Mangroves

MANGROVES FORESTBy: Iqra MuzaffarRoll No. 2723BS-III (Zoology)

WHAT ARE MANGROVES?

Mangroves are trees or plants which grow in the area between the land and water.

MangalIs the place where Community of organisms in the mangrove habitat.

MangroveTrees that flourish in the mangal.

IMPORTANT TERMINOLOGY

CHARACTERISTICS OF MANGAL:

• Inundation with tides

• Increasing salinity towards ocean

•Sandy clay soil

•Nutrient poor

•Nitrogen & Phosphorus are limiting

• Limiting mangrove growth only

•Organic nutrients deposited via siltation

•Fresh water streams & down-shore currents

•Most all are of terrestrial origin

• In sum: Mangal is a harsh place to live

CHARACTERISTICS OF MANGROVES:

•Trees and shrubs that grow in saline coastal habitats in the tropics and subtropics;

•They grow in loose, wet soils, salt water, and are periodically submerged by tidal flows;

•Their distribution throughout the world is affected by climate, salinity of the water, fluctuation of the tides, type of soil;

•Unique ecosystem generally found along sheltered coasts.

DISTRIBUTION OF WORLD MANGROVES

DISTRIBUTION OF WORLD MANGROVES

REGION AREA(km2)

%Global

South and SE Asia 75,170 41.4

The Americas 49,096 27.1

West Africa 27,995 15.4

Australasia 18,788 10.4

East Africa and Middle East

10,348 5.7

MANGROVE ECOSYSTEM

Divided into :•Abiotic component

•Biotic component

ABIOTIC COMPONENT1. Soil (sand+ mud + salt)

- ‘topsoil’ divided to sandy or clayey.

2. pH

- neutral or slightly acidic due to the ‘sulfur reducing bacteria’ and the presence of acidic silt.

3. Oxygen

- Dissolved oxygen : low – anoxic area

-Can only be home for anaerobic bacteria, which releases hydrogen sulfide gas (bad smell) when the bacteria bread-down the organic matter without oxygen.

4. Nutrient

- Because the soil is perpetually waterlogged, there is little free oxygen. Anaerobic bacteria liberate nitrogen gas, soluble iron, inorganic phosphates, and methane, which makes the soil much less nutritious.

5. Wind and waves

-windy and wavy depends on the movement of the sea water.

6. Light, temperature

- low light and temperature at low ground.

7. Salinity

- high content of salt.

BIOTIC COMPONENT

Divided to : 1. Vegetation

2. Zonation

1. VEGETATION

•Mangroves are ‘obligate inhabitants’, which cannot be found anywhere else

•Adapted to survive in swampy area

WHAT DO THEY NEED TO ADAPT TO?

-High Salinity

-High Sedimentation

-Reproduction

ADAPTATION TO HIGH SALINITY

1. Waxy Leaves

Leaf that has coated on the

outer side with a waxy cuticle that prevents water

loss.

ADAPTATION TO HIGH SALINITY

2. Salt exclusion at leaves

Ability of a mangrove to exclude

salt at thesurface of their

leaves. So, that the salt

content in the plant can be regulated.

ADAPTATION TO HIGH SEDIMENTATION

1. Prop roots

An adventitious root that arises from the stem, penetrates the soil, and helps

support the stem.


2. Pneumatophores

Pneumatophores or breathing roots (Sonneratia) are roots from the underground root system, which appear laterally. These roots are used for respiration of the plant.


3. Buttress root

Buttress roots (Bruguiera) are roots from the tree trunk and expanded to a structure which looks like a ‘flattened blade’. These roots provide mechanical support for plants that grow in soft and instable substrates.


4. Stilt roots

Stilt roots (Rhizophora), are roots from the tree and grow into the substrate. These roots are mechanical support for plants growing in silt and muddy substrate.

ADAPTATION TO REPRODUCTION

1. Vivipary normal

• Reproduction and growth while still attached to plant

• Fertilization

- Propagule growth (a ready-to-go seedling)

2. Maturity -> Drop off maternal plant

3. Float horizontally initially

• Dispersal to novel environments ideally

4. Float vertically with appropriate environmental conditions

5. Rooting and growth

6. Pollination through:• Wind (Rhizophora)

• bat or hawk moth (Sonneratia)

• birds and butterflies (Bruguiera)

• fruit flies (Nypa)

2. ZONATION

Intraspecific Differences in Environmental Tolerances

1. Salinity variations and adaptations for excreting salt

2. Tidal Inundation and adaptations for gas exchange

3. Low soil stability, Shore morphology, and adaptations for rooting

4. Sedimentation rates and types

Mangrove wildlife

Pictures show from left to right: Blue crab, Blue heron, Fiddler crab, Mangrove snapper

Mangrove wildlife

Pictures show from left to right: Florida fighting conch, Mangrove buckeye, Periwinkle,

American crocodile

MANGROVE ANIMALS ADAPTATION

1. Migratory Shorebirds

Different species of migratory shorebirds have different bill shapes and lengths allowing each species to probe the mud at different depths to find food. For the reason, large number of different shorebirds can feed on the same mudflat without competing with each other for food.


2. Mudskipper Fish

The mudskipper is really a fish. It has modified fins which help it to move on land. When on land, it breathes through its damp skin and by holding water in its mouth. Huge eyes on top of it to see better, allowing it to hunt for prey and also to escape from predators. These structural adaptation help the Mudskipper cope with the mangrove environment, catch prey and escape predators!


During high tide, the Tree-climbing Crab climbs up a tree avoid being eaten by predatory fish. Once out of the water, it must remain still to avoid being spotted by predators like the kingfishers and water monitor lizards. The above behavioral adaptations help the Tree- climbing Crab escape predators.

3. Tree-climbing Crabs

IMPORTANCE OF MANGROVES:•Mangrove plants form a unique ecosystem THAT consists of living

organisms and non-living factors such as soil and water.

• The leaf detritus provides food for animals such as worms, snails, mussels, oysters, shrimp.

• The roots of the mangrove provide shelter for many fish and other animals.

• Act as a buffer against the high winds and eroding waves of storms.

• The mangroves trap sediments and prevent them from building up further out to sea, which is damaging to other ecosystems like coral reefs and sea grasses.

•Mangroves can filter out pollutants like nitrates, phosphates and petroleum based products that are present in run-off.

•Mangroves contribute to our economy; they have a big influence on our fisheries, because so many commercially fished species breed or develop there. The mangroves also provide an important source of food for other marine life.

CAUSES OF MANGROVE DESTRUCTION

Destruction : “The action or process of causing so much damage to something that it no longer exists or cannot be repaired”

•Urbanization

•Agriculture

•Cutting for timber, fuel and charcoal

•Oil pollution

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