Ecosystems and Biodiversity

Ecosystems and Global Biodiversity

• Wolves were reintroduced to Yellowstone National Park in 1995; there are now 96 wolves in 10 packs.
• Wolves are crucial for maintaining ecosystem balance.
• The reintroduction of wolves led to a reduction in elk overpopulation.
• Over 60% of riparian plant species, like willows, showed significant recovery within a decade after wolves were reintroduced.
• Biodiversity was restored in the ecosystem.

Energy Flows and Nutrient Cycles

• The sun is the source of all energy in an ecosystem and its solar energy is used by plants for photosynthesis, which then provides nutrients to plant eaters.
• Producers, consumers, and decomposers form a chain supporting energy flow from the sun through plants to animals.
• Organisms sharing the same food types in a food chain belong to the same trophic levels.
• Ecosystems with the lowest nutrient levels support the fewest consumers.
• Highly productive ecosystems have huge energy flow.
• Chemicals are constantly recycled through the ecosystem to support the biosphere.
• Chemicals from the soil act as plant nutrients and are used by plants to grow and reproduce
• Plants nourish the animals feeding on them, and herbivores nourish carnivores.
• Nutrients return to the soil as decaying plant materials (humus).
• Human activities, such as artificial fertilizers, can add excess nutrients, leading to eutrophication and causing algae growth and the death of aquatic flora and fauna.
• Energy flow and nutrient cycling are essential for balancing ecosystems and ensuring food availability for all organisms.
• Energy flows into ecosystems through sunlight, captured by producers (plants) via photosynthesis
• Producers convert solar energy into chemical energy, forming the food chain's base.
• Consumers (herbivores, carnivores, omnivores) get energy by eating other organisms.
• Decomposers (bacteria and fungi) break down dead organisms, returning nutrients to the soil.
• Nutrients (carbon, nitrogen, phosphorus) cycle through ecosystems; decomposers break down organic matter and release nutrients back into the environment.
• The carbon cycle involves carbon moving between the atmosphere, organisms, and the earth through respiration, photosynthesis, and decomposition.
• The nitrogen cycle involves nitrogen converting into usable forms by bacteria, supporting plant growth.
• The phosphorus cycle involves phosphorus from rocks being used by organisms and eventually returning to the soil and water.
• Nutrient cycling supports soil fertility, enabling plant growth and efficient energy transfer ensures food availability for all trophic levels.
• Deforestation and pollution can disrupt these cycles, leading to ecosystem imbalances.

Dynamic Equilibrium and Feedback Loops

• Dynamic equilibrium is when an ecosystem maintains its natural balance and remains relatively stable.
• An ecosystem in dynamic equilibrium can return to its balanced state after natural or human-induced stresses.
• Feedback loops are reactions in response to environmental change.
• Positive feedback loops cause one or more components to increase, negatively impacting the ecosystem for example Crown of Thron Starfish (COT’s) in the GBR.
• COT's plague results from increased nitrogen and phosphorus levels from farming and urbanization, leads to increased plankton/food for COT and more destruction of coral.
• A negative feedback loop decreases the impact of change, bringing the ecosystem closer to dynamic equilibrium; for example, reintroducing grey wolves to Yellowstone.

Relationships Between Natural Systems

• The Gulf Stream moves warm water from the tropics to the North Atlantic, influencing atmospheric conditions by moderating temperatures in North America and Europe (Hydrosphere-Atmosphere Interaction).
• The North Atlantic Drift supports vegetation in Norway, while the cold Labrador Current limits vegetation in Greenland, demonstrating how ocean currents shape ecosystems (Hydrosphere-Biosphere Relationship).
• Melting ice in Greenland, caused by rising global temperatures, releases freshwater into the ocean, potentially weakening the Gulf Stream and altering weather patterns and ecosystems (Feedback Loops and Climate Change).
• Ocean currents affect marine life, climate, coastal landscapes, and water temperatures (Interconnected Spheres).
• The Amazon rainforest generates its own climate through evapotranspiration, releasing moisture into the air, which contributes to high rainfall and humidity (Atmospheric System).
• Deforestation disrupts the Amazon rainforest's self- generated climate cycle, reducing rainfall and increasing drought risk.
• The Amazon Basin, shaped by tectonic activity and river erosion, provides the landscape for diverse habitats and soil fertility depends on sediment deposition from the Andes Mountains (Geomorphic System).
• The Amazon River and its tributaries regulate water flow, supporting biodiversity and transporting nutrients and seasonal flooding replenishes soil nutrients, maintaining forest productivity (Hydrological System)
• The Amazon Rainforest supports millions of interacting species and logging and agriculture threaten these delicate relationships (Ecological System)

Wetlands and Coral Reefs

• Mangroves filter pollutants, dissolved nutrients (nitrogen and phosphorus), and excess runoff/sediment, leading to clear water that allows growth of coral reefs (nutrient cycles).
• Seagrass also filters sediment that passes through mangroves, connecting coral and mangroves.
• Mangroves and seagrass provide habitat for juvenile fish and crustaceans due to shelter and food availability (nutrients in water, phytoplankton, and mangrove leaves).
• Mangroves provide breeding grounds for healthier fish populations this adds to their economic value.

Value of Ecosystems and Biodiversity

• Ecosystems have value in providing benefits such as clean air, water, food, materials, and spiritual connections, while also providing income and resources.
• Environmental value includes biodiversity and genetic diversity.
• Wetlands and reefs serve as nurseries and breeding grounds for juvenile fish.
• The Great Barrier Reef has 133 species of sharks and rays, 1625 fish species, 3000 mollusk species, 630 echinoderm species, 6/7 species of marine turtle, 450 hard coral species and 150 soft coral species
• Towra Point has the white seahorse, pipefish, and pygmy squid.
• Florida has 20 rare/threatened/endangered species like the alligator, crocodile, manatee, and Florida panther and 400 species of birds use it as habitat and breeding ground.
• The Great Barrier Reef generates $56 billion/year from tourism and fishing.
• The Florida Everglades provide drinking water for 8 million people and food for 30 million people and generate $100 million in tourism/year (2021).
• $44 trillion of economic output depends on nature (½ of global economic activity) (World Economic Forum).
• Bees contribute to 1/3 of food production ($435 million/year).
• Social and cultural value includes heritage and intrinsic value.
• The Bajau Laut are indigenous hunter-gatherers in the Coral Triangle with a strong spiritual connection to the sea and reefs.

Ecological and Human Stresses

• Ecological stresses are natural changes that impact ecosystems, such as fires, flooding, succession, and climate (e.g., Mt. St. Helen’s eruption).
• Human stresses are changes from humans, such as deforestation and pollution (e.g., The Deepwater Horizon oil spill).
• An example of the relationship between ecological and human stresses is the COT outbreak on the GBR, where human activities increase nutrients, causing more predators.

Vulnerability and Resilience of Ecosystems

• Vulnerability is the quality that makes an ecosystem susceptible to harm.
  • Protected areas are less vulnerable; limited (specific) latitude is more so.
  • Extreme/unique ecosystems (coral reefs, cloud forests) are more vulnerable.
  • Proximity to humans increases vulnerability due to pollution and introduced species
  • Limited biodiversity increases vulnerability (mangrove monoculture).
  • Larger ecosystems are less vulnerable (GBR); smaller ones (Towra Point) are more so.
• Resilience is the quality that allows an ecosystem to recover from change.
  • Protected locations are more resilient, the ability to bounce back depends on the intensity, size, and duration of the change.
  • Resilience can be measured by how long it takes to return to dynamic equilibrium.
• Ecological integrity is the ability of an ecosystem to naturally maintain ecological processes, species, and a diverse community with minimal human intervention.
• Biocapacity is the capacity of nature/ecosystems to produce and renew resources used by people and absorb and filter waste generated by human activities.
• Away from human problems result in greater resilience.
• Designating rivers as "wild river distinction" with no human interference results in HIGH ecological integrity.
• Large ecosystems like the Amazon/Congo Rainforest have higher integrity as well as linked to more area and less human population.
• The USA has an ecological footprint of 5.1 Earths/year, Australia = 4.5 Earths/year, and India = 0.8/year.

Shifting Baselines and Tipping Points

• Shifting baseline syndrome is where people forget past environmental conditions and accept degraded states as normal.
• Tipping points are situations where small changes cause profound changes due to the accumulated impact of human activities.
• Warming temperatures lead to melting ice, which absorbs more heat, results in coral bleaching/ coral to brown algae reefs.

Strategies for the Sustainable Management of Ecosystems

• Evaluating strategies for sustainability includes intra-generational equity (present generations in developing world), intergenerational equity (present should not degrade for future), the precautionary approach (prevent damage), and biological diversity (protect for environmental biodiversity).
• The Lord Howe Island Rat Eradication Project (REP) is one successful conservation program because it increased biodiversity and numbers for birds such as Kermadec Petrel, while increasing seeds and seedlings for plant species like the little mountain palm.
• The Lord Howe Island Woodhen population surged from approximately 250 individuals before the REP to over 1,100 in 2023.
• Four snail species previously thought extinct on the island have been rediscovered.
• Continuous monitoring is essential; rodent detection checks in July 2023 involved over 950 device checks.
• The $10.5 million program budget is ongoing due to maintenance costs.
• Indigenous Peoples play a role in contemporary management practices such as "cool burning".
• Cool burning is a traditional fire management technique that is slow, observes animals, keeps flames below waist height, and is used in Bega to burn for soil health.
• The Indigenous Land and Sea Ranger program, conducted by the QLD Government (commenced 2007), now has 150 rangers working at 37 locations in QLD.
• The program assists First Nations organizations to employ/train rangers. and projects focus on fire management, feral animal/weed control, threatened native species monitoring, and the protection/conservation of cultural heritage sites.

Geographic Skills - Rural and Urban Place: Mumbai

• Mumbai is a port city known as the "Gateway to India" and an economic powerhouse, located at 19°N latitude and 72°E longitude on the west coast of India in Maharashtra, on the Arabian Sea.
• Mumbai was originally seven islands (archipelago) and land has since been reclaimed.
• Mumbai became the center of trade/commerce and India’s financial hub after 1947 (independence), investment in infrastructure for economy.
• The economy grew at an average rate of 6.3% annually in the 1990s/2000s.
• The Mumbai Metropolitan Region (MMR) has grown to 6328 square kilometers (includes corporate towers of major corporations like Bank of India, Microsoft, Amazon, and Spotify).

Challenges in Mumbai

• Mumbai's rapid population growth has increased from 3.08 million (1950) to 21.6 million (2024) which has a growth rate of 1.77 from 2023.
• The UN estimates the population will reach over 24 million by 2030.
• The population is more than doubled since 1991.
• There are 1000 + migrants a day.
• Natural increase contributes to the population growth in Mumbai because it has a fertility rate of around two children per woman, leading to approximately 1 million extra people being born every year
• The population density is 73,000 per square mile (189,069 per km2), and is 5th in world for density.
• Mumbai has the highest cost of living, with some of the most expensive real estate in India.
• 30-32% of Mumbai’s residents live in slums and slums account for 48% of the city’s housing stock.
• Colonial accommodation for workers in Mumbai – chawls (multi-story tenements) now overcrowded living conditions
• As of 2022 the city had unsold housing stock of 291,266 units while 53% live in conditions of poverty.
• Many residents live in informal/illegal settlements w/ insecure housing tenure and most have no utilities (water, power, sanitation, rubbish collection, roads).
• Mumbai’s geography as a peninsular, limits growth because the city has expanded to the north and then east.
• Only two highways connect the north to the south --> traffic congestion exists and road networks are congested with an increasing number of cars (1900 vehicles into 1km stretch of road increasing travel journeys by 50%.
• The railway network carries 8 million ppl per day, 2.6 times their official capacity, resulting in about 10 people deaths daily.
• Government finds it hard providing basic services – water, electricity, sewerage connection and garbage collection because lack of funding/ informal economy limits tax revenue.
• 60% of Mumbai depend on communal taps, with as many as 30 households sharing one tap.
• In some areas water only released 2 hours/day. Women are often the ones left to wait for this and only 60% of households are connected to sewage
• Disease is common – associated with poor sanitation. In Dharavi - 4000 cases of typhoid and diphtheria daily.

Responses in Mumbai

• Pradhan Mantri Awas Yojana (PMAY), aims to provide housing for the urban poor by 2022 by financial assistance of up to INR 2.67 lakh (4,947 AUD) for home construction
• Maharashtra Housing and Area Development Authority (MHADA) conducts lotteries to allocate subsidized housing.
• These schemes mainly cater for middle income families, with pricing far beyond the reach of the average family for example, the medium income is INR 36,000 (667 AUD) per month
• Maharashtra State Government responded to the lack of housing by offering slum redevelopment schemes with limited success as the sites were poorly maintained and limited services.
• An example of a poorly executed slum response example is the Lullubhai Compound where there were 72 buildings (5 and 7 story) and created under the Slum Rehabilitation Act in 2003- 9,300 residents but provided no schools or clean drinking water
• In 2025 a High Court review of the rehabilitation scheme recommends policies for rental accommodation and open spaces.
• YUVA – Youth for Unity and Voluntary Action lobbied to get the first school set up in the area and now conducts walk in the compound to find out what people need.
• Mumbai's metro began operating in 2014 and current plan for metro is to build 14 lines (360km network) which is hoped to ease traffic congestion.
• The Coastal Road is 29.2km (cut times by 20-25 minutes) and is built on reclaimed land out to the sea which is a climate change issue
• The Trans-Harbour Link is a 21.8 km bridge that will connect with the mainland and connect to new international airport
• SPARC (Society for the promotion of area resources centers) was formed in 1984 and now supports people to secure housing tenure/improve water and sanitation
• Community-managed toilet block project started in 2014, where they constructed 10,000+ seats in community toilet blocks, servicing 500,000 slum dwellers and engage the community in the construction and maintenace of these toilet blocks.