Conservation Flashcards
What is meant by biodiversity?
: the variability among living organisms from all sources including, inter alia, terrestrial marine + other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within a species, between species + of ecosystems” - convention of biological diversity
“The variety of life” - Gaston 2010
how can you quantify biodiversity?
No single measure will suffice
number: (species richness) Or Heterogeneity (Diversity index)
What is a disadvantage of using species richness to quantify biodiversity?
doesn’t consider differences in occurrence between counts) - doesn’t tell you how many of each species just number of species; gives a narrow perspective
how do we measure biodiversity?
traditional tools / environmental DNA
what is the advantage / disadvantage of eDNA to measure biodiversity?
from faeces, mucus etc; Can identify organisms present in habitat even if not present at exact time of sampling: broader measure
o Good for detecting traditionally elusive species
o Currently only available for well-funded research
What are biodiversity hotspots?
where there are peaks in biodiversity
what is the underlying problem with biodiversity?
population growth
Why is population growth a problem for biodiversity?
people compete with other organisms
More humans = fewer resources (food/space/light) for other organisms
what is the equation for the impact on biodiversity?
I = PAT equation (Holdren & Ehrlich 1974; Ehrlich & Ehrlich 1981)
o I = impact on biodiversity;
o P = population size;
o A = affluence (measured as per capita consumption);
o T = technologies & socio-political-economic arrangements to service that consumption.
what did new bold et al., 2015 say about biodiversity
“Human activities, especially conversion and degradation of habitats, are causing global biodiversity declines”
What does nature do for us?
Use Frameworks to simplify things:
- Values
- Ecosystem services
What are use values of biodiversity?
1) Direct. e.g. fruit (direct benefit by eating)
2) Indirect e.g. decomposition, use trees that have utilised nutrients produced by decomposition
What are non-use values of biodiversity?
1) Option value- Keeping something gives option to use it in the future (medicine? plants in the Amazon that we don’t know of yet that may help to cure problems.)
2) Bequest value - Idea of leaving something desirable for future generation
3) Existence/intrinsic value - Idea that biodiversity has value even in absence of humans, it has a right and reason to exist even in absence of humans
What is the Millenium ecosystem assessment (MEA)
o Called for by UN Secretary General in 2000
o Largest assessment of health of ecosystems
o Includes information from 33 sub-global assessments
o Authorized by governments through 4 conventions
o Prepared by 1360 experts from 95 countries
o Reviewed by 850 experts and governments
what is the objective of the MEA?
“To assess the consequences of ecosystem change for human well-being and the scientific basis for actions needed to enhance the conservation and sustainable use of those systems and their contribution to human well-being.”
What types of ecosystem services are there?
o Supporting
o Provisioning
o Regulating
o Cultural
What are the indirect drivers (reasons) of change (MEA)?
o Demographic
o Economic
o Sociopolitical
o Cultural & religious
What are the direct drivers (reasons) of change (MEA)?
o Changes in local land use and cover o Species introduction and removal o Technology adaptation and use o External inputs o Harvest and resource consumption o Climate change o Natural, physical and biological drivers
What is Natural Capital?
Natural capital can be defined as the world’s stocks of natural assets which include geology, soil, air, water and all living things. It is from this natural capital that humans derive a wide range of services, often called ecosystem services, which make human life possible.
Mangrove services?
o Nursery and adult fishery habitat o Fuelwood & timber o Carbon sequestration o Traps sediment o Detoxifies pollutants o protection from erosion & disaster
What are the threats to biodiversity?
o Habitat destruction& fragmentation o Overharvesting o Invasive alien species o Climate change o Fire & Pollution o Land use change (Agriculture) is still a threat but climate change is becoming more of an issue.
What are some causes of climate changes?
Fossil fuel burning, deforestation, Raising livestock + fertilising crops.
Why does agriculture contribute to climate change?
Clearing land for Agriculture (soya, grazing livestock - bad for methane emissions; manure turnover, fermentation in cows; fertiliser production accounts for 1.2% of global greenhouse gas emissions. (not inc. the transport, spraying + machinery). If you spray an excess of N2, it is converted by microbes into Nitric oxide.
Agriculture accounts for:
o 50% of the anthropogenic CH4 (methane) emissions
o 80% of anthropogenic N2O (nitrous oxide) emissions
How does melting permafrost affect the environment?
Permafrost = permanently frozen ground in high latitudes (warming atmosphere íthawing í release of Co2 + methane trapped in ice.
How does ocean acidification lead to reduced calcification?
Co2 absorbed by oceans which means H+ ions are released. These combine with Calcium carbonate, reducing the calcium carbonate available for calcification
What is calcification?
the deposition of calcium carbonate into skeletons and shells of lots of marine organisms.
What is permafrost and how does it contribute to global wawarming?
permanently frozen ground in high latitudes (warming atmosphere íthawing í release of Co2 + methane trapped in ice.
What is the Paris climate accord 2015?
International pledge to limit global warming to below 2 deg C (above pre-industrial levels). Pursue efforts to limit the temperature increase to 1.5 deg C.
Require best efforts through “intended nationally determined contributions” (INDCs) and for all Parties to report emissions on a regular basis.
What effects does climate change have on biodiversity?
Migration in birds
phenology changes (flowering date + leaf flush earlier)
Altered distribution.
What is the positive feedback loop of rising sea levels?
melting of snow rises sea levels but snow and ice are reflective so reflect heat so when melted they don’t, further warming the atmosphere.
why do changes in precipitation negatively effect the environment?
knock on effects: need the land for growing crops + livestock, aldo cause more + stronger cyclones + cause changes in distribution of land mammals depending on species and where they live.
What is ‘Landscape change’?
o a reduction in total amount of original vegetation
(habitat loss)
o subdivision of remaining vegetation into fragments (
habitat fragmentation)
o introduction of new land-use to replace lost vegetation
What are the different stages of landscape change? (Framework for Conceptualising Human Effects on Landscapes)
- Intact
- Variegated
- Fragmented
- Relitcual
Main changes to the landscape?
o Reduced area/size
o increased isolation of fragments (which increase the edge effect)
o edge effects (increase of straight edges: borders around the edge, which is influenced by the climatic conditions on the edge)
MacArthur and Wilson (1967) onIsland biogeography
Number of species that an exist on an island is decided by size and isolation/remoteness of the island.
Isolation effects species
- Regular movements
- Seasonal/migratory movements
- Dispersal movements between fragments (gene flow, recolonisation of populations, etc.)
What is a metapopulation?
A metapopulation is a group of populations that are separated by space but consist of the same species. These spatially separated populations interact as individual members move from one population to another.
What are wildlife corridors + example of animals that use it
- link of wildlife habitat (in-between non-habitat), generally native vegetation, which joins two or more larger areas of similar wildlife habitat.
- critical for the maintenance of ecological processes including allowing for the movement of animals and the continuation of viable populations
- e.g. Christmas Island red crab migration.
What is the matrix and why important?
Land between habitat fragments and changes in the matrix may be important to conservation (most the benefits were witnessed in the first 10% of the pine tree cover in the matrix).
7 drivers of habitat loss
- Logging
- Fire
- Mining
- Agriculture (the biggest cause)
- (beam) Trawling
- Urban Sprawl
- Light pollution
tree cover loss vs deforestation
Deforestation = wipe out all trees in one area
Tree cover loss = measurement of tree cover from sky (tree might have lost leaves but is not necessarily dead)
–> Big spike in tree cover loss (2016) might be due to big forest fires.
What is beam trawling?
Beam trawling is one of the most destructive form of bottom trawling, in which a large net attached to a heavy metal beam is dragged across the sea bed behind a boat, digging into and ploughing up the ground.
What is phototaxis?
Phototaxis is a kind of taxis, or locomotory movement, that occurs when a whole organism moves towards or away from stimulus of light.
Many animals attracted to light (e.g. moths) –> positively phototactic.
Many nocturnal animals are light-shy/intolerant –> negatively phototactic.
Why do small populations face different risks in terms of conservation?
o Conservationists concerned about what happens to small populations
o Small populations = higher (but variable) risk of extinction
o Small population size in itself does not necessarily mean that extinction will occur
o E.g. Himalayan tahr and Passenger pigeon
What is population viability analysis? (PVA)
” General rule: isolated pops with little or no immigration have reduced viability if small
“ Minimum viable population size = min. no of individuals needed for a pop to be viable (diff for diff species)
problems with PVA
what is a solution?
Problems
o Social factors
o calculating size doesn’t take into account Basic population processes
o If you have Species below MVP level people tend to give up on sp - “no hope” so it can be dangerous.
o PVA ignores whether habitat also viable - for a sp to be viable, the habitat needs to be viable.
So now focus on PHVA - population and habitat viability analysis
What is a solution to conserve populations vulnerable to Environmental stochasticity and natural catastrophes
have a back up population on other islands / in. other forests
what are components of Demographic stochasticity
a. Carrying capacity
b. Maximum sustainable yields
c. Threshold responses
What is carrying capacity?
the natural limit set on populations by availability of resources = K.
Fluctuates arooung the limits: pops aren’t stable.
There is some kind of limiting resource at K (normally food but also:Availability of nest sites is the limiting resource for wood peckers
What effects carrying capacity?
o Interspecific competition - one species affects resources available to another (Carrying capacity depends on how many sp in your pop you compete with)
o Different habitats (CC will be different in different habitats)
Competition can cause niche specialisation.
What are the two ways in which populations may grow?
Irruptive growth - explosions and crashes
o Regulated by resource availability
o Wide variation around carrying capacity
o Typical r-strategists
o Few species
o E.g. algae + algal blooms
Logistic growth - Sigmoidal curve
o Growth rate regulated by intrinsic factors (density-dependent mortality, birth rates)
o Typical K-strategists
o Most species
Why are small populations more at risk of pop crashes?
- likely to be at the slow growth rate + if mortality rate ↑ / birth rate not as high, it can cause a crash + extinction.
In small populations - individuals reproductive rate high but numbers low
What is Maximum sustainable yield and what are the risks?
Populations best sustain losses at inflection point K/2
Risk: Population declines to extinction even if mortality rate only slightly higher (i.e. if you miscalculate K can cause crashes).
What are the problems with applying MSY?
- Very difficult to get accurate estimates of population size: pops aren’t stable + fluctuate (so hard to get K/2)
- Carrying capacity changes; impossible to estimate
- Basic demographic data rare - can be diff to establish + vary between populations
- Difficult to get measures of other forms of mortality (natural death rates)
- Social systems, mating strategies, often unknown
- Pays to over-harvest long-lived species, drive extinct - e.g. fur and elephant tusks: only allowed 1.5% a year but if becoming extinct then the limited tusks become more vulnerable so for an individual trader it is beneficial.
What are the three main types of responses of British mammals to habitat fragmentation?
which animals do these tend to affect?
- Type 1 response: population declines to threshold then crashes to extinction (semi-natural species - otter + pigeon)
- Type 2 response: initial small ↑ then increasing decline to extinction (Edge species - door mice + bats: like bit of habitat frag (like the difference between the two))
- Type 3 response: marked rapid increases, peak, then slow decline to extinction (Mosaic species - deer + badges - do well with some frag but with too much they ↓)
