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Mangroves vs Nipa Palms - rival for survival

Mangrove forests in the Niger Delta are very valuable, providing ecosystem services, such as carbon storage, fish nurseries, coastal protection, and aesthetic values. However, they are under threat from urbanization, logging, oil pollution, and the proliferation of the invasive Nipa Palm (Nypa fruticans). 1

The Displaced

Mangroves trees are flowering plants that have a very special characteristic - they can grow in salty water. They grow in dense thickets, and are found in intertidal zones and estuary mouths between land and sea. This enables them to grow in coastal areas which are inundated with saltwater part of the time.  Typically they are found in tropical, subtropical and some temperate regions. There are at least 50 — and maybe up to 110 — mangrove species, ranging in height from 2 to 30 meters. Red (Rhizophora racemosa), white (Laguncularia racemosa) and black (Avicennia germinans) mangroves all grow in the Niger delta.

Mangrove trees are critical to the continuance of mangrove forests. They provide habitat for many other species e.g. crabs, fish, prawns, birds and some mammals. The roots act as shelter for young fish and invertebrates. As one example of their economic importance in the food industry, about 75% of the fish and prawns caught for commercial and recreational purposes in Queensland, Australia spend at least part of their lifecycles in mangroves.

A 2020 study of mangrove forest dynamics concluded

... highlights the importance of the mangrove forests to such ecosystems, because not only they are the most important primary food source, but also, they offer habitat to a large suite of fauna, which are important components of the trophic chain. 2

The Misplaced

Nypa fruticans, commonly called Nipa palm, was introduced into the area in the early 20th century by European colonisers. It is native to the coastlines of the Pacific and Indian oceans i.e. note the Niger delta is part of the Atlantic. When it was introduced, it enjoyed total protection by law. There are anecdotal accounts from Nigeria that people were prosecuted and imprisoned by the colonial administration for as much cutting a frond of the palm.

It is sometimes know as the mangrove palm, but it is not a true mangrove and is not as salt tolerant as true mangroves are.

The flowering stalk of the nipa palm is also juicy and edible, as are its nuts. The sap of the plant is sometimes converted to biofuel. The petals of its flowers can be brewed into a tasty tea and some parts of the plant are used medicinally.  In Asia, people use its leaves to make umbrellas, carriages, roof thatch, sun hats, baskets and mats.

The globular fruits of the nipa palm can grow up to 25 cm across. When the nuts are ripe, they  separate from the ball and float away on the tide, occasionally germinating while still water-borne.

The Consequences

Where is the invasion?

Continent: Africa
Country: Nigeria

The Niger Delta region is located where the Benue and Niger rivers meet and empty into the Atlantic Ocean. As you can see from the assemblage of  black dots on the second image, this area is the site of numerous oil fields. It is also the location of a large tract of mangrove forest.

For close to a century, the mangroves had kept these palms in check. However, in the last 20 years, the palms had overwhelmed and completely colonized most mangrove forests. 3

Mangrove trees are at risk in the Niger delta due to land use change (urbanization), oil drilling operations and spillages plus unsustainable timber gathering.

On top of this, the introduction of Nypa fruticans has had an adverse effect on mangrove survival due to the following factor

  • The rapid growth of the palms is facilitated by anthropogenic perturbations of the mangrove soil whose organic content had risen drastically as a result of constant deposition of human waste and other pollutants (Okoye et al. 1991). In areas where both nipa palms and mangrove grow, the latter are out-competed and their positions taken over by the palms.

There is high subsidence in nipa palm dominated areas because of the inability of the nipa's roots to compact the soil and prevent soil erosion as do the mangroves.

Local people say there are fewer fish and mollusks in areas where native mangrove trees have been replaced by nipa palm, and this is borne out by scientific studies. So removal of mangroves results in other species disappearing from the ecosystem, which in turn destabilises the ecosystem even further.

Many birds roost in the substantial branches of mangrove trees but are not able to do in nipa monocultures.

Remediation efforts

Mangroves are notoriously difficult to restore via planting.

Wetland habitats (like mangroves) are more dynamic than terrestrial habitats; they’re submerged in water for part of each day as the tides come in and roll out. If the water level isn’t just right, the seedlings don’t stand a chance at survival. Furthermore, plantings typically use only a single species of mangrove, even though most mangrove forests include many species. “Mangrove forests, like many forests, are composed of a mixture of trees and other communities. They are very complex,” says Lewis. 4

They are also in this case complicated by the competition of the nipa palms and the fragmented nature of the remaining mangrove patches. Several projects are under way in the Niger Delta region but they have been plagued by funding issues and other undermining concerns.


Dig Deeper

  1. Rapid Mangrove Forest Loss and Nipa Palm (Nypa fruticans) Expansion in the Niger Delta, 2007–2017[]
  2. Primary Sources and Food Web Structure of a Tropical Wetland with High Density of Mangrove Forest[]
  3. The Impact of Oil and Gas Exploration: Invasive Nypa Palm Species and Urbanization on Mangroves in the Niger River Delta, Nigeria[]
  4. Mangrove Restoration: Letting Mother Nature Do The Work[]
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