Ecosystems at Risk Flashcards
How do biophysical interactions led to diverse ecosystems and their functioning
- Latitude/ climate - diverse
- Precipitation (hydrosphere/atmosphere) - diverse
- Nature of soils which provides habitats for decomposer organisms
- Food webs - functioning
- Cycles (carbon, nitrogen, phosphorus)
How does climate/latitude led to diverse ecosystems
Different latitudes create different climates
Equator = humid, high temperature, high rainfall –> tropical rainforest
Poles = low temperature, low rainfall –> tundra ecosystems
How do cycles/ food webs led to diverse ecosystems/ functioning
Nutrient cycling leads to ecosystem productivity controlling the flow of energy and biomass.
Plants absorb nitrogen from the soil, this nitrogen allows a plant to photosynthesis and to maintain structure. Nitrogen is transferred around an ecosystem through the food chain and decomposition. Consumers such as herbivores, take in the nitrogen from their food allowing them to form tissue. Decomposers break down dead organic material and return nitrogen back into the soil. Nitrogen cycle increases the biomass of the ecosystem
What does elasticity mean
the rate of recovery of an ecosystem property following disturbance - how long it takes for an ecosystem to recover from a stress
What does amplitude mean
the amount of stress an ecosystem experience/ can experience before it can no longer return
What does malleability mean
the difference between the ecosystem’s final recovery level and its pre stress state - the greater the difference the less resilient the ecosystem is
What is the criteria to determine vulnerability and resilience of an ecosystem
Biodiversity
Extent
Location
Linkage
How does biodiversity impact vulnerability
greater Bodiversity = greater level/ opportunity to adapt or withstand change
monoculture = bad
Greater genetic diversity - greater chance that individuals will have characteristics that enable survival during stress events
Greater species diversity - greater more complex ecosystem (greater linkage), less impact if one species goes extinct
Ecosystems will keystone species have a higher vulnerability
Examples of biodiversity - vulnerability
Seagrass has high levels of genetic diversity enabling grass fields to grow back to pre-disturbance strength faster after grazing
Genetic diversity
Potato from south America
Coral Reefs contain 1,5000 species of fish and 400 species of coral enabling it to be resilient to change
Over 9,000 species of plants in Feinboss
Over 3 million species in the Amazon
Agriculture ecosystems are monoculture
How does extent impact vulnerability
Small extent = high vulnerability
Since fauna and flora confined to small areas, very suspectable to stress e.g. natural disasters
Changes speed which
amplitude
Example of extent impact on vulnerability of ecosystem
Feinboss Cape town - size of 4 football fields and has the rarest flowering species in the world with 5000 species in all. However the size of the ecosystem makes it extremely vulnerable to change e.g. landslide, urbanization
Dodo birds were restricted to Mauricous island leading to its extinction when the island was colonised
Made worst by islandisation
Coral reefs have a large extent 350, 000km2 which enables space for animal migration to protect them from stress
How does location impact vulnerability
Location of an ecosystem effects its functioning. A greater degree of familiarisation an organism has to a particular set of environmental conditions the more vulnerable an ecosystem is to change.
As well as proximity to humans
Example of location impact on vulnerability
Coral reefs require: (very extreme climate)
- located above 50m so sun light can penetrate
- 27 degrees
- water must be clear, clean and salty
- water must be nutrient deficient because it increased nutrients result in increased algae and thus decrease sunlight
the change of even a few degree can cause coral bleaching
Coral reefs also close proximity to humans thus greater vulnerability to exploitation for agricultural, urban and industrial use e.g. trolling, anchoring, overfishing, impact of run off
How does linkage impact vulnerability
The greater the level of interdependence within an ecosystem the greater the ability to absorb change - linked to species diversity
Example of linking impact vulnerability
The artic krill are the main primary consumers in which the ecosystem’s wood chain would collapse if their population declined.
What is a natural stress example
- Mt St Helens - natural catastrophic
natural events of an earthquake and volcanic eruption resulting in lateral blast in molten rock, ash clouds, landslides - Cyclones fires and droughts (not catastrophic)
Stats of Mt St Helen impact
- all vegetation for 25km destroyed
- 500 sq km of coniferous forest blown away
- only 14 out of 42 animal species survived
- ash cloud reduced oxygen levels on land and in water
- 67000 animals died from eruption and lava flow
- 1 500 000 animals died from ash fall
results of Mt St Helen eruption
- animals who survived the initial explosion died from a lack of food and clean water
- first animals to return were those with a wide food tolerance e.g. deer, mice, gophers
- oxygen deficient led to anaerobic organisms who don’t need oxygen to survive dominate water system
- disclimax and simplification of biodiversity
weedy plants with a wide tolerance have invaded the are becoming common - upper slopes between the new summit was still bare of vegetation, with a ‘Luner’ like surface
Cyclones as a natural stress
- not catastrophic
- Cyclones on the GBR can destroy small sections of coral but also do not have a major impact on the functioning as it can provide relief from crown thorn starfish invasion and they are a on a small scale localised and shortlived, unlike human modifications
What are the human modifications to ecosystems
IPODS
Islandisation
Pollution
Overharvesting
Habitat Destruction
Species Introduction
Human modifications - islandisation(explain)
Cause: leaving undisturbed pockets of habitat in amongst surroundings of modified habitats
Effect: As large animals need large reserve, the margins of rainforests have lost species. Also problems with disease may arise leading to piecemeal destruction of the ecosystem
- decreasing extent of ecosystem
Example of islandisation
Islandisation in the Amazon had impacted ant bird who follow ant colonies however due to psychologically evolved to stay in the dark and is unable to follow them out of the dense forests
Human modification - pollution
Cause: Pollution of CO2, methane and nitrous oxide into the atmosphere by human activity e.g. combusion of fossil fuels
Effect: enhancing the greenhouse effect
Example of pollution
Humans excess CO2 emissions
- seal levels are 10 - 20 cm, glaciers are -
- melting, more intense weather patterns (hurricanes, droughts, fires , floods)
- killed 60% of the krill population
- heavy impact on location dependent ecosystems e.g. coral reefs and pole regions
- coral bleaching
Human modification - overharvesting
Humans clearing land and removing species at a faster rate than they are replenished for agriculture, food sources, fuel sources
Stats on overharvesting
- humans overharvest trees 10 times faster than they replenish - 3 football fields from the amazon per minute
- 70% of marine species are being caught faster than they reproduce (trawl netting bi catch)
- up to half of the entire planets growth of plants and large growth of animal growth is harvested for humans yearly
Example of destruction of habitats
Fein-boss environment (biological hot spot)
highest concentration of plant species in the world.
40% of the original area was destroyed by human activities such as agriculture and the spread of the city
Destruction of the habitat destroys things reliant on the habitat
Human modifications - introduction of species
The introduction of a non native species
Threatens biodiversity of adapted organisms by introducing new predators
Example of introduction of species
- Hedgehogs were introduced from Scotland as a garden pet in the 1970s however they wouldn’t only eat the similar prey as native species but also caused the collapse of the dung bird breeding as they fed on their eggs
- Initially giant west African snails were introduced to be eaten however they invaded and reduced food sources for the unique species native to Hawaii. In turn they introduced killer snails to kill the giant west African snails however the killer snails also ended up destroying native Hawaiian species to the extent of extinction(90% now extinct) - use to be about 750 native species
How does the atmosphere impact the functioning of ecosystems
Atmosphere is the main source of the climatic factors
- temperature
- rainfall
- main source of nutrients- nitrogen, carbon, oxygen as well as water
- Sunlight
How does the hydrosphere impact the functioning of ecosystems
- Water cycle
- large bodies of water moderate the temperature of close land
How does the lithosphere affect the functioning of ecosystem
- determines the nature of soils which provide habitats for many decomposers organisms
- the recycling of the minerals essential
- the capacity of the soil to store nutrients
- differences in elevation
How does the biosphere affect the functioning of Ecosystems
- biodiversity -greater biodiversity means more complex functioning and more resilient
- food chains - cycling of nutrients
What are the nutrient cycles
- the carbon cycle
- nutrient cycle
- nitrogen cycle
- phosphorus cycle
Why do be value ecosystems acronym
H - heritage Value
U - Utility value
G - genetic diversity
I - Intrinsic value
N - Need to allow progresses of selection, evolution and change to continue
What are management strategies acronym
E - Exclusion
D- Design
E- Educate
A - Action
L - Legalization
Acronym for evaluating the effectiveness of a management strategy
B - maintaining biodiversity
I - Intergenerational equity
P - Precautionary
I - Intragenerational equity
