LECTURE 5 Flashcards
Name three services that ecosystems provide.
Provisioning services (food, water, material goods) Cultural services (spiritual, recreational) Support services (nutrient cycling)
Describe tropical forests.
Tropical forests are warm-adapted and sensitive to drought.
In what way does climate change impact tropical forests?
Climate change impacts the hydrological cycle
Impacts the increase or decrease of rainfall in an area; the severity and length of dry seasons (drought)
Climate change can impact tropical forest diversity
Give an example of climate change and its impact on tropical forests.
The megadrought in the Amazon in 2005 where 37% of the Amazon experienced severe drought
Increase in forest fires > increase in carbon dioxide released
How often do megadroughts occur?
Megadroughts typically occur every 100 years
How many megadroughts have occurred in the last 15 years?
2 megadroughts have occurred in the last 15 years
Describe cloud forests.
Cloud forests are very wet; experience cloud cover for much of the year (at the very top of mountains)
In what way does climate change impact cloud forests?
Climate change causes increased sea surface temperatures
Lifting cloud base hypothesis
Describe the lifting cloud base hypothesis.
An increase in sea surface temperatures (caused by climate change)
Moisture formation occurs at higher elevations
Resulting in rise of cloud bases
Point where clouds intersect with mountains moves up in elevation
Shift in suitable habitat for cloud forests to higher elevations
AND drying out of habitats where clouds used to form
Give an example of the lifting cloud base hypothesis.
Monteverde, Costa Rica
Rising cloud base resulted in the range shifts of reptiles, amphibians, and birds
Related to drying trends associated with climate change
Tropical amphibians are especially sensitive to dry periods (declines/extinctions occur)
Range shifts matched pattern predicted by warming climate (shift upslope and disappearance of upper elevation species) but related to DRYING CONDITIONS and not temperature
This is made more complex by species interactions.
Describe ecosystem feedback in the Amazon.
The Amazon has a complex internal system of moisture recycling
Evapotranspiration from one area produces moisture for rainfall in next area
Moisture recycling across Amazon and into Andes
If Amazon dries out enough that forest in an area is lost, it could cascade through the entire system
A decrease in forest cover over large areas paired w increase carbon dioxide from decomposition - affects global climate!
Discuss pine beetles in relation to tropical ecosystems.
Mountain pine beetles are also of concern
Range expansion east and north of historic range
Risk of northern pine forests across continent
Bark beetle and drought in Amazon and New Mexico
increased temp have caused bark beetle population explosion and drought in pinyon pine forests
More than 90% of trees have died in some areas
Beetles are spreading to high mountain ecosystems as well
What are some of the changes to the cryosphere being reported?
Glaciers are melting
Snowpack melting earlier in spring, forming later in fall
Permafrost getting deeper (surface soils are thawing)
Name two glacier/snowpack dependent ecosystems and explain the impact of the climate change on these ecosystems.
Tropical ecosystems and temperate ecosystems rely on meltwater from glaciers/snowpack for sources of water.
TROPICAL ECOSYSTEMS
Glaciers are disappearing due to temp increases and land use
i.e. Mount Kenya
Where 75% of glacier cover gone, 7 glaciers disappeared completely
i.e. Lori Kalis Glacier, Peru
Main outlet glacier of biggest tropical icecap in world
Retreating at a rate of 1km/decade
This causing a habitat shift
Land under the glaciers are being exposed, change in albedo
Increased water flow as glaciers are melting; decreased water flow once they disappear
Coldwater ecosystems fed by glaciers receive less water and experience increased temps > resulting in loss of habitat for cold water species
TEMPERATE ECOSYSTEMS
Glaciers melting in Alps, Glacier National Park, Himalayas
Snowpack declining in size and melting earlier
Water flow in streams and rivers decreases (fed by melting snow in spring)
Increased droughts occur > impacting riverine and riparian vegetation
i.e. Ponderosa Pine
Range shift upslope by 100m over the past century
Related to melting snowpack > young pines reliant on meltwater for survival in late spring/summer droughts
When the snowpack disappears, the recruitment of pines drops
Situation is exacerbated by deforestation; mature pines are cut down and not replaced
Less cold water species at high elevations for same reasons as in Tropics (loss of water form glaciers)
Describe ecosystem feedback in the tundra.
Tundras have a short growing season and soils freeze over before vegetation decomposes
Thus, there is a buildup of large amounts of frozen organic matter
Thawing of Arctic soils due to increased temperatures
When the soil thaws, there is an increase in decomposition, and methane is released
Increased growing season leads to increased photosynthesis but not enough to compensate for decomposition inputs to the atmosphere
Net effect: positive feedback
Warming leads to more GG released, leads to further warming
Tundra plants are short and light in color (high albedo)
Boreal conifers are tall and darker
As conifers expand into tundra, the albedo of the area shifts
This also contributes to warming
