Plant invasion in mangrove forests worldwide

Abstract Plant invasion is a major threat to natural ecosystems, and mangroveforests are among the most threatened ecosystems in the world. However, since mangrovespecies primarily occur in the saline and intertidal environment that is inhospitable for most terrestrial and freshwater plants, it is commonly assumed that mangroveforests are resilient to plant invasion. Still, many salt tolerant aquatic and terrestrial plantsas well as epiphytesare found to invade the mangroveforests, and we know little about those invasive plants, their functional traits, invasion patterns and pathways and their ecological consequences. In a survey of global literature, we found a total of 57 plants reportedly invasive in the world’s mangroveforests. These plants possessed the traits of salinity tolerance, tolerance to anaerobic condition, high fecundity and rapid growth. About 19% of invasive plants were anthropogenically introduced for coastal land stabilization, and the rests were accidental introduction. Invaders were found to colonize along the forest edges or forest interior, but mostly in the raised lands. That is, the presence of diversified microhabitats such as raised land and intertidal mudflat might help both halophyticand non- halophyticplants to invade the mangroveforests. Some invaders (30%) were transient, but many (70%) could persist for a longer time; and these species could modify habitat conditions, impede natural regeneration of mangrovesand disrupt their faunal assemblage. Together, plant invasion in mangroveforests is much more widespread and problematic than commonly perceived, underscoring the need for the integration of invasive plant management strategy into mangroveforest management.