Lecture 26 - Global Change Flashcards
Name 2 consequences of deforestation.
- Reduced Area: Reduction of the area available for populations → detrimental to organisms
- Increased isolation: increased distance between patches of habitat → biodiversity loss
What are the 3 key areas that global change is affecting
- Deforestation and habitat fragmentation
- Invasive Species
- Climate change
Define invasive species and how it impacts ecology.
Give an example
Invasive Species: A species that arrives (often with human assistance) in a habitat it had not previously occupied and then establishes a population and spreads autonomously.
Spartina alterniflora for erosion control → became the dominant species. Destroyed native grasses, altered invertebrate diversity, affected shorebirds.
How have humans mediated invasion?
Humans bypass biogeographic filter, increasing chances of species that wouldn’t have passed this filter on their own of surviving.
What’s the relationship between CO2 and temperature?
Extremely well correlated when you look at the graph of thousands of years
Why are Artic/ northern hem expected to increase mos in temperature?
Arctic/northern hem are expected to increase in temperature the most because as T rises and ice disappears, ice covers aren’t there to reflect away the sun, and blue water attracts the sun. As the blue water attracts more sun, the ice melts faster.
How many degrees did temperature increase in 20th century? What could this lead to?
0.6-1.0 C during the 20th century
predicted to alter the hydrological cycle, and thus ocean-atmosphere interaction: Global consequences.
What is the El Nino Southern Oscillation? How is it caused? What is it responsible for?
the El Nino Southern Oscillation (ENSO) is a large-scale atmospheric and ocean phenomenon that influences ecological systems on a global scale
During ENSO, trade winds weaken or even reverse → no more upwelling of cold nutrient rich water.
– Responsible for climate variability around the globe
What are some consequences of ENSO?
During mature phase of El Nino, warm surface water shuts off upwelling reducing nutrient supply, and reducing phytoplankton production.
Reproductive failure, migration, death
How did ENSO affect the Great salt lake
Strong El-Nino of 1982-83 was source of many storms deep into interior of N. America.
Induced a trophic cascade in Great Salt Lake: Increased precipitation with Great Salt Lake basin.
1983-87 lake rose 3.7 m
Wurtsbaugh and Smith Berry found lake salinity dropped by 50 g/l and the lake was invaded by predaceous insect Trichocorixa verticalis.
How is ENSO linked to climate change?
rease in ENSO frequency and strength is linked to regional climate– more vigorous hydrological cycle induced by anthropogenic CO2 which is causing temperature to rise.
Explain 4 Ecological consequences of global change.
Give examples and experiments related to each.
- Phenology (the timing of seasonal activities of animals and plants) and physiology of organisms.
Earlier breeding, earlier arrival of migrants, increase in growing season (up to 4 days/decade in some parts of Europe) - Physiology
Experiment showing the effects of ocean acidification on coral reef builders.
Calcification → harder time making their skeletons as the ocean become increasing in CO2. - Range and distribution of species
• Expected to shift ranges toward the poles or higher altitudes to the extent that dispersal and resource availability allow.
• • • Alpine plants grow at higher altitudes - shift by 6.1 m/decade.
• • • Animal species northward expansion up to 6.1 km/ decade.
- Change in distribution of Southern bird
- • • Plot the change in status (shrink or enlarged).
- • • Each dot represents population
- • • Expect that if no change, red line should go through origin.
- • • Seaweed communities in retreat from ocean warming
- Shifts in community structure
Response by individual species may disrupt their interactions with others at the same or adjacent trophic levels (predator-prey interactions, competition)
ex: The wild madder (small flowering plant) produces new shoots in January for the following spring. Shoot production is inhibited by low temperatures. Its northern limit is correlated with the 4.5 C isotherm.
Plant distribution at higher latitudes (N and S of 30o latitude) is often related to the lethal temperature that precludes survival.
Damage by ___ is the single most important factor limiting plant distribution in these regions –some plants can tolerate it and others can’t.
FROST
Explain the “Atlantification” of the Arctic Ocean
Circulation changing, influenced by the strength of the North Atlantic Oscillation wchich is changing due to climate change.
ArcticReceive water from pacific ocean and the atlantic ocean.
Differ in the amount of silica:nitrate they can take.
Diatoms only found in high-arctic domain (high silicon requirement)
Phaeocystis (poor food quality) in atlantic domain.
Disrupts ecosystem
Explain how Ocean acidification impacts ecological communities
Tropical Oceans Predictions:
• Corals will become increasingly rare
• Algae will become more abundant
• Because coral reefs support so many animals, biodiversity will decline
