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BIOL10010: life's complexity > communities and ecosystems > Flashcards

communities and ecosystems Flashcards

1
Q

define ecological community

A

a community is a group of potentially interacting species that occur together in space and time

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2
Q

how do communities delineate

A

Communities delineated in different ways
Taxonomic affinity: does not interact with one another
Guild: e.g. all dependant on tree hollows for breeding
Functional groups: roles they play within their community

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3
Q

key processes of ecological communities

A

The species present in a community can be viewed as the outcome of a set of filters

E.g. a regional species pool can have dispersal limits - the outcome of evolution and biogeography
Abiotic filter - the fundamental niches of the species control the abiotic filter through environmental limits
Biotic filter - the realised niches of the species control the biotic filter through species interactions

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4
Q

what are ecological communities influenced by?

A

Regional species pool
Dispersal
Environment
Species interactions

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5
Q

ecological communities are constantly changing

A

Communities are never static
Changes due to changes in
- regional species pool
- dispersal
- environment
- species interactions

Can also all be contributed to chance
Evolution and extinction
Dispersal success and failure
Occurrence of disturbance

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6
Q

changes in the species pool

A
  • Evolution and diversification
  • Extinction
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7
Q

changes in dispersal

A
  • Species introduced by people are a clear example of changing dispersal
  • But dispersal occurs naturally too (often haphazardly)

Environments disturbances:
- Discrete events that change resource availability and/or the physical environment
- Natural: bushfires, floods, cyclones, volcanoes, disease
- Human-generated: habitat clearing, pollution

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8
Q

Species interactions

A

Invasive species can have large impacts through their species interactions

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9
Q

Succession in vegetation communities

A
  • Succession: natural changes in the composition and structure of an ecological community over time
  • The replacement of one community by another
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10
Q

Defining vegetation communities by structure

A
  • Tree height
  • Crown - the tallest layer of foliage
  • Crown cover - the proportion of ground covered by the crown (0-100%)
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11
Q

Communities can differ based on

A
  • Their species (and the relative abundance of the species)
  • The sizes and layers of vegetation (for plant communities)
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12
Q

define species diversity

A

the composition of a local ecological community with respect to its richness (number of species), evenness (distribution of abundances of the species), or both

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13
Q

Species diversity → stability and productivity

A

↑ species diversity
↑ trait diversity
↑ functional diversity
↑ redundancy and opportunity

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14
Q

Functional diversity

A

Greater diversity
Resource consumption, transformation and provision
Physical environment
Chemical environment
Interactions among species
Thus often see links between species diversity and functional diversity

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15
Q

Primary succession

A

-Occurs when organisms colonized bare rocks introduced by retreating glaciers or volcanic eruptions

  • Rock lacks both soil and life forms
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15
Q

Pioneer species

A

hardy organisms that can thrive in harsh conditions
E.g. lichen: symbiotic organisms comprised of a fungus and algae or cyanobacteria

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16
Q

Climax community

A

a community with a relatively stable species composition

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17
Q

Secondary succession

A
  • Occurs when organisms recolonise a habitat that was cleared by a disturbance
  • The climax community regrown is very different from the first climax community
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18
Q

Communities can differ based on

A
  • Their species (and the relative abundance of the species)
  • The sizes and layers of vegetation (for plant communities)
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19
Q

Defining vegetation communities by structure

A
  • Tree height
  • Crown - the tallest layer of foliage
  • Crown cover - the proportion of ground covered by the crown (0-100%)
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20
Q

Species diversity

A

the composition of a local ecological community with respect to its richness (number of species), evenness (distribution of abundances of the species), or both

Species diversity → stability and productivity

↑ species diversity
↑ trait diversity
↑ functional diversity
↑ redundancy and opportunity

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21
Q

Functional diversity

A

Greater diversity
- Resource consumption, transformation and provision
- Physical environment
- Chemical environment
- Interactions among species

Thus often see links between species diversity and functional diversity

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22
Q

Communities and functional diversity

A

Species diversity doesn’t influence community dynamics directly, but species diversity can increase functional diversity

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23
Q

What is an ecosystem?

A
  • Sum of all interactions between biotic and abiotic factors in the environment
  • A biological community of interacting organisms and their physical environment
24
Q

Terrestrial biomes

A

Tundra: low temperature + low rainfall
Desert: high temperature + low rainfall
Rainforest: high temperature + high rainfall

25
Q

Energy and nutrients in ecosystems

A
  • Physical and chemical environment
  • Key factors are energy and nutrients
  • Organisms need to either make their own energy (autotrophs), or feed on each other (heterotrophs)
  • Organisms need to obtain key nutrients to survive
26
Q

Trophic Levels

A

Species within an ecosystem are connected with each other through a network of feeding relationships - food web

27
Q

Food chains:

A
  • Is a sequence of organisms eating one another, from producers to consumers, along which energy flows in an ecosystem
  • Is a portion of a food web, most commonly a simple sequence of prey species and the predators that consume them
  • Usually has 3-4 trohpic levels
28
Q

Bottom-up limitation

A

ecosystems are primarily regulated by the availability of nutrients and energy

29
Q

Food webs:

A
  • A group of organisms in an ecosystem with trophic or energetic connections
  • Each level has species with similar ways of getting energy
  • Includes multiple interaction or interlinking food chains
  • Indicates which organisms are the consumers (predators), primary consumers (herbivores) and which are primary producers (vegetation)
30
Q

Top-down limitation

A

ecosystems are primarily regulated by consumption pressure from higher trophic levels

31
Q

Biogeochemical cycling

A

recycling of inorganic material between living organisms and their environment

32
Q

Trophic cascades

A
  • The rate of consumption at one trophic level results in a change in species abundance or composition at lower trophic levels
  • Often associated with changes in abundance of large carnivores or apex predators in an ecosystem
33
Q

Nutrient cycling

A

The phosphorus cycle ​​Weathering of Rocks: Phosphorus originates from the weathering of phosphate rocks, releasing phosphate ions (PO₄³⁻) into the soil and water

Absorption by Plants: Plants absorb phosphate from the soil through their roots, incorporating it into organic molecules like nucleic acids and ATP

Consumption by Animals: Animals obtain phosphorus by eating plants or other animals, using it for growth, energy transfer, and cellular functions

Decomposition: When plants and animals die, decomposers (bacteria and fungi) break down their organic matter, returning phosphorus to the soil in the form of phosphate

Sedimentation: Over time, some phosphorus is washed from soil to bodies of water, where it can settle in sediments. Eventually, geological processes may uplift these sediments to form new phosphate rock, restarting the cycle

34
Q

Nitrogen cycle

A
  • Involves the movement of nitrogen atoms between biotic and abiotic components in the ecosystem
  • Mostly stored in the atmosphere as a gas
  • Nitrogen is only converted into a usable form through nitrogen fixation via other organisms
35
Q

Nitrogen fixation

A

assimilation of nitrogen gas into organic compounds by microorganisms
Once converted into ammonia, plants can convert it into proteins

36
Q

Sulfur cycle

A

Water cycle:
Residence time: amount of time water remains in a particular reservoir

37
Q

Biodiversity Loss

A

Biodiversity loss is the process of cumulative species extinctions leading to changes in ecosystems

Biodiversity and nature underpin all aspects of life, but its capacity to do so is declining

Causes
Human-caused drivers
Reduction in number and size of species populations
Species extinction
Ecosystem changes

38
Q

Biodiversity Recovery

A

Protected area management
- Protected areas are a key action to slow biodiversity loss → reduce habitat loss
- Can be the last place some species are found in the wild
- Not a panacea: other drivers need to be addressed too

Restoration actions
- removing/reducing extinction drivers to return to a more natural state
- revegetation
- invasive species removal
- re-establishing ecosystem processes (e.g. fire)

Intensive threatened species management
- Intensive threatened species managementIntensive threatened species management in captivity has an important role
- Breed up individuals to release back into the wild and raise public awareness

39
Q

Extinction vortex

A

a circular chain of events that build on one another to further decrease population size, leading to extinction

40
Q

Worldviews

A
  • Worldview: a concept of the world held by an individual or a group
  • “Western” worldview is dominated by a divide between Nature and Culture
  • nature-culture dualism
  • “Indigenous” worldview is one in which people are embedded in the world around them. - There is no divide between “nature” and culture
  • This worldview considers the environment along a continuum”
41
Q

Caring for Country

A
  • Caring for country embodies set stewardship values for land and sea environments which are deeply embedded in Aboriginal culture
  • Responsibility for and the inherent right to manage one’s Country in a way that is ecologically, socially, culturally and economically sustainable
  • using resources
  • the spirit and future generations
  • health, education and economy
42
Q

Managing country - cultural burning

A

Burning practices developed by Aboriginal people to enhance the health of the land and its people
Intimate and reflexive - boots on the ground
Performed at the right time for the right purpose
Cultural burning can include:
- Burning or prevention of burning of Country for the health of particular plants and animals
- Patch burning to create different fire intervals across the landscape or it could be used for fuel and hazard reduction
- Burning to gain better access to Country, to clean up important pathways, maintain cultural responsibilities and as part of culture heritage management
- It is ceremony to welcome people to Country
- Or it could be as simple as a campfire around which people gather to share, learn and celebrate

43
Q

Tropical savanna

A
  • Most fire-prone environment on Earth (found either side of the equator where there is a prolonged seasonal dry period, but where biomass production is high
  • Currently, most of Australia’s tropical savannas burn late in the dry-season, when fuel loads are high and dry and when lightning begins to strike
44
Q

Tropical savanna climate

A
  • Warm tropical climate
    6-7 month long dry season
  • Intense 5 month wet season
    1 month “build up” at the end of the dry season
  • dry lighting strikes
45
Q

Late dry season wildfires

A
  • Unburnt fuel accumulated through the dry season to the build up
  • Dry lightning strikes ignite huge, hot and canopy destroying fires
  • Carbon released into the atmosphere contributes ca.3% of Australia’s carbon emissions
46
Q

Indigenous cultural burning

A
  • Indigenous burning aims to target small areas early in the dry-season, while fuel load are low and still moist - fires can be controlled and new growth over the next months attracts animals
  • This is a highly managed and sophisticated management regime based on strict laws (kinship and cosmology)
  • Has a big knock on effects for biodiversity (landscape heterogeneity) and ecosystem health
47
Q

Ecological disturbances: events that influence the makeup of an ecosystem

A

Vegetation
Climate
Ignition

48
Q

Indigenous fire management (cultural burning)

A
  • Is intimate and reflexive to local settings - requires a “feet on the ground” relationship with country
  • Is performed under strict cosmological and kinship protocols for a range of reasons: spiritual, ritual, pragmetic, economix
    The net effect is:
  • reduced landscape fuel loads
  • reduced vertical connectivity of fuels
  • protection of fire sensitive ecosystems
  • connection to country and improved indigenous lives and livelihoods
49
Q

The Anthropocene

A

Characterised by:
- Biodiversity loss
- Changing land use
- Increase in agriculture, GHGs in atmosphere, use of technology

50
Q

Key impacts of the Anthropocene

A
  • Upsetting the balance of biogeochemical cycles
  • Changes to the composition of the atmosphere
  • Loss of biological diversity
51
Q

Upsetting the biogeochemical balance

A

Key changes:
- Combustion of fuels to industry/home:Combustion of fossil fuels adds new pathway for carbon dioxide release to atmosphere
- Photosynthesis: Land clearing means that there is less vegetation, absorbing less carbon dioxide
- Fossil fuels (oil, gas, coal): Extraction of slow-moving, long-term reservoir of carbon

Impacts:
- CO2 in the atmosphere: More CO2 in the atmosphere increases the greenhouse effect, causing global warming
- Dissovled CO2: Increasing dissolved CO2 increases ocean acidity, affecting marine life
- Feedback loops accelerate changes eg. as oceans warm the capacity to dissolve CO2 decreases

52
Q

Habitat fragmentation results in

A

Population isolation
Habitat loss
Biodiversity reduction
Edge effects

53
Q

Edge effects

A

changes that occur at transitional regions between habitats

54
Q

Ecosystem services and Nature-Based Solutions

A

Ecosystem services
- Conditions and processes through which natural ecosystems and the species that make them up, sustain and fulfil human life whether directly or indirectly
- Encompass goods, services and aesthetic/cultural benefits

  • Water and air purification
  • Natural resources (forage - seafood)
  • Maintenance of soil fertility
  • Pollination
  • Provision of recreational opportunities
  • Carbon cycling
  • Prevention of flooding, erosion
55
Q

Sustainability

A

conserving or enhancing ecosystems so as to benefit from specific ecosystem goods and services without compromising others

55
Q

Nature based solutions

A

“actions to protect, sustainably manage, and restore natural and modified ecosystems that address societal challenges effectively and adaptively, simultaneously benefitting people and nature.”

56
Q

climate change adaptation

A

a variety of actions that are meant to reduce or compensate for or adapt to the adverse impacts that arise from changes in the Earth’s climate

57
Q

climate change mitigation

A

action or changes in societal behaviour taken to reduce or eliminate greenhouse (GHG) emissions and/or to remove GHGs from the atmosphere to prevent significant adverse climate effects

BIOL10010: life's complexity (4 decks)

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