1. 45-1 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Chapter 45: Human impacts

2. 45-2 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Humans in Australia The Australian biota evolved in an increasingly arid climate following the break-up of Gondwana Immigration of other fauna started when continent approached South-East Asian plate (bats, rodents) People entered northern Australia at least 40 000 yrs ago Initial impacts were from fires European colonisers came in 1500–1600s to ‘conquer and civilise’ the land

3. 45-3 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Humans in Australia (cont.) Grasslands were turned over to pasture Forests were cleared Cities were built without adequate planning for wastes and effluents Now, ecosystems are under threat by –loss of biodiversity –coastal and urban development –inappropriate land and water use –over-exploitation of resources –spread of exotic species

4. 45-4 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Losing biodiversity It is likely that 20% of all species will become extinct in the next 30 years 27 mammals and 1 bird species have become extinct since European settlement Seagrass beds are at risk due to water quality Biodiversity hotspots –Examples: flora of south-western Australia, north Queensland rainforest, wet sclerophyll forest Hot spots may reflect the areas most studied, so relative sampling intensity must be considered

5. 45-5 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Discussion question 1: Why conserve biodiversity?

6. Ecosystem services Bioresources Aesthetics Philosophy Custodial reasons About 1.4 million species have been described, total unknown Functional classifications may be easier and more ecologically informative than taxonomic ones 45-6 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

7. 45-7 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Tropical forests Unparalleled diversity of species Natural disturbances are tree fall and fire Rapid nutrient cycling enables high production Low nutrient storage in soil, high in biomass, so clearing removes nutrients Slash-and-burn agriculture uses small plots, but is only productive for a short time Rainforest regeneration is very slow –affected by selective weeding and absence of animals for dispersing seeds

8. 45-8 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Land clearance and habitat fragmentation Many land fragments are too small to support viable populations. Impacts of fragmentation depend on Ecology and dispersal ability of organisms Dependence of species on native vegetation ‘Stepping stones’ For plants, small refuges may be important

9. 45-9 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Habitat corridors link adjacent fragments These links effectively increase habitat size Facilitate movement of animals (and genes) between patches, so encourage viable population sizes BUT They also help spread weeds, pests, diseases, deleterious genes and fires Fragment shape and ratio of edge-to-middle are important factors

10. 45-10 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Fig. 45.5a: Habitat fragmentation Copyright © Byron Lamont, Western Australian Herbarium

11. 45-11 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Introducing new species Intentional and unintentional introductions have led to ecological disturbances e.g. Phytophthora cinnamomi fungus (causes dieback disease), rabbits, foxes, feral animals, Japanese sea-star, black-striped mussel, cats Strict quarantine controls now apply Successful invaders have –high mobility, fecundity and survival –a lack of natural predators –a broad diet –tolerance to a wide range of conditions

12. 45-12 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Integrated pest management The coordinated use of several control techniques –Example: rabbits  viruses (myxomatosis and rabbit calicivirus)  poisoning  warren ripping  fumigation Cane toad –failed to control sugar cane beetles, and became a pest itself by out-competing native species for food –has toxic skin secretions that kill vertebrate predators –has now reached Kakadu—major ecological disaster likely

13. 45-13 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Fig. B45.3c: Spread of the cane toad

14. 45-14 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Impact of weeds A weed is a ‘plant growing in the wrong place’ Usually opportunistic species, e.g. blackberry, Bitou bush May grow rapidly and provide cover for foxes, rabbits May degrade native animal habitats Ornamental (garden) species can become weeds if they spread into native bush, e.g. Pittosporum undulatum

15. Fig. 45.6: The weed Spartina 45-15 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

16. 45-16 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Fresh water is the key to life A critical resource in Australia River flows have been altered  reduced biodiversity Flood control  death of terrestrial trees (Murray River) Water harvesting  salinity, temperature, oxygen changes, pollution Watering points encourage hard-hoofed animals (that compact the soil) as well as native grazers that reduce vegetation cover

17. 45-17 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Holding on to soil Land clearing  no surface litter layer or root mat  greatly accelerates top-soil loss Compaction by hard-hoofed non-native animals reduces porosity  increased water run-off Reduced vegetation cover  increased wind erosion Improved farming practices include –no-till system –leaving stubble after harvest

18. Fig. 45.9: Wind erosion 45-18 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

19. 45-19 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Discussion question 2: What would cause soil acidification?

20. Soil acidification Repeated application of ammonia-based fertilisers without liming Addition of organic acids Growing legumes Plant yield drops when pH reaches 5 or less 12–24 million ha agricultural land is presently at or below pH 4.8 Improved land management is vital Acid sulphate soils are common in coastal areas 45-20 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

21. 45-21 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Dryland salinity Salt is naturally present in soil or groundwater, but out of reach of plant roots In wet areas rain washes salt out of soil; in dry areas soil salinity is higher Tree removal causes reduced evapotranspiration (and hence discharge) of ground water, so water table rises When less than 2 m from surface it rises further, by capillarity Recharge (from rainfall) and discharge zones may be far apart  Need catchment-based management

22. 45-22 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Fig 45.10: The salinisation process

23. 45-23 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Irrigation salinity Results from irrigating soils to grow crops Excess water recharges ground water Discharge is slow because there are no deep- rooted trees Water table rises and brings salt to surface Signs of salinised soil –replacement of salt-sensitive species with tolerant ones until no plants can survive –salt scald occurs and then crust forms –salt drains into streams, into river system and the sea

24. 45-24 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Prevention of dryland salinity Stop clearing native vegetation Replant using deep-rooted species, e.g. eucalypts By 2050, approx 17 million ha in Australia are predicted to be affected by dryland salinity –south-west WA is worst affected (> 4 million ha) –SA, Victoria and NSW are also affected –ground water levels are still rising in Murray–Darling basin

25. 45-25 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Polluting the atmosphere Even the Arctic icecap has black soot; global effects of pollution are the ozone ‘hole’ and global warming Ozone (O 3 ) layer is 13–20 km above earth Shields earth from destructive UV radiation Constantly created by action of sun on oxygen Depleted by natural and man-made constituents in the air, e.g. chlorofluorocarbons (CFCs) When rate of destruction of ozone > rate of formation, ‘hole’ forms

26. 45-26 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Effects of UV radiation Depend on the wavelength: A, B and C UV-C and -B are the most harmful, but nearly all filtered out by ozone layer For each 1% decrease in ozone there is a 2% increase in UVB at earth’s surface UV radiation reduces uptake of CO 2 by phytoplankton UV-A causes sunburn and skin cancers Montreal Protocol target is to get ozone levels back to normal by mid-21 st century

27. 45-27 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Greenhouse effect Natural warming of earth Greenhouse gases CO 2, N 2 O, CH 4 and water vapour absorb heat that would be lost to space, raising temp of earth by 30°C Post-industrialisation levels of these gases are rapidly increasing, mostly due to fossil-fuel burning

28. 45-28 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Fig. 45.14: Mechanism of the greenhouse effect

29. 45-29 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Global warming Intergovernmental Panel on Climate Change (IPCC) was established in 1988, and in 2001 concluded that warming over the last 50 years was due to human activities. Climate models project global surface temperature will rise 1.4–5.8°C, and sea levels rise 9–88 cm, by 2100 Rainfall patterns will change in space and time Changes in ocean currents may occur

30. 45-30 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Coral bleaching Coral polyps stressed by warm water expel their symbiotic algae, and die Bleaching has been reported in reef corals from all tropical oceans Coral distribution patterns may change as a result of global warming

31. Rising sea levels Sea levels are expected to rise due to heating and expansion of seawater Many low-lying cities are at risk, and some whole nations, e.g. Nauru 45-31 Copyright  2009 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

32. 45-32 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Reduction of emissions 30% of Australian CO 2 emissions are due to fossil fuel use, agriculture, land clearing and forestry

33. Discussion question 3: What are the best ways to reduce CO 2 emissions? 45-33 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

34. Some ideas for reducing CO 2 emissions More efficient lighting, cars, industry Change to cleaner fossil fuels (e.g. natural gas) Adopt non-carbon fuels (solar thermal, photovoltaic, wind, geothermal, tidal) 45-34 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

35. 45-35 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Towards sustainability Convention on International Trade in Endangered Species (CITES): bans trade in listed species Environmental Protection and Biodiversity Conservation Act 1999 (Cwlth) conserves ecosystems and their components Victorian Flora and Fauna Guarantee Act 1987 Protection of whole habitats is achieved through Nature Reserves and National Parks Permits are now required for some activities, e.g. clearing native vegetation

36. Fig. 45.17: Exotic wildlife trade 45-36 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University

37. 45-37 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Managing natural communities for conservation Prevention of degradation is needed across a variety of land tenures, not just reserves Market-based approaches (i.e. farmers paid to manage natural areas) are gaining popularity Traditional use of fire to produce diversity of habitat patches is being recognised

38. 45-38 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Restoration ecology: resetting the clock Whole landscapes may need restoring, e.g. wheat belt in WA Need data on habitats, species, patterns Incorporate a suitable disturbance regime to produce mosaic of habitat patches  high diversity Replanting methods may include direct seeding of local species Soil fungi and bacteria should be incorporated from unmodified systems

39. 45-39 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University Ecologically sustainable development (ESD) A sustainable society  ‘all human activity takes place within the limitations set by the environment’ In 1992 the Australian government adopted a National Strategy for ESD (NSESD) to safeguard intergenerational equity, with seven main objectives A global society developed along ESD principles is the only solution

40. Summary The impact of humans on the Australian environment has greatly accelerated over the last 200 years More than half of agricultural land in Australia is affected by land degradation Human impacts have effects on a global scale Ecologically sustainable development is required if the resources on which life depends are to be maintained 45-40 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Biology: An Australian focus 4e by Knox, Ladiges, Evans and Saint Slides prepared by Karen Burke da Silva, Flinders University