Ecosystems Flashcards
What is an ecosystem?
A system formed by the interaction of all living organisms. Within an ecosystem, all of these elements are interacting with each other all of the time. All energy is coming from the sun. `
What are diverse ecosystems?
- a result of unique biophysical interactions at varying scales, the interaction of the biotic and abiotic elements result in diverse ecosystems
- e.g. coastal dunes, freshwater wetlands, intertidal wetlands, coral reefs, arid areas, alpine, rainforests
How are diverse ecosystems shaped?
- spatial patterns of these ecosystems depend on 4 spheres (bio, litho, hydro, atmo)
- result of climactic factors (temperature + precipitation)
- hydrologic processes (surface water flow, snow melt, ocean currents)
- geomorphic processes (aspect, altitude, gradient, soils)
How and what is ecosystem functioning
Ecosystem functioning = the ability of an ecosystem to capture, store and transfer energy, nutrients and water throughout the system
This depends on 2 key processes: energy flows and nutrients cycling
What are energy flows
Energy flows through an ecosystem from the sun to the plants (producers, producing energy via photosynthesis) and animals through the trophic levels.
Energy is lost as heat is produced at each level of consumption - there are fewer organisms at the top of the chain.
How does latitude impact energy flow
Equatorial ecosystems receive more regular and stronger daily insolation –> more energy available.
therefore tend to have higher biodiversity
What are the trophic levels
Top - bottom: Tertiary consumers (large carnivores) Secondary consumers (small carnivores) Primary consumers (herbivores) Producers
(greatest number found at the bottom)
What are nutrients cycles
- nutrients are central to the functioning and growth of organisms
- fixed supply of nutrients, continually cycles through biosphere
- ecosystems with higher biodiversity have higher amounts of nutrients as the amount of matter that decomposers affects the amount of nutrients that can be recycled
- net primary productivity
- nitrates, carbon, sulfur, phosphorus, water and oxygen
Net primary productivity
based on the biodiversity and nutrients cycled - the amount of material that an ecosystem produces.
Tropical rainforests = 1800g/m2/year (similar to kelp forests)
Deserts = 80g/m2/year
Optimal Functioning - Climax Communities
- ecosystems go through stages of development
- successions
- climax community = an ecological community that has reached the final stage of ecological succession and cannot support additional flora and fauna, it is highly functional
Succession
- succession: process that begins after a significant disturbance or extinction of existing community, can occur in areas that have never been colonised b4, leads to species diversity as new species adapt to change and find a niche
Disturbances preceding succession include:
Human impacts: deforestation, pollution
Natural stresses: fire, drought, tropical cyclones, tsunami
Ecosystem at risk:
- one that is subject to difficult environmental conditions (aridity, high salinity, extreme temperatures, lack of nutrients) or those slow to develop and or regenerate after change
dynamic equilibrium
a situation in which stability is achieved in an ecosystem
- all ecosystems function in a state of dynamic equilibrium or a continual state of balanced change
beyond the limits of equilibrium
a change beyond the limits means that the system as a whole cannot exist in its original state –> concept of elasticity
vulnerability
the lack of defence an ecosystem has against unforeseen changes in the environment
resilience
the ability to adapt to changes in the environment, the speed which ecosystems recover their typical features after disturbance
(stress - disequilibrium - succession - new equilibrium/climax)
what makes ecosystems vulnerable
- lack the ability to / are slow to develop or regenerate after change
- low nutrients levels and energy supply, low net primary productivity, low biomass, lack of decomposers
BELL influences vulnerability and resilience
Biodiversity = number of species / variety Extent = size Location = where it is (latitude, proximity to human population) Linkages = complexity of the food web
define biodiversity
the variety of all living things; the genetic information they contain and the ecosystems they form
define extent
refers to the size of a particular ecosystem
- ecosystems that are restricted to a relatively small area and have a disturbance are particularly vulnerable as they cannot relocate
define location
latitude, distance from the sea, proximity to human population
define linkages
(aka interdependence)
- the higher the interdependence, the higher an ecosystems ability to change
Characteristics of a resilient ecosystem
high: genetic and species biodiversity, ecosystem biodiversity, size of ecosystem, interdependence
low: duration and magnitude of stress, neighbouring human populations
Impacts due to human induced modifications
deforestation, overgrazing, mining, urbanisation
Stress and disturbances can be classified as:
natural / human induced
intentional / unintentional
gradual / catastrophic
HUGIT
heritage utility genetic diversity intrinsic value the need to allow natural chnage
heritage value
universal / national value for future generations (particularly traditional and cultural value)
example = uluru and the great barrier reef
utility value
either an existing or potential utility value (sources of food, medicine, chemicals, fibres)
- ecosystems also protect catchments, regulating temperature, recycle nutrients and have a role in human activities like tourism (monetary value)
maintenance of genetic diversity
greater resilience
diminished biodiversity puts ecosystems at risk
intrinsic value
inspirational, aesthetic and spiritual needs; contributing to emotional + spiritual wellbeing - particularly within indigenous communities
also the commodification of beauty
the need to allow natural change to occur
allowing the evolutionary process to continue. Natural disturbance and even human disturbance within ecosystems will allow for ecological succession and unique adaptation
Services that ecosystems provide
include land, water, vegetation and atmosphere into a flow of essential goods and services (clean air, water, food)
global economic value of all ecosystem services
$46 trillion, which is greater than the GDP of all nations combined
value of protecting land
protective land gives 100 times more value than converting it to some other use
coral reef value
greater than 1 trillion dollars annually
coastal wetland value
greater than 1 trillion dollars annually
management strategies: contemporary and traditional
agreement that ecosystems need to be managed throughout the world and there are two approaches to management:
traditional (aka indigenous approach)
contemporary
Traditional management
Stewardship: people have a responsibility to protect and nurture the land for the benefit of future generations (people currently living on the land are custodians / caretakers of the land)
Often traditional management is undertaken by indigenous ppls
Contemporary mangement
Prescription: the protection of a habitat, involving the prevention of human activity in that area
Conservation: planned use of natural resources in an efffort to reduce waste and environmental damage
Utilisation: replacement of an ecosystem with a manmade environment that is capable of generating a yield or income (agriculture, ski fields) these are sacrifice zones
Exploitation: use of an ecosystems resources with little regard for the ecological consequences
Management at a variety of scales
- local: local governments (cutting down trees, etc)
- regional: laws governing
- global: unesco
