Biology Module 3 + 4 - Biological Diversity and Ecosystem Dynamics

Selection Pressures

Abiotic factors such as:

• Temperature

• Soil type

• Light intensity

• Water availability

• Gas concentration in water

Biotic factors such as:

• Competition for resources

• Predators

• Availability of prey

• Number of mates

• Number of disease-causing organisms

• availability and abundance of food

Abiotic Selection Pressures

• In terrestrial → temperature range, light and water availability most commonly affect the abundance and distribution of a species

• In aquatic → salinity is a key selective pressure

Environment Pressures

• In Australia → rainfall, temperature and landform patterns significantly affect the distribution and abundance of vegetation and ecosystems

Changes in Population

Cane Toads

• Native to South and central America

• Deliberately introduced to Australia in 1953 to control the Greyback Cane Beetle, in sugar cane plantations

• They quickly spread from their original release site in northern QLD to NT and northern NSW

• Population travels approx. 60km a year and has increased from 102 to 200 million

• Feed mainly at night

• Ground dwellers

• Eat insects, snails, frogs, birds and small mammals/reptiles

• Absorb water through their skin

• No known predators

Toxins

• Cane toads contain toxins that kill any animals that try to kill them

• Glands on their shoulders produce bufotoxin, which acts on the heart and central nervous system, causing rapid heartbeat, hyper-salivation, convulsions and paralysis

• Toxin can be absorbed through membranes around the eyes, mouth and nose

Selection Pressures

• e.g. Cane toads → predators with characteristics such as vulnerability to bufotoxin and increased preference to eat cane toads are removed from the population.

• Predators that have increased resistance to bufotoxin and those that are reluctant to eat cane toads are the ones that survive and reproduce

Prickly Pear

• Introduced in the 1800’s in Australia from the USA to start a cochineal dye industry

• The growing conditions enabled the plant to propagate and cover 24 million hectares by 1920

• It became a pest and a lot of money and time was invested into reducing its numbers

Controlling the spread

• Early control methods → burning, crushing and the use of herbicides

• By 1912, the prickly pear travelling commission was established → researched control agents

• Cochineal beetle and Cactoblastis moth (showed the best results and was primarily used) were imported

Energy and the Food Chain

• Food chain → shows the flow of energy through the community

• Typical food chain: Producer → herbivore → carnivore → another carnivore

• → = is eaten by and the flow of energy

• Food webs → complex set of interacting food chains within an ecosystem. They show all the interacting and interconnecting food relationships

Biomass Pyramid

• At every step of the food chain energy is lost as heat and wastes

• Biomass is lost as undigested material and wastes

Predation

• Predator-prey relationship → feeding relationship where the predator obtains its food by killing and eating another animal

• e.g. venus flytrap eats insects

Consequences of Predation

• Predators affect the abundance and distribution of their prey

• If the prey species can replenish itself as fast as it is predated, its population will remain stable

Factors that affect Predator and Prey Populations

• Number of predators competing for the same prey

• Availability of the prey’s food

• Reproduction rates

• Death rate

• Ratio of males to females

• Size of the ecosystem for supporting predator and prey numbers

• Movement between ecosystems

• Number of shelter sites available

Competition

When 2 or more organisms use 1 or more resources in common such as:

• Food

• Shelter

• Mates

Types of competition

• Intraspecific → compete with members of the same species

• Interspecific → compete with members of another species

Plant Competition

• Plants can complete for soil nutrients, water, space and sunlight

Allelopathy

• The production of specific biomolecules by one plant, that can be beneficial or detrimental to another plant

• Allelochemicals → produced by a plant to keep another plant from growing in its space

• They may also release a chemical to change the amount of chlorophyll in another plant

• E.g. eucalyptus leaf litter is allelopathic for certain soil microbes and plant species

Animal competition

• Animals possess many defence mechanisms that may be used in intraspecific and interspecific competition

• E.g. attack predators with teeth, claws, stingers, chemicals

• E.g. camouflage, mimicry

Consequences of Competition

• Affects reproduction and survival rates

• Commonly, one species is more successful meaning the others population will drop in numbers

• If one species is dominant for a long period of time the other will have decreased reproduction rates and increased deaths therefore leading to possible extinction

Decomposers

• Organisms that cause decay

• E.g. fungi, bacteria

• They make the materials produced by the decomposition available to plants

• By breaking down dead material, they provide the nutrients that other organisms need to survive

• As decomposers feed on dead material, they leave behind nutrients which sinks into the soil

Adaptations

• Is a characteristic that an organism has inherited and that makes it suited to its environment

• An organisms chance of survival increases when adaptations work together

3 types of adaptations:

• Structural -> how an organism is built e.g. physical features

• Physiological → how an organism functions e.g. variations in the metabolism

• Behavioural → how an organism acts or behaves e.g. response to a stimulus

Symbiotic Relationships

• Symbiosis → interactions in which 2 organisms live together in a close relationship

• Symbiosis usually involves providing protection, food, cleaning or transportation

Mutualism

• Bothe species in the relationship benefit

• E.g. The clown fish is protected from predators and cleans the anenome

Commensalism

• One species benefits and the other is unaffected

• E.g. Barnacles adhere to whales/turtles allowing them to be transported to diverse areas rich in food

Parasitism

• One species is benefited and the other is harmed

• E.g. Parasite obtains shelter from the host while it feeds upon its tissues/ fluid

• Ectoparasite → live on the host

• Endoparasite → live in the host

• Macroparasite → visible to the naked eye

• Microparasite → can only be seen with a microscope

Consequences of Symbiosis

• Increased evolutionary diversification (biodiversity)

• Development of new species from the integration of their genetic material (symbiogenesis)

• Sources of new capabilities for organisms which enhances evolutionary ‘fitness’

Biological Diversity

• Refers to the variety of all forms of life on earth, the diversity of the characteristics that living organisms have and the variety of ecosystems of which they are components

• Diversity → what allows for evolution and adaptations

Genetic Diversity

• Populations with reduced genetic biodiversity risk extinction in the long term

• If there is biodiversity within a population → chance some may have pre-existing ability to survive and go on to reproduce

Theory of evolution

• Living organisms arose from their common ancestors or a common life form and have changed over time

• Differences that occur among groups of living organisms imply that living things change over time

• Similarities occur in living things and suggest a common ancestry: basic chemistry has remained relatively unchanged

Darwin Wallace Theory of Evolution

• Proposes that natural selection and isolation could account for how organisms adapt/evolve

Natural selection depends on:

• Variability

• Heritability

• Over-reproduction

• Competition between organisms/survival of the fittest

Neo-Darwinism

• The explanation of Darwinian evolution based on modern genetics

• Variation → applies to differences in the characteristics of individuals within a population

• Heredity and variation are essential for this evolution to occur

Types of Speciation

• Occurs if 2 populations become so different that they can no longer interbreed

• Allopatric speciation → occurs when populations become isolated

Process:

1. In a parent population that has a large range with common gene pool, there is a regular flow of genes due to mating events between individuals

2. Part of the population becomes separated due to physical barriers, This prevents the flow of genes between the parent populations and the isolated populations

3. The 2 populations experience different selection pressures that favour some individuals with specific characteristics. This alters the frequency of specific genes

4. If the population are separated long enough, the gene pool of each population will change in isolation

Natural Selection

1. Variation within a population

2. Change in conditions (selective pressure introduced)

3. Individuals without favourable characteristics die

4. The individuals that survive, reproduce

5. Individuals pass on the favourable characteristics to the offspring

Life on Earth

• The environment on early earth provided conditions for inorganic molecules to form organic molecules

• Organic molecules then reacted with each other to form more complex organic compounds

• Membranes formed around organic molecules to produce the first primitive cell called prokaryotic cells

• Cells developed specialised compartments to carry out different chemical reactions

• Larger cells ingested smaller cells, resulting in membrane-bound organelles such as chloroplast and mitochondria. These new cells are called eukaryotic cells

Diversification of life on earth

• Cells clustered together and some cooperation between those cells occurred, colonial organism will result

• When these cells began to specialise to carry out particular functions, it led to higher organisation and the selection of multicellular organisms

Urey-Miller Experiment

• Modelled early water cycle

• Discovered biomolecules such as amino acids and proteins can form from basic chemical compounds

• These results created the field of prebiotic chemistry

Measuring Populations

• Abundance → the number of individuals in a population

• Distribution → where the population of a species is spread within an ecosystem

Quadrat Method

• Used to estimate the abundance of plants

• Quadrats are used to cover randomly selected representative areas for estimating the percentage cover of an area

Capture-Release-Recapture Technique

Used to calculate the abundance of animals. Animals are:

1. Captured

2. Sample animals are tagged

3. Animals are released

4. Animals are given time to mix back into the population

5. Another sample captured

6. Number of tagged animals in the second sample are counted

Transects

• Provide an accurate and easy method of representing an area simply

• Commonly used to give an idea of the variation that may occur

Changing Australian Ecosystems

Evolution of Australian Biota

• Scientists analyse evidence of organisms from the past to determine how organisms in the present day have evolved

• Monotremes → lay eggs

• Marsupials → a mammal of an order whose members are born incompletely developed and are typically carried and suckled in a pouch on the mother's belly

• Mammals → an animal that breathes air, has a backbone, and grows hair at some point during its life

Climate Change

Distribution and abundance of present day plants in Australia origins:

• Those already on the continent when it split from Gondwana

• Those that dispensed from South East Asia to Australia

• Introduced species

Origins of animals that led to present day fauna:

• ‘Original residents’ → those that were on the continent when it split from Gondwana

• Asian ‘Immigrants’ that arrived when sea levels were low

• Those introduced by immigrant traders or late arrival aboriginals

• Those introduced by European immigrants

Changing Flora and Fauna

• Linked with the movement of continents and the effects on climate

Microevolutionary Changes and Speciation

Environmental Change

• Resources may be limited

• Living organisms will begin to compete for light, soil nutrients, and water in plants. or food, shelter, mates and breeding territory

Natural Selection

• Some individuals have variations in their features that make them better suited to the change in environment

• A diverse range of individuals allows the population to be better able to survive a sudden change

• Diversity allows some organisms to compete more successfully for available resources and survive to breed and pass on their genes

Macroevolution

• Takes place over millions of years, measured as geological time and results in a new species

Microevolution

• Takes place over shorter periods of time and results in changes within populations, but it generally doesn’t produce new species

Evolution of the Horse

Convergent and Divergent Evolution

Darwin and Wallace

• Studied and observed similarities in structure

• Darwin-Wallace theory of evolution by natural selection and location therefore can account for both, certain traits in variants to better survive

Divergent Evolution

• In closely related species, the basic similarities between organisms could be a result of their relatively recent divergence

• Natural selection account for differences as they moved into different habitats, exposed to new selective pressures, result in evolution by natural selection to become different

Convergent Evolution

• More distantly related species show similarities, result of similar environment, exposed to similar selective pressures and so natural selection could account for similarities

Adaptive Radiation

• Describes evolutionary variation in species that evolved from common ancestor

• Because of the migration of organisms into new environments, organisms begin to occupy new niches

Punctuated Equilibrium VS Gradualism

Two types of evolution that can occur in a species. A species can exhibit one or both of these evolutionary patterns

Gradualism

• Suggests that populations slowly diverge by accumulating changes in characteristics due to different selection pressures

• Suggests transitional forms should exist

Punctuated Equilibrium

• The rapid speciation which occurs after extinction events to realise vacated niches

• If there is no environmental change there is no evolution

• Evolution occurs in short bursts of rapid changes, followed by long periods of stability within populations

• Gould and Eldridge used fossil evidence showing ongoing changes

• A population living in stasis. There is no change in its environment and little change is observed in the fossil record

• Part of the population is isolated by a change in the environment

• The small, isolated population experiences strong selection pressure from the sudden change in conditions

• Due to small size of the population, there are no fossils representing any transitional forms

• If environmental conditions change and populations reunite, there may be competition between the populations

• A larger population and a stable environment make evolutionary changes less likely

Evidence of the Theory of Evolution

Biochemical Analysis

• Biochemistry → study of chemicals found in cells

Amino Acid Sequencing

• A protein that is found in a wide range of organisms is usually studied to examine amino acid sequences and evolutionary relatedness

• The sequence of amino acids in the protein is analysed and similarities and differences between organisms are identified

• Similarities imply that the organisms may have shared a common ancestor

• Differences imply that organisms have evolved

Phylogenetic Trees

• Branching diagrams showing inferred evolutionary relationships

• Number of differences is proportional to the length of time since the organisms are separated

DNA-DNA Hybridisation

• Based on the assumption that DNA molecules of closely related species have a similar nucleotide base order

• DNA double strand is split lengthwise by applying heat (disassociation)

• Separated strands from the 2 species are mixed

• The 2 strands from the different species combine (reassociation) and form a ‘hybrid’ DNA molecule

• The more closely matched the base pairs are, the stronger the binding of the strands

• The higher the temperatures are required to separate hybrid strands the more strongly combined and therefore the more closely related

Comparative Anatomy

• The study of similarities and differences in the structure (anatomy) of living organisms

• More similarities in the structure of organisms implies that they must have separated from a common ancestor more recently

DNA Sequencing

• The exact order of nucleotide bases in the DNA of one species is compared with the sequence in a similar DNA fragment of a second species

• The more closely related the species, the closer the order of nucleotides bases in the DNA

Biochemical Evidence

• Suggests that organisms that share a common ancestor have fewer differences in the DNA base sequences

• Limitations → techniques complex, rely on highly specialised computer technology, expensive

Homologonous Structures

• Organs that have the same basic plan to their structure, but show modifications because they are used in different ways, are termed Homologonous - they have the same evolutionary origins

Pentadactyl Limb

• The 5 digit limb of all vertebraes have the same basic bone plan

• As all vertebraes share this common basic structure, it suggests that they share a common evolutionary origin

Vestigial Structures

• Evolutionary remnants of body parts that no longer serve a useful function within the population

• Presence of vesitgial structures provides evidence of common ancestry e.g. coccyx

Comparative Embryology

• The comparison of the developmental stages of different species

• Similarities can be used to infer relationships between organisms

Biogeography

• The study of geographical distribution of organisms, both living and extinct

Flightless Birds

• Example of where biogeographical evidence supports macroevolution

Fossil Evidence

• Palaeontology is the study of fossils

• Fossils provide direct evidence of the existence of an organism in the past

Relative Dating

• Relies on the assumption that fossils found higher up in rock strata are younger than lower fossils, so fossils are dated relative to one another

• Actual age of fossils cannot be determined however they can be put into chronological order

Stratigraphy

• Relies on sedimentary rocks being formed in layers with the oldest rocks being at the bottom and youngest on top

Palaeomagnetism

• The study of the record of Earth’s changing magnetic field in rocks, sediments or other materials

• Some magnetic minerals in rocks lock in a record of the direction and intensity of Earth’s magnetic field when the rock was formed

• Approx. dates can be determined from previous magnetic reversals

Absolute Dating

• Or Radiometric dating

• Enables the actual age of a specimen to be determined using the radioactive elements that are present in the specimen

• Fission-tracking-data → a technique used to establish the age of a mineral sample from its uranium content

• The age of the specimen can be determined by measuring the amount of uranium remaining and the density of fission tracks

• Potassium-argon dating → a technique used to determine the age of a rock by measuring the ratio of radioactive argon to radioactive potassium in the sample

Transitional Forms

• Represent successive change in organisms over a long period

Limitations of Palaeontology

• Fossil record is incomplete and so it is not a random sample or past life

• There is a lack of fossils representing the majority of early or soft-bodied organisms and there is an unequal representation of transitional organisms

• There is some doubt about the correct age sequence of some fossils, since radiocarbon dating can be used to date fossils only as recent as up to 50 000 years ago

Australian Megafauna

• During the Pleistocene Epoch, Australia was home to a group of giant animals known as the Australian Megafauna

Theory 1: Changes in Climate

• The continent dried out due to the ice age

• Rainforests were contracting due to a drying climate

• As the climate became hotter and drier, fires broke out

Arguments

• For → large animals would have died out when water became scarce, may have died out because they could not manage the sudden change in temperature

• Against → the last ice age did not have this effect, earlier extinctions seems to have occurred before the peak of the last ice age

Theory 2: The arrival of humans

• Evidence suggests that humans hunted the megafauna and as the larger animals were slower, they were the ones that were killed

Arguments

• For → the smaller species of megafauna that became extinct has short limbs, which would have made them slow

• Against → there is no fossil evidence of kill sites and little evidence of humans and megafauna coexisting

Theory 3: Level of nutrients

• The low level of nutrients in the soils of Australia may have caused a nutrient depletion throughout the food web, resulting in smaller animals'

Humans and Megafauna Coexisting

• The bones of megafauna and tools suggest coexisting at Cuddie Springs Fossil Site

Paleontological and Geological Evidence

Palaeontology

• In 1669, Nicolas Steno published his work on the principles of stratigraphy

• Law of Superposition → in any sequence of rocks that is undisturbed, the oldest layers will be at the bottom and the youngest layers at the top

• Law or original horizontally → all sedimentary strata are deposited horizontally to start with and only tilt or bend due to subsequent forces

• Law of lateral continuity → stratum of rock will be continuous until something disturbs it

• Law of cross-cutting relationships → in any rock sequence, the layer that crosses or intrudes another is the younger rock layer

Radioactivity

• The discovery of radioactivity enabled the establishment of absolute dating methods whereby materials could be given an age in years

• Proxy data → the evidence that scientists use to reconstruct past ecosystems

Paleontological evidence

• Fossils are generally found in sedimentary rocks

• Classify fossils in → mineralised remains such as moulds and casts, organic remains, impressions, track fossils

Molecular Biomarkers

• Trace evidence of the existence of a living thing found in rocks and soils

• E.g. pigments in sedimentary rocks, evidence of nucleic acids, carbohydrates, lipids, and amino acids

• Evolutionary acids between organisms may be inferred by these biomarkers and help to build a more accurate geological timescale biomarkers are also useful for identifying past human activity

Ice core drilling

• Global carbon dioxide levels are steadily increasing and have been linked to climate change

• Scientists are interested in changing climates of the past and how they affected life on earth to help them predict future effects of current climate change

Claude Lorius

• French glaciologist

• Discovered and developed paleo-atmospherics → the interpretation of past environments from the study of gases and other materials trapped in ice

Ice Cores

• Special equipment made to receive cylinder shaped samples

• A core sample reveals the changes in properties of the snow

• Radiometric dating of certain isotopes allows absolute dating of layers

Aboriginal and Torres Strait Islander History

• Artworks that act as primary evidence for scientists who wish to understand the change in ecosystem in Australia

Technology

Radiometric Dating or Geochronology

• The process whereby scientists determine age in years of a fossil, rock or mineral

• Based on the content of radioactive isotopes, igneous and metamorphic rocks can be dated this way

• The parent isotope undergoes radioactive decay and releases energy and/or particles to become a more stable daughter atom

Measuring Radioactivity

• Measured using nuclear reactors, mass spectrometers, laser beams, special microscopes

• Sensitive High Resolution Ion Microprobe (SHRIMP) → dates very resilient grains of minerals

• Fission track dating → decaying uranium atoms leave marks in the surface of grains as they release particles and energy (electron microscopes are used to see the tracks)

Gas Analysis

• Levels of carbon dioxide effect the air temperature

• Carbon dioxide is a greenhouse gas that traps solar radiation to keep the earth warm enough to sustain life

• An increase in greenhouse gases → an increase in temperature of earths atmosphere and oceans

• Carbon dioxide levels are used to infer past climates

Human Induced Changes

• Accurate data on human population growth → allows the designing of mathematical models that can assess the impact of human activity on ecosystem health

Increasing population

• Increased efficiency of food production → selective breeding, the use of fertilisers, pesticides and herbicides, a better understanding of the needs of plants

• Reduced human mortality rate → antibiotics, better hygiene practices, vaccination programs, screening for common diseases

• Use of biotechnology to produce disease-resistant, water efficient plants and animals has reduced the impact of extreme climate conditions on food production

• Water availability → main factor limiting crop growth

• More people → higher demand for space and resources → food, materials for construction of infrastructure, freshwater, increases in the need for waste disposal

Agriculture

• Neolithic Revolution → increased human populations → humans transitioned from hunters and started to cultivate crops and domesticate animals

• Irrigation → developed alongside domestication of plants as a means of producing a surplus and so water was diverted away from its natural courses

• Selective breeding of crops and livestock → altered features in favour to large yields

• Human access to reliable food and water sources improved → agricultural practices began to alter critical processes in ecosystems

Soil Erosion

• Refers to the removal of topsoil to distant areas by wind and water

Main causes:

• Removal of vegetation

• Soil cultivation practices that break up soil structure

• Increased stocking rates of hard-hooved animals grazing on land, leading to the breakup of the soil

• Compaction of the soil of heavy machinery with loss of rain infiltrations and increased water pooling on the surface

• Salinisations of soils

Pollution

• Refers to the presence in the environment of any unwanted substances that causes harm

• Main concern is the effect of agricultural chemicals

• Comes in the form of → fertilisers, pesticides

Eutrophication

• Refers to the overgrowth of cyanobacteria in waterways due to an increase in the availability of phosphorous-containing compounds such as those in fertilisers and detergents

• Algal bloom poses a threat to native plants and animals in water ways through both loss of light and the presence of cyanide-containing toxins in many species of cyanobacteria

Introduced species

• Animals and plants were brought in from overseas

• E.g. European rabbit, European red fox

• Many European species out-compete native species for water, light, habitats and nutrients

Ballast Water

• Ballast water is used by ships to improve their stability on long ocean voyages

• When the water is picked up → marine species are also picked up and transported across the oceans to distant sites

Land Clearing

• Refers to the removal of native vegetation for urban or agricultural development

• Trees need to be removed → sustain growing populations, create space to grow food

• Contributes to → soil salinisation and erosion, removal of nesting sites and habitats

Mining

Contributes to land degradation by:

• Extraction and refining of ores leaves behind chemical pollutants which accumulate in soil and waterways

• Acid wastes are produced, which change the acidity of waterways

• Topography of the land is altered by the removal of topsoil and vegetation, leading to soil erosion and siltation of local waterways

• Air pollution with oxides of sulfur and nitrogen may lead to the production of acid rain which destroys vegetations and soil invertebraes

Extinction

• Leading cause →habitat loss

Mass Extinction

• Special category of extinction where not just a species disappears, but entire families and orders of organisms are wiped out at the same time

Two mass extinctions

• Permian-Triassic extinction: 245mya marine based organisms were affected

• Cretaceous-Tertiary extinction: loss of the dinosaurs 65mya

Biodiversity

• Habitat loss can affect biodiversity

• The Environment Protection and Biodiversity Conservation Act 1999 (EPBC) was created to meet Australia’s obligations as a signatory to the Convention on Biological Diversity

3 levels:

• Genetic Diversity

• Species Diversity

• Ecosystem Diversity

Impacts on Biodiversity

Models to Predict Future Population Changes

• Historical information is critical in explaining the present and predict the future of the environment

• Recognition of different rates and types of change in the past is crucial in understanding change in the present and to manage human activity in the future

• Scientists use models of biological communities to predict the effects of human impacts on their populations

• Trends in populations mapped along with trends in abiotic factors can help scientists make mathematical links between a steady rise in atmospheric temperature and the features of a species

Environmental management involves 2 aspects:

• Baseline information known as equilibrium model

• Measurements of change known as the non-equilibrium model. Disturbances such as storm, fore, flood, drought, overgrazing, land clearing are factored in

Models to Manage Human Impacts

Palaeontology

• Provides data for building models to help guide uture ecosystem management

• Fossils provide information about what past environments were like

• Models can be constructed on the environmental requirements of organisms in the past and predict changes to those present species that are closely related to them

Can use the fossil record to:

• Determine how the organisms have changed over time

• Understand how the organisms may be related

• Understand why the organisms have become extinct

• See the effects of species extinction on other organisms

• Recognise changes in the past distribution of organisms in order to provide information about how the distribution may be currently changing

Restoring Ecosystems

Mining Sites

• The Mining Act 1992 establishes definitions of harm and the subsequent management of mine sites to minimise harm

• The effects include → physical disruption to the earth and the potential harm from the processing of the ores

• All mining companies must complete an environmental impact statement as a part of their mining license application

Sustainable Development

• Conservation of biodiversity and environmental integrity

• Precautionary principle → the burden of proof needs to be on the company to convince that their plan is ecologically sustainable

• Limits should apply according to the ability of the environment to supply what is required

• Human efficiency and ecological resilience are important factors

Control and Rehabilitation

Strategies for environmental control and rehabilitation of mine sites include:

• Removal of any infrastructure, including machinery and buildings

• Making sure that mine entrances and shafts are sealed and secure

• Removal of contaminated soil

• Revegetation and landscaping of the environment

• Regular testing of local waterways for signs of chemical contamination

• Control of gas emissions

• Control of dust generated

• Scheduling of truck movement to limit noise pollution

• Stabilising all underground tunnels

• treatment of tailings and other chemical waste

• Fencing the site to protect it while it re-establishes

• Control of weeds and feral pests such as rabbits while vegetation re-establishes