06. ECOSYSTEMS IN THE ANTHROPOCENE Flashcards
What was the significance of the Victorian government’s? 1988 Flora and Fauna Guarantee Act?
legal recog of imp biodiv for human + planet survival
What were the outcomes of the of the 1992 Earth summit?
- UN Convention to combat desertif
- UNFCCC
- Conv on Biological Div 1992
What were the outcomes of the Convention on Biological Diversity?
- signed by 173st
- req all sigs to devt nat biodiv strats + action plans - report updates every 5yrs
- nagoya protocol (fair access to genetic resources)
- cartegena protocol (GMOs)
- strat plan for biodiv 2010 = Aichi targets (2011-20)
- SDGs (2015-)
What did Aichi Target 12 promise?
- prev extinct of known threatened spp
- improve/sus of spp most in decl by 2020
Define ecosystem services
benefits humans derive from the environment + its resources
e.g.
- 2bn ppl rely on wood as primary E source
- nat pollinators contrib $560bn/yr to gl econ
(IPBES Global Assessment - Lecture 31, BIOL10010)
What are the 4 categories of ecosystem services?
- cultural e.g. recreational
- provisioning e.g. food
- regulating e.g. pollination, erosion regulation
- supporting e.g. nutrient cycling, PT
Key implications of IPBES Global Assessment
overall 50 yr global downward trend for regularory ecost services (a/t varying levels of sci certainty)
Evidence of rapid species extinction in the Anthropocene
- 20-25% assessed spp = at sig risk of extinct (IUCN Red List)
- =1mil spp
Animal groups in order of extinction risk
- amphibians
- mammals
- birds
- reptiles
- fishes
Global drivers of species extinction
v
Efficacy of current conservation action
NOT EFFECTIVE
- 25-25% assessed spp = at sig risk of extinct (IUCN Red List)
- =1mil spp
NEED TRANFORMATIVE CHANGE
- =1mil spp
What threat does biodiversity loss pose to the global economy?
biodiv loss = #3 in list of Top 10 Global Risks by Severity (World Econ Forum 2022)
5/top10 = environmental
Define the anthropocene
Refers to the geological epoch in which human activities are the primary influence on the environment.
preceded by holocene = prime environ for humans to thrive + expand
What are the biological indicators of the Anthropocene?
- inc soil N + P content bc fertilisers
- rapid inc in atm CO2 + CH4 conc
- dram inc in spp extinct
- deforest for ag, logging + urban devt
Identify the key biological and earth system processes that maintain stable climactic, atmospheric and environmental conditions on Earth
must remain w/in hard planetary boundaries for
- CC (C conc of atm)
- biosphere integ (biodiv)
- land-system change (defor)
⇒ Planetary Boundary Assessment 2015 = 4/9 processes already exceeded safe limit (Steffen et al. 2015)
Describe the carbon cycle and explain its link to anthropogenic climate change
land:
- plants absorb CO2 from atm during PT
- prod of PT = stored as plant biomass = C sink
- animals/bact/microbes eat plants + release C into atm thru resp
- plant biomass → soil biomass as plants drop leaves/die → embedded in sediment over time = becomes rock/ff
ocean:
- phytoplankton PT → create sugars from CO2 in air
- marine orgs respire/decompose → release C02 into water (some stored in ocean sediment)
- carbon transferred bw ocean surface, deep ocean + reactive sediments (C sinks) → released into atm via air-sea gas exchange
Outline how much carbon is in each major carbon reservoir and how much moves between them
per yr - Gt
flux:
- PT 120Gt/yr
- resp 60 Gt/yr
- microbial resp/decomp 60Gt/yr
- air-sea gas exchange 90Gt/yr each way
reservoirs:
- biomass 600Gt
- soils 1500Gt
- rock 100mil Gt
- FF 5-10K Gt
- ocean surface 1000Gt
- reactive sediments 6K Gt
- deep ocean 37K Gt
- sediments 150Gt
When do fossil fuels accumulate?
when dead plant matter accumulates faster than it can decay → layers of orgo C = FF
What are two ways human are changing the carbon cycle
added deforestion + burning FF → losing C sinks + inc amt C02 released into atm
= contrib 9 extra Gt C per yr into atm → 1/2 removed by fast C cycle but rest remains in atm
Explain how the anthropogenic alterations to the carbon cycle is causing global warming
inc inbalance bw carbon emissions + capacity of natural fast C cycle to remove C from atm → atm C02 conc x2 since pre-ind era (Met Office, 2021) → human enhanced GHG effect → gl warming
Outline the major impacts of anthropogenic climate change on ecosystems
atm:
- inc gl temps
- inc freq of extreme weather events
ocean:
- acidification
- inc H20 temp
- sea lvl rise
land:
- some inc plant growth (a/t lim)
- inc fire freq
- melting permafrost
Does the overall amount of carbon in the plant system change?
no but it does flow from diff reservoirs w/in system
Why is the formation of rock and fossil fuels not considered to be part of the ‘fast’ carbon cycle?
occurs over geological time scales
Explain the Intergovernmental Panel on Climate Change (IPCC)
Roles:
- assess + summarise research into drivers of CC
- assess threats posed by CC + how to reduce
Importance:
- prov transparent + reliable info
- central auth on CC action
- 195 members - diverse perspectives on CC
Outline the different climate scenarios presented by the IPCC’s AR6
Low emissions:
- SSP1-1.9 + SSP1-2.6
- emissions peak now
- 1.5-C warming
Intermediate emissions
- follows current trend
- SSP2-4.5
- emissions peak 2050
- 2.7 warming by 2100
High emissions
- SSP5-8.5 + SSP3-7.0 (’biz as usual’)
- emissions cont grow
- 4-5C warming by 2100
What are the key differences between implications of 1.5 and 2 degrees of warming?
- coral reefs - cover decl 70-90% @ 1.5C → non-existent @ 2C
- forest - inc severe forest biomass decl + inc defor/wildfires
- biodiv/ecosystems - 6% insects, 8% plants + 4% verts habitat range dec 50% @ 1.5C → 18/16/8% @ 2C
What proportion of animals in Australia are endemic?
- 87% mammals
- 93% reptiles
- 94% frogs
(Lecture 33, BIOL10010)
Australia is one of 17 _ nations
megadiverse (Lecture 33, BIOL10010)
Outline scope of species extinction in Australia
- 110 extinct since Eur col
- 1800sp = high risk
- 35% global mammal extinctinction
- 50% decl in avg bird abundance since 1985
- Aus = 2nd highest rate of biodiv loss (Waldron et al. 2013)
(Lecture 33, BIOL10010)
Australia is the ‘extinction capital’ for what taxonomic group?
mammals
‘Evil quartet/sextet’
=proximal (cf fundamental) drivers of extinct
- invasive intro spp e.g. cats kill 1.7bn native animals in Aus/yr (Lecture 33, BIOL10010)
- habitat loss/frag
- over exploitation e.g. TAS tiger
- co-extinctions
coined by Diamond (1989)
two novel factors:
- CC e.g. Gilbert’s poteroo = sml pop + range → 1 fire could cause extinct.
- disease
Ecosystems are fundamentally comprised of…
interactions bw living + non-living components
List some characteristic interactions in Australian ecosystems
- ice/snow x snow gums
- fire x euc forests
- sitting water x wetland spp
- high rain x RF spp
- low rain x desert spp