Chapter 6: Sustainable Management of TRF and Mangroves

PART 1: WHAT IS SUSTAINABLE MANAGEMENT?

Sustainable management of tropical rainforests (TRF) and mangroves means:

• Using these environments in a way that meets current needs without damaging them, so they can continue to support future generations.

How are tropical rainforests used by people?

Place for habitation, place for recreation, source of food,source of raw materials

How are TRF and Mangroves important to the environment? (Environmental Functions)

• Generate oxygen 

• Contribute to carbon storage 

• Provide habitats for diverse animal life 

• Provide protection from soil erosion 

• Provide protection from coastal erosion

GENERATE OXYGEN - TRF

• Release oxygen through photosynthesis (absorb carbon dioxide, water and sunlight) 

But it also…

• Purifies the air by absorbing other air pollutants and intercepting small particles at the leaves, which are washed to the ground when it rains, thus improve air quality. 

• Lowers air temp. 

  • Provide shades and reduces the amount of direct sunlight that reaches the surface. 

  • Through evapotranspiration.  The water that plants absorb through their roots is released into the air as water vapour. This process uses heat from the surrounding, thus cooling it. 

CONTRIBUTE TO CARBON STORAGE

• Absorb CO2 from atmosphere during photosynthesis, balances the amount of CO2 being added to the atmosphere through other natural processes. 

Tropical rainforests and mangroves absorb carbon dioxide during photosynthesis and store it in their biomass (such as trunks, leaves, and roots) as well as in the soil. This reduces the amount of carbon dioxide in the atmosphere, thereby lowering the amount of heat trapped and helping to regulate the Earth’s temperature.

Provide habitats for diverse animal life - TRF

• Multiple vegetation layers create many niches (specific role or position an organism has in an ecosystem, including how it lives, where it lives, and what it eats)

• Dense vegetation provides shelter and protection

• Year-round warm and wet climate supports plant growth

• Many plant species create varied food sources

Multiple vegetation layers create many niches (specific role or position an organism has in an ecosystem, including how it lives, where it lives, and what it eats)

TRF have layers such as the emergent layer, canopy, understory and forest floor.

Different animals live in different layers (e.g. birds and monkeys in the canopy, insects and reptiles on the forest floor).

This increases the number of habitats available, supporting many species.

• Dense vegetation provides shelter and protection

Thick plants, vines and large trees offer hiding places from predators and spaces for nesting or breeding.

Year-round warm and wet climate supports plant growth

• Continuous plant growth produces abundant food sources such as fruits, leaves, nectar and seeds.

• These support herbivores, which in turn support predators, increasing biodiversity.

Many plant species create varied food sources

High plant diversity means animals can specialise in different foods, allowing many species to coexist.

How mangroves provide habitats for diverse animal life:

• Complex root systems provide shelter

• Mangroves act as nursery grounds

• Abundant food supply

• Supports both land and marine animals

Complex root systems provide shelter

• Prop roots and aerial roots form a maze-like structure.

• This offers hiding places for fish, crabs and shrimp, protecting them from predators.

Mangroves act as nursery grounds

Young fish and marine animals grow among the roots where water is calmer and predators are fewer.

Abundant food supply

Fallen mangrove leaves decompose to form detritus, which feeds many organisms like worms, crabs and small fish.

Supports both land and marine animals

• Birds nest in mangrove trees, while aquatic animals live in the water around the roots.

• This creates overlapping habitats, increasing biodiversity.

PREVENT SOIL EROSION

• The leaves, branches and stems of the rainforest plants slow down falling raindrops before they reach the ground. 

• More water will infiltrate and percolate into the soil, reducing surface runoff 

• Raindrops hit the soil with less force

• Roots also bind the soil together, making it harder to erode. 

• Overall soil erosion by flowing water is minimised.

Prevent coastal erosion _ mangroves

• dense root systems of mangrove plants help to trap and stabilise loose sediments on the coast

• sediments are less likely to be washed away by waves, currents , and tides

• roots, trunks and branches of mangrove plants cause friction with with waves hitting the coast

• The waves lose a significant amount of energy, thus reducing coastal erosion

Salt secreting leaves + Sonnertia (unable to secrete salt thru their leaves)

• remove salt from saline water that their roots have absorbed

• concentrated salt solution secreted by the leaves evaporate

• salt crystals that are left behind on the leaf surfaces are subsequently removed by rain or wind

Sonnertia

• deposit excess salt in older leaves which they eventually shed

• prevent salt from building up within the plant

Pencil roots ( Avicennia)

• Appearance: Thin, pencil-like roots that grow vertically upwards out of the mud.

• Function: Respiration. They function as snorkels. Tiny pores called lenticels on the bark absorb oxygen from the atmosphere during low tide.

Cone roots (Sonnertia)

• Appearance: Thick, heavy, cone-shaped roots that grow upwards from underground cables.

• Function: Respiration and Wave Defense. Like Avicennia, they use lenticels to breathe. Their thick, woody structure also helps absorb the impact of incoming waves at the sea edge.

Prop roots (Rhizophora)

Grow from the branches and lower toward the ground.

help the plant breathe and provide it with support as they form a broader base around it

Knee-bend roots (Bruguiera)

bends upwards to emerge above the soil surface before bending downwards into the soil at regular intervals

supports the tree