Mangroves and Deforestation

Question 1

Characteristics of the location mangroves grow in? (3-4pt)

Answer 1

• Mangroves have special adaptations to live in salty, oxygen-poor soil
• They contain a complex salt filtration system and a complex root system to cope with saltwater immersion and wave action.
• Mangroves grow in inter-tidal zones with salty, brackish to saline tidal waters.
• The soil which Mangroves grow in are muddy, water-logged and deficient in oxygen.
• They are halophytic trees (i.e. they are salt-tolerant trees that are adapted to live in harsh coastal conditions).
• Special Characteristics of Mangrove Forests:
  1. Adaptations to low levels of oxygen
  2. Uptaking nutrients from atmosphere
  3. Limiting salt intake (halophytic trees)
  4. Increasing survival of offspring
  5. Limiting water loss

Question 2

Horizontal Zonation of Mangroves?

Answer 2

• Acronym: BRAS (Bruguiera, Rhizophora, Avicennia, Sonneratia, from inland towards coastal zone, from least to most salt-tolerant)

Question 3

Avicennia (3pt)

Answer 3

• Coastal zone
• Avicennia
  → Pencil-like roots
  → Grow up to 30cm in height

Question 4

Sonneratia (3pt)

Answer 4

• Sonneratia (Colonise mud banks that are usually exposed at low tides)
  → Cone-shaped pneumatophores/roots (conical roots)
  → Grow up to 40-60cm in height
  → Conical roots can grow in a radius of more than 10 m.

Question 5

Rhizophora (3pt)

Answer 5

• Middle zone
• Rhizophora
  → Stilt roots arching out from their trunk down to the ground for extra support and air absorption
  → Prop roots from branches to prop them up when the roots reach the mud

Question 6

Bruguiera (2pt)

Answer 6

• Inland zone
• Bruguiera (Grow best in drier parts of mangrove belts where the soil is stiff clay, flooded only occasionally by the high tides)
  → knee-like roots that emerge from the ground then loop back in, often with a knobbly bump at the highest point of the loop that resembles a knee.

Question 7

Characteristics of Mangrove Forests (Adaptations) (main characteristic of mangroves - 1pt long sentence around 4 subpts in it)

Answer 7

Characteristics of Mangrove Forests (Adaptations)
* Mangroves are halophytic (salt-tolerant) trees that have specialised adaptive features that allow them to tolerate salty, brackish to saline tidal waters and survive in the waterlogged, anoxic muddy soil within the coastal intertidal zone.

Question 8

Leaves of mangroves (1 main pt, 4 subpt)

Answer 8

Leaves
Salt glands within leaves – salt excretion and accumulation
* Avicennia
* secretes salt through special pores or salt glands within their leaves.
* The secreted concentrated salt solution evaporates and becomes salt crystals which are later removed by wind or rain.
* Unwanted salt is also stored in leaves which then fall off when old and remove the salt from the tree (or be removed by wind or rain).

Question 9

Roots of mangroves (main point, 3 subpt)

Answer 9

Aerial Roots (pneumatophores) - Salt exclusion (ultrafiltration), aerial roots, wide-spreading to provide anchorage
* Aerial roots can take on different forms: the pencil-like roots, the cone-shaped roots, the prop or stilt roots and the knee-like roots.

1. salt exclusion (ultrafiltration)
2. wide spreading roots to improve anchorage to provide support in unstable mud
3. aerial roots to take in oxygen

Question 10

1. Salt exclusion (ultrafiltration) (root) 2pt, 1 subpt

Answer 10

1. Salt exclusion (ultrafiltration)
   - To tolerate salt
   - Rhizophora (prop or stilt roots), Sonneratia (Conical roots), Bruguiera (knee-like roots) (they don’t excrete salt in leaves – only avicennia does)
   o They reduce salt intake via layers of microscopic pores in the roots and by filtering out as much as 90% of the salt found in seawater as it enters their roots.

Question 11

2. Wide-spreading roots to improve anchorage and to provide support in unstable mud (3pt, 2subpt)

Answer 11

2. Wide-spreading roots to improve anchorage and to provide support in unstable mud
   - All
   - Prevents the tree from collapsing due to unstable ground
   - Rhizophora (prop or stilt roots)
   o Prop roots also help to anchor trees firmly in the muddy ground.
   o Stilt roots improve stability of tree by providing a broader base and support

Question 12

3. Aerial roots to take in oxygen (4pt, 1-3 subpt for each - 2 1 2 3)

Answer 12

3. Aerial roots to take in oxygen
   - All
   - Help in the aeration of roots to take in oxygen to thrive and prevent suffocation in the oxygen-poor (anaerobic) soil.
   o ↑ surface area of root exposed to air = ↑ O2 taken in
   o Soil is oxygen-poor and O2 is needed to carry out life processes (e.g. respiration)

• Aerial roots = pneumatophores
  o Pneumatophores are specialised roots that act like snorkels when partially flooded and have pores called lenticels that cover their surface where oxygen exchange occurs.
• Take in oxygen via lenticels on the surfaces of the roots.
  o The lenticels contain substances that are hydrophobic, meaning they repel water, so when submerged, water cannot flood into the root.
  o Prevents water from taking
• Contain large air spaces (aerenchyma)
  o To transport air
  o To provide a reservoir of air during high tide when the aerial roots may be submerged.
  o Ensure that the mangrove still can carry out life processes (e.g. Respiration) when it is unable to take in oxygen from the pneumatophores during high tide when the roots may be submerged.

Question 13

Characteristics of aerial roots? (3-4)

Answer 13

• Aerial roots = pneumatophores
• Take in oxygen via lenticels on the surfaces of the roots.
• Contain large air spaces (aerenchyma)

3. Aerial roots to take in oxygen
   - All
   - Help in the aeration of roots to take in oxygen to thrive and prevent suffocation in the oxygen-poor (anaerobic) soil.
   o ↑ surface area of root exposed to air = ↑ O2 taken in
   o Soil is oxygen-poor and O2 is needed to carry out life processes (e.g. respiration)

• Aerial roots = pneumatophores
  o Pneumatophores are specialised roots that act like snorkels when partially flooded and have pores called lenticels that cover their surface where oxygen exchange occurs.
• Take in oxygen via lenticels on the surfaces of the roots.
  o The lenticels contain substances that are hydrophobic, meaning they repel water, so when submerged, water cannot flood into the root.
  o Prevents water from taking
• Contain large air spaces (aerenchyma)
  o To transport air
  o To provide a reservoir of air during high tide when the aerial roots may be submerged.
  o Ensure that the mangrove still can carry out life processes (e.g. Respiration) when it is unable to take in oxygen from the pneumatophores during high tide when the roots may be submerged.

Question 14

Fruits of mangroves - main characteristic (1pt)

Answer 14

Propagules – viviparous nature of reproduction
* Mangroves are viviparous.
- Meaning: (of a plant) reproducing from buds which form plantlets while still attached to the parent plant, or from seeds which germinate within the fruit.

Question 15

Fruits of mangroves - what, how? (3-5pt, 2 subpt)

Answer 15

• Propagules
• Reproduce through Propagules
• the seed germinate into propagules while still attached to the parent tree.
• This helps them to grow rapidly upon falling to the soil below once they are ripe.
  o increases chances of survival in the harsh environment.
  o Propagules can photosynthesize while still attached to the mother tree.
• Sharp end of Rhizophora anchors firmly in the mud like a javelin (Prop/Stilt roots)
• Avicennia, where fruits are buoyant, take root in coastal areas after floating in water for some time.

Question 16

Deforestation
Benefits of forests (3mainpt)

Answer 16

● Natural resource
● Abundant, renewable and usable
● Enhance the quality of human life
● Sinks of Carbon Dioxide
- The world’s forests absorb and store carbon in both above and below the ground biomass.
● Habitats for biodiversity conservation
- The world’s forest area primarily designated for biodiversity and forest within protected areas have increased since 1990.
● Providers of important environmental services
- Forests managed for clean water supply, resilience against disasters, recreation, cultural and spiritual activites have increased since 1990. (ecosystem services)
● Sustaining livelihood and economic opportunities
- Forests supply the world’s population with wood and non wood forest products in low-income countries

Question 17

Renewable vs Non-Renewable Resources (3pt)

Answer 17

• Renewable resources can naturally replenish themselves while non-renewable resources cannot.
• This means that non-renewable resources are limited in supply and cannot be used sustainably.
• However, renewable can become non-renewable if they are used up faster than they can be replenished.
• sustainability practice of using natural resources responsibly so they can support both present and future generations.

Question 18

Ecosystem Services - meaning?

Answer 18

• Ecosystem services are the direct and indirect contributions of ecosystems to human well-being and have an impact on our survival and quality of life.

Question 19

Ecosystem services - value? (3pt)

Answer 19

Value of Forest Ecosystem Services
● The term “ecosystem services” is used to ascertain the value of nature
● Loss of ecosystem services affects the environment, economy and well-being
● Threats: habitat destruction, pollution, invasive species
- E.g. deforestation → impacts on soil erosion and biodiversity and water cycle

Question 20

four types of ecosystem services?

Answer 20

1. Provisioning Services
   * Ecosystem services that describe the specific material or energy outputs from ecosystems.
   - Food
   - Raw Materials
   - Freshwater
   - Medicinal Resources
2. Regulating Services
   * Ecosystem services that act as regulators.
   (eg. regulating the quality of air and soil or by providing flood and disease control.
   - Local climate and air quality
   - Carbon sequestration and storage
   - Moderation of extreme events
   - Waste-water treatment
   - Erosion prevention and maintenance of soil fertility
   - Pollination
   - Biological Control (regulating pests and diseases that attack plants, animals and people)
3. Habitat or Supporting Services
   * (underpin almost all other services) -> supporting services aid the functioning of all other services
   * ecosystems provide living spaces for plants or animals; they also maintain a diversity of different breeds of plants and animals.
   - Habitats for species
   - Maintenance of genetic diversity
   - A foundation for
   o Nutrient Cycle
   o Water Cycle
   o Soil Formation
4. Cultural Services
   * They include the non-material benefits people obtain from contact with ecosystems like aesthetic, spiritual and psychological benefits.
   - Recreation
   - Mental and physical health
   - Tourism
   - Aesthetic appreciation and inspiration for culture, art and design
   - Spiritual experience and sense of place

Question 21

provisioning services - 1pt, 4subpt

Answer 21

• Ecosystem services that describe the specific material or energy outputs from ecosystems.
• Food
• Raw Materials
• Freshwater
• Medicinal Resources

Question 22

regulating services - 1pt, 7subpt

Answer 22

2. Regulating Services
   * Ecosystem services that act as regulators.
   (eg. regulating the quality of air and soil or by providing flood and disease control.
   - Local climate and air quality
   - Carbon sequestration and storage
   - Moderation of extreme events
   - Waste-water treatment
   - Erosion prevention and maintenance of soil fertility
   - Pollination
   - Biological Control (regulating pests and diseases that attack plants, animals and people)

Question 23

habitat or supporting services - 2pt, 3subpt, 3 subsubpt

Answer 23

3. Habitat or Supporting Services
   * (underpin almost all other services) -> supporting services aid the functioning of all other services
   * ecosystems provide living spaces for plants or animals; they also maintain a diversity of different breeds of plants and animals.
   - Habitats for species
   - Maintenance of genetic diversity
   - A foundation for
   o Nutrient Cycle
   o Water Cycle
   o Soil Formation

Question 24

cultural services - 1pt, 5subpt

Answer 24

4. Cultural Services
   * They include the non-material benefits people obtain from contact with ecosystems like aesthetic, spiritual and psychological benefits.
   - Recreation
   - Mental and physical health
   - Tourism
   - Aesthetic appreciation and inspiration for culture, art and design
   - Spiritual experience and sense of place

Question 25

Deforestation in the Amazon Rainforest - main points (3pt)

Answer 25

Deforestation in the Amazon Rainforest * Causes of Deforestation * Effects of Deforestation * Forest Conservation Measures

Question 26

Causes of Deforestation - 7pt

Answer 26

1. Cattle Ranching 2. Subsistence Agriculture / Small-scale agriculture 3. Large-scale Agriculture / Commercial Agriculture: Soy Cultivation 4. Logging 5. Transport Infrastructure Development 6. Hydroelectric Power Dam Construction 7. Mining and Oil & Gas Development

Question 27

Main Reasons for Deforestation - 7pt

Answer 27

* Generate Revenue * Create Employment * Boost Industrial Development * Increase Food Production * Acquire land to settle in and farm * Improve accessibility * Generate electricity production and improve navigation

Question 28

Effects of Deforestation Economic - positive impacts (3pt)

Answer 28

* More revenue earned * Reduce Brazil’s foreign debt * Provide employment/jobs for people in labour intensive economic activities (e.g. mining and logging operations and plantation)

Question 29

Effects of Deforestation Economic - negative impacts (4pt)

Answer 29

* Renewable forest resources (e.g. timber) are getting depleted faster than the rate of replenishment * Non-renewable resources (e.g. oil and iron ore) will eventually be depleted * Depletion of non-renewable resources will also lead to the closure of industries and unemployment * No future revenue to be gained in the long run

Question 30

Effects of Deforestation Social/ Social-Cultural - positive impacts (3pt)

Answer 30

* Many subsistence farmers and landless farmers are given more land to grow crops to feed themselves and the local population. * This will alleviate starvation and hunger. * As the cultivation carried out in these areas is intensive, the yield increases and can support a higher population density.

Question 31

Effects of Deforestation Social/ Social-Cultural - negative impacts (4pt)

Answer 31

* Disappearance of tribal/indigenous people * Threaten lifestyles of tribal/indigenous people as they may encounter difficulty in adapting to a new environment due to resettlement by the government. * Undermine the land rights of the tribal/ indigenous people as land may be taken away from them for other purposes such as oil extraction * Loss of traditional culture and knowledge of the forest due to colonization, missionary influence and when they are introduced to new methods of agricultural practices

Question 32

Effects of Deforestation Physical/Environmental - Positive Impacts

Answer 32

No positive outcomes at all.

Question 33

Effects of Deforestation Physical/Environmental - Negative Impacts (main) - 4 pt

Answer 33

Effect on water cycle and resources Effect on soil fertility Effect on flora & fauna Effect on climate change (Regional & Global)

Question 34

Effects of Deforestation Physical/Environmental - Negative Impacts: Effect on water cycle and resources 3pt, 3subpt

Answer 34

Effect on water cycle and resources * Due to the lack of interception and tree roots to bind soil particles, there is an increase in soil erosion & where soil is easily dislodged. Rapid run-off leads to frequent landslides. - Landslides damage properties and cause the loss of lives of villagers living near forests. * Increased sedimentation & flooding as eroded soil ended in river and silting it. - Floods damage settlements and cause the loss of lives. * Water pollution due to more soil particles washed into river, which is harmful to riverine fisheries. - This will affect the livelihood of people dependent on the rivers for their source of food and water.

Question 35

Effects of Deforestation Physical/Environmental - Negative Impacts: Effect on soil fertility 3pt

Answer 35

Effect on soil fertility * Decline in soil fertility as nutrient cycle broken since loss of trees means no decomposition. Rapid surface run-off which carries away fallen leaves, twigs and branches before they can decay results in decline in decomposition and hence loss of soil fertility. * Soil is also subjected to leaching as rain carries nutrients out of topsoil into lower layers as it moves down the soil, resulting in loss of soil fertility. * This can eventually lead to desertification where land becomes barren as it does not support plant growth. This will lead to the loss of arable land.

Question 36

Effects of Deforestation Physical/Environmental - Negative Impacts: Effect on flora & fauna 3pt

Answer 36

Effect on flora & fauna * Destruction of flora & fauna as many animals are killed when trees are felled and burnt. This may cause extinction of many plant and animal species in the rainforest especially when they cannot adapt to a new environment. * e.g. In Brazilian Amazon, critically endangered species of fauna, such as the spectacled bear, and flora such as the Brazilian Cherry Tree. * Plants of medicinal value which can be used to treat many diseases are also destroyed. Therefore, this is a loss of valuable resources that can be used by future generations.

Question 37

Effects of Deforestation Physical/Environmental - Negative Impacts: Effect on climate change (Regional & Global) 2pt

Answer 37

Effect on climate change (Regional & Global) * Modifications to the atmosphere as with less transpiration, there will be lower and irregular rainfall. Increased level of carbon dioxide also contributes to global warming and leads to climate change. * When forests are cleared by burning, haze results. The haze is blown by winds into surrounding countries causing health problems such as throat and lung infections.