearly simultaneously (Wilcut et al. 1988 )." Smith et al. (2004) state that, "On Lake Okeechobee the ability of P. repens to disperse and become established at different water depths was evaluated in a series of experimental pond studies. These studies revealed that fragments remain buoyant for extended periods and so facilitate the dispersal of P. repens within the lake. If fragments become anchored to sediment that is either exposed or in shallow water, they can readily root and establish mature plants; Once established, P. repens can thrive in depths of 75cm or less and can survive prolonged exposure to flooding depths greater than I m. In this manner, low water periods can contribute to the dispersal and colonization pattern of P. repens in the lake. When coupled with lake elevation data, these findings suggest that low water levels or draw downs would increase the marsh area susceptible to P. repens invasion."          Location Specific Impacts: Lake Okeechobee (United States (USA))   Reduction in native biodiversity: Smith et al. (2004) states that, "Since the 1970s, more than 6,000haof native plants, including spikerush (Eleocharis cellulosa) and beakrush (Rhynchospora spp.) and open water habitat have been displaced by P. repens in areas of Lake Okeechobee's marsh where inundation depths often are less than 50cm."