Climate and Life on Earth V: Global change - biodiversity in the Anthropocene 2 Flashcards
Describe the mutli-level loss of biodiversity
- species-level
- population-level
- ecosystem-level
Describe species-level loss of biodiversity
global and local extinctions
Describe population-level loss of biodiversity
declines and extinction
Describe ecosystem-level loss of biodiversity
loss of wilderness and biotic homogenization
Describe the global rate of species extinction
10-100x higher than average rate over the past 10 million years, and is accelerating
Describe declines in abundance of mammals, birds, reptiles, amphibians and fish since 1970s
- 60%
- 16,704 populations
- representing 4,005 species
- 23% in the Nearctic
- 89% in the Neotropics
What is Biodiversity Intactness Index [BII]
= average abundance of originally present species across a broad range of species, relative to abundance in an undisturbed habitat
Describe BII
- translucent bars indicate the corresponding relative biodiversity values if novel species are treated as equivalent to those originally present
- numbers can surpass 100% because gains may outnumber losses)
List some ways of capturing biodiversity loss
- ecosystem extent and condition
- species extinction risk
- ecological communities
- biomass and species abundance
- nature for indigenous peoples and local communities
Describe ecosystem extent and conditions
declination relative to earliest estimated states (currently 47%)
Describe species extinction risk
25% in most animal and plant groups studied
Describe ecological communities
- biotic integrity
- declined by 23% average in terrestrial communities
biotic integrity
the abundance of naturally-present species
Describe biomass and species abundance
- global biomass of wild mammals fallen by 82%
- vertebrate abundance declined rapidly since 1970
Describe nature for indigenous peoples and local communities
72% of indicators show ongoing deterioration of important cultural elements
List some direct drivers of decline
- land/sea use change
- direct exploitation
- climate change
- pollution
- invasive alien species
List some indirect drivers of decline (values and behaviours)
- demographic and sociocultural
- economic and technological
- institutions and governance
- conflicts and epidemics
What is the biggest driver of decline
- habitat degradation/loss
- commodity-driven deforestation in the tropics
Describe deforestation
- 50% Earth’s species live in tropical forests
- ~9 million hectares forest lost / year
Describe the indirect effects of deforestation
- climate change: 13% of total GHG emissions
- loss of agricultural productivity: triggers major shifts in rainfall and increased temperatures worldwide
- increased conversion of forest to agriculture to compensate
Describe the effects of increasing temperatures in the tropics
- generates large upward-moving air masses
- cause teleconnections that flow outward
teleconnections
ripples in the upper atmosphere
List some drivers of tropical deforestation
- industrial animal agriculture is main driver
- beef > soy (for fodder) > palm oil > timber > paper products
- beef = >67% deforestation
List some ‘forest risk’ commodities
palm oil, soya, beef, leather, timber, and pulp and paper.
Describe fishing
- c. 100 mt of animal biomass harvested from the ocean each year
- c. 6Bn tonnes of fish and invertebrates have been taken from the world’s oceans since 1950
- 75% of the major marine fish stocks currently depleted, or overexploited
- 70,000 reported industrial fishing vessels cover >55% of the oceans
- smaller fisheries involve > 100 Mn people
- huge population declines, but few extinctions so far (except in reefs)
Define climate change
the large-scale, long-term shift in the planet’s weather patterns or average temperatures
Give some evidence for climate change
- higher global air and sea temperatures
- changing patterns of rainfall
- retreating glaciers
- declining sea ice in the Artic
- declining ice sheets in Greenland and Antarctic
- sea level rise
- increased frequency and intensity of extreme events
- changes in nature: timing of life cycle events and shifts in ranges
Describe climate change
- since 1900, global average surface temperature has increased by 1 °C (2019 average: 1.11 +/-0.1 °C, Met Office)
- since 2000, 18 of 19 hottest years recorded since 1850 have occurred
- since 1900, sea levels have risen by c.10 cm around UK and c.19 cm globally, with the rate of sea-level rise increasing in recent decades
- predicted extinction risks from climate change accelerate with global temperature rise
List some causes of climate change
- anthropogenic
- non-anthropogenic, natural
Describe some anthropogenic factors causing climate change
- increased concentration of GHGs
- pollution: ozone and aerosols
- land-use change (direct impacts on reflectance)
Describe some non-anthropogenic factors causing climate change
- El Niño (release of heat from Pacific ocean)
- changes in Earth’s orbit (inc. insolation)
- sun spots (inc. insolation)
- volcanic activity (inc. re-radiation)
When the environment changes, organisms either
- change behaviour (e.g. in phenology – breed earlier)
- move (e.g. niche tracking – head north, move upslope)
- adapt (e.g. change phenotype)
- go extinct…
Describe species changing behaviour in response to climate change
- since ‘60s, many European and N American bird species breeding 8-10 days earlier
- since 1970, 70% California butterfly species have advanced first flight date by 24 days
Describe species movement in response to climate change
- since 1972, >50% European birds, butterflies & dragonflies shifted ranges 20-240 km north
- colonisation of temperate zone with subtropical flora & fauna
- bird range and tree lines shifting ranges upslope (Andes, Himalayas)
Why do species go extinct under climate change?
- nowhere to go: habitat fragmentation, isolated on mountain tops
- spatial and temporal mismatches: different spp. change or move at different rates; asynchronies between predators and prey, etc
- species enter range of novel pathogens or predators
- rate of environmental change faster than rate of evolutionary change
Discuss some extinctions linked to climate change
- mountain restricted species
Discuss a mountain restricted species linked to climate change
harlequin frogs (67% species extinct)
Describe coral reef extinction
- coral reefs bleach (increased sea surface temp.)
- 16% extinct species during 97-98 el Niño
- 95% of Great Barrier Reef surveyed with >30% bleaching during 2016-2017 el Niño (as yet unknown impact on extinction)
around … of population declines driven by climate change alone
7%
Biggest biodiversity impacts come from
combined effects of climate and land use change
RCP =
relative concentration pathways (emissions scenarios used by the IPCC)
Predicted extinction risks from climate change
accelerate with global temperature rise
Describe the governmental action to tackle climate change
- decarbonize
- scale-up conservation and restoration of natural ecosystems: incentivise ecosystem stewardship
- stop subsidizing bad practice
- tax/penalise harm to the biosphere and climate system
- take the value of nature into account when making decisions: national and company accounting, replace GDP with metrics that prioritise wellbeing over material wealth
Describe decarbonisation
incentivize renewables, tax fossils
bad environmental practice
big oil, coal, over-exploitation of lands and seas
How can businesses tackle climate change
- decarbonize
- eliminate deforestation and other destructive practices from supply chains
- invest in nature and renewables
Give some examples of businesses engaging with climate good practice
- pledges for zero deforestation in supply chains (e.g. Wilmar, Asia Pulp & Paper, Cargill)
- 870+ companies developing GHG emission reduction targets
- across-the-board investment in renewable power generation
- pledges to invest in nature-based solutions
- nature-positive economy
- Taskforce for Nature-related Financial Disclosure (TNFD)
What can individuals and communities to tackle climate change
- diet change: plant-based
- decarbonise purchases and travel
- hold governments to account
- spread the word
- conduct and communicate good research
Describe the research necessary
- natural science underpinning biodiversity’s influence over ecosystem functions and properties
- social science underpinning values and valuations
Describe forests
- produce oxygen
- regulate hydrological cycles
- moderate climates
- store carbon
- monocultures may be more vulnerable to disease and potentially less able to withstand changing environmental conditions
- tree diversity stabilises the system
- generated through density-dependent processes such as those mediated by disease and herbivory
- made possible by the pollination of flowers and dispersal of seeds by numerous specialized organisms
- much of the diversity of microbes, pathogens, insects, birds and mammals in the forest system is not directly generating services to humanity, it is supplying something more fundamental by allowing the ecosystem to regenerate in perpetuity, and to withstand and recover from disease and environmental change
Biodiversity is structured by biodiversity services
(i) community assembly
(ii) interaction networks
(iii) nutrient transfer
(iv) biogeochemical cycling
biodiversity services
- underpin and determine the stabiility, resilience, magnitude and efficiency of the functions and properties of ecosystems
community assembly
biotic and abiotic interactions (including environmental filtering, competition and host–parasite interactions) which together determine the distribution of species and their abundance in communities
interaction networks
architecture of mutualistic and antagonistic interactions underlying pollination, seed dispersal, predator–prey cycles, etc.
nutrient transfer
breakdown of nutrients and transfer across the environment
biogeochemical cycling
cycling of chemicals, e.g. C, N, through the biosphere and lithosphere
Describe ecosystem service valuation
- intrinsic and instrumental values When economic valuation is done correctly (i.e. robust assessment and weighting of values), the outcome is green environmental policy (left, green arrow implying positive effects on biodiversity and ecosystems) that leads to environmental conservation, restoration, protection and sustainable practice.
instrinsic
cannot be valued economically
instrumental
contribute to human welfare in many and varied direct and indirect ways
