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Conservation strategies Bio3B. Environmental strategies Environmental strategies involve maintaining habitats and controlling changes eg reafforestation,

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Presentation on theme: "Conservation strategies Bio3B. Environmental strategies Environmental strategies involve maintaining habitats and controlling changes eg reafforestation,"— Presentation transcript:

1 Conservation strategies Bio3B

2 Environmental strategies Environmental strategies involve maintaining habitats and controlling changes eg reafforestation, biological control

3 Reafforestation How it works planting of trees/shrubs & other plants Examples Planting to reclaim areas affected by salt or erosion Replanting after mining Restoring native bushland along roads and paddocks to provide a bush corridor Replanting along drains and swamps to repair damage of human impact Replanting to absorb carbon dioxide Benefits Provides habitat, food & shelter for native animals Helps repair damaged areas (eg salt affected, eroded areas) Bush corridors allow small animals to move in safety – allows a larger area for foraging & connects small isolated populations  increase genetic diversity Absorbs carbon dioxide & reduces pollution Knowledge needed for effective use Species originally present – so replanting is as close to the original as possible Species that are salt tolerant Preferred food sources/habitat for animal species you’re trying to attract Propagation/germination techniques – eg many species need fire to germinate Symbiotic associations (eg orchids have a mutualistic relationship with fungi, sandal wood & Australian Christmas trees are semi parasitic on wattles, callistemons or eucalypts)

4 Biological control How it works an organism is found that acts as a control agent – usually predator or disease Examples Cactoblastis moth eats prickly pear Calicivirus/myxomatosis kills rabbits Lady birds & wasps eat insect pests (eg aphids, mealy worm) Dung beetle disposes of cattle dung so there is nowhere for blowflies to lay eggs Irradiated (sterile) male fruit flies released to breed with females  no offspring Benefits Once in place no need for further human intervention – its self regulating It reduces use of poisons Knowledge needed for effective use The control agent must not be able to become a pest itself: It is specific & won’t harm anything else, it won’t introduce a disease, it dies out when the food source dies out & it won’t hybridize with native organisms

5 Introduced species Examples of introduced species Reasons for introductionEffects of introduction FoxFor huntingPredation of native species Cat, dogEscaped from houses, dumpedPredation of native species RabbitsBrought in as food sourceCompetition for feed, overgrazing & burrows cause erosion Goats, sheep, cattle, horses, camels, water buffalo Escaped from farms, dumpedCompetition for feed, overgrazing causes erosion, hooves damage river banks CarpEscaped, dumpedCompetition for food sources, predation, reduces native species Cane toadBrought in to control cane beetle Predation of native species Corellas, cockatoosEscaped, dumpedCompete for resources – especially nesting sites Prickly pear, brambles, arum lilies Escaped, dumpedCompetition, reduces native species Duckweed, water hyacinth Escaped, dumpedChokes water ways

6 Pest Control Pest control involves removing the pest without damaging other species in the ecosystem Different strategies include biological control, pesticides Principles for selecting the type of control used include type of pest, control agents available, sensitivity of ecosystem, cost Problems include pesticide residues in food species, toxic effects on friendly species, contamination of waterways and biological magnification, pesticide resistance, cost, escaped biological control agents (eg cane toad)

7 Short answer 2004 a & b European settlement in Australia has had a range of harmful effects on the environment. Widespread clearing of land for agricultural purposes has had a serious impact. a) Name four environmentally harmful effects of widespread land clearing. Introduced species are another major problem that came with European settlement. Grasses and other weeds have escaped from farms to establish themselves in bushland. b) Briefly explain two different ways these non-native plants can harm natural ecosystems.

8 Short answer 2004 a & b European settlement in Australia has had a range of harmful effects on the environment. Widespread clearing of land for agricultural purposes has had a serious impact. a) Name four environmentally harmful effects of widespread land clearing. Increased/changed salinity Increased soil erosion/increased runoff Decreased soil fertility Loss of animal habitat Loss of biodiversity Easy access for introduced species Climate change Desertification Rising water table/waterlogging/increased flooding Named effect on a neighbouring ecosystem 1 mark each to maximum of 4 Introduced species are another major problem that came with European settlement. Grasses and other weeds have escaped from farms to establish themselves in bushland. b) Briefly explain two different ways these non-native plants can harm natural ecosystems. Out-compete native species, leading to loss of biodiversity Native animals die when their food plants are excluded May be a food source for introduced species Changes to fire behaviour, so fires may be more or less frequent May be toxic to some native species, hence decline in numbers An example will be accepted instead of an explanation. e.g., outcompete native species such as bridal creeper smothering native vegetation May introduce disease and transmit to native vegetation 2 marks/line, maximum 4

9 Short answer 2004 c (c) To combat introduced pests, scientists sometimes use a strategy called biological control. i)Briefly explain what is meant by biological control. ii) List three precautions that must be taken to ensure biological control does not get out of control itself.

10 Short answer 2004 c (c) To combat introduced pests, scientists sometimes use a strategy called biological control. i)Briefly explain what is meant by biological control. Introduction of a natural enemy (predator, parasite, disease) to control pest numbers ii)List three precautions that must be taken to ensure biological control does not get out of control itself. The control must be specific The control must not introduce a disease The control must not be able to become a pest itself The control dies out when the food source dies out The control will not hybridize with native organisms

11 Short answer 2004 d & e Another problem is caused by the fertilisers used in agriculture and gardens. In particular, phosphate fertiliser can kill native plants that require little phosphate and it also causes toxic algal blooms in waterways. Part of the problem is caused by the fact that roadside drains in urban areas drain into waterways, carrying with them anything that goes down the drains. d)Name four actions that householders can take to help minimise nutrient pollution of roadside drain water. e)List four reasons why it is important to conserve our native biodiversity.

12 Short answer 2004 d & e Another problem is caused by the fertilisers used in agriculture and gardens. In particular, phosphate fertiliser can kill native plants that require little phosphate and it also causes toxic algal blooms in waterways. Part of the problem is caused by the fact that roadside drains in urban areas drain into waterways, carrying with them anything that goes down the drains. d)Name four actions that householders can take to help minimise nutrient pollution of roadside drain water. Use low-phosphate/slow release/organic fertilizer Don’t wash cars on driveways Don’t flush food scraps down drains Dispose of pet droppings correctly Minimize fertilizer use/Plant natives that minimize fertilizer use/smaller gardens Use low-phosphate detergents and household products Don’t overwater/use a wetting agent Don’t overfertilize Don’t fertilize in winter e)List four reasons why it is important to conserve our native biodiversity. Aesthetic value of biodiversity Ethics – is it right to destroy biodiversity? Custodial – we should preserve biodiversity for future generations Utility – biodiversity may provide useful products (e.g. medicines) Ecosystem stability – biodiversity contributes to ecosystem services Recreation Ecotourism Scientific research Education Better ability to cope with environmental change/greater genetic diversity

13 Extended answer d Conservation of biodiversity in our ecosystems is a very high priority for biologists and governments around the world. However, not all organisms enjoy the same level of protection. Poison baits for rats and mice are sold in every supermarket but the community is horrified when whales are killed. Use named examples to illustrate the biological factors that should be considered when deciding the level of protection that should be given to various species.

14 Extended answer d Conservation of biodiversity in our ecosystems is a very high priority for biologists and governments around the world. However, not all organisms enjoy the same level of protection. Poison baits for rats and mice are sold in every supermarket but the community is horrified when whales are killed. Use named examples to illustrate the biological factors that should be considered when deciding the level of protection that should be given to various species. Up to 8 marks for individual points that have been explained/described Aesthetics Ethics/culture Economics – cost of protection of species Economics – benefit/importance to human economy of species (eg harvesting or tourism) How common is the species? How widespread is the species? Is the species a pest or does it have known uses? What is the chance that the species will go extinct? If the species goes extinct, will it lead to the extinctions of other species/ecosystem instability? What kind of protection is needed? What is the recruitment rate/reproductive potential of the species? What is our knowledge about the species? Need to conserve genetic diversity/biodiversity Up to 2 additional marks for very well elaborated additional points, 1 mark for each point Examples, can be rats/whales – up to 4 marks Named example of species needing high protection Reason for protecting species Explanation of type of protection needed Named example of species not needing high protection Reason for not protecting species/giving low protection Explanation of type of actions permitted against species


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