Cambridge A Level Environmental Management (AS only) 8291 — 2018 May/June Paper 2 · Variant 1

1 (a) Fig. 1.1 shows the flows and stores of nutrients in a tropical rainforest ecosystem. biomass leaf fall uptake by plants precipitation weathering litter soil 13% of 14% of nutrients nutrients run-off decomposition leaching Key store of nutrients flow of nutrients input / output Fig. 1.1 (i) Calculate the percentage of nutrients stored in biomass in the tropical rainforest ecosystem shown in Fig. 1.1. ...................................... % [1] (ii) State what is meant by the term biomass. ........................................................................................................................................... ...................................................................................................................................... [1] (iii) With reference to Fig. 1.1, describe the interactions between the stores of nutrients within a tropical rainforest ecosystem. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [3] (iv) Explain how precipitation influences the stores and flows of nutrients in a tropical rainforest ecosystem. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [4] (v) Explain why more nutrients are stored in biomass than in the litter and soil in a tropical rainforest. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [3] (b) Fig. 1.2 shows human activities that lead to deforestation of a tropical rainforest. 5% other* 10% logging 20% large-scale 45% small-scale commercial agriculture agriculture (oil palm) 20% pasture (cattle ranching) *other includes urbanisation, mining, construction of roads and dams Fig. 1.2 (i) Describe the ways in which the human activities shown in Fig. 1.2 affect the nutrient cycle in the tropical rainforest shown in Fig. 1.1. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [5] (ii) Suggest ways in which the impact of human activities on tropical rainforest ecosystems can be reduced. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [3] [Total: 20]

Mark scheme: 1(a)(i) 73%; 1 1(a)(ii) (mass of) living / biotic / organic (components of the ecosystem) (per unit area / ecosystem); mass of living organisms, in a given area, measured in grams per square metre; 1 1(a)(iii) nutrients are recycled in the ecosystem; (inorganic compounds / nutrients) from the soil are absorbed by plant roots into the plant; assimilation (into organic compounds) / (secondary) productivity; growth; stored as wood / new biomass; dead leaves / dead organisms / leaf fall are incorporated into leaf litter; leaf litter is broken down / decays; due to the action of detritivores / microbial action; humus formation; nutrients are released into the soil store as (inorganic compounds / minerals) soil is enriched; 3 Question Answer Marks 1(a)(iv) precipitation outputs: run-off, removes nutrients (dissolved in precipitation); leaching removes nutrients from the soil store by; percolation to groundwater; precipitation inputs: nutrients, dissolved in rainfall; e.g. nitrite; throughfall / interception / leaf drip / stem flow; infiltration of rainwater into soil store; nutrients dissolved in solution; allows the uptake of nutrients by plants; by diffusion / active transport; used in plant growth and stored in biomass; (chemical weathering) of bedrock releases nutrients into the soil store; 4 1(a)(v) rapid rate of decomposition of (organic material); due to increased rate of microbial activity; high temperature and high humidity / rainfall provide optimum conditions for this (rapid decomposition); rapid incorporation of nutrients into humus; rapid recycling of nutrients / nutrients spend a relatively short time period in litter and soil; longevity / nutrients are incorporated by organisms over a long period of time in growth; 3 Question Answer Marks 1(b)(i) removal of the biomass; increased surface run-off; increased nutrient loss from soil store; increased leaching of soil; soil erosion / soil degradation; the destruction of the vegetation results in loss of habitat; loss of food supply; loss of nesting and breeding sites for the community of organisms; declining populations; biodiversity loss / species are vulnerable / threatened / at risk of extinction; effect on climate / hydrological cycle, e.g.; a change in rates of evaporation / evapotranspiration; a change in precipitation rate; risk of flooding; subsistence agriculture has the highest percentage use (45%) but has less effect on the nutrient cycles; the ecosystem can be restored through natural succession; only small fragmented areas are used; nutrients are replenished through nutrient recycling; the effect of logging (10%) will be dependent on the type of logging / area of land involved; cattle ranching (20%) / plantation (20%) have greater effect due to removal of biomass from large areas; overgrazing; soil compaction by trampling; pasture land has less effect on nutrient cycles, as the ground is covered with vegetation and soil cover is maintained (compared to plantation where the soil is part exposed during the growing season) / and manure is added; although the lowest percentage of deforestation (5%) is from the ‘others’ category, e.g. mining, dams, these have a greater effect due to complete removal of biomass and soil pollution; 5 Question Answer Marks 1(b)(ii) sustainable agriculture in conservation areas; e.g. agroforestry which combines using the land for growing a suitable crop within the forest thus maintaining the forest; use crop rotation; subsistence agriculture using small fragmented areas with sufficient time for natural succession; sustainable use of forest resources; selective logging in timber managed areas; removing some trees from forest while maintaining the overall forest as opposed to clear cutting large areas; preventing the illegal logging of specific species; afforestation; of fragmented forest areas; re-growing the forest; protected areas / protected forest reserves; national parks; restricting impact of human activity by, e.g.; raising awareness through education of the economic value of and benefits of maintaining forest cover and its associated wildlife; ecotourism; 3

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2 Fig. 2.1 contains information about the Mekong river basin in Southeast Asia and the sites of some dam-building projects. CHINA Snow and glacier melt is the main source of VIETNAM freshwater in the upper course of the river.MYANMAR Hanoi Gulf of Tonkin LAOS The river flow is influenced by the monsoon rains (May to October). Vientiane THAILAND Bangkok CAMBODIA Phnom Penh The Mekong delta: Gulf of Thailand VIETNAM • is an area of low land where the Mekong river splits into smaller rivers • is inundated by saltwater Mekong delta when river flow is low during the dry season (November to April) South China Sea • is a major rice-growing N region of the world • has a population of 0 200 km approximately 17 million. Key capital city agriculture Mekong river basin boundary forested area Mekong river land outside Mekong river basin dam-building projects sea national boundary lake Fig. 2.1 (a) (i) With reference to the information in Fig. 2.1, explain why the Mekong delta is prone to flooding. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [4] (ii) Explain how global warming could impact on the environment and on the population in areas such as the Mekong delta. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [6] (b) (i) Outline two benefits of dam-building projects, such as those shown in Fig. 2.1. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [4] (ii) Suggest the negative impacts of constructing dams on the Mekong river. Refer to Fig. 2.1 in your answer. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [6] [Total: 20]

Mark scheme: 2(a)(i) a low-lying area / close to sea level; glacier melt (coincides with); monsoon rainfall / increased precipitation in wet season; increased input of water / river flow / volume / discharge; increase surface run-off; from higher land; reduce infiltration of soil; soil saturation; high water table; less interception in agricultural land due to reduced forest cover; 4 Question Answer Marks 2(a)(ii) environment: increase in temperature; increased melting of glaciers; increased river flow into delta; thermal expansion of sea water; rise in sea level; increased inundation of delta/increased tidal surge; long-term flooding of delta region; salt water intrusion; reduced freshwater stores in river, lake, wetland; salinization of soil; change in hydrological cycle; e.g. increase in storm / frequency / intensity; increased length of dry season; population: effect drinking water supply; effect on rain-fed irrigation; effect on the suitability of land for growing crops; effect on agricultural output of delta; loss of livelihood; migration of population inland; ecological effects; 6 Question Answer Marks 2(b)(i) reservoir stores water during heavy rain / water from glacier melt; for drinking water / domestic use; use in industry; provides a water supply during the dry season; irrigation water for agriculture; extends the growing season ; hydroelectric power generation; electricity supply for cities, e.g. Vientiane; flood protection; control of river flow to lower course of river reducing frequency of downstream flooding; economic value of dams; tourism opportunities; employment opportunities provided by dam building projects; recreation activities; e.g. sailing, fishing; 4 Question Answer Marks 2(b)(ii) effect on the natural flow of water, rate of flow; reduced flow of water to lower course of river; transport of sediments downstream is effected by the build-up of sediment in the dam; reduced supply of nutrients downstream/ reduces soil fertility of farmland in the lower course of the river; effect on agricultural activity; reduced supply of water for rain-fed irrigation; e.g. rice–growing in Mekong Delta; lowering of water table; destruction of wetlands; ecological disruption / effect on freshwater species; effect on freshwater lakes; e.g. reduced supply of water to (Tonle Sap) lake; effect on freshwater fisheries; loss of livelihood for people dependent on the fisheries; increased salinization of delta region; effect on ecosystems destroyed by dam-building; deforestation; dust and noise during dam building; forced displacement of people evicted from their lands and homes; 6

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3 Fig. 3.1 shows the number of major oil spills from tankers in the world’s oceans in four successive decades. 260 240 220 200 180 160 number of 140 major oil spills 120 100 80 60 40 20 0 1970 − 79 1980 − 89 1990 − 99 2000 − 09 year Fig. 3.1 (a) With reference to Fig. 3.1, describe the change in the number of major oil spills and suggest reasons for this change. [10] (b) Briefly describe the main sources of marine pollutants other than oil spills. Using examples, explain to what extent the pollution of the marine environment can be managed by individual countries. [30] [Total: 40]

Mark scheme: 3(a) A decreasing trend is shown in the number of oil spills from tankers in each decade (245, 93, 77 and 35 oil spills). The largest decrease occurred between the 1970s and 1980s with a decrease of 152 spills subsequently followed by a slowing in the rate of decrease. The number of oil spills was six times greater between 1970–79 to, compared to 2000– 09. Suggested reasons for the changes may include reference to changes in shipping regulations; changes in the size and the design of ships for oil transportation or to an overall reduction in the transport of oil, linked to decreasing demand and the use of alternative fuel and energy resources. Please use level descriptors 1 10 3(b) The question requirements are: • to describe the main sources of pollution other than oil spills • to use examples of the management of marine pollution • to explain to what extent marine pollution can be managed by individual countries Indicative content: Sources of marine pollution include, for example, sewage; agricultural run-off; industrial wastewater; natural sources; drainage of coastal ecosystems; deforestation; dredging and urban development. Reference can be made to the management of marine pollution by individual countries through examples of laws or policies; the management of waste; changes in agricultural practices; coastal ecosystem restoration; shipping regulations; the establishment of protected areas; pollution controls; as well as education, awareness and research. For example pollution of the Great Barrier Reef is effectively managed through the establishment of a marine park and zoning plan. An assessment may consider that as sources of pollution occur some distance from their effect and cross international borders, for example air pollution or due to maritime transportation which together, with the dispersal of marine pollutants make management difficult. Environmental management resulting from international management plans may be more effective, for example, UNEP’s Regional Seas Program. Please use level descriptors 2 30

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4 Fig. 4.1 shows two examples of an ecological island. ecological island ecological island entrance pest-proof access sea fence Sipopo Maungatautari Equatorial Guinea New Zealand Africa Fig. 4.1 (a) Describe and explain what is meant by an ecological island. Refer to Fig. 4.1 in your answer. [10] (b) ‘The most effective methods for the conservation of ecosystems exclude all human activity.’ Using examples of different methods of conservation of ecosystems, discuss how far you agree with this statement. [30] [Total: 40]

Mark scheme: 4(a) The meaning of an ecological island should be described through the use of examples. An island separated from the mainland and surrounded by sea as shown in Fig.4.1. A small habitat surrounded by different environmental conditions and different habitats e.g. a small pond in woodland. An ecological island can be natural or man-made. Man-made ecological islands e.g. a park in a city, or the ecological island created by building a pest proof fence as shown in Fig. 4.1. Other examples include wildlife parks or game reserves. Essentially an ecological island is an area that contains species that cannot mix with other populations of the species. An ecological island offers a range of conservation benefits. They can ensure the survival of vulnerable species by reducing competition for food or other resources or by excluding predation. Please use level descriptors 1 10 Question Answer Marks 4(b) The question requirements are: • to discuss methods of conservation which exclude human activity • to discuss methods of conservation which involve human activity • to use examples Indicative content: Conservation methods range from strict nature reserves, isolated ecological islands and protected areas with complete exclusion of human activity. Some areas allow access though permit only or for research purposes. Other less strict reserves will allow ecotourism and educational visits but other forms of human activity are banned. National parks allow open access to visitors and recreational activities. Managed resource areas allow the sustainable use of resources within conservation areas with traditional forms of agriculture and forestry. An assessment should consider whether the preservation of species, habitats or ecosystems is more effective, if humans are excluded. An alternative perspective may consider that conservation is more successful when human activity is involved; either through direct intervention in the conservation of the species or with community involvement. Conservation is valued and considered important from an economic perspective, e.g. for ecotourism. The effectiveness of the methods used with reference to criteria such as education, research opportunities, public awareness, economic value and sustainability should be considered. Please use level descriptors 2 30

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5 Fig. 5.1 shows the total global population and its percentage annual growth rate, from 1900 to 2015. 9 2.25 8 2.00 total global percentage population 7 1.75 annual / billion percentagepercentage annualannual growth rate 6 growthgrowth raterate 1.50 5 1.25 4 1.00 3 globalglobal populationpopulation 0.75 2 0.50 1 0.25 0 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Fig. 5.1 (a) Briefly describe the changes in the percentage annual growth rate of the global population from 1900 to 2015. Suggest reasons for these changes. [10] (b) Using examples from countries at contrasting levels of economic development, describe the impact of population change on resources. [30] [Total: 40]

Mark scheme: 5(a) Changes in the percentage annual growth rate of the global population should be described with reference to an overall increase between 1920 and 1970 and an overall decrease between 1970 and 2015. Variation in the overall rates of increase and decrease during these periods should be considered. Increasing percentage annual growth rate can be attributed to reasons such as increased birth rates, a reduction in the rate of infant mortality, medical improvements and incentives to have larger families. Slower periods of growth rate at can be attributed to significant periods of war, disease or famine. Reasons for a decreasing percentage annual global growth rate can include reference to family planning, the increased use of contraceptives, and population policies. Continuing decreasing growth rate can be linked to economic and social development. Please use level descriptors 1 10 Question Answer Marks 5(b) The question requirements are: • to use contrasting examples • to describe the impact of population change on resources Indicative content: An answer may consider issues arising from an increasing global population, with overpopulation negatively impacting on global resources. Demand for food is expected to continue to grow due to the rising global population. Increased crop and meat production and increasingly more biofuels will be required. This will increase pressure on land resources. Expansion of farmland into areas less suitable for agriculture will require greater use of irrigation and fertilisers. More irrigation will impact on the quantity of water; the use of fertilisers will result in more water pollution. More and more of the natural environment will be used and destroyed e.g. deforestation of the tropical rainforest for agriculture will result in soil degradation. A growing population will also require land for housing and industry as well as agriculture. Alternatively a decreasing percentage annual growth rate of the global population may eventually lead to equilibrium and optimum population size. A fairer distribution of resources, the sustainable use of resources and protection of resources with less impact upon global resources. Please use level descriptors 2 30 Question Answer Marks Section B descriptor levels: Descriptor Award Mark Consistently meets the level criteria Mark at top of level Meets the criteria, but with some inconsistency Middle, mark to just below top mark Meets most of level criteria, but not all convincingly Just below middle, mark to just above bottom mark On the borderline of this level and the one below Mark at bottom of level Section B (part a), Level descriptors 1 8–10 marks The response: • contains few errors • shows a very good understanding of the question • shows a good use of data or the information provided, where appropriate • provides a balanced answer 5–7 marks The response: • may contain some errors • shows an adequate understanding of the question • shows some use of data or the information provided, where appropriate • may lack balance Question Answer Marks 1–4 marks The response: • may contains errors • shows limited understanding of the question • shows little or no use of data or the information, where appropriate • lacks balance Section B (part b): Level descriptors 2 Responses: Level one, 25–30 marks • fulfil all the requirements of the question • contain a very good understanding of the content required • contain a very good balance of content • contain substantial critical and supportive evaluations • make accurate use of relevant vocabulary Level two, 19–24 marks • fulfil most of the requirements of the question • contain a good understanding of the content required • contain a good balance of content • contain some critical and supportive evaluations • make good use of relevant vocabulary Level three, 13–18 marks • fulfil some requirements of the question • contain some understanding of the content required • may contain some limited balance of content • may contain brief evaluations • make some use of relevant vocabulary Question Answer Marks Level four, 6–12 marks • fulfil limited requirements of the question • contain limited understanding of the content required • may contain poor balance of content • may not contain evaluations • make limited use of relevant vocabulary Level five, 1–5 marks • fulfil a few of the requirements of the question • contain a very limited understanding of the content required • are likely to be unbalanced and undeveloped • evaluative statements are likely to be missing • make no use of relevant vocabulary

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