| Date | November 2020 | Marks available | 6 | Reference code | 20N.1.bp.3 |
| Level | SL and HL | Paper | 1 | Time zone | |
| Command term | Explain | Question number | 3 | Adapted from | N/A |
Question
The map shows land use changes that led to the loss of mangrove swamps in selected Southeast Asian countries in 2012.
[Source: Drivers of mangrove loss in Southeast Asia, Daniel R. Richards, Daniel A. Friess, Proceedings of the National
Academy of Sciences Jan 2016, 113 (2) 344–349; DOI: 10.1073/pnas.1510272113.]
Identify the dominant land use that is replacing mangrove swamps on island A.
Estimate the percentage of mangrove swamp loss caused by urban development B.
Outline one physical factor necessary for the formation of a mangrove swamp.
Explain two environmental consequences of the loss of mangrove swamps in coastal areas such as those shown on the map.
Markscheme
Aquaculture
Accept answers between 15 and 20 % (units not required).
Award [1] for the factor and [1] for explanatory development.
For example: Mangroves grow in the coastal intertidal zone [1], where freshwater mixes with saltwater [1].
Other possible factors include:
- In areas of low energy waves/sheltered areas, where slow moving water allows fine sediments to accumulate.
- In areas of tropical/sub-tropical climates / water temperatures of 20 °C, which provide ideal environmental conditions for growth
- Shallow waters, allowing roots to be exposed and continue to grow.
Award [1] for the consequence and up to [2] for development / explanation /exemplification.
For example: Removing the mangroves may mean the coastline is less protected from hurricanes / tropical cyclones [1], as mangroves absorb wave energy [1] and dissipate the force of the storm [1].
Other possibilities include:
- loss of biodiversity
- loss of breeding and feeding grounds for fish
- removal of natural filters of run-off from farms and sewage
- removal of potential stabilization of shorelines / prevention of erosion.
Examiners report
Done well.
Done well.
Generally no problem but at times the factor was not adequately developed.
This was understood and answered well by most. However, some were not focused on the consequence of the loss, instead discussing the importance of mangroves, for example, for biodiversity but not explaining how their loss would have environmental consequences.
