Overview of the Importance of Mangroves and Seagrass ...nepa.gov.jm/presentation/overview-mangroves-seagrass.pdf · What are Mangroves and Seagrass? Mangroves are predominantly tropical

Overview of the Importance of Mangroves and Seagrass Ecosystems

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Seagrasses “The Rain Forest of the Sea”

So why then would you Destroy the AMAZON??

Mangroves, the backbone of Tropical coastlines

Outline

What are Mangroves and Seagrass

Importance of Mangroves

Importance of Seagrass

Symbiotic Relationship of Mangroves, Seagrass and Coral Reefs

Threats to Mangroves and Seagrass

What are Mangroves and Seagrass?Mangroves are predominantly tropical plants with an elaborate root system that inhabit intertidal (between land and sea) zones of sheltered tropical shores, islands, and estuaries. There are 69 species found worldwide

Four species are found in Jamaica; they are Red, Black, White andButtonwood Mangroves

Seagrass are underwater flowering plants growing in shallowcoastal waters.

Three species are commonly found growing in Jamaican waters Thalassia sp, Syringodium sp. and Halodule sp. with Thalassia being the most dominant

Mangrove forests and seagrasses are some of the world's most

threatened tropical

ecosystems

Importance of MangrovesMangrove Forests serve many purposes including:

Basis of marine food chain

Species Habitat

Nursery Ground

Wave buffering

Flood Control

Sediment Filtering and Water quality improvement

Carbon fixation

Basis of marine food chain Nothing is wasted in a mangrove forest.

Species Habitat

Mangroves provide habitats and feeding grounds for more than 220fish species, 24 reptile and amphibian species, 18 mammal species and 200 bird species. Some of which include:

Economically Important fish (grunt, parrotfish, snapper, snook, tarpon, barracuda, mackerel)

Marine and terrestrial birds (brown pelican, frigate bird, great blue heron, green heron, royal tern, ibis, mangrove cuckoo, white crown pigeon, Jamaican wood pecker, west Indian whistling duck {endangered}

Reptiles (crocodiles, lizards, snakes)

Crustaceans (lobster, shrimps, crabs)

Amphibians, Mollusks (oysters), seahorses

Various species of algae and sponges

Invertebrates (mangrove jellyfish, starfish,

sea squirts*)

Nursery Ground Some reef fish require mangrove forest to complete their life cycle:

Adult fish migrate to mangrove forest to spawn (lay eggs or larvae)

Juvenile fish depend of mangrove roots to serve as a refuge from large predators.

When they grow larger (less susceptible to predators) they move to more open habitat such as seagrass and coral reefs e.g. grunt, parrotfish, snapper, barracuda

They then return to mangrove forests to spawn.

It is estimated that 75% of game fish and 90% of commercial fish rely on mangrove forests at some point in their lives.*

Recent studies have shown that the rainbow parrotfish (largest herbivorous fish in the Atlantic)is so dependent on mangroves that it became locally absent after the forests were removed. *

Wave BufferingComplex root structure and abundance are crucial to prevent erosion by absorbing heavy wave impact and dissipate wave energy from severe storms such as hurricanes* e.g. Font Hill - St Elizabeth, Farhquars Beach - Clarendon, Indonesia, Thailand, Burma.

Farhquars Beach - Clarendon 2001

Farhquars Beach - Clarendon 2004

Effects of Mangrove Removal on coastline

Galin Point, Font Hill, St Elizabeth

Before (2001)

After 2004

Flood Plain

Mangroves are associated with riverine systems where they act as flood plains absorbing EXCESS water during periods of heavy rain.

E.g.

Black River, St Elizabeth

Fresh River, Ferry, St. Catherine

Milk River, Clarendon

Duhaney River, St. Andrew

Wetland being modified in Bush Cay, Trelawney.

Wetland Reclamation being conducted in Parottee, Black River, St. Elizabeth (approved subdivision)

Area flooded after rains

Reclaimed/Modified Sections of Fresh River Flood Plain

The effects of wetland modification (north of highway) for development is evident along Mandela Highway in Ferry where the highway becomes severely flooded during heavy rains

*Wetland coverage in Jamaica is steadily declining from 12000ha in 1980 to 9600ha in 2005

Sediment Filtering and Improved Water QualityHelps to retain sediments and nutrients from terrestrial areas thereby improving water quality. Critical marine ecosystems (seagrass and coral reefs) are protected from sedimentation and nutrients which can cause eutrophication, toxic algal blooms, smothering and eventually death of these habitats.

The health of these ecosystems is dependent on clear nutrient poor water, so that sunlight is able to penetrate the water column and sustain these habitats.

Carbon FixationThey absorb the green house gas Carbon Dioxide from the atmosphere (lessening global warming)- Planting mangroves is now being internationally recognized as one of the options for the prevention of global warming.

Organic matter such as fallen leaves forms nutrient rich sediments on forest floor creating a peat soil layer (fuel) and stores organic carbon

• You have not said anything about salinasand temporary pools which are important for waterfowl/biodiversity

Salinas at low and high tide behind Mangroves stand, Paradise, Hanover

Mangroves are associated with Salinas. These areas provide a habitat for various species of crabs and wading birds (great blue heron, egrets, green herons)

Salinas/Salt Ponds

Wading birds feed on small fish as well as small crabs that live in burrows within the Salinas

Importance of Seagrass

Provides food and shelter for marine animals

Sediment Stabilization

Water Clarity and Nutrient Cycling

Provides food and shelter for marine animalsPrimary food source for manatee and turtles (endangered), urchins and parrotfish also feeds directly on seagrass blades

Like mangroves many commercially important fish species depend on seagrass as a nursery and feeding ground to complete life cycle.

Species such as goliath grouper, grunt, snook, snapper, parrotfish, barracuda and tarpon forage in seagrass beds where they spend their juvenile stage eventually foraging unto coral reefs.

Other species that depend on seagrass include queen conch, spiny lobster, stingrays, shrimps, various species of urchins and stony crab (mangroves and seagrass are interdependent nursery habitats.) Other associates organisms include sea cucumber, worms, anemones, ascidians, seahorses.

Sediment StabilizationBinds shallow water sediments in coastal waters with their rhizomes and baffles wave and currents with their leafy canopy. This traps sediments and allow for stabilization hence sustaining beaches and counteracting erosion.

Beach erosion in Negril has been linked to loss of seagrass beds. The seagrass blades serves as a habitat for micro organisms (foraminifera) that helps to produce beach sediment. This account for 47% of sand in Negril. Loss of seagrass beds equates to loss of these micro organisms hence a reduction in the sediment budget and a increase in erosion along Negril Beach.

Water ClarityRemoves land based dissolved nutrients as a result of runoff from hinterland through absorption by seagrass blades, associated epiphytes, microalgae and root system. The removal of sediments and nutrients (phosphorus and nitrogen) from the water column results in high water clarity and nutrient-poor waters required for the survival of seagrass and coral reefs.

Effect of Sedimentation on Seagrass beds

Bloody Bay, Negril May 2003

Bloody Bay, Negril October 2003

In the last five years alone, approval has been granted to relocate approximately 165,919m2 (41 hectares/101acres) of seagrass here in Jamaica. The estimated survival rate is 80% for transplanted beds, however this figure does not account for the amounts lost during the actual transplanting phase, anthropogenic related losses or natural disasters

Symbiotic Relationship of Mangroves, Seagrass and Coral Reef

Mangroves filter nutrients and sedimentation from land based runoff hence improving water quality before reaching seagrass

Seagrass further filters nutrients and sedimentation before discharge unto reefs (improved water quality).

Reefs acts like a buffer to dissipate wave energy before reaching seagrass beds and mangrove stands thereby maintaining integrity of the coastline

Mangroves and Seagrass in the Caribbean strongly influence the community structure of fish on neighbouring coral reefs.

**We depend on these ecosystems to sustain our way of life as theydepend on us to protect and conserve them for continued sustainability

Protects Coastline from erosion and destructive wave energy

Threats to Mangroves and SeagrassMangroves and Seagrasses are affected by natural events however these effects are exacerbated by human activity. Specific problems include:

Increased suspended matter in coastal waters

(coastal developments and degraded watersheds)

Tourism and Real-estate development

Dredge (Port and Harbour developments), reclamation, fish and shrimps ponds e.g.. Falmouth

Thermal discharges e.g.. JPS Power Plant, Old Harbour Bay

Agriculture, Charcoal and fish pots

Beach development e.g. Negril* North coast hotels

Effluent and gully discharge

Oil Pollution

Propeller and anchor damage

Use of drag nets

Public perception and disregard

Continued destruction of Mangroves, Seagrass and Coral Reefs to facilitate development will see a decline in biodiversity, increase in coastal erosion and storm impacts. It is therefore important that we protect and conserve what is left of these threatened ecosystems to ensure continued health and sustainability of our coastline and marine resources.

Chalene

THANK YOU☺

References Fonseca M., Kenworthy W., Thayer G. 1998. Guidelines for Conservation and Restoration of Seagrass in United

States and Adjacent Waters.

Lewis R., 2004. Ecological engineering for successful management and restoration of mangroves forest.

Myers M., Mangrove ecology of Florida and the Caribbean

O’Sullivan C.,2005. The importance of Mangroves

www.worldbank.org. Erosion is Primary Environmental Challenge In Thailand, Says New World Bank Report

www.greenpeace.org Impact of coastal development of seagrass beds

www.mangroves.org

www.biologynews.net

www.ambergriscaye.com. The Importance of Mangroves

www.panda.org Mangrove Importance

www.panda.org Up to 26 times more fish found on reefs near mangrove forests

www.flmnh.ufl.edu Importance of Seagrass

www.bvi.gov.vg

Report on a workshop held in West Indies Laboratories, St Croix, US Virgin Islands,1982

Coral Reefs, seagrass beds, and mangroves: Their interaction in the coastal zones of the Caribbean.

Department of Geology and Geography, UWI 2000.Beach Sands Resource, Assessment Negril, Jamaica

Central Research Institute of Electric Power Industry Public Communication division,2002. Sequestration of CO2form planted Mangroves.