GEOGRAPHY P2 - Ecosystems of the Planet (GCSE OCR A)

Polar regions Climate & Seasons (Both, Arctic, Antarctic)

Long cold winters, short cool summer

Covered by snow and ice throughout the year

Low angle of Sun in sky ⇒ low temp

Half year in darkness, half in light

<250mm annually as air descends at 90°

Arctic specifically:

-46°C to -26°C because of:

- Sea does not fall below -2°C

- Gulf Stream: Arctic weather travels south and warm weather travels north

Antarctica specifically:

-62°C to -55°C because of:

- Altitude: 2300m

- Antarctica's weather kept within continent ∵ circumpolar winds and currents travelling around the coastline

Location of polar regions (Arctic and Antarctic)

No land at north pole = no desert

Land in Russia & Canada = tundra

Antarctica = land at south pole = desert

No land = tundra

Flora of polar regions (Arctic and Antarctica)

Arctic:

Treeless, w/ only low 2m tall shrubs: mosses, grasses, flowers. 1700 species of plant live in the tundra

Antarctica only:

Plant life less plentiful as 1% is ice-free. 100 species of moss and 300-400 species of lichen

Fauna of polar regions (Both, Arctic, Antarctica)

Land mammals include wolves, foxes, and reindeer. Sea animals include walruses and whales.

Both have very productive seas due to large volumes of phytoplankton

Arctic only:

Gentoo/emperor/Adélie penguins

Some migrate south during winter

Polar bears here.

Antarctica only:

Fur/Weddell/elephant seals

Temperate Grasslands Climate

Cooler than Savannah

Extreme: Summer >30°C, Winter -20°C

Average rainfall 250-750mm (75% of which in summer)

Snow = reservoir of moisture to help start of summer growing

Summer can bring droughts & wildfires to maintain the grasslands

Temperate Grasslands Location

40°-60°

Plains of North America

Veldts of Africa

Pampas of South America

Steppes of Eurasia

Temperate Grasslands Flora

Trees and shrubs struggle to grow, but willow and oak grow along river valleys. 2m tall tussock grasses are found in clumps on the landscapes. 50cm buffalo and feather grasses grow across the land. Sunflowers and wild indigos can grow among the grasses

Temperate Grasslands Fauna

Burrowing animals such as gophers and rabbits

Large herbivores such as kangaroos, bison (typically in prairies of NA), and antelopes.

Carnivores such as coyotes & wolves, and eagles & hawks.

Temperate Forests Climate (+seasons)

4 seasons of equal length due to the tilt of the Earth and Sun's rays hitting different places more directly at different times of the year. Warm summer, mild winter.

Rainfall: 750mm - 1500mm (2nd highest), Temp.: 10°C

Cloud cover keeps temperature above 0°C

High rainfall ∵ is at meeting point of Ferrell and Polar cells: warm tropical air rises over denser, cold polar air creating low pressure → rainfall

Temperate Forests Location

40°-60°

Deciduous:

Eastern NA, east Asia, west Europe

Evergreen:

New Zealand, SA, east Australia, south China, Korea, Japan

Temperate Forests Flora

Trees have a growing season of 6-8mo, only growing 50cm per year

Deciduous trees shed their leaves during the winter season: Elm, beech, sycamore, oak, chestnut (Canopy).

Trees and shrubs are 5m tall for hawthorns to 20m for ash and birch (Understorey). Forest Floor covered in brambles, grass, bracken and thorns.

Temperate Forests Fauna

Some migrate to warmer places and others hibernate to escape the cold

Australia: koalas & opossums

NA: Black bears - have a heavy fur coat and build a 5in layer of fat before hibernation

Squirrels, owls, pigeons, rabbits, deer, mice, foxes.

Hot Deserts Climate

<250mm annually

Often >40°C

No cloud cover ∴ very cold at night

Hot Deserts Location

15°-30° (TROPICS)

Sahara (North Africa), Mojave (West NA), Gobi Desert (South Asia)

Hot Deserts Flora

Most plants are xerophytic (drought-resistant). Their roots are either long to tap into groundwater or spread across the surface to absorb whatever rain falls. Cacti & Yucca.

Cacti have thick, spiky, waxy leaves to prevent animals eating them and to lower surface area, lowering transpiration.

Thin grasses in places with rainfall

Bushes grow far apart to reduce competition for water and seeds lie dormant until rain falls.

Hot Deserts Fauna

Many animals are small and nocturnal

- Meerkats occupy complex underground tunnel systems and eat scorpions (immune to their venom), lizards and small rodents

- Camels' humps store fat instead of having it around the body and serving as unwanted insulation. They have thick hair on their ears, long eyelashes to keep out the sand and wide feet

Sidewinder rattlesnakes' unusual sideways motion keeps them moving in shifting sands and ensures only two parts of their body are touching the sand

Tropical Grassland (Savanna) Climate (+seasons)

Shorter wet season when the Sun moves overhead, bringing the ITCZ with it. Longer dry season when the ITCZ moves away.

Cloud cover is limited for most of the year, allowing for daily temp of 25°C. Temperature ranges ∵ reduced angle of the Sun in the sky for part of the year

500 to 950 mm of rain per year

Tropical Grassland (Savanna) Location

5°-30°

Around Congo Basin

Venezuela

Brazilian highlands

Mexico

Northern Australia

Tropical Grassland (Savanna) Flora

Tall, spiky pampas grass grows to 3m

Baobab tree has large swollen stems and a 10m diameter trunk. Root-like branches hold a small number of leaves to reduce transpiration. Bark is thick to retain moisture and roots are long to tap into deep water supplies.

Many trees are drought-resistant (xerophytic) or fire-resistant (pyrophytic)

Tropical Grassland (Savanna) Fauna

40 different hoofed animal species

Herbivores: gazelles, impalas, elephants, giraffes, wildebeest, zebras, rhinos.

Carnivores: cheetahs, lions, leopards, dogs, hyenas

Tropical Rainforest Climate & Water cycle

Constant high temperatures & wet - 26-28°C with >2000mm of convectional rainfall (falls in afternoon)

No seasons, every day has 12hr daylight, 12hr darkness

Humid due to rainfall and transpiration from dense vegetation

Cloud cover varies (more in afternoon) & reduces heat loss

Water cycle has some components added:

- Evapotranspiration = transpiration + evaporation

- Interception = leaves intercepting the water, which falls due to drip tips

- Stemflow = stems & branches of plants intercept water

Tropical Rainforest Location & names of some

0°-30°

Rainforests: Central American, Amazonian, Madagascan, Southeast Asian, Australasian, Congo River Basin

Tropical Rainforest Soil & Nutrient Cycle

Infertile soil ∵ competition

Nutrient cycle:

- Forest floor is hot and damp, so fungi and bacteria thrive, allowing for fast decomposition of plant leaves & litter into humus (humic acid increases chemical weathering)

- Organic material recycled quickly by nutrient-hungry plants and trees. Roots close to surface to take advantage of any nutrients available

- Greatest store of nutrients is the biomass

Litter = humus - decomposed material, and leaf litter

Tropical Rainforest Flora & Layers of rainforest

Growing season is constant

15M plant and animal species

300 species of tree in 1km², incl. mahogany, ebony, rosewood.

Layers:

1) Emergent (50m)

2) Canopy (30m)

3) Understory (20m)

4) Shrub layer (small trees & shrubs adapted to shade)

Tallest trees are supported by buttress roots. Trunks are thin and branchless, competing for space

Leaves are dark green & smooth, with drip tips to shed water

Vine-like plants (lianas and epiphytes) grow around and between tree trunks connecting the rainforest for animals

Tropical Rainforest Fauna

Most live in the canopy layer. Insects are the largest group.

Toucans, jaguars, monkeys, chameleons, frogs, snakes, orang-utans, poison dart frog (brightly coloured to warn predators w/ poison on back)

Tropical Rainforest Interdependence

- Trees rely on decomposers to break down leaves and litter and release nutrients. Decomposers rely on plants to shed their leaves for food

- Carnivores rely on herbivores, they rely on producers, which rely on the soil, oxygen, sunlight, water

- People rely on plants and animal for food and a place to live

- Lianas and epiphytes rely on trees to receive sunlight & grow

Rainforest deforestation in relation to soil, nutrients & water

Fewer trees to intercept rainfall and fewer trees to protect the forest floor as the roots hold the soil together so there's increased soil erosion and more leaching, removing nutrients. Land becomes drier & humidity drops as there's less evapotranspiration ⇒ desertification. No leaf litter to be returned to the ground so humus is not replaced → rapid loss of nutrients by leaching. The resultant acidic soil releases iron and aluminium resulting in a red, unproductive, ferralitic soil. This results in fewer nutrients for plant use, contributing to further deforestation.

Location of Peruvian Amazon Rainforest

East of Peru - takes up 60% of Peru - 3rd largest rainforest in the world

Uses of Peruvian Amazon Rainforest

- Medicinal plants - rainforest plants can cure diseases such as cancer, digestion problems, and can cure addiction

- Archaeology - remains of buildings constructed by ancient civilisations like Chachapoyas

- Timber - high-value hardwood - legal/illegal logging widespread

- Oil & Natural gas

- Minerals & Gold

- Agriculture (growing soybean), biofuel farming (majority of cars run on biofuels), and cattle ranching

- Hydroelectricity - 15 large dams export electricity for Brazil's aluminium and extractive industries

Threats to the Peruvian Amazon Rainforest

- Extensive logging for hardwoods like mahogany - 95% of which is illegal & unregulated. Trees are being felled in national parks, destroying habitats & food chains, affecting biodiversity, and causing deforestation

- China is invested into oil exploitation in Madre de Dios, home to >10% of world's bird species and is a popular tourist destination

Extraction of oil → oil leaks & pollution of water courses

- Gold found in alluvial (river) deposits in Peruvian Amazon exploited by huge machines and involves blasting of riverbanks and removal of rainforest to provide access to remote areas. Mercury is used → harm to aquatic ecosystems and poisoning local tribes who depend upon rivers for food and water.

- Fires are used to clear land (provide nutrients for 2 seasons, before becoming infertile) and sometimes go out of control, wiping out habitats and animals.

- HEP (Hydroelectric power) requires flooding of large areas of the rainforest, displacing lots of indigenous people

- Highways (Trans-oceanic Highway - a road project to connect Pacific ports to a major highway in Brazil) will cause more deforestation and worsen illegal logging in protected areas. In 2015, plans were announced to extend Peru's 'jungle highway' through Manu National Park, where biodiversity "exceeds that of any other place on Earth" (UNESCO).

Purus-Manu Conservation Corridor

- The Purus-Manu Conservation Corridor in the Madre de Dios region in southeast Peru supports long-term biodiversity conservation and benefits the native communities living in the Corridor.

- 10M ha, the largest preserved area in the Peruvian Amazon and one of the most biodiverse regions in the world. (2015: Further management strategies put in place).

- It is made of the Alto Purus and Manu National Parks together with several indigenous community reserves

- Threatened species such as river dolphins, red howler monkeys, spectacled bears, and mahogany

- Provides water, food, medicine, clothing, and housing to the ~60 local communities.

Management types of the Peruvian Amazon (apart from Purus-Manus Corridor)

Forest Stewardship Council (FSC)

National Parks & Natural Reserves

Indigenous Reserves & Community Forests

FSC description & examples

A certification program to address tropical deforestation and illegal logging to ensure sustainable forest management.

In the Peruvian Amazon, management plans are required for all forest-related activities, implementing FSC regulations (2000).

Certified operations in Peru include Green Gold forestry in Loreto and Consorcio Forestal Amazonica in Ucayali.

FSC advantages

- Organisations work together (e.g., gov and NGOs) to prevent illegal logging of timber with clear regulations & enforcement

- Incentivises businesses to become a member and only legally log wood in rainforests

▫ Price premiums - cost of products pushed higher because it is FSC certified - normally 10% of profit

▫ Cheap memberships (<$2500 for medium for-profit company)

▫ Promises greater market access

FSC disadvantages

- Government can be tricked into buying illegal wood, e.g., the government of Sao Paulo was caught purchasing illegal Amazon timber

- Membership & meeting certification standards is expensive = lower profits for logging companies so they may turn to illegal logging

- Companies may not see the market benefits

- Lack of enforcement & network of conservation organisations in several countries

- Certification process is long, and is difficult to prove legal land holding, with lots of paperwork to keep up to date with, putting companies off

- The premiums are restricted to high-value products and is temporary

National Parks & Natural Reserves description & examples

Almost 10% of Peru is some form of protected area. These include national parks (gov owned), reserves (private owned), national sanctuaries, reserved zones, buffer forests, hunting reserves, communal reserves, national forests. Largest reserve: Pacaya-Samiria covering 2 million ha in northern Peru, followed by the Manu National Park and Biosphere Reserve (1.5 million ha).

National Parks & Natural Reserves advantages

- Hardly any attempt to control/organise nature - untouched

- Combines conservation, research and sometimes recreational tourism (Inca Trail)

- Has assistance from Peruvian gov, national & international NGOs, World Bank Global Environment facility and the United Nations Environment program

National Parks & Natural Reserves disadvantages

- Only 10% of Peru

- Not monitored properly ∵ understaffed

- Expensive maintenance and monitoring so less likely to fund a park/reserve

Indigenous Reserves & Community Forests description

Indigenous people and community groups have a voice in forest conservation/use. Investment in community forestry is achieved by enabling investment or grants which provide no financial return but lay the ground for future activity and asset investments.

Indigenous Reserves & Community Forests advantages

- Communities in Mexico successful at developing timber operations

- Amazonian communities successful in gaining recognition for subsistence use and extractive reserves of products like rubber and Brazil nuts

- Several have transitioned forest use operations in payments for ecosystem services

- Deforestation rates in areas of indigenous/community managed forest are lower than in state managed protected areas.

- In the Amazon, indigenous communities can sustainably use the forest through shifting cultivation, trade of non-timber forest products, and selective logging

- Often have power to prevent illegal land incursion, whereas gov protected areas are often understaffed w/o resources to enforce boundaries

- Enhances rural livelihoods and provides income opportunities

Indigenous Reserves & Community Forests disadvantages

- Lack of investment - capital investment is needed to efficiently harvest, transport, and market their products, and to scale up to larger operations (e.g., chainsaws → efficient, low-waste wood processing equipment)

- Gender inequality: women perform many community activities related to forest management whilst men are consulted in the policy making process

- Requires tenure security: rights of access, rights of control and restricting access for others, rights to harvest & manage. Some only have varying degrees of tenurial rights: in southern Peru, outside Manu National Park, indigenous groups have been granted partial tenure rights to their forest territory but the national gov has granted rights to natural gas exploitation.

- These rights are often with a set of regulations which community groups often lack capacity or resources to follow and they may have difficulty accessing forest certification

Coral reef climate

- Must have temperature range 23-25°C (otherwise polyp becomes stressed and expels zooxanthellae ∴ becomes bleached)

- Water must be clear (unpolluted & w/o sediment ∴ not in mouth of river) and no deeper than 30m to allow for photosynthesis

- Must have wave action to oxygenate water for coral's respiration

- Must have saline water (Ca2+) & sediment for polyps to make CaCO₃ skeleton

- Coral reefs are located on the seabed surrounding land, before water depth increases - continental shelf

List of coral reefs & their locations

- Great Barrier Reef (on north-east coast of Australia),

- New Caledonia Barrier Reef (northeast of Australia)

- Red Sea Coral Reef

- Mesoamerican Barrier Reef (on east coast of Mexico)

- Florida Reef (on east coast of Florida)

- Andros Coral Reef (south of Florida)

Flora of coral reefs

- Turtle grass and manatee grass are commonly found in the Caribbean Sea providing shelter and a habitat for reef animals like the young of lobsters

- Plants fertilised by N₂ and P from coral polyp

Fauna (excluding coral polyps and zooxanthellae) of coral reefs

- Has 25% of world's fish species

- Parrot fish eat polyps and excrete sand

- Starfish suck out middle of polyp like a soup

- Clams settle on the coral bed and filter plankton from seawater

- Eels live within the coral, pouncing on small fish

- Larger mammals like dugongs consume large quantities of sea grass

- Groupers & octopuses work together

- Surgeon fish - extract food from the Green Turtle's back

- Tube worms and molluscs donate hard skeletons

- Fish constantly excrete ammonia which can be absorbed by corals & algae, and the fish benefit as they can eat the coral

Coral polyps & zooxanthellae

- 1 polyp is 2-3 cm in length and feeds on plankton. It has a mouth and tentacles and secrete CaCO₃ to make a mineral skeleton to fix them in place on the ocean floor, building the structure of the reef

- The coral is able to consume zooplankton which consumes phytoplankton (primary producers), as well as bacteria and edible detritus that enter the system by upwelling from the ocean floor

Symbiotic relationship between zooxanthellae and coral polyp:

- Algae (zooxanthellae) live within the tissues of the polyp giving the coral its vibrant range of colours.

- The zooxanthellae photosynthesise and give the coral polyp the organic matter and oxygen for it to respire, whose products (CO₂, H₂O) are used by zooxanthellae to photosynthesise.

- The zooxanthellae benefit by having a habitat and access to waste materials produced by the polyp (nitrogen for proteins, and phosphorous for phosphates) which fertilise the zooxanthellae

Location of Andros Barrier Reef

Centred on Andros Island, 200km long linear (∴ barrier) feature parallel to shoreline, shallow lagoon with mangrove forests between the land and reef.

Human uses of Andros Barrier Reef

- Sponge farming & fishing - coral reefs form nurseries for 25% of the world's fish stocks. Reefs can yield ~ 15 tonnes of seafood/km² per year. Generates $70M per year

- Tourism - brings $150M/year

- Medical treatments (e.g., cancer & HIV) - scientists believe that some chemicals released by coral species for self-protection could have applications for the treatment of viruses and cancers

- Protection from flooding during hurricanes & coastal protection - act as buffer zones as they cause waves to break earlier (∴ reducing wave's energy by the time they arrive at coast), reducing coastal erosion and loss of property on the shoreline

Ecological importance of Andros Barrier Reef

- 164 species of fish and coral

- Sheltered conditions for growth of mangrove forests and for breeding grounds for fish

Threats to Andros Barrier Reef

- Over-fishing (commercial and recreational) - corals killed by physical contact with anchors, boat hulls, and people's feet. Over-harvesting of sponges can have harmful impact on reef ecosystem.

- Pollution - agricultural chemicals, oil discharges, sewage, silt eroded from hillslopes, discharges by rivers/boats/ships (especially from deep-sea fishing) cause water to become cloudy, reducing photosynthesis for zooxanthellae.

- Climate change & global warming - higher temperatures causes stress in corals, so they expel zooxanthellae, negatively impacting nutrient flows, bleaching the coral, and killing it. Projections suggest reefs in Bahamas will experience thermal stress severe enough to cause bleaching after 2040.

List of management strategies for Andros Barrier Reef

Andros West Side National Park

North Marine Park & South Marine Park

Coral nurseries

New National Park at Joulter Cays

Crab replenishment

Description of Andros West Side National Park

Designated by gov in 2002 to balance fishing & sponging with resource conservation, recreational fishing, and ecotourism.

Advs/Disadvs of Andros West Side National Park

+ Developments are strictly controlled

+ Some areas prohibited for use, others not

+ Does not restrict tourism

- Not particularly rigid boundaries

Description of North & South Marine Park

Eastern side of island. Regulates some activities, such as fishing, collecting wildlife, mining, vessel anchoring, scuba diving, discharging of material.

Advs/Disadvs of North & South Marine Park

+ Restricts use of wildlife and prohibits activities that would endanger species and the coral reef

+ Money given to the organisation contributes to conservation of coral reef w/ no corruption

- In areas exempt from prohibition, people will cluster there to get their wildlife to sell

Description of Coral nurseries

E.g., Exuma Cays Land and Sea Park where threatened species are conserved and monitored prior to being planted back in the coral reef

Advs/Disadvs of coral nurseries

+ Is a community driven project - locals feel responsibility to plant, clean and maintain corals and are trained to do so

+ Supported by Nature's Hope for South Andros (local partner)

+ Conserves and replenishes reef

- Relatively small-scale - only community-wide

- Requires time and money to educate locals

Description of New National Park at Joulter Cays

Plans to establish a new National Park to the north of Andros Island at Joulter Cays - area prized for fishing and shallow water ecosystem. It is under pressure from excessive fishing and marine discards.

Description of crab replenishment

Ensures a sustainable crab population for future generations (e.g., Crab Replenishment Reserve)

Evidence of success for management in Andros Barrier Reef

From 2013 → 2020:

- Benthic Index (amount of live coral): Impaired → Fair

- Coral Condition: Impaired → Fair

- Recruitment (new coral polyps entering reef): Impaired → Fair

- Grouper population: Fair → Fair

- Large parrotfish population: Fair → Good