Syllabus Points
- Human activities that can affect biodiversity and can impact on the magnitude, duration and speed of ecosystem change include examples of;
- Habitat destruction, fragmentation or degradation
- The introduction of invasive species
- Unsustainable use of natural resources
- The impact of pollutants, including biomagnification
- Climate change
- Conservation strategies used to maintain biodiversity are;
- Genetic strategies, including gene/seed banks and captive breeding programs
- Environmental strategies, including revegetation and control of introduced species
- Management strategies, including protected areas and restricted commercial and recreational access
- Australia’s Biodiversity Conservation Strategy 2010–2030 presents a long-term view of the future and the actions that need to be implemented to conserve biodiversity
- Identification and classification of an ecological area as a conservation reserve also requires consideration of the commercial and recreational uses of the area, as well as Indigenous Peoples’ usage rights
- International agreements about biodiversity encourage international cooperation in the protection of unique locations, including
- World Heritage sites, for example, Shark Bay, Great Barrier Reef
- Biodiversity hotspots, for example, south west WA
- International migration routes and areas used for breeding, for example, by birds, whales, turtles, whale sharks
- Contemporary technologies, including satellite sensing and remote monitoring enable improved monitoring of habitat and species population change over time
- Understand that biodiversity typically positively correlates with ecosystem resilience in the face of human impacts.
- Understand that human impacts can be direct or indirect, and have examples of each.
- Re-visit the concept of Biodiversity Hotspots in terms of the level of human impact they have faced.
- Understand the signs of a healthy ecosystem vs an unhealthy one.
- Work through the meaning of the term "Habitat Destruction" and the impacts of the following three forms on biodiversity :
- Fragmentation
- Urbanisation
- Agriculture
- Understand that conservation strategies can be classified as Genetic, Environmental or Management and explore examples of each.
- Understand that the classification of areas as nature or conservation reserves requires consideration of the commercial and recreational use of the area and the rights and values of indigenous people.
Human Impacts on Biodiversity
Signs of a healthy Ecosystem
Watch...
- Stable in extreme conditions
- High level of biodiversity
Watch...
Habitat Destruction and Fragmentation
- Increased human population has caused in increase in demand for natural resources.
- This has drastically changed our land-use and in turn, ecosystems and habitats.
- In some cases, this land use results in the destruction of habitats, in other cases in fragmentation.
- When a habitat is lost, a species is vulnerable to local or global extinction.
- For example, the felling of trees for timber removes most vegetation and thus habitat is lost for many other organisms.
Urbanisation
- Urbanisation is: The extreme modificatio nof an ecosystem by humans to support a human population of increasing density.
- This occurs as people migrate to towns and cities from rural areas.
- Also, due to natural population increase (births greater than deaths), these urban areas are continuing to grow.
- Urban ecosystems have a drastically low biodiversity, and are dominated by people.
- Biogeochemical cycling severely interrupted in these ecosystems.
- Increased gas outputs compared to sequestration
- Increased water drawn from fresh reservoirs prior to reaching ocean
- Increased disposal of waste from outside systems into a small number of tiny landfill sites.
- Accumulation of non-biodegradable wastes such as oils, rubbers, plastics.
- Urbanisation is are considered a permanent loss of the previous natural ecosystem.
Agriculture:
- People need to eat!
- And we have become accustomed to eating a small percentage of Earth's organisms. Thus we turned to farming rather than foraging and hunting.
- What did you eat for breakfast? What have you packed for lunch? What will you eat for dinner?
- The chances are a HUGE portion of your three main meals are from agriculture...
- Meat: Cattle, Sheep, pigs, poultry.
- Grains and seeds: Wheat, rye, barley, canola
- Plantation grown Fruits
- Plantation grown Vegetables
- Plantation grown pulses (beans, peas, etc)
- How much of your meals were "collected" from an natural ecosystem?
- Here in Australia, and in most parts of the world, we are forcing the growth of non-local organisms in order to feed ourselves the food we are used to.
- In Australia we should be eating the following:
- Meats: Kangaroos, Wild Turkeys, Possums, Emus, Anteaters, Lizards and Snakes
- Grains: Sourced from local grasses and ground into flours to make dampers and breads
- Invertebrates: Catepillars, cicadas, witchety grubs, bush honey ants
- Fruits and vegetables: Yam, wild passionfruit, wild oranges, bush tomato, bush banana, bush plums, mulga seeds and wattle seeds. Also gather honey and nectar from bees, honey ants, flowers and trees
- How much of your diet suits your local ecosystem's supplies?
- In order to supply the foods we "prefer" we clear the land and create monocultures (single species)
- We are starting to realise that local species are likely to have been the answer to all of our agriculture problems all along...
Habitat Fragmentation:
- Habitat Fragmentation: is when a habitat of an ecosystem is separated from the rest of the ecosystem (becomes isolated).
- This can occur due to land clearing for a range of purposes (roads, fences, paths, agriculture, housing, etc)
- Once a habitat becomes isolated from the rest of the ecosystem, the individuals in that habitat cannot interact or interbreed with the rest of its population.
- They cannot share genetic diversity and (as discussed previously) diversity correlates with resilience in adverse conditions.
- They will not persevere as easily through environmental pressures and may become locally extinct.
- The bad news is...We are STILL clearing land in Australia.
- The good news is...We have reduced our rate of clearing significantly.
Conservation Strategies
Conservation is a major field of Science and Management in recent decades and our arsenal of strategies is continuing to increase.
We can group most strategies into one of 3 major categories:
Genetic Conservation Strategies
Environmental Conservation Strategies
We can group most strategies into one of 3 major categories:
Genetic Conservation Strategies
- Preserve the evolutionary potential of species and populations
- Seed banks for plants
- Preserving genetically unique populations in situ
- Genetic testing as a major step in breeding programs to conserve evolutionary potential
- Do Some Research - Svalbard Global Seed Vault
Environmental Conservation Strategies
- These strategies aim to regenerate ecosystems
- The creation of corridors of vegetation between isolated habitats.
- Revegetating with plantings and seeding
- Control of invasive species
- Reintroduction of native animals through translocations and breeding programs
- Do Some Research - The Gondwana Link Program
- These strategies aim to manage humans and our impacts via research-informed rules and regulations.
- Laws against hunting/poaching/harvesting/illegal habitat destruction
- Protection of ecosystems via naming them Nature Reserves, National Parks, Sanctuaries, World Heritage Sites
- Before doing so we must consider if it is commercially valuable, used recreationally, or is of cultural significance to Indigenous People
- Monitoring of populations and research into population dynamics
- Promotion of community awareness
- Do Some Research - What is the difference between a Nature Reserve and a National Park in Australian Law?
Land and Soil Degradation
Degradation: a reduction in quality or integrity
- The degradation of land can come about via over-stocking of herbivores (specifically those with hard hooves which disturb the soil)
- These herbivores also overgraze, leading to lack of vegetation and further instability of soil due to lack of roots.
- This causes soil to be loosened and nutrient rich topsoil lost via erosion
- One major flow-on effect of this in Australia is...
- This occurs due to the process of Dryland Salination
- Dryand Salination occurs when salts, normally found under the surface are taken to the surface via a rising water table, the water then evaporates, leaving the salt behind on the surface.
- The water table rises due to:
- the absence of deep rooted plants which draw from the underground water store via transpiration.
- an increase in irrigation from bores.
- This is a problem because the topsoil and surface becomes far too salty for plants to survive and the land becomes barren and void of plant life.
Introduced and Invasive Species
Introduced species are species that do not naturally exist in an ecosystem, but have been brought in by human activity (not necessarily intentionally!)
Some introduced species become invasive.
An invasive species is one that manages to esablish a population in a new area.
Sometimes the term "pest" is used instead of "invasive" it means the same thing!
Invasive species in Australia:
Some introduced species become invasive.
An invasive species is one that manages to esablish a population in a new area.
Sometimes the term "pest" is used instead of "invasive" it means the same thing!
Invasive species in Australia:
- Believe it or not, Australia is actually rather lucky in terms of our invasive species.
- We are an island continent, meaning we have managed to prevent the spread of many pests and pathogens to our ecosystems over the years.
- A few examples of diseases we do not have:
- rabies
- mad cow disease
- foot and mouth disease
- rabies
- We have strict laws on the importing of exotic species (some include jail time!)
- In earlier years we were not so "aware" of our impacts and our Nation allowed many animals and plants to be brought onto Australian Soils.
- We are still trying to eradicate, some of these...
- Cane toads
- Goats
- Camels
- Pigs
- Feral Cats (pets)
- Wild Dogs (pets)
- Foxes
- Rabbits (pets)
- Mice (pets)
- Rats (pets)
- Rainbow Lorikeet
- Gazania (still for sale in nurseries!!)
- Environmental Management of Invasive Species:
- Chemical Control
- Pesticides, includes herbicides, insecticides and baiting
- Biological Control Agents
- General Predators: a species that consumes many the pest
- Specialised Predators: a species that targets one pest species
- Parasites: a species that targets the pest species and may cause death through illness.
- Microbial Diseases: a pathogen (fungi, bacteria, virus) that causes death through illness.
- Culling
- Hunting and killing the pest organism in order to eradicate it or reduce its abundance.
- Reintroductions
- Introducing threatened species into ecosystems in which the pest has not yet inhabited (or no longer inhabits).
- Chemical Control
Unsustainable use of Natural Resources
- Unsustainable use is the use of resources more quickly than they can be naturally restored.
- One major example is over-harvesting, which stems from several factors:
- exponential increase in the human population
- expanding markets
- increasing demand
- improved access and techniques for capture
- exponential increase in the human population
- Overharvesting for extended periods of time depletes species until they cannot recover.
- Aquatic species are especially threatened by overharvesting, due to a situation known as the “tragedy of the commons”.
Tragedy of the commons: common resources are more heavily exploited because harvesters do not show as much restraint in areas they don’t own.
Management Strategies for Over-harvesting:
- Creation of protected areas (eg. Ningaloo reef)
- Monitoring of organisms (eg. research into fish stocks)
- Application of fishing licences, quotas, seasons and sizings.
- Laws against harvesting those species which are vulnerable to extinction (eg. weedy sea dragons, potato cod)
Pollutants and their impact
Read this insightful passage from WWF:
“Look at any ecosystem and there could be multiple forms of contamination—streams full of toxic chemicals from industrial processes, rivers overloaded with nutrients from farms, trash blowing away from landfills, city skies covered in smog. Even landscapes that appear pristine can experience the effects of pollution sources located hundreds or thousands of miles away.
Pollution may muddy landscapes, poison soils and waterways, or kill plants and animals. Humans are also regularly harmed by pollution. Long-term exposure to air pollution, for example, can lead to chronic respiratory disease, lung cancer and other diseases. Toxic chemicals that accumulate in top predators can make some species unsafe to eat. More than one billion people lack access to clean water and 2.4 billion don’t have adequate sanitation, putting them at risk of contracting deadly diseases.”
Eutrophication
“Look at any ecosystem and there could be multiple forms of contamination—streams full of toxic chemicals from industrial processes, rivers overloaded with nutrients from farms, trash blowing away from landfills, city skies covered in smog. Even landscapes that appear pristine can experience the effects of pollution sources located hundreds or thousands of miles away.
Pollution may muddy landscapes, poison soils and waterways, or kill plants and animals. Humans are also regularly harmed by pollution. Long-term exposure to air pollution, for example, can lead to chronic respiratory disease, lung cancer and other diseases. Toxic chemicals that accumulate in top predators can make some species unsafe to eat. More than one billion people lack access to clean water and 2.4 billion don’t have adequate sanitation, putting them at risk of contracting deadly diseases.”
Eutrophication
- Eutrophication is characterized by excessive plant and algal growth
- Caused by increased availability of nutrients, sunlight and/or CO2
- It is a natural process that allows for sedimentation.
- Human activities have accelerated the rate and extent of eutrophication through the run-off of fertilisers into waterways.
- The increased nutrients causes algal to blooms occur:
- limiting light penetration
- reduces growth of plants
- causes die-offs of plants
- lowers the success of predators that need light to catch prey
- High rates of photosynthesis depletes carbon and raises pH to extreme levels
- limiting light penetration
Biomagnification (read here!)
Plastic
- A huge amount of ribbush us plastic, and eventually that plastic will end up in water ways.
- Either in the shape it was molded into in the factory (e.g a waterbottle) or as microplastics, so small they can enter cells.
- Animals often confuse plastic rubbish for sea plants or creatures they would normally consume.
- They then die from intestinal blockages.
- Many microplastics have been 'confusing' our cells into thinking they are hormones.
- This leads to hormonal imbalances and flow-on effects on immunity, mental health, and digestive health and SO much more.
- This research is so recent that it has not made your textbook or curriculum yet.
- If you are interested though...have a read: https://www.npr.org/2011/03/02/134196209/study-most-plastics-leach-hormone-like-chemicalswww.npr.org/2011/03/02/134196209/study-most-plastics-leach-hormone-like-chemicals
- Australia's Biodiversity Conservation Strategy 2010-2030 is the guiding framework for governments to conserve our national biodiversity to 2030.
- It provides an overview of the state of Australia's biodiversity
- It outlines collective priorities for conservation
- All state, territory and local governments in the nation must ensure their policies and processes align with this strategy.
- You can download all 102 pages of it here: www.planning.vic.gov.au/__data/assets/pdf_file/0021/213717/Background-Documents-Commonwealth-Biodiversity-Conservation-Strategy-2010.pdf
- Or, you can get an overview of the sorts of topics it discusses with a quick look at the contents page and example outcomes and target below.
Climate Change & International Collaboration on Biodiversity.
Your Nelson Textbook does a brilliant job of covering Climate Change. Read Pages 218 to 224. Then watch the clips below and answer Question Set 7.6.
There is a brilliant table in your textbook which summarises 3 main types of international biodiversity projects (p. 226). Translate this table into your study notes and quizlet cards. These are an important bank of examples for short and extended response style questions on Biodiversity Conservation.
There is a brilliant table in your textbook which summarises 3 main types of international biodiversity projects (p. 226). Translate this table into your study notes and quizlet cards. These are an important bank of examples for short and extended response style questions on Biodiversity Conservation.