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BIOL10010 Introductory Biology: Life's Complexity > 05. ECOLOGICAL COMMUNITIES > Flashcards

05. ECOLOGICAL COMMUNITIES Flashcards

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1
Q

Define community

A

grp of potentially interacting spp that live together in space and time (Magurran 2004)

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2
Q

How do we often define communities

A

by vegetation of area e.g. melb’s 3 biomes = plains, coastal, hills - defined by landscape ft

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3
Q

Why do ecological communities exist?

A

eco comms arisen bc interactions bw spp over time in response to environ cond/demands.

history of geog land mass → shapes climate/resources → shapes div of eco comms

e.g. tundra ecosystem occurs in coldest regions of world vs desert ecosystems occur in hottest

→ landscape + spp that habitate it = reflections of e/o

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4
Q

What key processes influence ecological communities?

A

comms:

  • selection
  • drift
  • diversification - X speciation
  • dispersal

analogous to ft of pops: selection, genetic drift, mutation, gene flow

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5
Q

Define selection in relation to ecological communities

A

selection = changes in comm structure caused by deterministic fitness (non-random) diff bw taxa i.e. what taxa is most fit for temp/rainfall/soil/fire regime etc.

also note: selection pressure = varies over space/time; is ongoing; is density-dep

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6
Q

Define drift in relation to ecological communities

A

drift = random changes in comm structure/abundance of diff taxa

neutral process bc X features = favoured

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7
Q

Define diversification in relation to ecological communities

A

dinc in taxonomic div of comm over time due to evol i.e. evol of new lineages from existing lineages

outcome = new genotypes, forms, varieties, sub-spp + spp

ST or LT

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8
Q

Diversification can happen quite rapidly when…

A

selection pressure = sufficiently lg + generational length = sufficiently short

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9
Q

Define dispersal in relation to ecological communities

A

mvmt of indiv from one place to another

can occur at any stage of life cycle

involves immig/emig + impact varies dep on source/reciever, size of mig grp, dir of mig (one/both ways), and dist (long dist or link local comms = metacomm)

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10
Q

What is a metacommunity

A

grp of local comms occupying set of habitat patches + linked by disp of multi potentially interacting spp (Leibold et al. 2004)

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11
Q

What is a species pool?

A

grp of spp capable of persisting in an area

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12
Q

What does Keith 2017 conclude about the influence of history on Australian vegetation?

A

Aus veg comrpised of spp pools = reflections of evol filters (water + nutrient availability), abiotic factors (temp + fire regimes) + biotic factors (comp pred)

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13
Q

Name five of Australia’s biomes

A
  • rainforest
  • savannah
  • heathlands/scrubs
  • semi-arid eucalypt woodlands - mallee land
  • freshwater wetlands
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14
Q

When was Australia’s warmest and wettest period?

A

late Palaeocene/early Eocene (50-60mya) - right before sep from Ant starts

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15
Q

When did the first arid climate arise in Australia?

A

late Miocene (7-12mya)

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16
Q

When did Australian contact with Asia start?

A

late Oligocene/early Miocene (18-25mya)

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17
Q

Since Australia’s seperation from Gondwana, what have been the overall climate trends?

A

cooler

drier → inc fire freq

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18
Q

When did major climate cycles (glaciation/inter-glaciation) start?

A

beginnign Pleistocene (2.58mya)

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19
Q

How has volcanism aided biological productivity in Australia

A

inc nutrient-density of soil → inc fertility

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20
Q

Outline the historical compositions of key Australian vegetation formations

A

Rainforest - G relic+ intrusive tropical

Heathlands - G autochthonus

Savannahs - G autochthonus + intrusive tropical

Tussock grasslands - intrusive cosmo

Alpine herbfields/shrubland - G autochthonus

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21
Q

What are dry-adapted traits called?

A

xeromorphic

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22
Q

What are fire-adapted traits called?

A

pyrophytic

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23
Q

What ecological processes have particularly influenced Australian plant communities?

A
  • selection - temp, aridity, fire, nutrients etc
  • diversification
  • dispersal - from G or Asia
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24
Q

What is alpha diversity?

A

measure of a local eco comm according to its richness (# diff spp), evenness (relative abundnace of spp w/in comm) or both

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25
Q

What is beta diversity?

A

extant of change in comm composition/degree of diff across region

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26
Q

Name two indexes used for measuring the level of diversity of an ecological community?

A

Shannon + Simpson

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27
Q

What are two factors to consider when measuring the diversity of an ecolical community?

A
  • detectability of spp - visibility can dep on life cycle stage/time of yr
  • taxonomy
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28
Q

What is the difference between geographic and environmental space?

A

geog = 2D

environ = sum of all factors that influ environ e.g. roughness, southness, rainfall etc i.e. conditions + resources

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29
Q

Outline the difference between the fundamental and realised niche

A

fund = idealised multidim hyperspace that encompasses range of cond/resources that enable spp to survive

realised = space actually occ by spp - smler bc factor in: comp, disperal lims, disturbance events, stochasticity → can cause local extinct that mean spp X persist w/in fund niche

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30
Q

What are environmental gradients?

A

factors that influ environ cond → impact what spp can thrive/persist

e.g. eco niche of terr plants driven by cover, aspect, solar radiation, temp

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31
Q

What is competitive exclusion?

A

when one spp dominates over others in LT due to comp for sames resources

e.g. Elaeocarpus dentatus abundnace = lower when Nothofagus present (Leathwick & Austin 2001)

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32
Q

What is resource partitioning?

A

when spp changes morphology (size/shape - char displacement) OR behaviour (nocturnal/diurnal) → dec comp

e.g. alloptatric pops of Hydrobia (mud snails) = similar sizes vs sympatric pops H. ulvae is consistantly larger than H. ventrosa (Knox et al.)

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33
Q

How does spatial and temporal variability allow for co-existence of competing species/populations?

A

carves out space/time for spp/pop to have excl access to resources

e.g. Sedum smalii thrive in shallow soil vs Minuartia uniflora prefer deeper soil (Begon et al. 2006) → habitat w variable soil depth will enable co-existance

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34
Q

Name two subjective methods of classifying community patterns in space

A
  • structure - according to height + density of veg
  • what spp dominates/present
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35
Q

What are the limitations of classifying communities subjectively?

A

each comm = unique + rarely fulfills all char of formal def

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36
Q

Outline two objective methods of classifying community patterns in space

A
  • data-based pattern analysis
    • assoc (what spp commonly occur together)
    • classif
    • ordination (what specific environ cond are assoc w certain spp) OR cluster graph??
  • mapping
    • classify spp
    • then model r/ship bw spp → predict across space (map)
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37
Q

Outline the different classifications of community interactions and give an example

A
  • mutualism (+/+) - hummingbird/dianthus (nectar/pollination)
  • comp for resources (-/-) - nothofagus/Elaeocarpus dentatus trees in nz (light)
  • predation + parasitism (+/-) - ladybird eats aphids
  • commensalism (+/0) - epiphytes
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38
Q

What is unique about parasites’ habitats?

A

host = alive → able to grow, respond + adapt

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39
Q

Example of protozoan parasite

A

malaria infects RBC

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40
Q

What form of organisms are most and least commonly parasitic?

A

most - opalinata, mesozoa, pentastomida

least - sarcodina, cnidaria, mollusca, chordata

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41
Q

Host species commonly…

A

have >1 parasite

mammals avg 8

birds avg 9

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42
Q

Even though parasites are commonly very small…

A

their totals abundance means they can have sig impact in eco comms

43
Q

Draw the parasitic life cycle

A

v

44
Q

Define predation through an ecological lense

A

consumer benefits at (mortal) cost to prey - e.g. incl herbivores/insectivorous plants

45
Q

Direct impacts of predation on populations

A
  • abundance of indiv
  • evol of pred/prey spp - adaptations (e.g. camo) + gene pool - consider the impact of koalas choosing euc leaves w high N content + lower toxic chems
  • distrib of spp
46
Q

Indirect impacts of predation on population

A
  • behaviour of prey
    • e.g. hiding - Grasshopper in CT - hiding from spiders → dec daily activity 18% + dec grass content of diet 70% → 42% → pop decl (Schmitz 1998)
  • spatial arrangement
    • e.g. birds of preferred prey size stay away from Sparrowhawk nests (Forsman et al. 2001)
47
Q

What is a keystone predator?

A

pred that plays such a sig role in eco comm that its absence would drastically change/end comm

48
Q

Compare the impact of intimidation on prey with direct consumption

A

intimid has just as strong impact of prey demographics as direct consumption (Preisser et al. 2005)

poss bc behavioural changes → reduce fitness → pop decl

49
Q

Consequences of introduced species herbivory on Australian vegetation

A
  • change veg composition + structure - height/density
    • inc cover
    • inc exotic weeds
  • dec plant spp richness

commonly bc grazing spp

50
Q

Predation is an _ species interaction

A

exploitative

51
Q

Describe the predator-prey cycle

A

Image 6

52
Q

Food webs are reflections of…

A

trophic r/ships bw orgs

53
Q

What are sub-webs?

A

food webs that incl difficult to detetect orgs i.e. parasites

54
Q

What is the purpose of a topological food web?

A

quantify # + distrib of trophic conn using data

55
Q

What are trophic cascades?

A

conseq of pred-prey rships that alter abundnace/biomass/prod of spp/functional gp/trophic lvl further down food chain

2 types:

  • top-down control = pred have lg influ on comm i.e. keystone pred e.g. sea otters → sea urchins → kelp
  • bottom-up control = prod/prey have lg influ on comm

can occur simul

56
Q

What do food webs do?

A

summarise tropic r/ships

57
Q

Across what scales can we study interspecific interactions?

A
  • temporal
  • geog
  • morphometric (body size)
58
Q

Outline two examples of interactions that differ on temporal scale

A
  • tumbling flower beetle x eudicot flower = earliest known insect poll of flower - 99mya (Cretaceous)
  • cane toad x sand goannas = novel pred-prey interactions → goannas harmed by bufotoxin → lower abundance in areas w CT (Feit et al. 2018) → trophic cascade bc inc abundnace goanna’s prey (Feit et al. 2018)
59
Q

Outline one example of an interaction that occurs on a geographic scale

A
  • bogong moth x mt pygmy possom
  • BM larval stage in plains NSW/QLD → mig >1000km to cool caves of VIC alpine zone → poll plants along way + imp food source for MPP
  • droughts in NSW/QLD → decl abundnace BM + light poll in VIC alpine zone = disrupting mig → trophic effect bc worsenign MPP endangerment
60
Q

Outline two examples of an interaction that occurs on a morphometric scale

A
  • humpback whale x antarctic krill (60mm/2g)
  • fur seal x antarctic krill
61
Q

Which scenario of climate change and chlorophyll concentration is best for krill habitat?

A

RCP2.6 (Hill et al. 2013)

62
Q

Which scenario of climate change and chlorophyll concentration is worst for krill habitat?

A

RCP8.5 bc relative gross habitat growth potential is lowest at all lvls of chlorophyll concentration than RCP4.5 and RCP2.6 (Hill et al. 2013)

63
Q

Antarctic krill is a _ species in the antarctic area

A

keystone

64
Q

Why is chlorophyll important for krill?

A

krill feed on phytoplankton, which need chlorophyll to photosynthesise

65
Q

Simple trophic web for antarctic community

A

sun → phytoplankton → krill → humpback whales + fur seals

66
Q

Mutualistic relationships are the result of…

A

co-evolution

67
Q

Define co-evolution

A

when unrelated orgs evolve in a co-ord manner

68
Q

Types of mutualistic relationships

A

specific = bw 2 spp

diffuse = bw multi spp

69
Q

Outline mycorrhizae

A
  • fungi col roots of plants
  • occurs in ~80% plant spp
  • mutualistic r/ship bw plants + fungi
    • F supply H20 + nutrients (e.g. N + P)
    • P supply PT prods (e.g. sugars)
  • results
    • P inc resistance to pathogs
    • creates mycorrhizal networks → transmit H20, nutrients + info (via biochem signals) bw plants → changes P behaviour/function = root/shoot growth/PT rate/foliar nutrition/defense response
70
Q

What do mycorrhizal networks do?

A

transmit H20, nutrients + info (via biochem signals) bw plants

→ changes P behaviour/function = root/shoot growth/PT rate/foliar nutrition/defense response

e.g. aphid under attack from beetle sends signal to nearby P → release chem that repels beetles + attracts parasitic wasp to attack beetle

71
Q

Outline an example of an animal-plant mutualistic relationship

A
  • flying foxes x multi spp plants
  • FF feed on nectar/blossoms/fruit of many spp plant → imp poll across Aus + Pac
  • decl FF pop (driven into more uban environ) → neg impact on multi spp in non-urban plant comms
72
Q

Outline an example of an animal-algal mutualistic relationship

A
  • coral x zooxanthelle
  • zooxanthelle live w/in coral pollups = dep on coral for habitat
  • coral depend on zooxanthelle as nutrient source
73
Q

Antagonistic coevolution can be compared to…

A

an evolutionary arms race

74
Q

Outline an example of antagonistic coevolution

A
  • toxic newts (prey) x garter snakes (pred)
  • GS evolved inc resistance to newts’ tetrodotoxin → pressure on newts to inc toxin
  • BUT res X geog uniform - variation in res = driven by selection (Brodie et al. 2002)
75
Q

Outline two examples of how a disruptions to an interspecific interaction impacts the broader ecological community.

A
  • potoroos x truffles x mycorrhizae
    • sml mammals (e.g. long-nosed potoroo) feeds on truffles (subterr fruiting bodies of myc fungi) → disp spores → ‘ecosystem engineers’
    • decl pop of sml native mammals since Eur col → dec truffle abundance → threatens multi plant spp bc X germinate/survive w/out mycorrhizal partner
  • coral x zooxanthelle
    • heat stress → coral expels zooxanthelle → ‘bleached appearance’
    • w/out zooxanthelle coral starves + dies
    • bleaching events corr w heat waves - CC
76
Q

Explain how the disruption of the mutualistic relationship between coral and zooxanthelle impacts other components of reef communities.

A

inc ocean temps/freq of heat waves → inc coral heat stress → expel zooxanthelle → ‘bleached’ appearance + starve → die
→reef spp lose habitat
→ decl freq corallivore fish bc decl food source (living coral)
→ inc freq excavator fish bc inc food source (coral skeleton)

(Stuart-Smith et al. 2016)

77
Q

What types of community change are important over short time scales (years-centuries)?

A

selection, disp, drift

(evol div req longer time)

78
Q

Define and outline orderly succession and compare to stylised succession

A

nat changes to comp + structure of an eco comm over time

(implies replacement of one comm by another)

i.e. devt of one spp in area makes environ more suitable for diff spp to thrive → dominate

more realistic than total ‘replacement’ = ‘stylised succession’ = devt of diff veg comm in one space

79
Q

Mountain ash is a _ species because…

A

keystone bc habitat for animals + responsible for storing lg amts C → imp for nutrient cycling

80
Q

Decline in mountain ash

A

pop has 1/2 since 1997

81
Q

Mechanisms to conserve mountain ash trees

A

maintain ~200m buffer zones of unlogged forest around trees → protect from:

  • edge effects
  • changes in microclimate
  • impacts of nearby logging
  • fire
  • disease
82
Q

How does disturbance impact ecological communities’ composition and structure?

A

influences selection, dispersal and drift.

over long time periods can even influence evol div bc spp emerge that are better adapted to specific disturbance regimes

83
Q

Define and outline the significance of disturbance regime

A

dist reg = LT pattern of dist across geog area. measured by freq, size + intensity → determien prob/nature of next dist

est using historical data

84
Q

Why are changes to disturbance regimes considered a threatening process?

A

changes to DR alter rate/nature of selection, dispersal and drift → rapidly change comp of eco comm - main concern = biodiv loss

e.g. too freq burning → decl mt ash + inc shrub forests = cascade bc habitat loss for animals → extinction/endangerment

85
Q

Can a native species be considered invasive? If so, why?

A

e.g. COTS

Yes it is considered a pest because it is colonising regions beyond its natural habitat and abundance beyond its natural capacity as a direct result of human activity (agriculture fertilisers - floods - pollute ocean water - provide nutrients for COTS - inc COTS abundance - outbreak spreads bc currents carry larvae sth)

86
Q

Cats and foxes are considered _ species in Australia

A

feral

(cats kill >1mil animals/day)

87
Q

Factors that influence a species’ vulnerability to predation by feral species

A
  • habitat
    • birds in grasslands/shrubland/open forest/coastal habitats = more likely to be preyed upon by cats than in RF/freshwater areas (Woinarksi et al 2017)
  • body size
    • birds w body mass 1-3g = morely likely to be preyed upon by cats than 5g (Woinarksi et al 2017)
88
Q

List feral herbivores in Australia and outline their impact on the landscape

A
  • rabbits
  • horses
  • camel
  • deer
  • goats

→ change veg thru grazing + trampling → cause soil erosion + damage waterways

89
Q

How can we manage the threat COTS pose to the GBR?

A

improve ag reg + water qual bc fertilisers polluting ocean -> stim COTS pop explosion -> devo impact on coral abundnace + ecosystem it supports bc keystone spp

90
Q

Benefits and limitations of conservation of a single species

A

benefits:

  • tangible target
  • conceptually simple
  • charismatic spp captures general pub’s attn → spark convos abt conserv

limitations:

  • expensive e.g. captive breeding = $mils/yr
  • risky
  • futile if spp has X viable habitat
91
Q

Benefits and limitations of conservation of ecological communities

A

benefits:

  • target multi spp simult → more eff use of $/resources
  • comprehensive/non-discrim - accounts for interspecfic interactions bc benefits all spp, X just cute/cuddly ones

limitations:

  • req land/resource protection
  • comm often subj to multi threat simult → more complex
92
Q

Describe the Banksia Woodlands of the Swan Coastal Plain and outline the threats the community is facing

A

key ft:

  • listed endang 2016
  • SW WA biodiv hotspot - 600+ plant + animal spp incl 20+ threatened spp

threats

  • habitat loss/frag bc ubant devt/ag
  • mining
  • dieback bc intro fungal pathog phytophthora
  • invasive spp
  • CC - inc temp + altered rain patterns

implications:

  • honey possum = endemic to SW WA = threatened bc habitat loss
93
Q

What threats does the Baw baw frog face and what actions have been taken to protect them?

A

CC + introduced pathogens

captive breeding program

94
Q

What is the EPBC Act and what does it stand for?

A

‘environ protection and biodiv conserv’ act = Aus’ fed conserv legislation → framework to manage ‘matters of national environ sig’ (MNES)

1999

95
Q

What are the different types of MNES?

A
  • threatened spp
  • mig spp
  • threatened eco comms
96
Q

Has the EPBC Act been effective?

A

widely regarded as ineff bc only intervened handful of times

overall environ = still in st of decl + spp = under inc threat

samuel review underway → recs intro new nat standards + intro ind environ regulating body

97
Q

Describe the Australian Threatened Species Index (2019) trends for birds and mammals 1985-2016

A
  • birds = steady decl 1985-2016
  • mammals = stabilised 1985-96, improved 1996-98, declined again and stabilised 1999-2016
98
Q

Describe two examples of threatened ecological communities threat posed

A

giant kelp forests of south-east Australia

  • favours cold water
  • endangered 2012
  • vertical habitat for other spp (e.g. southern handfish = endangered spp)
  • threats = CC (inc water temp + extreme storms) + inc nutrient availability

lowland RF of subtrop Aus

  • critically endangered 2011
  • tall closed forest
  • biodiv hotspot
  • prev one of Aus’ lgst RF but contracted sig bc clearing (timber, ag) + urban devt
  • now highly fragmented
  • grey headed flying fox pop decl dramatically
99
Q

Urban development is creating…

A

ecological deserts

100
Q

Tussock grass overgrowth and disturbance regimes

A

space bw tussock grass allows for other spp to grow

→ changing dist regs means tussock may overgrow → dec biodiv

solution = regular burning + targeted grazing

101
Q

Example of why managing threats to ecological communities is difficult but important

A

Melb Strategic Assessment 2009 aimed to offset Vic Volcanic planis temp grasslands habitat loss but failed bc delays aquiring land
urgency = inc $ land + dec soil qual

102
Q

Resource partitioning averts the problem of…

A

comp excl

103
Q

Describe four types of resource partitioning

A
  • habitat
  • activity
  • diet - diff dietary niches
  • diet - gen vs spec

BIOL10010 Introductory Biology: Life's Complexity (8 decks)

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