Environmental Management 0680 | Paper 1 Mock 01 | Principles of Environmental Management

(a) Method that saves the most water per day [1]

Using a watering can instead of a hose, saving 350 litres per household per day. [1]

This is by far the largest single saving, reflecting the very high flow rate and extended use time of garden hoses.

(b) Total water saving if all six methods adopted [1]

\[ 40 + 30 + 15 + 350 + 25 + 20 = 480 \text{ litres per household per day} \] [1]

(c) Why water conservation is important even in water-rich countries [4]

1. Treating and distributing water requires significant energy input (pumping, filtration, chemical treatment, heating). This energy consumption contributes to greenhouse gas emissions, so reducing water use also reduces carbon emissions. [1]
2. Over-extraction from rivers and aquifers can damage freshwater ecosystems by lowering water levels, reducing river flows and drying out wetlands that support diverse wildlife. [1]
3. Climate change is making rainfall patterns less predictable and increasing the frequency of droughts, even in regions that currently receive plentiful rain. Conserving water now builds resilience against future shortages. [1]
4. Population growth increases total water demand. Even where per-capita supply is currently adequate, a rising population can turn abundance into scarcity if consumption habits remain unchanged. [1]

(d) Why many households do not adopt water conservation methods [4]

1. Many people are simply unaware of how much water they waste or of the cumulative environmental impact of individual household consumption. Without awareness, there is no motivation to change. [1]
2. In areas where water prices are low or where water charges are not metered (flat-rate billing), there is little financial incentive to reduce consumption because usage does not affect the bill. [1]
3. Some conservation measures require an upfront investment: installing a dual-flush toilet, a low-flow showerhead, or a rainwater harvesting system all cost money that households may not prioritise over other spending. [1]
4. Habits are difficult to change. People become accustomed to long showers, hosing the garden, and running half-empty washing machines. Conservation measures may be perceived as inconvenient or requiring effort for a saving that feels invisible at the individual level. [1]

(a) Ecosystem with the highest economic value per hectare per year [1]

The coral reef, with an estimated economic value of 352 249 USD per hectare per year. [1]

(b) Comparison of ecosystem services: tropical rainforests vs wetlands [4]

1. Tropical rainforests store more carbon (250 tonnes C per hectare) than wetlands (200 tonnes C per hectare). [1]
2. Both have high biodiversity, though rainforests are rated "very high" compared to "high" for wetlands. [1]
3. Wetlands provide much higher water purification services (rated "very high") compared to rainforests (rated "moderate"). Wetlands act as natural filters, trapping sediment and breaking down pollutants. [1]
4. Wetlands also provide greater flood prevention (rated "very high" compared to "high" for rainforests). Wetlands absorb and store excess water during heavy rainfall, releasing it slowly and reducing downstream flooding. [1]

Overall, the two ecosystems provide complementary services: rainforests are stronger in carbon storage and biodiversity, while wetlands excel in water-related services (purification and flood prevention).

(c) Why coral reefs have the highest economic value despite lower carbon storage [4]

1. Coral reefs support extremely valuable fisheries that provide food and livelihoods for millions of people in coastal communities globally. [1]
2. They provide coastal protection by absorbing wave energy, reducing the impact of storms and erosion. Replacing this natural defence with artificial structures (sea walls, breakwaters) would cost billions of dollars. [1]
3. Coral reefs generate very high tourism income through activities such as diving, snorkelling and boat tours. Reef tourism is a major source of revenue for many tropical island nations. [1]
4. The high biodiversity of coral reefs supports pharmaceutical research and the discovery of novel compounds with medical applications, giving them significant commercial and scientific value. [1]

Economic value captures more than just carbon storage; it reflects the full range of goods and services an ecosystem provides, including provisioning (food), regulating (coastal protection), cultural (tourism) and supporting services.

(a) The no-take zone (Zone A) is positioned directly over and surrounding the coral reef. [1]

This placement ensures the most ecologically sensitive habitat receives the highest level of protection.

(b) Why coral reefs are areas of high biodiversity: [2]

• Coral reefs provide a wide variety of habitats and niches due to their complex three-dimensional structure. The branching coral, crevices, overhangs and sandy patches between coral heads each support different communities of organisms. [1]
• This structural complexity supports organisms at many trophic levels, from photosynthetic algae and coral polyps at the base, through herbivorous fish, invertebrates (sea urchins, starfish, crustaceans) and small predatory fish, up to large predators (groupers, sharks). Coral reefs support approximately 25% of all marine species despite covering less than 1% of the ocean floor. [1]

(c) Two differences between management rules in Zone A and Zone B: [4]

Difference 1:

• In Zone A (no-take zone), all fishing and extraction of organisms is completely prohibited. No marine life may be removed, whether commercially or recreationally. [1]
• In Zone B (regulated fishing zone), fishing is permitted but controlled through regulations such as catch limits, minimum fish sizes, seasonal closures during breeding periods and restrictions on gear types (e.g. banning trawl nets). [1]

Difference 2:

• In Zone A, boat access and anchoring may be restricted or prohibited to prevent physical damage to the coral reef from anchors dragging across the seabed. Only research vessels with special permits may enter. [1]
• In Zone B, boats are permitted but may be restricted to certain types or sizes, and may be required to use designated mooring buoys rather than dropping anchors to minimise seabed damage. [1]

(d) Short-term and long-term effects on fishing communities: [6]

Short-term effects:

• Fishing communities lose access to some of their traditional fishing grounds within the MPA, particularly the no-take zone. This directly reduces the area available for catching fish, potentially lowering income. [1]
• Fishers may need to travel further from the port to reach areas outside the MPA boundaries, increasing fuel costs, time at sea and the risks of fishing in unfamiliar or more exposed waters. [1]
• Some fishers may need to retrain or find alternative employment (tourism, aquaculture, boat maintenance) during the transition period, which can cause economic hardship and social disruption. [1]

Long-term effects:

• Fish populations within the protected area are expected to recover and increase in both numbers and size over time. As populations grow, adult fish and larvae move beyond the MPA boundaries into the surrounding fishing grounds, a phenomenon known as the spillover effect. This can lead to larger and more sustainable catches in adjacent waters. [1]
• Healthier fish stocks mean larger individual fish are caught, which command higher market prices. Overall fishing income may exceed pre-MPA levels as the ecosystem recovers. [1]
• The MPA could attract ecotourism (snorkelling, diving, glass-bottom boat tours), creating alternative income streams for the community. The coral reef and abundant marine life within the no-take zone would be the main attraction. [1]

(a) Total number of species in each habitat: [2]

Habitat A (Forest): 28 + 15 + 22 + 35 + 12 + 85 = 197 species [1]

Habitat B (Grassland): 3 + 8 + 45 + 18 + 6 + 60 = 140 species [1]

(b) Which habitat has higher species diversity: [2]

• Habitat A (forest) has the higher species diversity, with 197 species compared to 140 species in Habitat B. [1]
• The forest has particularly higher numbers of tree species (28 vs 3), bird species (35 vs 18), mammal species (12 vs 6) and insect species (85 vs 60). The complex, multi-layered structure of the forest provides more distinct habitats and ecological niches. [1]

(c) Why a habitat with more species is generally more stable: [2]

• A habitat with more species has more complex food webs with multiple connections. If one species declines (through disease, drought or other disturbance), other species can fill its ecological role, so the overall ecosystem continues to function. This is known as ecological redundancy. [1]
• Greater genetic diversity across many species means the ecosystem as a whole is better equipped to withstand environmental changes such as disease outbreaks, climate fluctuations or the introduction of invasive species. A less diverse system is more vulnerable because losing even one key species can trigger a cascade of further losses. [1]

(d) Why grassland has more individual herbaceous plants and insects: [3]

• Grassland receives more direct sunlight at ground level because there is no dense tree canopy shading the surface. This allows herbaceous plants (grasses, wildflowers) to photosynthesise at maximum rates and grow in very high densities (1,200 individuals recorded). [1]
• The large number of herbaceous plants provides an abundant and accessible food supply for herbivorous insects (grasshoppers, caterpillars, beetles), supporting very high insect populations (4,500 individuals). Flowers also attract pollinators in large numbers. [1]
• The open, warm conditions at ground level in grassland favour insect reproduction and activity. Insects are ectothermic (cold-blooded) and are generally more active and reproduce faster in warmer, sun-exposed habitats. [1]

(e) Likely effects of converting grassland to a single-species tree plantation: [5]

• A monoculture plantation (one tree species) has very low structural diversity compared to natural grassland. The uniform canopy and sparse understorey provide far fewer habitat types and niches, reducing overall species diversity. [1]
• The 45 species of herbaceous plants currently in the grassland would be shaded out as the plantation canopy closes. The 60 insect species and 18 bird species that depend on these plants and the open grassland habitat would lose their food sources and nesting sites. [1]
• Grassland mammals (6 species, 85 individuals) are adapted to open habitat and would be unable to thrive in a closed-canopy plantation. Species dependent on grass seeds, burrows in open ground or visibility for predator avoidance would be displaced. [1]
• Over time, the plantation might attract some forest-adapted species, particularly if it provides some canopy cover and leaf litter. However, a monoculture plantation supports far fewer species than a natural forest because it lacks the structural complexity, dead wood and diverse food sources. [1]
• Overall, converting the grassland would likely reduce the total biodiversity of the reserve. A diverse, species-rich grassland (140 species) would be replaced by a structurally simple monoculture that might support only a fraction of those species. The reserve managers should carefully weigh this loss against any benefits the plantation might provide. [1]

(a) Percentage increase in the city's population between 1995 and 2025 [2]

Population increase = 12.0 - 2.5 = 9.5 million [1]

\[ \text{Percentage increase} = \frac{9.5}{2.5} \times 100 = 380\% \] [1]

The city's population increased by 380% over the 30-year period, nearly quintupling in size.

(b) Trend in the percentage of the population living in informal settlements [1]

The percentage living in informal settlements has increased steadily from 25% in 1995 to 48% in 2025, nearly doubling over the 30-year period. This means that not only is the total population growing, but an increasing proportion of that growing population lives in unplanned, under-serviced settlements. [1]

(c) Two reasons for the rapid growth of the city's population [2]

1. Rural-to-urban migration: People move from rural areas to the city seeking better employment opportunities, higher wages, access to education, and improved healthcare services. Push factors in rural areas (poverty, land shortages, lack of services) combine with pull factors in the city to drive migration. [1]
2. Natural increase: The city's population has a young age structure (many people of reproductive age), so birth rates are substantially higher than death rates. This internal population growth compounds the growth from migration. [1]

(d) How the decline in access to clean water and sanitation could affect health [3]

1. Waterborne diseases: Lack of access to clean water forces people to use contaminated water sources (rivers, shallow wells, stagnant pools), dramatically increasing the spread of waterborne diseases such as cholera, typhoid, and dysentery. [1]
2. Sanitation-related contamination: Poor sanitation means human waste is not properly collected or treated, contaminating water sources and living areas with faecal pathogens. Open defecation and overflowing pit latrines in densely packed informal settlements spread disease-causing organisms through direct contact and via flies. [1]
3. Compounding health crisis: The combined effect of poor water and poor sanitation leads to high rates of diarrhoeal diseases, particularly among children under five, increasing infant mortality and reducing life expectancy. Malnourished children are especially vulnerable, creating a cycle of disease, malnutrition, and poverty. [1]

(e) Two strategies to improve living conditions in informal settlements [2]

1. In-situ upgrading: Upgrading infrastructure within existing informal settlements by providing piped clean water, sewage systems, and electricity connections, rather than demolishing settlements and displacing residents. This approach is more affordable and less disruptive than relocation. [1]
2. Secure land tenure: Providing secure land tenure (legal ownership or long-term leasehold) to residents of informal settlements. This gives people the confidence and legal incentive to invest in improving their own homes, because they know their investment is protected and they cannot be evicted without compensation. [1]

(a) Top predator in the food web [1]

The top predator is the red-tailed hawk. [1]

A top predator (apex predator) is a consumer at the highest trophic level that is not preyed upon by any other organism in the food web. The red-tailed hawk feeds on both the roadrunner and the rattlesnake, and nothing feeds on the hawk.

(b) Two food chains of four organisms [4]

1. Desert shrub → desert tortoise → roadrunner → red-tailed hawk [2]
2. Seeds → kangaroo rat → rattlesnake → red-tailed hawk [2]

Any valid chain of four organisms taken from the food web, where each arrow follows a correct feeding relationship, is acceptable.

(c) Two adaptations of a cactus for desert survival [4]

Adaptation 1: Thick, waxy cuticle

• The cactus has a thick, waxy outer layer (cuticle) on its stem that reduces water loss by evaporation. [1]
• This allows the cactus to retain the water it stores internally, even in extremely hot and dry conditions where evaporation rates are high. [1]

Adaptation 2: Spines instead of leaves

• The leaves of a cactus are reduced to spines, which dramatically reduces the surface area available for transpiration (water loss through stomata). [1]
• The spines also serve a secondary function: they deter herbivores such as the desert tortoise from eating the cactus and accessing its stored water. [1]

Other acceptable adaptations include: an extensive shallow root system for rapid absorption of rare rainfall; a swollen stem that acts as a water storage organ; and CAM photosynthesis, which opens stomata only at night to reduce daytime water loss.

(a) An ore is a naturally occurring rock or mineral from which a metal or other valuable substance can be economically extracted. [1]

The key word is "economically": many rocks contain traces of metals, but only those with a high enough concentration to be profitably mined and processed are classified as ores.

(b) Two environmental impacts of open-pit mining: [2]

• The excavation removes all vegetation and topsoil from a large area, completely destroying the natural habitat and displacing wildlife. This leads to a loss of biodiversity, as species that depended on the original ecosystem can no longer survive there. [1]
• Mining operations generate large quantities of dust and noise, polluting the air and disturbing both wildlife and nearby human communities. Heavy machinery, blasting and the transport of rock produce continuous noise, while fine dust particles can cause respiratory problems and settle on surrounding vegetation. [1]

Other acceptable answers include: water pollution from acid mine drainage (when sulfide minerals in exposed rock react with rainwater to produce sulfuric acid), visual pollution and landscape scarring, or contamination of soil with heavy metals.

(c) How the mine site could be restored after extraction: [2]

• The pit could be backfilled with waste rock and overburden, then covered with a layer of stored topsoil. Native vegetation (grasses, shrubs and trees) can then be replanted to restore the ecosystem. Over time, wildlife will recolonise the area as the habitat recovers. [1]
• Alternatively, the pit could be allowed to fill with groundwater to create an artificial lake. The surrounding land can be landscaped and planted to create a recreational area, nature reserve or wildlife habitat. This approach can provide long-term community and ecological benefits. [1]

(a) Layer of the atmosphere containing the ozone layer [1]

The stratosphere. [1]

The ozone layer is located approximately 15 to 35 km above the Earth's surface, within the stratosphere (which extends from about 12 km to 50 km altitude).

(b) Role of the ozone layer in protecting life on Earth [3]

1. The ozone layer absorbs most of the harmful ultraviolet (UV) radiation from the Sun before it reaches the Earth's surface. Ozone molecules (O\(_3\)) are particularly effective at absorbing UV-B and UV-C wavelengths. [1]
2. Without this protective layer, increased UV radiation reaching the surface would cause significantly higher rates of skin cancer, cataracts and immune system suppression in humans. [1]
3. UV radiation also damages the DNA in plant cells, reducing crop yields and forest productivity, and harms phytoplankton in the oceans. Phytoplankton are the base of marine food chains and are responsible for a large proportion of global oxygen production, so their decline would have cascading effects throughout marine ecosystems. [1]

(c) How CFCs cause ozone depletion [3]

1. Chlorofluorocarbons (CFCs), released from products such as aerosol sprays, old refrigerators, air conditioning units and foam packaging, are chemically stable in the lower atmosphere and slowly rise into the stratosphere. [1]
2. In the stratosphere, intense UV radiation breaks apart CFC molecules, releasing free chlorine (Cl) atoms. [1]
3. Each chlorine atom acts as a catalyst: it reacts with an ozone molecule (O\(_3\)), converting it to ordinary oxygen (O\(_2\)) and chlorine monoxide (ClO). The ClO then reacts with another oxygen atom to regenerate the free chlorine, which goes on to destroy more ozone. A single chlorine atom can destroy thousands of ozone molecules before it is eventually removed, making CFCs extremely destructive even in small quantities. [1]

(d) Why the Montreal Protocol is considered a successful agreement [3]

1. The Montreal Protocol (1987) established a binding international framework to phase out the production and use of CFCs and other ozone-depleting substances. Nearly every country in the world ratified it, making it one of the most widely supported environmental treaties in history. [1]
2. As a direct result of the phase-out, atmospheric concentrations of CFCs have decreased measurably, and the Antarctic ozone hole has begun to show signs of recovery. Scientists project that the ozone layer will return to pre-1980 levels by the middle of this century. [1]
3. It demonstrated that international cooperation can successfully address a global environmental problem when there is clear scientific evidence of the threat, political will to act, and the availability of viable alternative substances and technologies to replace the harmful ones. [1]