Case Study: Sundarbans Flashcards
Describe the location and extent of the Sundarbans coastal zone.
Extends over 10,000km2 of southern Bangladesh and India on the Bay of Bengal.
Identify 2 natural features
- The world’s largest delta.
- Extensive mangrove forest, the climatic climax vegetation
Name the three rivers that feed into the Delta
- Ganges
- Brahmaputra
- Meghna
Identify the 5 natural processes that play a role in creating the landscape
- Deposition
- Tidal processes
- Marine erosion
- Aeolian (wind) transport & deposition
- Succession
Outline the role played by deposition in the formation of the landscape.
- Rivers like the Ganges carry a lot of fine sediment, depositing it as they slow near the Bay of Bengal.
- Over time, sediment forms islands in river channels, creating a network of interconnected channels called khals.
- Islands and channels stay stable due to cohesive silt and clay, resisting erosion.
Outline the role played by tidal processes in the formation of the landscape.
- Twice daily, tides move saline water north into the delta and back south to the Bay of Bengal.
- This flow forms large (up to 2 km wide), straight N-S channels, linked by smaller khals.
Outline the role played by aeolian processes in the formation of the landscape
- Fine silt and clay are deposited in the delta, while lighter sand moves toward the river mouths near the coast.
- Some sand builds up on the banks, forming chars.
- When dry and above the waterline, sand is blown inland by south-westerly Monsoon winds, creating sand dunes.
Outline the role played by vegetation succession in the formation of the landscape (mangroves)
- Sediment buildup keeps delta islands above water under normal conditions.
- Vegetation succession starts with halophytic (salt-tolerant) pioneers and progress to climatic climax vegetation of mangrove forests if undisturbed.
- Once established the roots system stabalises the islands of sediment, prevent erosion and traps more sediment
Outline the role played by vegetation succession in the formation of the landscape (sand dunes)
- Stabalises the chars
- Provides more protection
- Leads to increased deposition in the river channels
- Leads to formation of more islands
Identify 3 good provided for the mangrove forest & outline economic or environmental opportunities they provide
- Wood from the forest can provide fuel for heat & cooking, for furniture and construction (including thatch for roofs).
- The rich ecosystem provides many food items e.g crab, shrimp, honey, leaves, and fruit.
- Commercial products include textiles from furs and skins, natural dyes, wax, glue, medicines and paper.
Identify 3 services that the mangroves provide for people and outline the environmental and economic benefits
- Protection from flooding & cyclones.
- Important carbon sink & sequesters around 4 billion tonnes of CO2 a year.
- Value for ecotourism, education, and
scientific research as well as for cultural, spiritual, and religious reasons.
Identify three key risks for people living in the Sundarbans and outline the challenges they pose
- Royal Bengal tigers kill 22 people annually 1935-2006 and are becoming an increased risk due to deforestation & population growth decreasing there habitat
- Eustatic sea level rise leads to coastal flooding which causes an increase in soil salinity which harms agriculture and also impacts freshwater supply
- Cyclones are becoming more intense and frequent with 13 super-cyclones in the last 23 years
- Coastal resources are becoming over-exploited due to growing population and destructive fishing techniques
Identify 3 ways people are adapting
- Salt tolerant varities of rice to deal with the increased salinity of soil from salt water intrusion
- NGOs are building latrines on higher ground to avoid water contamination in floods
- USAID have trained 30,000 people in the use of improved agricultural techniques more suited to the conditions caused by climate change.
Outline two examples of resilience shown by people in the face of the challenges faced
- The mangrove forest allows people to be resilient in the face of a storm – a density of trees of 30 per 0.01 hectares can reduce the destructive force of a cyclone by up to 90%.
- When only used for traditional activities, the forest has an economic value of $12,000 per hectare (fishing, timber, tannin, and seafood).
Outline two examples of mitigation in the face of the challenges posed by climate change
- Community access to natural resources on khas land (government owned land protected for use by local populations) as well as access to the forest and fishing.
- Afforestation of mangrove forest on some islands.
Identify reasons why the resilience of local people is being eroded over time and why mitigation strategies may be insufficient.
- The forest ecosystem continues to be degraded in many areas, reducing the level of protection it provides and the range of goods and services it offers. This is due to continued population rise and loss of land due to erosion and over exploitation of resources.
- The number of deaths from tiger attacks in increasing over time
- Sea levels continue to rise, and the threat of cyclones increases as global temperatures continue to rise due to the enhanced greenhouse effect.
