Directed Reading Flashcards
How can you prove the Indian Savanna ecosystem is not anthropogenically derived? (P1)
- Showing the ecosystem holds various endemic species native to the area
What does TGB stand for? (P1)
tropical grassy biomes
Why is there systematic bias against TGB research compared to amazon rainforest? (P1)
- belief = ‘secondary ecosystems’ not worth of conservation
- Seen to be ‘recent in origin’ through rainforest degradation
What percentage species in the Maharashtra Madagascar grasslands are endemic? (P1)
40%, despite the area being seen as one of the most ‘degraded grasslands’
What does an exponential species discovery curve imply? give example (P1)
- Shows species are yet to be discovered and there is a lack of research
- Its the case for the campo rupestre ecoregion
In what conditions/characteristics are species most likely to be discovered first? (P1)
- Southern latitudes
- Lower altitudes
- Wetter conditions
**Needs to be a conscious effort to look elsewhere to discover new species
How many endemic species were found in the Indian Savannas and how many are reported to be threatened by extinction? (P1)
- 206 endemic species
- 17 reported to be threatened by the risk of extinction
When has been the biggest increase in species described? (P1)
In the past two decades
Why does the reforestation of Savannas do more harm than good and how can we tell? (P1)
- Causes decline of endemic plants such as drimia razii in the Maharashtra
- Can see an open-canopy ecosystem since the Holocene by looking at fossil records
What does ericoid mean? (P2)
needle-like plants
What is the hypothesis for P2 regarding shrubification and soil C content?
Low productivity tundra biomass shift to higher productivity shrub vegetation may lead to a loss of the a abundant soil C
How does the shift from ericoid to ectomycorrhizal plants stimulate soil C loss? (P2)
- woody species stimulate positive priming, stimulating decomposition of recalcitrant plant litter
- ectomycorrhizal fungi produce and exude carbon degrading compounds
Give an example of a plant that has recalcitrant plant litter (P2)
Empetrum Nigrum - produces phenolic compounds with slow decomposing properties
What are some other phenomena that lead to net C loss with shrubification?
- input of leaf litter into the system
- accumulation of snow leading to increased winter soil temps
What do higher respiration and photosynthesis rates in shrubby vegetation imply? (P2)
C is fixed at a faster rate and not sequestered in the soil
- Absorbed quicker but released and not stored
What did P2 find regarding SOC content comparing forest and deciduous shrubs and tundra heath?
- Found SOC content was lower in forest and deciduous shrubs compared to usual tundra heath - predicted to be because of increased decomposition and more C loss
What is causing ‘browning’ of the Arctic? (P3)
Summer drought and wildfires
How much lower was vegetation greenness in 2012 in the worst areas of the Nordic Arctic Region compared with previous years? (P3)
58% lower
What has led to increased vegetation change in the Nordic Arctic Region? (P3)
Increased precipitation and paludification (formation of wetlands)
How do pests cause vegetation change? (P3)
Climate-change induced expansions in the outbreak ranges of canopy-defoliating insects cause vegetation change
How can we observe plant damage by defoliation? (P3)
Looking at NDVI values, NDVI decreases with increased defoliation
What other effects can weather events have on plants? (P3)
Increase in:
- summer frost
- salt spray
- flood damage
When is NDVI worse affected? (P3)
- 2012 upland site found NDVI most affected when pests also defoliate the understory of the canopy
Why is there less risk of summer frost damage in upland Arctic sites? (P3)
plants are more frost resistant with thicker leaves
What problems will temperature fluctuations bring? (P3)
- Snow cover will become more irregular exposing plants to ambient fluctuations in temperature
- Fluctuations will also lead to increase in pest insects and pathogens due to increased growing season length
How fast is climate change driving poleward range edge expansion of marine species? (P4)
72km per decade
What is meant by climate velocity? (P4)
the rate and direction that isotherms move across the seascape
Give two examples of time period where species have been under extreme weather conditions and its effects? (P4)
- Late ordovician (450mya) was extreme cooling and many low lat species went extinct
- End-permian mass extinction (250mya) lead to ocean warming killing 80% of marine life, they migrated northward until there was no more habitable space
What is meant by acclimation and extirpation?
Acclimation = process by which an organism adjusts to changes in its environment over time: physiological, biochemical or behavioural
Extirpation = local extinction of a species or population in a particular geographic area or region, while it still persists elsewhere in its natural range
What does extirpation do and where does it usually occur? (P4)
- It causes populations to move into new locations and vacate historical territories
- Happens at the trailing edge of immigration where species can no longer maintain positive growth rates
How do changing temperatures affect marine organisms? (P4)
- Affect protein structures and membrane fluidity; affecting metabolism
What does OCLTT mean? (P4)
oxygen and capacity limitation of thermal tolerance
- Changing temps mean fish oxygen demand is higher than oxygen content in the surrounding water
- Means there isn’t enough oxygen to distribute to tissues
What groups of taxa are the most sensitive and which are the most resilient to change? (P4)
- Larvae and Juveniles most sensitive
- Larger marine organisms are most resilient as they are more mobile - wider range of conditions available
Why is moving deeper for cooler temps not always a viable option for marine organisms? (P4)
More chance of hypoxia deeper in the ocean
What are spatial refuges? (P4)
- nearby ‘safe zones’ from extreme stressful conditions
- occur within the spatial mosaic due to processes such as upwelling and internal waves
- can be less than 1km apart
How do warming ocean affect food web production? (P4)
reducing nutrient flow into photic zone
What is required for sustainable leading edge invasion of a species? (P4)
self-persistance (involves flexibility in habitat/diet) or ongoing immigration
What do species with small adult home ranges rely on to expand their range? (P4)
- Species such as coral rely on their early life stages in currents
- Corals have been moving northward because of currents
What are the biotic threats of marine life migration/change? (P4)
- selective pressures and predation
- interactions between species can be altered by temp etc (less likely to detect prey for e.g.)
- changes in habitat may lead to species consuming ‘junk food’ species that decline prey quality
Give an example which shows how leading edge is stronger than the trailing edge? (P4)
Humboldt squid present at both poles but not at the equator
Why do long-lived species exhibit a delayed response to climate change? (P4)
less frequent chance for evolution (long-generation time)
How are trade-offs relevant in marine ecosystem change? (P4)
- trade-offs with other metabolic processes to evolve a wider thermal tolerance
- Putting more effort in to adaptations and not other processes e.g. (adaptations for the prey/predator to enhance its role if mortality rates from invasion are not high enough to cause extinction)
How are temperature gradients different in the ocean than on land? (P4)
Temperature gradients are weaker in the ocean and organisms will have to move further/deeper to experience the same temp change as they would on land
How has ‘Global Greening’ slowed down rising temps in global land surface air temperatures? (P5)
Global greening has slowed down the rise in global land-surface air temperature by 0.09 ± 0.02 °C since 1982
increased evapotranspiraton (terrestrial hydrological cycle), changing atmospheric circulation , decreased albedo etc.
Where has LAI increased? (P5)
boreal eurasia, europe, india, amazonia, sahel
Where did LAI not change air surface temperature and why? (P5)
- north america and east asia
- effects of large-scale atmospheric circulation changes mask local vegetation feedbacks
Where is this feedback from evapotranspiration most dominant? (P5)
Regions where biophysical feedback has changed - important for looking at interventions in mitigation and adaptation
How does evapotranspiration reduce surface air temperature? (P5)
- Water molecules absorb surrounding environment heat to turn in to a gas, cooling the air
- Shading and moisture release can reduce surface temp
- Latent heat loss
How does a lower albedo from increased LAI reduce surface air temperature? (P5)
- vegetation absorbs more incoming solar radiation rather than reflecting it back into the atmosphere
- Less solar energy is available to heat the surface and surrounding air
