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WETLANDS

WHAT ARE MARSHES (WETLANDS)?

In the context of Seychelles, a wetland is a reservoir of fresh water or brackish water and normally found in the forest but sometimes can be found along the coast. It is a habitat for many plants and animals specially adapted to those conditions like Mangroves, terrapins, fishes and birds.

RAMSAR DEFINITION.
Areas of marsh, fen, peat land or water, whether natural or artificial, permanent or temporary with water static or flowing, fresh, brackish or salt, including area of marine water, the depth of which at low tide does not exceed six meters.

TYPES OF WETLANDS.
ESTUARIES: Where rivers meet the sea and salinity is intermediate between salt and fresh water (e.g. delta's, mudflats and salt marsh or mangrove areas for example Port Glaud)
MARINE: Not influence by river flow (shorelines and coral reefs for example East Coast, Ste.Anne areas)
RIVERINE: Land periodically inundated by river overtopping (Lanmar Soupap – La Digue)
PALUSTRINE: Where there is more or less permanent water (North East Point, Mare aux Cochons, La Plaine Hollandaise- Praslin )
LUCUSTRINE: Area with permanent water with little flow ( same areas as above like North East Point, Mare aux Cochons, La Plaine Hollandaise- Praslin).
RAMSAR CONVENTION:
The convention on wetlands is an intergovernmental treaty adopted on the 2nd February 1971 in the Iranian city of Ramsar. The convention notes the "wise use" of wetlands as sustainable utilization for the benefit of mankind in a way compatible with the maintenance of the natural properties of the ecosystem."NATURAL PROPERTIES OF ECOSYSTEM" were defined as:
Those physical, chemical and biological components, such as soil, water, plants, animals and nutrients, and the interactions between them.

Major invasive water weeds:
Water hyacinth- Pistia stratiotes
Water lettuce – Eichhornia crassipes
Water fern – Lemna major

Water lettuce and Water Hyacinth are the major invasive water weeds present in the marshes of the Seychelles. Both spread exorbitantly and cover the area quickly, blocking the sunlight, oxygenation of the water, blocking the niche space of the individual organisms in the marsh like the fish, birds, insects, etc. Due to their rapid growth and death the depth of the water body decreases and sedimentation starts to take place consequently minimize the water holding capacity of the marsh.
In Seychelles, these weeds affect the aesthetic values of the wetlands, deplete the oxygen supply and decrease the aquatic biodiversity.
In other African countries, these weeds cause great economic loss by blocking navigation, fish catch and pollution of the river and lakes.

 

La Plaine Hollandaise on Praslin

Mare Aux Cochons (front view)

Mare Aux Cochons (side view)

Wetland education

Public sensitisation on wetlands

Takamaka wetland

Waterway through mangroves on Aldabra

Low tide at a costal wetland

Wetland day activity

Coastal wetland outlet

Major Mangrove species of the wetlands:
Coastal wetlands are fringed with the mangroves; there are seven species of mangroves present in the coastal front.

Mangliyer Blan – Avicennia marina
Mangliyer rouge – Rhizophora mucronata
Mangliyer Fler - Sonneratia alba
Mangliyer Passyans – Xylocarpus granutum
Mangliyer latte – Bruiguiera gymnorhiza
Mangliyer Ptifey - Lumnitzera racemosa
Mangliyer zone – Ceriops tagal
Var – Hibiscus tiliaceous
Coconut – Cocos nucifera
Patatran – Ipomea convolvulus
Fouzyer lanmar – Achrostichium aureum
Major freshwater wetland plants:
Var – Hibiscus tiliaceous
Coconut – Cocos nucifera
Patatran – Ipomea convolvulus
Fouzyer lanmar – Achrostichium aureum
Grasses –
Lerb lanmanr - Polygonum arvensis
Bulrush –
Sedges – Cyperus species

WETLAND'S  ROLE:
The Seychelles Wetlands are though not very big in land area; still they play a significant role in the protection of the coastal region. Wetlands protect

Fisheries habitat.

I. Provide fisheries habitat for spawning, nursery, feeding or cover habitat for fish.  This includes:

a. Pelagic species:
Sardinella spp and Atherinidae spp.
b. Demersal and Semi-demersal species:

Carangidae - Caranx spp; Mullidae – Pseudupeneus spp.; Lutianidae – Lutianus kasimira, Lutianus fulviflamma; Lutianus argentima-culatus; Lethrinidae – Lethrinus nebulosus, Lethrinus lentjan, Lethrinus caeruleus; Serranidae – Epinephelus summana; Gerridae – Gerres oyena; Plectorhyncidae – Diagramma pictus, Gaterin sordid; Sphyraenidae – Sphyraena barracuda.

Low tide, Periophthalmus sobrinus and P. keolrenteri can be observed.

II. Other aquatic fauna that is important or endemic.  This includes:

Crustacea - Scylla serrata, Uca annulipes, Sesarma impressa,  and Cardisoma carnifex.

Peneidae, the Peneus and Penaeopsis genera.  This includes Peneus japonicus, Peneus semisulcatus, Peneopsis rectatus, and Peneopsis japonicus.

Bivalves – Quidnipagus palatam, Gafrarium tumidum, Gafrarium pectinatum, Anadara antiqyata and Ctena divergens

Threatened and endangered species habitat.

I.Provides important habitat for any species threatened or endangered species list of animals or plants.

Important mangrove species include Rhizophora mucronata, Bruiguiera gymnorhgiza, Sonneratia alba, Avicennia marina, Lumnitzera racemosa, Xylocarpus granutum, Ceriops tagal, Pandanus hornei and Verschaffeltia splendida.  There are no endiemic plant species in the mangal.

Endemic insects such as Rhagovelia, Nepidae and  Notonectidae.

Endemic sub species of terrapin Pelusios castanoides intergularis and Pelusios subniger parietalis.

II. Contained one or more threatened or endangered species

Water storage for flood water and storm runoff.
Provide temporary storage of floodwater or storm water runoff to the extent that they make an important contribution to:

    A. Reduces the magnitude or frequency of floodwater or storm water risks to   public safety or of damage to public or private property.
    B. Reduces the scouring and erosion of stream banks.
    C. Maintains the stability of important habitat for aquatic life.
    D. Using average annual, 10 year, 50 year and 100 year storm frequencies in   generating hydrographs for the wetland's inlet, outlet and at critical locations      downstream for hydraulic and hydrologic analysis.

Surface and ground water protection.
Contribute to the protection or enhancement of quality to the surface or ground water:

    A. Recharges any of the following: well head or aquifer protection area or a Class A or Class B ground-water area;
    B. Reduces levels of contaminants in surface waters which recharge underlying or adjacent ground waters;
    C. Contributes to the flows of Class A surface waters;
    D. Enhances or protects water quality through chemical action, by the removal of nutrients, by the retention or removal of sediments or organic matter or by moderating the adverse water quality effects of soil erosion or stormwater runoff;
    E. Retent and remove nutrient or trap sediment.

Erosion control through binding and stabilizing the soil.
Protects a shoreline, riverbank or stream bank from excessive erosion by dissipation of wave and current energy or by binding and stabilizing the soil.

Education and research in natural sciences.

    I. Provides valuable resources for education or scientific research are significant                 wetlands.
    II.  Has a history of use for education or research or scientific papers exist on a wetland.
    III. Has one or more characteristics, which potentially make it unique or valuable for             education or scientific research purposes.

Serious efforts are being made to:
Reverse trend in the loss, modification or degradation of wetland functions in Seychelles by end 2005.
Incorporate and recognize wetland functions in resource planning, management and economic decision-making for all national projects, programs and activities by beginning 2003.
Maintain and enhance wetland functions and values derived from wetlands throughout Seychelles.
Adopt wise use of wetlands that ensures and enhances the prospects of a sustainable and productive manner for future generations of Seychellois

Possible areas of assistance:
To the Public

The Wetland Unit of the Ministry of Environment has a direct role in the planning application of any development in a marsh or wetland areas. Approval is granted based on the classification of the wetland area, environmental impact of the development, biodiversity importance etc.
We play a major role in the flood management, as the wetlands are the main reservoir of the flood water - keeping the outlets open and periodic visiting of the marsh sites are prime targets of work during heavy rain period.

Monitoring and Enforcement
Routine monitoring of the wetlands, checking on the encroachment and illegal reclamation, issuing warning, and enforcement letters giving technical advice on the development of an area are undertaken under this unit. We help people to solve their wetland problem without largely affecting the habitat.

Monitoring and Management, Invasive Control
As the water weeds, water lettuce and water hyacinth are the major invasive weeds, close monitoring of the weeds growth and development; periodic control using manual methods are practiced. This activity is on going on Mahe, Praslin and la Digue.

Prospective Wetland Areas of Eco-Tourism Concern:

  • La Plaine Hollandaise ( Praslin)
  • Port Glaud - Coastal Wetland and Mangroves
  • Mare Aux Cochons (National Park)
  • Takamaka Wetlands (Near Chez Batista Restaurant)
  • Wetland at Plantation Club Hotel (Baie Lazare)

Seychelles National Wetland Conservation and Management Policy

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