13. Impact of Invasive Nypa Palm (Nypa Fruticans) on Mangroves in Coastal Areas of the Niger Delta Region, Nigeria

Invasive nypa palms (Nypa fruticans) are a major threat to mangroves and coastal systems in the Niger Delta region in Nigeria, apart from oil and gas exploration. The palms were first introduced as foreign species to curb coastal erosion over a century ago (i.e. 1906). They later became invasive and started multiplying in the last 30 years. The palms have acclimatized to the coastal environment by developing superior root system, which they use to tap available nutrients. They also have tough and buoyant seeds, which aid in their wide dispersal. These qualities of the palms had made them to have an edge over the mangroves. Oil and gas exploration, which is responsible for numerous oil spillages, is a major cause of mangrove decimation. The establishment of open waste disposal sites in coastal areas have also contributed to the changes in soil and water qualities, leading to further decline in mangroves, with a resultant increase in invasive nypa palms. The palms change the pedology, hydrology and landscape architecture of the coastal environment once they are established. Therefore, a threat to the mangroves is a threat to the entire coastal system, which benefits from the ecosystem services provided by the mangroves. Mangroves may disappear completely from the Niger Delta in the next 50 years if the encroachment of the palms continue unabated. However, this problem can be resolved by the removal of the palms through mechanical, physical or chemical means. Soils on which the palms grow can be excavated to remove the allelopathic properties, after which the palm soil should be replaced with mangrove soil. To ensure smooth re-colonization of the coast, mangroves propagules with good genetic quality should be selected, nurtured and transplanted from the nursery to the coastal areas. The mangrove propagules should be monitored and protected from further invasion by nypa palm after planting.