Investigation of alien invasive plants in Huizhou Mangrove Natural Reserve.
Alien invasive plants in Haozhaolou and Xiezhouwan in Huizhou Mangrove Natural Reserve, Guangdong, China, were investigated. Forty-nine species were found in both of Haozhaolou and Xiezhouwan. Twenty-one species of alien invasive plants were evident in both areas, whereas 12 species were recorded for Haozhaolou and 16 species were registered for Xiezhouwan, accounting for 24.49 and 32.65% of the total number of species, respectively. Paspalum dilatatum, Sonneratia apetala, Wedelia trilobata and Ageratum conyzoides were widely distributed in Haozhaolou. Eupatorium catarium, Lantana camara and A. conyzoides were extensively distributed in Xiezhouwan. Many of the alien invasive plants originated from America, among which 14.29% were introduced intentionally as useful species, 61.90% were introduced unintentionally through goods and transportation facilities, and 23.81% were distributed by wind and water flow. Direct damage to mangrove caused by alien invasive plants is slight, but the threat to ecological landscape and biodiversity of natural reserve is serious.