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Lectures 16-23
Forest Health, Coral, Kelp, Colonisation, Agriculture, Economics
| Question | Answer |
|---|---|
| What happens to plants in drought periods? | Close stomates to avoid water loss. No CO2 going in, no photosynthesis = relying on starch reserves = carbon starvation High drought intensity = hydraulic failure (too much tension in vessels + water column breaks (cavitation) + risk of pathogen damage |
| Water Transport | only moves from high to low potential (more negative) in higher temperatures, the driving force from leaf -> air is much higher, so higher water loss when stomates are open (drier atmosphere = greater water loss) |
| Desiccation | when plants dry out their leaves in order to withstand extreme dryness, then return to normal when conditions are wetter Isohydric plants CAN anisohydric plants CAN'T |
| What can plants do? | - close stomates further (but this increases leaf temperature) - adapt xylem vessels to tolerate greater water loss but osmotic adjustments (increase solutes in cells and lower osmotic potential, which leads to a lower water potential) |
| SW Western Australia | groundwater levels are dropping, leading to drier soils. CC is leading to hotter temps and drier conditions = starvation, hydraulic failure, pests = species contractions/shifts |
| Tree Examples (1) | Jarrah + Marri = found higher up and have very deeps roots so don't need to dry their leaves out as much to get water from the soil, but are more at risk from hotter temps and need much wetter conditions |
| Tree Examples (2) | Powderbark + Wandoo = shallow roots in clay, so must dry out more because it's harder to get water from clay. Do better in drier conditions and are found further North |
| Coral Formation + Ocean Acidification | animal (polyp), algae (zooxanthellae), mineral (calcium carbonate exoskeleton) which is sensitive to dissolution in acidic water OA: caused by increased uptake of CO2. Less CaCO3 produced and it breaks down, so none for corals (poleward migration) |
| Coral Bleaching | loss of algal symbionts and photosynthetic pigments due to prolonged increased ocean temp. Deprives corals of dominant food source (corals expel zooxanthellae and turn white). |
| Reptiles | Have temp dependent sex determination (tuatara = FM) - nocturnal + active at cold temps - slow to reproduce + long lifespans - eggs develop for 1 year in shallow nests |
| Models used (3) | - physiological model describing thermal reaction norms for embryos - mechanistic model of soil temp - population viability model |
| Tuatara Populations | Already a male-based sex ratio and as males are larger, they consume more resources which leads to low reproduction rates of females. Increasing temps = more males so eventually no females will be left and population will collapse |
| How to prevent this | Shade rookeries over nesting areas to protect from solar radiation remove eggs and incubate at specific temperatures then take them back to the island assisted colonisation |
| Impacts of CC on Agriculture | higher CO2 = increased biomass but decreased nutrient content higher biotic stressors = changes in diseases + pests higher abiotic stressors = droughts, floods, higher temps, loss of diversity |
| Winners | E and SE Asia, N Europe, North America = increased crop yields |
| Losers | Africa, Australia, NZ, S Europe, South America = decreased production + yield |
| Genome Editing | CRISPR Breeding: specifically modify bases to faster improve crops + favourable traits (much quicker than traditional cross-breeding) |
| Invasive Species Terminology | Weed = subjective/qualitative Impact = subjective/quantitative Naturalised = objective/quantitative Non-native = objective/quantitative |
| Kelp Anatomy | Holdfast: root-like structure anchoring the plant to the ocean floor Stipe = stem Blades = leaves (where all photosynthesis and nutrient uptake happen) Stipe + blades = thallus Ecklonia radiata/golden kelp = species in WA |
| Effects of warmer water on kelp | increased erosion, decreased growth rate Kelp can't recover due to: herbivory, recruitment blocking from turfy seaweed, allee effects (when populations aren't self-sustaining) |
| Tropicalisation | when tropical predators expand with warmer waters + eat kelp |
| Assisted Colonisation Definition | trying to improve the likelihood of a species surviving by putting them in an area out of their known range and doing it because you think there would otherwise be a high chance of extinction. partic. species with low dispersal ability/fragmented habitats |
| What is it controversial | - not everyone supports novel assemblages of species - invasive and has the potential to disrupt ecological interactions and spread parasites and disease - scientific uncertainty around long-term impacts |
| Example 1 | 1. Pedder galaxias - after LP was dammed, invasive trout moved in. 31 galaxias were moved to Lake Oberon and were successful, while those remaining died |
| Western Swamp Turtle | Thought to be extinct but was rediscovered in 1953 but populations have never thrived invasive predators (foxes), habitat loss, environmental change - seasonal wetlands that dry out in summer. as rainfall decreases wetlands dry out for longer 7,5 now 5,7 |
| Translocation | Models used to predict good locations 2016 - Trial 1 (35 juveniles across 3 sites) 2021-present (112 juveniles in Scott NP) |
| Technology-use subsidies | generally have high cost and don't reduce as much CO2 |
| Technology development | cheaper, if they work countries that invest the most gain the most (good incentive) |
| ETS | government sets emissions limit + creates and distributes permits. People buy/sell. Cons = expensive, risk of corruption, volatile prices |
| Carbon Tax | low application cost, effective, but people don't like taxes |
| Current Australian Policy | Safeguard mechanism = inventors who create new renewable energy technologies will be rewarded with payments + encouraged to invest into further R+D (e.g. selling methane from waste) |
| Cons of Aus Policy | - only applies to the 250 highest producers - firms don't usually emit less carbon, they just sequester/reduce carbon in other areas - poor additionality (actions might have happened anyway) |
Created by:
mishm
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