9. Geography: Land environments change and management

Answer 1

salinity an excess of salt in soil
or water, making it less useful for
agriculture
groundwater water held
underground within water-bearing
rocks or aquifers

Answer 2

drainage area (or basin) an
area drained by a river and its
tributaries
ecology the environment as it
relates to living organisms
anthropocentric the belief that
humans are the central and most
important component of the
universe
monoculture cultivating a single
crop or plant species over a wide
area over a prolonged period of
time
exotic species species
introduced from a foreign country

Answer 3

dryland ecosystems
characterised by a lack of
water, including cultivated
lands, scrublands, shrublands,
grasslands, savannas and
semi-deserts; the lack of water
constrains the production of
crops, wood and other ecosystem
services
desertification the
transformation of land once
suitable for agriculture into desert
by processes such as climate
change or human practices such
as deforestation and overgrazing

Answer 4

ringbark :removing the bark
from a tree in a ring that goes
all the way around the trunk;
the tree usually dies because
the nutrient-carrying layer is
destroyed in the process.
national park :an area set aside
for the purpose of conservation
biodiversity the variety of plant
and animal life within an area

Answer 5

ecological species :species that
helps maintain or care for the
ecology of an area, and creates
and maintains habitats for other
species
ecological corridor :wildlife
corridor that connects wildlife
habitats that have been separated
by human activity or structures
such as roads, enabling wildlife to
move between habitats that have
become fragmented

Answer 6

Causes and Impacts of Environmental Change

Causes of Environmental Change
* Land degradation due to clearing or overgrazing.
* Decreased crop yields due to erosion by wind and water.
* Destabilized soil due to introduction of rabbits and competition with native animals.
* Tourism leading to clearing of sand dunes and mountain slopes for housing and ski runs.
* Overgrazing leading to nutrient-rich soil being washed or blown away.
* Climate change affecting land degradation due to higher sea levels and reduced soil absorption.
* Urban communities producing large quantities of waste, which seeps into groundwater and runs off into rivers and sea.
* Introduced plant species choking the landscape and competing with native vegetation.
* Salinity occurring naturally in areas with low rainfall and high evaporation.
* Excess irrigation and clearing natural vegetation leading to water table rises.

Answer 7

Agriculture Degradation in Australia

• Climate, topography, water supply, and soil quality are major factors affecting land use.
• White settlers brought seeds and animals from Europe to Australia, intending to farm as they had done at home.
• Australia’s soils are naturally low in nutrients and have a poor structure, making it difficult to farm.
• Over-irrigation and deforestation can raise the watertable and bring salt to the surface, decreasing soil fertility.
• Variable rainfall and long-lasting droughts leave the earth dry, barren, and unproductive.
• Floods can wash away a farmer’s livelihood and leave the land flooded.

Kangarao Farming as a Sustainable Solution

• Kangaroo farming is presented as an alternative sustainable solution to land degradation.
• Advocates claim it would be more environmentally friendly, lessen soil compaction and vegetation trampling, and provide human health benefits.
• Critics argue it is not commercially viable in the long term due to various species characteristics.

Global Land Degradation

• Land degradation is a global issue, with global arable land availability decreasing from 0.37 hectares in 1961 to 0.18 hectares by 2018.
• In Australia, approximately two-thirds of the land used for agricultural production is degraded.
• Around 42% of the world’s poorest people live on the most degraded lands.

Answer 8

Land Degradation and Global Food Production Challenges

• Africa is a vulnerable continent, losing 65% of its arable lands and 25% of its overall land area to desert.
• Experts estimate 10 million hectares of land needing rehabilitation annually to reverse current trends in land degradation.
• The world’s population is expected to rise from 65% in 1950 to 85% by 2030, putting pressure on the fragile environment.
• Land degradation is a global problem, with 75% of the Earth’s total land area classified as degraded, with 60% used for agricultural production.
• Every year, 24 billion tonnes of fertile soil is lost worldwide, with the worst affected areas being in sub-Saharan Africa.
• Land degradation and shortages of farmland and water resources are undermining global food production.
• The challenge is to manage the land sustainably for the future and reverse the trends.
• Soil formation is a complex process influenced by time, climate, landscape, and organic material availability.
• Large-scale clearing and poor agricultural practices have left the land vulnerable, with erosion being a natural process.
• Land degradation is often the result of many small actions and events, with the effects of these actions building up over time.

Answer 8

Land Degradation Factors and Impact

Factors Contributing to Land Degradation
* Poor management leads to nutrient loss for plant growth.
* Removal of vegetation makes land vulnerable to erosion.
* Urban development encroaches on agricultural land, causing waste disposal in landfills.
* Poor agricultural practices, especially related to irrigation and chemical fertilisers, can lead to soil becoming saline or acidic.

Causes of Environmental Change
* Small changes can have a dramatic impact on land.
* Industrial activities account for 25% of environmental change in the Asia-Pacific region.
* Poor farming practices over time make the land unproductive.

Causes of Environmental Change in the Asia-Pacific Region
* Watertable rises, heavy rain leaches nutrients from topsoil, gullies form, evapotranspiration decreases, roads destabilize hillsides, erosion, silt blocks rivers, wind removes topsoil, reduced eltration, after deforestation, oxygen released by vegetation.

Effects of Land Degradation
* Soil becomes exhausted, crop yields fall, costs rise as more fertiliser is needed.
* Valuable topsoil is washed into rivers and out to sea.
* Excess nutrients cause foul-smelling algal blooms.
* Water quality decreases, poisoning fish and posing a threat to all aquatic life.

Answer 8

Salt Origin and its Impact on Australia’s Land Degradation

Salt Origins
* Salt has been an environmental issue for earliest civilizations around 6000 years ago, with Sumerians causing land degradation due to poor irrigation practices.
* Salt has become a major contributor to land degradation in Australia, destroying native vegetation and threatening livelihoods.

Salt Storage and Pre-European Settlements
* Salt stores from shallow seas and saltwater lakes lain dormant below the land surface, mostly in groundwater.
* Rain, winds, and weathering of mineral-carrying rocks deposit salt on the land’s surface.
* Australia’s native vegetation had built up some tolerance to salt levels in the soil, allowing the watertable to remain at a constant level.

Salt Problems in Australia
* Dryland salinity occurs in areas not irrigated, where settlers replaced native vegetation with crop and pasture plants.
* This led to increased salt concentrations, leading to vegetation death and soil erosion.
* Irrigation salinity occurs in irrigated regions, where overwatering causes salty watertable to rise to the surface.
* Some salt is washed into rivers and transported to other places.

Answer 9

Solution to Salinity Problems in Australia

• Implementing programs to identify and monitor problem areas.
• Changing irrigation practices to reduce overwatering.
• Planting deep-rooted native trees and shrubs in open areas.
• Developing new salt-tolerant crops like new wheat strains.
• Replacing introduced pasture grasses with native vegetation like saltbush.
• Using satellite technology to map areas at risk for early intervention.

The Impact of Salty Watertable
* Before European settlement, land was covered with deep-rooted vegetation, exposing the salty watertable.
* The land was cleared for seasonal crops, and livestock overgrazed the vegetation.
* The watertable started rising.

Murray–Darling Basin Royal Commission 2018
* Allegations of inadequate management, negligence, and water theft in the Murray–Darling Basin.
* The South Australian Government ordered a Royal Commission into the Basin management.
* The report found that existing management strategies needed overhaul to divert more water from irrigation and back into the environment.

Adapting to Salinity Issues in Vietnam
* Vietnam’s Mekong Delta region is a major exporter of rice and shrimp.
* Drought and early dry season due to climate change are allowing sea water to encroach on farming land.
* Scientists are developing salt-resistant rice strains and using brackish water for shrimp cultivation.

Answer 10

Soil Loss Causes

Sheet Erosion
* Water flows smoothly over a surface, removing a large, thin layer of topsoil.
* Can occur down a bare slope when the amount of water exceeds the soil’s absorption capacity.
* Strategies include planting vegetation, adding mulch, or ‘terracing’ the landscape.

Rill Erosion
* Rapidly flowing water concentrates in small channels (rills) in open agricultural areas.
* Strategies include tilling the soil, building contours, and planting grass.

Gully Erosion
* Often starts as rill erosion.
* Over time, rills deepen and widen as water carves deeper into the soil.
* Soil is washed into rivers, dams, and reservoirs, muddying water and killing marine species.
* Strategies include stopping large water flows, planting vegetation or crops, building diversion banks, and constructing dams.
Tunnel and Wind Erosion in Australia

Tunnel Erosion:
* Water flows under soil’s surface, creating tunnels.
* Tunnels collapse due to livestock or agricultural machinery, creating potholes or gullies.
* Strategies include planting vegetation to absorb excess water and breaking up its flow.
* Major earthworks may be needed to repack soil in affected areas.

Wind Erosion:
* Wind picks up fine soil particles and blows them away.
* More common during drought or overgrazing.
* Soil can be transported long distances and deposited in urban areas.
* Strategies include planting vegetation, mulching, wind breaks, and avoiding overgrazing.

Answer 11

Desertification: Risks and Causes

Risks of Desertification
* Rising population pressures land for food and shelter, leading to overuse and exhaustion.
* Dryland regions are at risk of desertification, affecting over 41% of Earth’s land surface.
* These regions support population and agriculture but degrade rapidly when not managed.
* Over two billion people live in these areas in 168 countries.

Causes of Desertification
* Human-induced environmental change, influenced by environmental, political, cultural, and economic factors.
* Poor management of dryland environments leads to desertification.
* Increasing populations, agricultural production demand, and soil overuse degrade productive areas.

Examples of Desertification
* Dust Bowl in the 1930s due to drought and poor land management.
* Overgrazing in Patagonia and Sahara Desert.
* Gobi Desert expanding into China due to deforestation, overuse of water resources, and overgrazing.

Impact of Desertification
* 12 million hectares of productive land lost annually due to desertification.
* Human-centered approach to land use has magnified the problem of desertification.

Answer 12

Economic, Social, and Environmental Factors Contributing to Deforestation

Economic Factors:
* Overgrazing and overcropping for income increase.
* Intensive farming depletes soil nutrients.
* Crops not suitable for the environment require irrigation.
* Switching from cultivation to grazing for more money.
* Clearing trees for fuel wood and construction.

Social Factors:
* Increased population and lack of infrastructure prevent land degradation.
* Poor farming techniques lead to deforestation.
* Large-scale deforestation due to the use of wood as fuel.
* Desperate subsistence farmers farm marginal land during droughts, creating a cycle of destruction.

Environmental Factors:
* Low rainfall, frequent droughts, and high evaporation dry out soil.
* Overgrazing leads to loss of vegetation and soil compactness.
* Drylands are often located in mountain ranges, exposing soil to evaporation and wind erosion.
* Poor quality marginal lands are used, not suitable for agriculture.

Political Factors:
* Control of political borders, conflict, and expansion of agricultural areas reduce nomadic pastoralists.
* Governments construct permanent water wells for nomadic grazing, promoting increased herd sizes and land degradation.

Answer 12

China’s Desertification and Green Wall Initiatives

• The Gobi Desert in Mongolia eats 360,000 hectares of grasslands annually, while dust storms remove 2000 square kilometers of topsoil.
• China spends $5 billion annually on combating desertification, aiming to reclaim all the treatable land area by 2050.
• The Great Green Wall of China, a plan to create a 40000-kilometre series of forest strips, is envisioned to protect farmland and waterways against wind erosion.
• Every citizen over 11 is expected to plant at least three saplings each year, with over 88 billion trees planted since the start of the millennium.
• By 2021, 18 million hectares of forest have been restored, increasing forest cover from 12% in 1980 to 23%.
• Despite an increase in forested areas, only 2% of China’s original vegetation remains, and the area affected by desertification shrinks by almost 2000 square kilometers annually.
• Restoring grasslands is a key rehabilitation program, including moving people and changing land use from grazing to tree crops and forests.

Answer 12

Impacts of Desertification and Combating It

Desertification Impacts
* The world loses approximately 12 million hectares of land annually, a size three times the size of Switzerland.
* It leads to environmental change, allowing desert sand dunes to migrate and smother former farmland.
* It affects the wellbeing of over one billion people, leading to over-exploitation and food insecurity.
* Social and cultural networks are lost as villages are abandoned.

Tackling the Problem
* Desertification, climate change, and loss of biodiversity were identified as the greatest challenges to sustainable development during the 1992 Rio Earth Summit.
* The United Nations Convention to Combat Desertification 1994 (UNCCD) was developed to improve living conditions, maintain and restore land and soil productivity, and reduce drought impacts.
* The stewardship worldview encourages cooperation and supports people to develop their own solutions.

Case Study: Combating Desertification in China
* China is severely affected by desertification, affecting about 25% of the total land area and negatively impacting 400 million people.
* The Gobi Desert in Mongolia swallows 360,000 hectares of grasslands each year, and dust storms remove 2000 square kilometers of topsoil.
* China spends $5 billion each year on combating desertification, aiming to reclaim all the treatable land area by 2050.
* China has slowed the rate of desertification by more than one-third of 1999 levels.

The Great Green Wall of China

Answer 13

Invasive Species and Their Impact on Environment

Understanding Invasive Species
* Invasive species are plant or animal species that colonize areas outside their normal range and become pests.
* They can threaten indigenous species and take over valuable farming land and native habitats.

Invasive Grazing Bans
* Between 2005 and 2010, a total ban on animal grazing on 7 million hectares of land was implemented.
* This was part of a larger plan to restore over 660 million hectares of grasslands at an estimated cost of approximately A$4 billion.
* After three years of grazing bans, vegetation rate increased from 20% to over 60%, and local sand storms reduced.
* The ban has been extended and is still in force, with farmers paid a subsidy to safeguard their livelihood.

Impacts of Planting Green Walls
* Environmental benefits include slowing desertification, acting as windbreaks, and reducing erosion.
* However, it also reduces biodiversity and provides poor habitat for endangered native animal and bird species.
* Monoculture is highly susceptible to disease, and many tree species chosen were not native.
* Initial rapid growth of trees used a lot of soil moisture and lowered watertables.
* Plantations generate less leaf litter than native forests, resulting in less nutrients entering the soil.

Animal Pests - Goats, Foxes, and Rabbits
* Goats arrived in Australia with the First Fleet in 1788, but have become feral, posing a threat to inland pastoral areas and native forests.

Answer 14

Goats as Eco-friendly Weed Control Methods
* Goats have been used to eradicate saffron thistle in Western Australia within three years.
* Goats are environmentally friendly, eliminating the need for herbicides and fertilisers.
* Soil quality is improved naturally by goat droppings, and they can be used in environments where other control methods are not viable.
* Goats have been used as a method of weed control in plantation forests and on large pastoral runs.

Mainland Quokkas Threats
* Mainland quokkas, known locally and internationally, are threatened by feral foxes and feral pigs.
* Foxes introduced in the late 1920s have had a dramatic effect on quokka numbers.
* Fox baiting and pig control measures are considered partly effective, but mainland quokkas remain severely threatened.

Control of Foxes and Rabbits
* Foxes are the only natural predator of rabbits.
* Control methods include biological methods like introduction of viruses, chemical methods like poison baits, and mechanical methods like destroying warrens.
* Once rabbits are eradicated, the environment can regenerate.

Answer 14

Feral Goats and Their Environmental Impact
* Feral goats cause extensive environmental damage by overgrazing native vegetation, causing erosion and preventing plant regeneration.
* Goats strip vegetation from steep hills, increasing erosion rates and leading to the development of gullies.
* During drought, goats pose a direct threat to domestic and native wildlife, creating an additional food chain imbalance.
* The impact of goats is worse in regions where rabbits are also out of control.

Foxes and Rabbits in Australia
* Foxes and rabbits were introduced into Australia by early settlers, spreading rapidly.
* Foxes pose a significant threat to agriculture and native fauna, carrying diseases and parasites.
* Rabbits place significant pressure on the environment, competing with native wildlife for food and damaging vegetation.

Invasive Plants and Their Impact
* Introduced invasive plant species, often referred to as weeds, pose a significant threat to the environment and agriculture.
* Examples include Paterson’s Curse and Viper’s Bugloss, which thrive in areas of high winter rainfall and have adapted to cope with dry summers.
* The nutritional value of these plants is low, and their consumption can be toxic, leading to liver damage, loss of condition, and potentially death.

Controlling Invasive Species
* Trials in Western Australia have found that goats can be used to control a wide variety of invasive plant species, such as saffron thistle.
* Goats can also be used to control hundreds of different invasive plant species, which are toxic to grazing livestock.

Answer 15

Koala Conservation and Threats

Koala Vulnerability and Endangered Species
* In 2019, koalas were listed as vulnerable in Queensland, New South Wales, and the ACT.
* In 2022, the Australian Government officially listed koalas as an endangered species.
* Loss of habitat is a major concern, with a lack of diversity among eucalyptus species.
* Control methods include sterilisation and relocation.
* Population growth can put an entire colony at risk.
* Koalas starve due to lack of food during drought or favourable breeding seasons.
* Protected colonies have been established to ensure koala survival.

Elephant Conservation
* In 1930, 10 million elephants roamed across 37 countries in Africa.
* By 1979, almost 90% of the wild elephant population had been wiped out.
* By 2007, the estimated range of elephant numbers had declined further.
* In 2018, the population had continued to decline, with numbers down to around 415 000.
* Poachers seek to sell meat, ivory, and body parts to the lucrative Asian market.
* Expanding human populations also threaten elephants, as they need land for crop and livestock growth.
* The loss of elephants poses a significant environmental threat to local ecologies.

Answer 15

Fox Population Recovery and Biodiversity Protection
* Fox populations are reduced by hunting, baiting, and shooting, but recover over time.
* Scientists are developing biological controls and virus or birth control to interfere with fox reproductive systems.

Middle Island Maremma Project
* Middle Island, a Little Penguin colony, was home to a thriving colony of Little Penguins.
* In 2006, an experiment was launched using Maremma dogs to guard and protect the remaining penguins.
* The program was successful, with evidence of penguins breeding and a rebound in 2013 to 180.
* In 2017, 70 penguins were killed in a fox attack, reducing the breeding population to 14.

Biodiversity Protection
* Governments have established national parks to protect native species.
* These parks provide safe habitats for native species, but unchecked, native species can cause landscape damage.

Culling Iconic Australian Natives
* Urban settlements have threatened native Australian species like koalas, kangaroos, and wallabies.
* In 2013, 700 koalas were killed in humane euthanasia to prevent starvation due to overpopulation of manna gum forests in the Otway Ranges.
* Researchers in 2015 called for koalas to be culled in parts of Victoria, New South Wales, and Queensland, where the local populations were infected with the disease chlamydia.

Answer 16

Elephants’ Impact on Wildlife and Ecosystems

Elephants’ Role in Wildlife Management
* Elephants use their tusks to access water, maintain open spaces, and eat small shrubs and trees.
* Their high consumption of plants and dung affects soil quality, promoting biodiversity.
* Gaps in vegetation allow new plants to grow and pathways for smaller animals.
* Up to 30% of African trees depend on elephants for seed dispersal and germination.

Elephants in National Parks
* Confining large animals to national parks can lead to population explosion.
* Elephants consume up to 136 kg of food in a single day, disrupting traditional migration paths and degrading landscapes.
* Kruger National Park, Africa’s first national park, has seen an increase in elephant numbers, causing concerns about population control.

Ecological Corridors
* Ecological corridors allow wildlife to move between similar habitats separated by human development.
* They limit human encroachment and allow for re-colonisation of disturbed environments.

Banff Wildlife Bridges in Canada
* The Trans-Canada Highway in Banff National Park in Canada has constructed 41 underpasses and seven overpasses as ecological corridors.
* These corridors reduce collisions between animals and vehicles, cater to different species’ needs, and ensure genetic diversity.

Answer 17

Australia’s Crab Migration and Mount Hotham’s ‘Tunnel of Love’

Christmas Island Bridges and Tunnels
* 40 to 50 million red crabs migrate to the ocean annually on Christmas Island.
* Major road crossing points are identified by park rangers.
* Tunnels and overpasses are built to protect crabs from vehicles.
* 12 kilometers of permanent fencing are in place to prevent crabs from climbing over.
* Road closures during peak season facilitate crab mass movement, a major tourist attraction.

Mt Hotham ‘Tunnel of Love’
* The Alpine National Park region’s ski fields and roads have altered the habitat of the mountain pygmy possum.
* Male and female pygmy possums only meet during the breeding season.
* Construction of ski runs and the Alpine Road at Mt Hotham blocked the migration route, increasing male risk and traffic flow.
* A rock corridor and ‘tunnel of love’ under the Alpine Road allowed safe passage for males and new habitats.

Answer 18

First Nations Australian Land Management Technologies

• First Nations Australians developed their own systems of land management prior to European arrival.
• These practices were linked to their knowledge and societal structure based on kinship.
• Fire was used to manage grasslands, encouraging plant growth and attracting various animals.
• Management strategies were governed by seasonal changes and local cycles of growth and weather.
• Cultural burning practices allowed First Nations Australians to shape the land to suit their needs while maintaining sustainable and healthy environments.
• First Nations Australians have adapted to environmental change over at least 60,000 years, taking only what they needed for the land to ensure its sustainability.
• Farming techniques involved working with the environment, nurturing edible plant growth, maintaining animal habitats, and building aquaculture systems.
• Spiritual and cultural connections to Country included responsibility for ensuring the health of the land and its water.
• Cultural land management practices involve working with the land and its elements rather than seeking dramatic changes.
• Fire was used to control plant growth and maintain grassland environments.
• The use of fire has significantly impacted the species of plants that thrive in Australia today.

Answer 19

Season-Based Land Management in First Nations Australians

• First Nations Australians maintain their country’s resources through seasonal migration.
• Their knowledge of their culturally responsible environments influences their land management practices.
• Detailed knowledge of weather systems and their resources allows them to move around their country with specific purposes.
• Yolngu People in north-east Kakadu know each of their five seasons brings different opportunities for food collection and cultivation.
• Different Peoples and Cultures have varying calendars, but seasonal events provide information about what to do.

Answer 20

Managing Kakadu Wetlands: A Case Study

• Kakadu, a region with over 2000 plant species, has been home to the Bininj and Mungguy communities for over 50,000 years.
• The region’s landscape includes savannah, woodlands, escarpments, ridges, wetland, flood plains, and tidal flats.
• The introduction of buffalo by European colonizers in the 1800s led to extreme changes, causing extreme habitat destruction.
• The buffalo population expanded from less than 100 animals to over 350,000, causing significant soil erosion and changing floodplain characteristics.
• The Department of Sustainability, Environment and Water authorized a massive culling program to remove the buffalo, but an invasive native plant species spread unchecked, choking wetlands and preventing waterbirds from feeding and recolonising the region.
• The CSIRO conducted research into sustainable land management practices of the Bininjs and Mungguy, introducing a joint management initiative centered on traditional fire management.
• The initiative has resulted in the wetlands being home to a rich assortment of flora and fauna, providing an internationally recognized example of sustainable land management.
• Some First Nations Australian communities rely on the buffalo as a food source and have negotiated permission to raise and maintain a domestic herd.
• Traditional knowledges are increasingly used in conjunction with conservation techniques developed from European traditions and science.

Answer 21

Indigenous Cultural Practices and Land Conservation
* Recognizing the dynamic ability of indigenous practices to counteract the impact of exploited lands.
* Respecting the value of native plants and their uses, with First Nations Australian businesses and communities advocating for their use.

Parwan Valley Land Degradation
* Significant land degradation due to human interactions since European settlement.
* Land cleared for dairy farming, leading to erosion of poor, unstable soil.
* Gully and tunnel erosion in the White Elephant Range, causing further soil erosion.
* Since the 1940s, regeneration projects focus on controlling rabbit populations to rebuild and sustain the landscape.