2.1.4 Succession as a primer for land reclamation

Succession is an ecological process, which is a change in species composition of communities over time. It is the result of abiotic (physical and chemical) and biotic agents of change. Mangroves are regarded as land forming organisms [10]. Thus mangroves are natural land reclaimers. This is because their adventitious root system traps sediments during tidal flow, and accumulate it over a long period of time. Presence of sediments leads to the gradual formation of terrestrial areas, which becomes the habitat for plants. Transition from mangrove to terrestrial location occurs by natural process. Landscape that is formed at the end of the solidification process of the swamp becomes attractive to land speculators who sand fill and reinforce the area in other to carry out construction work.

the site is prepared through pilling, dredging, sand filling, grading and

enable it to support the mounting of crude oil well head and the laying of

the location, which eventually leads to the gradual loss of the coastal

biodiversity [11].

after solidification.

Figure 5.

59

2.2.3 Stream expansion and canalization

DOI: http://dx.doi.org/10.5772/intechopen.82053

concreting. Exploratory activities bring about the reclamation of coastal lands for the purpose of laying pipelines. It also involves the establishment of well heads and booth camps. During exploration the coast is first dredged, cleared of vegetation and reclaimed in other to create a plat form for mounting pillars that carry oil pipelines and well heads. This occurs during off-shore drilling in mangrove swamps. Surrounding areas of the swamps are usually dredged and sand-filled to

The Impact of Landscape Reclamation on Mangrove Forest and Coastal Areas in the Niger Delta…

pipelines (Figure 5). Concrete bases are constructed on this platform to carry the pipes from the drilling point, which may be at an off-shore or on-shore site to the refinery. These activities automatically put pressure on the coastal community when other infrastructural activities such as living quarters for staff, health facility, recreational ground and educational facilities are established for workers and their families. A concatenation of these activities changes the geography of

environment to landscape reclamation. The implication of the influx of activities at the coast is the solidification of the swamps resulting to the gradual loss of

This is a situation where rivers near ports are expanded to accommodate large

ocean going ships. Canalization is done to enable ships to berth at the wharf, without running aground. During canalization, earth moving dredgers are deployed to excavate the benthic soil. The scouring of the river bottom crushes and destroys a lot of organisms such as shell and non-shell fish community in that location. The dredged soil that is evacuated from the river bottom is dumped on land surface and smothers coastal vegetation such as mangroves. Accumulation of dredged spoil converts the swamp to terrestrial area and also changes the physico-chemistry of the coasts [3]. Expansion of creeks allow for navigational activities, commerce and construction. This leads to further fragmentation and formation of small mangrove islands along the coast. Changes in land form lead to changes in the biogeography of the area. Terrestrial land form eventually evolves from an aquatic environment

Crude oil pipeline and well head situated in reclaimed coastal area in the Niger Delta, Nigeria.

## 2.2 Indirect cause

### 2.2.1 Sand filling

Almost every coastal area in the Niger Delta has had one abandoned project or the other, one of which is sand dump. Sand mining activity is a lucrative business in the Niger Delta and is embarked upon by both private individuals and government officials. Local sand mining is done manually by the digging of sand from the bottom of the river during low tide and conveyed ashore in hand dug canoes. Sand mining is also done with more sophisticated machines, where pumps are used to convey sand from the bottom of the river unto land via long pipes. The continuous pumping and pouring of sand ashore after a while lead to the formation of sand mountains, which are more often abandoned at the end of the business (Figure 4). Deposited sand is usually evacuated by trucks to buyers. The environmental problem of this practice is that the sand dumped by the shore smothers plants and animals around the area and changes the coast from a marshy to a sandy area.

### 2.2.2 Exploratory activities

Oil and gas exploration is the main exploratory activity that occurs in the Niger Delta region. It occurs at on-shore or off-shore locations [3]. Before exploration
