Environmental Management and Rehabilitation

Biosphere and Ecosystems

• The biosphere encompasses all life on Earth, integrating both biotic (living) and abiotic (non-living) components.
• Ecosystems consist of communities of organisms interacting with their physical environment.

Abiotic Factors

• Key abiotic components in ecosystems include:
  • Terrestrial: light availability, soil quality, geology, climate, rainfall.
  • Aquatic: temperature, depth, salinity, current, dissolved oxygen.

Biotic Factors

• Biotic factors encompass all living organisms and their interactions within an ecosystem:
  • Producers: plants and photosynthetic microorganisms.
  • Consumers: animals reliant on producers for food.
  • Decomposers: fungi and microbes that recycle nutrients from dead organisms.

Predator-Prey Dynamics

• Predator-prey relationships are essential, with predators such as orcas and seals demonstrating population fluctuations based on prey availability.
• A sustainable ecosystem requires more prey than predators to ensure survival.

Competition

• Competition occurs over limited resources: food, space, mates.
• Intraspecific competition involves individuals of the same species, while interspecific competition involves different species.
• Plants exhibit competition through allelopathy, where they release chemicals affecting surrounding vegetation.

Symbiosis

• Symbiotic relationships can be mutually beneficial (mutualism), harmful (parasitism), or neutral (commensalism).
• Coral reefs, for example, rely on mutualism between corals and symbiotic algae for structural complexity and diversity.

Disease in Ecosystems

• Infectious diseases are significant threats, spreading through pathogens and potentially leading to population declines (e.g., Devil Facial Tumour Disease in Tasmanian devils).

Ecological Niche

• An ecological niche is an organism's role within its ecosystem, influenced by both biotic and abiotic factors.
• The competitive exclusion principle states that two species cannot occupy the same niche simultaneously.

Population Measurement Techniques

• Sampling techniques include quadrats for plants, transects for distribution, and capture-recapture methods for mobile organisms.
• Capture-recapture formula: (S1 x S2) / M2 estimates population size, where S1 is the initial captured number, S2 is total captured later, and M2 is the marked individuals in the second sample.

Extinction Events

• The Australian Megafauna, including species like Diprotodon and the Thylacine, went extinct primarily due to climate changes and human influence.
• Factors contributing to extinction involve habitat destruction, competition with introduced species, and direct hunting.

Evidence for Past Ecosystems

• Palaeontology and geology reveal past ecosystems through fossil records and rock strata.
• Aboriginal rock paintings provide insight into historical flora and fauna, reflecting ecosystem changes over time.

Technologies for Historical Change Analysis

• Radiometric dating determines the age of materials through radioactive isotopes.
• Gas analysis using different methodologies helps assess past atmospheric conditions.

Human Impact on Future Ecosystems

• Human-induced selection pressures, such as habitat destruction, exploitation of resources, and pollution, significantly affect biodiversity.
• Overpopulation leads to resource depletion and heightened competition among species.

Salinisation and Agriculture

• Land clearing for agriculture disrupts natural water balance, leading to increased soil salinity and decreased fertility.
• Sustained salinisation damages organisms and ecosystems, marking a critical environmental issue.

Pesticides and Ecosystem Health

• Pesticides may eliminate both pests and beneficial organisms, leading to bioaccumulation and biomagnification along food webs.
• This dynamic creates selection pressures that challenge species adaptability.

Eutrophication Process

• Fertilizer runoff contributes to nutrient overload in waterways, resulting in algal blooms that disrupt aquatic life.
• Adaptation or relocation becomes crucial for species under altered conditions.

Introduced Species Challenge

• Non-native species disrupt ecosystems by outcompeting native species for resources, leading to biodiversity loss.

Climate Change Impact

• Human-induced climate change leads to temperature increases, sea level rise, and frequency of extreme weather events, stressing ecosystems.
• Mining activities also pose significant risks, often leading to habitat degradation and necessitating rehabilitation efforts post-mining.

Future Biodiversity Management Models

• Historical extinction events inform models predicting future biodiversity impacts, emphasizing the need to address human environmental interactions proactively.### Mining Rehabilitation
• Clearing and stockpiling vegetation, seeds, and seedlings is essential for future site rehabilitation after mining.
• Tailings, which are waste materials generated from mining, require proper treatment to mitigate environmental impact.
• Upon mining completion, the pit must be refilled either with landfill or water to create a dam.
• Stockpiled soil is spread over the area to promote natural regrowth of vegetation in stages, facilitating a return of native plants and animals.

Agricultural Land Degradation

• Soil is critical for sustainable agriculture in Australia, providing the foundation for food production globally.
• Traditional ploughing increases erosion rates by exposing topsoil to rain and wind, resulting in loss of fine particles and nutrients.

Erosion Control Methods

• Minimising ploughing through the use of environmentally friendly chemicals can effectively kill weeds without disturbing topsoil.
• Re-planting vegetation with tree roots stabilizes soil, significantly reducing erosion risk.
• In urban settings, clear land can lead to sediment wash-off into local waterways, necessitating protective measures.
• Australian law mandates construction sites to implement temporary silt traps to prevent sediment pollution in waterways.

Vegetation Role in Erosion Prevention

• Maintaining vegetation cover on road verges and around new developments helps prevent erosion.
• Native vegetation not only stabilizes soil but also creates wildlife corridors, providing food and beginning the process of ecological rehabilitation.

This quiz explores essential concepts in environmental management, focusing on the rehabilitation of mined areas, the impact of agricultural practices on soil erosion, and the legal measures for construction sites in Australia. It also delves into ecological principles such as bioaccumulation and the significance of abiotic factors in ecosystems.