Outline two ecosystem services in a named biome.

Explain the causes, and the possible consequences, of the loss of a named critically endangered species.

Using examples, discuss whether habitat conservation is more successful than a species-based approach to protecting threatened species.

Examples may include:

Tundra:
permafrost/glaciers in tundra;
…provides important storage in hydrological cycle;
ice in tundra provides reflective surface/increases planetary albedo;
…thus moderating global temperatures;
Wetlands:
decomposers/high productivity in swamps/wetlands;
…provides filtration of inorganic nutrients / water purification;
storage of water in wetlands;
…prevents flooding / provides ideal resting grounds for migratory birds;
Tropical rainforests:
high biodiversity in TRF;
…promotes ecotourism/recreation;
high rate of photosynthesis in TRF;
…maintains balance of O₂/CO₂ in atmosphere;
Boreal/temperate forests:
tree populations in boreal/temperate forests;
…prevent soil erosion on mountainsides;
forest canopies in forests;
…provide shade/shelter/habitat for diversity of species.

Note: Numerous valid examples can be credited, but to gain full credit (2 marks per service) candidates must identify relevant component of biome [1 mark] and outline the service it provides [1 mark] as in MPs above.
Be careful only to credit “services” (maintenance/establishment of favourable conditions) and not “goods” (consumable/harvestable/physical products).

Award [2 max] if no biome is identified. If more than one biome is given, credit only highest scoring biome addressed.

Causes [4 max] could include:
habitat loss / deforestation;
habitat degradation / pollution;
narrowly distributed / endemic;
poaching / overhunting;
illegal trafficking of species;
disease;
small population size/gene pool / inbreeding;
specialised niche;
slow reproduction rate / specialised reproductive behaviour;
high trophic level/top predator;
low/negative cultural value;
influence/competition/predation from invasive species.

Consequences [4 max] could include:
loss of an aesthetically attractive organism;
loss of ethically significant life / breach of biorights;
loss of biodiversity;
increase in organisms upon which the species fed or competed with;
decline in other organisms due to loss of food source;
if keystone species, widespread impacts/cascade effects on food chains/ecosystem;
economic costs from loss of ecosystem services provided by the species;
economic costs from loss of tourism opportunities;
social impacts on local culture as important/significant cultural loss.

Accept reference to decline of any species that is endangered, critically endangered or currently extinct.
If more than one species is addressed only credit the highest scoring example.

Note: MPs given above need to be embedded in a valid case-study/account of a named species to gain full credit and not simply listed as bullet points as per MPs. e.g. The distribution of thylacine/Tasmanian tiger became limited/endemic to Tasmania in early 20th century (MP3); As it was thought to be a threat to sheep farming, it was hunted (MP11); bounties were given to promote the level of hunting (MP4). The introduction of domestic dogs spread disease amongst thylacines (MP6) leading to further decline.

If MPs are simply given without such context of a named species and its specific issues then give [2 max] for causes and [2 max] for consequences.

Answers may demonstrate:

• understanding concepts & terminology of habitat-based methods for conservation; species-based methods for conservation; international and national protection; international, national and local conservation organisations; ecosystem services; food chains and food webs; succession; threats to biodiversity; pollution consequences, eg bioaccumulation and biomagnification; threats from climate change; food production systems; human population growth; sustainable development; EVSs;
• breadth in addressing and linking range of threats to biodiversity; scale of different threats; challenges in LEDCs to develop sustainably; consequences of different EVSs; variety of habitat-based methods for conservation; variety of species-based methods of conservation;
• examples of both habitat- and species-based methods; threatened and protected areas and species; organisations involved in conservation;
• balanced analysis of the varying success of habitat and species conservation to protect threatened species;
• a conclusion that is consistent with, and supported by analysis and examples given eg success of the conservation of threatened species will depend on the context, nature of the threats and a combination of strategies is likely to be necessary with both habitat and species approaches used. If the habitat is not conserved and restored, a species whose population has been increased using species-based methods, will not survive in the wild.

Refer to paper 2 markbands, available under the "your tests" tab > supplemental materials.

This question frequently revealed some inaccurate grasp of concepts where candidates confused the term biome with specific ecosystems (e.g. Amazon rainforest) and/or ‘services’ with ‘goods’.

Generally well-answered, but where candidates failed to gain significant credit, it was largely through not having a specific named case study to which they could refer. A good number of candidates paid little heed to the number of marks available and were satisfied to name just one cause and one consequence.

Generally, responses to this question evaluating habitat-based and species-based conservation were of good quality although, again, candidates without specific case studies to which they could refer did less well.