Flashcards in all Deck (483)
define conservation biology
applied scientific discipline seeking to counter biodiversity loss
- response of biologists to anthropogenic impacts on natural world
what are the 3 components of conservation biology?
and what is it concerned with?
1. quantify loss and impacts
2. identify causal mechanisms
3. devise strategies to reduce impacts
concerned with long term viability of entire systems
give 2 examples of how you may quantify loss and impacts
- avian bird monitoring : farm and woodland bird species declined with 50% drop in farmland birds
- study urban development as fastest growing land used quantify impact on species richness, pop densities, genetic diversity, predate/disease risk
give 2 examples of identifying causal mechanisms
- wood warbler: 1995-2008 60% pop decline, most specialised in African wintering habitat so change here likely causal factor
- plant pollinator interactions such as between oil collecting bee and oil secreting orchid, plant decline may be due to climate change or reduced pollination in urban area
explain protected area gap analysis and skylark plots as examples of devising strategies to reduce impacts
- protected area gap analysis: gap species are threatened by extinction but not in protected areas- identify where species live without protection., analyse where higher priority gaps in protected areas, designed in relation to patterns of species
- skylark plots: decline due to switch in farming type, can spray an area of field with herbicide so natural vegetation can grow benefiting birds but many are against it making their land look poor- fields with 2 plots per hectare have significant benefits and improve foraging and breeding success of the birds
what is the noble savage concept?
in ancestral times was believed there was harmony between humans and nature but incorrect
- lower pop density= fewer resources= resource overuse= damage to natural world
give 2 examples of the noble savage concept
1. pacific islands- colonised <3000ya, over 2000 bird species extinct (10% all bird species) due to human colonisation and introduction of non native species
2. easter island- off coat S.America, colonised 318AD, deforested 1400AD, forest used for fuel, timber for houses, boat making for fishing which also led to overfishing, all natural resources lost and society extinct
what 3 main conclusions can be made from the noble savage concept?
1. human have always impacted natural world (concept is wrong)
2. some species benefit
3. are shifting baselines
- where is there higher deforestation rates?
- what % UK temperate forest
- why may rates have increased?
- increased pop size so more damage
why has the time taken to add 1 billion to a pop decreased and what is it thought the pop will stabilise at by the end of the century?
rapid pop growth
- what % global available energy used by humans
- what % local energy do industrialised nations use
- what % globe bears footprint of our change
- what % fertile land is used by humans
how does human pop growth and resource use lead to loss of biodiversity?
more industry, agriculture, fisheries, forestry leading to land use and cover change, altered bio geochemical cycles, natural compounds harvested, biological invasion
what is crisp discipline?
response to rapid biodiversity loss
what other disciplines may need to be applied when identifying causal mechanisms to reduce impacts and what needs to be taken into account?
economic and social science
need to take local peoples attitudes into account and their say over the situation
whats the relationship between rate of biodiversity loss and knowledge gain?
rate of biodiversity loss > rate of knowledge gain
give 3 points about biofuels
- generally considered carbon neutral
- can't be grown on agricultural soil
- oil palm often used but has led to mass forest destruction and extinction of orang-utans may follow
what is the kakapo example?
- nocturnal parrot in New Zealand
- used to be common but declined when settler introduced domestic animals that predated them
- moved to predator free offshore island, supplements given to increase breeding to every year rather than 3-4 years
- biased sex ratio with mainly male chicks
- new resources added and sex ratio restored
what was the romantic transcendental ethic in 1850s and who were the leaders?
leaders: John muir, Henry throeu, Ralph Emerson
- semi religious idea
- believed in preservation and leaving the world untouched
- not economically value focused
- led to Sierra club,, preservationist movement, Yosemite, national park
what is the resource conservation ethic in 1900s and who were the leaders?
leaders: John mill, gifford Pinchot, teddy roosevelt
- practical approach
- aligned with ecosystem service approach
- aim to protect nature due to economic reasons
- led to multiple use concept
what is the evolutionary ecological land ethic?
- 1950s Aldo Leopold merged resource conservation ethic and romantic transcendental ethic, avoiding muirs semi religious aspect and mills strict utilitarian approach
- view that ecosystems are integrated systems based on interdependent processes and that components can't be tinkered with without risking collapse
- foundation of modern conservation
when was the first modern conservation biology textbook published and by who?
1980- Soule and Wilcox
what 2 reasons are there for why we select conservation units?
1. essential for effective and efficient planning given limited space
2. aim to protect biodiversity
how much money is actually spent on global conservation and what is the required spend fo James et al and McCarthy et al?
James: $27.5 billion required $6 billion actual (20%)
McCarthy: $78 billion required actual 10% of this
the variability among living organisms within species, between species and of ecosystems
what's the difference between the units of the taxonomic and ecosystem approach as conservation units?
taxonomic: genetic diversity, populations, sub species, species
ecosystems: habitats and ecosystem services
give 6 factors about the genetic diversity unit
- diversity important for increasing pop resistance
- more diverse a pop the greater the capacity to cope with changing environments
- preserving ancestral plant species can help better breed plants and may improve yields in closely related crop species
- varies spatially
- just because is diverse doesn't mean it contains unique species
- without knowing extent of diversity this conservation unit may not be practical
a group of the same species whose members can interbreed
what 3 things does having multiple populations increase the probability of and mean that you would use it as a unit?
- maximising genetic diversity
- protecting local adaptations
- insurance against local disasters
where may genetic data be lacking to determine if separate populations?
in the black pine in Europe as some species distributions are distinct but others not so obvious and can occupy many areas
what issue may focusing on populations as a unit lead to?
parochial (local not global interests) and inefficient conservation
describe the great crane project as a local rather than global success
1600: cranes extinct in UK
1980s: recolonised but only about 10 pairs
2009: reintroduction programme £400,000 per year to increase UK numbers
2015: first breeding of reintroduced birds
- the European pop has had a large increase since 1990s and are IUCN least concern
- 11 other crane species are threatened with global extinction
- UK species not at global risk so only locally successful and money better spent on globally endangered
give 6 disadvantages of population as a unit
- pop are difficult to define
- based on assumptions of genetic divergence between pop which is rarely tested
- often multiple pop
- more focus on local concerns rather than global
- some distributions unclear
- can lead to a narrow outlook and inefficient conservation
what is more likely conserved if a sub species is conserved and used as a unit?
species genetic diversity and more unique adaptations
explain an example where investment in subspecies conservation failed
dusky seaside sparrow
- subspecies restricted to Florida
- $2.5 million investment
- extinct in 1990
- no genetic differences in subspecies, are genetically identical to non threatened sub species
what % of continentally distributed again subspecies lack genetic distinctiveness?
and why may this make sub species based conservation problematic?
assumes sub species represent genetic variation
promotes parochial conservation
give 4 advantages of species as the traditional conservation unit
- species irreplaceable
- public understanding
- data most frequently collected at this unit
- easy to recognise and define
give 3 disadvantages of species as a unit and examples for 2 of them
- unsuitable taxonomy (Manx shearwater of least concern and balearic shearwater that's critically endangered with 7.4% decline each year split in early 1990s)
- taxonomic inflation (in Philippines may be >100 extra avian endemics, used to be 13 albatross species now 21, 33 lemur species in 1994 now about 100)
- most species undescribed
what % of these terrestrial species are described?
why were habitats developed as a conservation unit and what are 4 advantage ?
in response to accusations that species focused conservation ignores many species
+ will likely protect a great deal of species
+ habitat loss major driver of extinction risk (80% endangered terrestrial vertebrates threatened with habitat loss)
+ reasonably good data on habitat loss
+ protect ecosystem services
give 2 disadvantages of habitats as a unit and and example of why for each
- at a finer scale habitats difficult to define (oak woodland may contain other trees so can't generalise it as oak)
- easy to miss parts of habitats with the most species if species have a small range (frogs have around 1,000 species in 100km cell)
when did millennium ecosystem assessment start and what does it assess?
2001- assessing impacts of environmental change on human wellbeing
what are the 4 ecosystem service types in detail?
1. supporting services (for production of other ecosystems services such as primary production, nutrient cycling)
2. provisioning services (products obtained from ecosystems- food, freshwater, wood)
3. regulating services (benefits obtained from regulation of ecosystem processes including climate, disease, floods, water purification)
4. cultural services (non material benefits such as aesthetic, mental wellbeing)
explain the pollination and productivity examples for provisioning services
1. pollination- key for food crops and fruit and seed production with a global value of $27 billion per year
2. productivity- primary productivity increase with plant species richness (more grass=more cow milk)
explain the sea defence example for ecosystem regulatory services
- super cyclone orissa in India 1999
- flooding and tidal surge
- mangroves buffered villages slowing down the surge and reducing deaths by 69% in villages <10km from the coast
explain the wellbeing example for cultural services
- children in high rise flats have higher concentration levels when views of green space
- people in parks with more plants have greater mental well being
what increases when ecosystems are sustainably managed?
net economic value
give 7 disadvantages of ecosystem services as unit of conservation and example
- ecosystem diservices (malaria costs Africa $12 billion per year due to healthcare, lost work days, tourism loss)
- lack of data (only 4 services mapped : c storage, c sequestration, grassland production, water provision)
- limited info on relationship between biodiversity and ecosystem service provision
- biomass may be more important than species number
- cultural services depend more on perceived to actual biodiversity
- service provision may be dependent on large numbers of people
- lack of spatial harmony between ecosystem services and biodiversity
roughly how many species of these?
are humans evenly distributed?
no- some occupy areas of higher human pop density so experience more threats
what are the 4 main methods of priority setting?
1. taxonomically unique species
2. keystone species
3. umbrella/flagship/indicato species
4. rare/threatened species
in terms of taxonomic distinctiveness what is the New Caledonia birds example?
Kagu and green backed white eye
the white eye is the sole family representative with greater conservation importance, representing more genetic and functional diversity
who formalised the distinctiveness equation and when and what is it?
vane wright 1991
distinctiveness= max branches from root/ branches from root for that species
what are 4 modifications for the distinctiveness equation?
- counting shared nodes not branches
- taking branch length into account
- future distinctiveness
- combine with other metrics but only works for some groups
what is mays equation for distinctiveness?
= max no. of descendents on path from root/ no. of descendents on path from root
define keystone species and what role do they play in an ecosystem?
' a species whose impact on its community is large and disproportionally larger relative to its biomass'
keeps ecosystem intact and maintains species richness
describe the starfish in N America as a keystone species (Paine 1966)
in rock pools- when removed system collapsed from 15 to 8 species
starfish are predators preventing other species from dominating as if this happens other species will be excluded by competitive exclusion
what is the community importance index and what does it mean if it is over 1?
change in community trait/ change in focal species biomass
if >1 keystone species
in what 3 ways is keystone species a limited approach for assigning priorities?
- many keystone species are only identified from anecdotal evidence
- robust identification of species difficult and often needs removal experiments
- a few non keystone species can have equivalent effects
briefly describe the umbrella/flagship/indicator species priority setting approach
shares concept that protecting single species can protect many
differ in characteristics from focal species
can aid conservation but if used in isolation won't generate enough protection
what is an umbrella species?
species that require a large area for conservation
- protect other species with similar habitat requirements
- usually large vertebrates with large home ranges
give an example of an umbrella species
1950- 2 million
2010- 95% decline now critically endangered
- many areas of former range extinct due to change from natural habitat to agricultural land and hunting pressures
what is a flagship species?
characteristic species that promotes conservation of region/habitat
explain the seahorse and Chinese panda example for flagship species
- se grass beds provide habitat and nursery area for fish and are important in C cycle
- aim to protect their bamboo areas
- but is a lot of bamboo in areas where pandas extinct
- is less of a need to protect bamboo areas if panda extinct but this ignores other important species living there
what is an indicator species?
species with narrow ecological tolerance and so are found under specific sets of conditions
- help to protect indicated habitat
- if indicator species disappears incentive to protect habitat may decline
give 3 features of rare species
- small geographic range size
- small pop size
- habitat specialist
who proposed the 7 kinds of rarity chart?
the great white shark and devils hole pupfish are both rare but whats the difference?
shark lives in many oceans of different sea types but the pupfish Is isolated
not all rare species are threatened - give an example
seychelles small day gecko
- endemic with small geographic range
- high density and pop size
- broad specificity
- naturally occur in forests but can survive in agricultural and urban areas so unlikely to go extinct
common species can become rapidly extinct explain the extinction of Rocky Mountain grasshopper
very common in US around 1880 but 30 years later in 1902 they became extinct - perhaps loss of breeding habitat as grassland became agricultural
explain the extinction of the passenger pigeon
25-40% N.American birds passenger pigeons
3-5 billion when europeans discovered America
explain the extinction the American chestnut tree
abundant on eastern seaboard
pops destroyed by fungal pathogen (95% decline)
leaves nutrient rich and decay rapidly which led to alterations in nutrient cycling and decrease in freshwater stream invertebrates
what are common species important for??
functionally important for ecosystems
what is population viability analysis for prioritising species by extinction risk?
- based on detailed demographic data on current pop size, birth and death rates and how vary with environment
- but impractical for most species as insufficient data
give 7 features of the IUCN red list
- started 1960s
- 65,00 species assessed
- all birds, mammals, amphibians, corals
- global assessments for fish and plants underway
- rate of assessment increasing
- identifies species at risk of global extinction and drives conservation for those species
- could be considered subjective categories
what are the 5 aims of IUCN red list ?
- classify threat to assign priorities and measure conservation progress
- consistent when used by different people
- improve objectivity through clear guidance
- facilitate comparisons across taxa
- give people using lists better understanding of classification process
what % pop size reduced and how much area of occupancy for each:
- critically endangered
- >90%, <10km2
- >70%, <500km2
- >50%, <2000km2
what are near threatened species?
likely to qualify for threatened category in the near future
what 6 things are the IUCN evaluations based on?
- range size
- pop size
- no. of pops
- severely fragmented pops
- pop trend
- extreme pop fluctuations
what are the 2 types of range size?
- extent of occurrence (area within range boundary)
- area of occupancy (occupied grid cells)
what is pop size?
when looking at pop size what must reintroduced individuals have done before being counted?
number of sexually mature individuals capable of reproduction
reintroduced must have bred successfully as usually struggle to behave normally and usually have lower reproductive success
what is the number of populations (IUCN)?
number of distinct groups with little demographic or genetic exchange
when looking at severely fragmented pops where are most individuals found?
what data is usually used?
in small, isolated subpopulations
data on distribution of habitat usually used as little info on links between populations
how is population trend considered for IUCN?
when is a species considered endangered?
- over 10 years or 3 generations
- important for long lived animals such s elephants
- observed, inferred or suspected in past or predicted in future
- endangered if decline >50% with unknown, continuing or irreversible causes
what are edge species?
evolutionary distinct and globally endangered
- nearing extinction
- giant salamander, purple frog, social lapwing
(but just because extinct doesn't mean functionally important in ecosystem)
what 3 types of sites does conservation usually target?
protected areas, wider landscape conservation, specific management
for protected areas what are the arch targets for 2020? and what is the half-earth goal?
17% land/freshwater is protected areas
10% marine protected areas
half earth goal= 50% terrestrial land under protection
what is an example of wider landscape conservation?
restoration and agri-environment schemes which pay farmers to look after environment
what are specific management sites?
sites selected to maximise effectiveness, such as invasive species control as can lead to extinction of other species
what are the 2 scales of prioritisation?
global- selection of large regions of conservation value , important for biodiversity, well defined prioritisation schemes, not very robust
local- specific localities within hotspots, more limited standardisation for choosing areas
what are the 9 prioritisation strategies for global scale?
CE: crisis ecoregions
BH: biodiversity hotspots
EBA: endemic bird areas
CPD: centres plant endemism
MC: megadiverse countries
G200: global 200 ecoregion
HBWA: high biodiversity wilderness areas
FF: frontier forests
LW: last of wild
who proposed the biodiversity hotspot concept, when, what was the criteria and what was discovered?
Norman Myers 1988
- at least 1500 endemic vascular plants
- <30% area retains original natural vegetation
- found 35 hotspots covering 2.3% land with 50% worlds plants, 43% birds, mammals, reptiles, amphibians
what 2 things are global strategies based on?
vulnerability and irreplaceability
what is vulnerability? what 4 things is it measured as? what are 3 good indicators of vulnerability? and what is one downfall?
likelihood biodiversity values are lost in a site
- % habitat loss
- human pop density
- protected area coverage
- total forest cover
- total forest cover poor indicator
- habitat loss assumes current loss predicts future loss
- human pop density and protected are coverage only ok
BUT: no schemes use number of threatened species, some prioritise high vulnerability others low
what are irreplaceability indicators?
the extent spatial options for conservation targets are reduced when a site is lost- depends on pop size, dynamics, distribution
what is the most common irreplaceability indicator and what is there a strong relationship between?
strong positive relationship between plants and endemism in different groups
at the local scale of prioritisation who and when was the nature conservation review and what is it?
1977 Derek ratcliffe
aimed to find a way to select the best wildlife sites in UK- is the min set of locations to protect biodiversity
what 10 criterion needs to be critically assessed at the local scale of prioritisation to provide a good understanding of key issues?
- recorded history
- position in ecological/geographical uni
- potential value
- intrinsic appeal
what do larger sites contain?
more species, larger population, fewer edge effects
what does having less of an edge effect mean?
less external activity pressure from human intrusion into reserve which would degrade quality
why is high habitat diversity good and what are downsides of it?
+ promotes high species richness
+ multiple habitat sites for species at different stages of the life cycle
- only valuable if all habitats of high quality
- can reduce species richness as habitat specialists or generalist species can't maintain viable population
why may it be naive to prioritise sites with high species richness ?
not all species are equal
which is threatened and which is irreplaceable?
a) less species, more endemic, less threatened species
b) more species, less endemic, more threatened species
what may a site containing very generalist species be an indicator of?
does it make more sense to study specialist species or total species richness?
specialist- changes which site is the optimal choice, more accurate
when looking at rarity what needs to be considered?
long term viability
what are the SSSI guidelines for the Natterjack toad?
includes established and important sites
established: those occupied for over 5 years
important: those with populations larger than the average
areas least modified by humans should be prioritised as are the most natural but what are 3 issues with this?
- difficult to quantify
- most areas highly modified
- human modified areas more valuable
in terms of fragility and threat which sites are most worthy of protection and when does it apply?
sites with more threatened species/habitats
- only if threatened countered by site based protection but often this not the case such as for N deposition or said rain
in terms of typicalness which sites are considered better to protect?
what is an issue with these kinds of sites?
sites most characteristic of focal habitat
- a set of species representative of each habitat to which an ideal set is compared at each site
BUT: causes selection of similar sites so little variety
in terms of recorded history what sites need protection and why?
sites with long history of ecological research- helps us understand the natural world as are indicators of environmental change due to humans and climate change
why may sites at the edge of distributions be more variable?
- data on limiting conditions can inform management
- unique local adaptations
- facilitate range shifts in response to climate change
what needs to be considered about a sites value?
if it will increase in the future and if there's potential to contribute to habitat restoration, also educational value needs to be considered
in what 3 ways can climate change increase or decrease sites value in the future?
- changing habitat type
- focal species moving away from reserve
- new species may colonise
in terms of intrinsic appeal what sites are more important?
sites with charismatic taxa
- can be right approach if want to conserve recreational ecosystem services
beyond ratcliffe's criteria what is the representation idea?
each species must be represented by at least one viable population In protected site
why may Ratcliffe's criteria not be relied upon for representation?
globally 300 critically endangered vertebrates aren't in protected areas
in terms of cost effectiveness explain the Australian nature reserves example
- the target is 15% of each of 58 major habitats are in protected areas
- the conservation benefit increases with cost of purchase of land and management but is massive variation
- replacing the least effective 1% keeps costs the same but increases no. of habitats, meeting the target from 18 to 54
give an example of a species with a small geographic distribution and population size
snow bunting bird in Scottish highlands
what increases the risk of extinction and give an example of a species with a population like this
e.g. big horn sheep in North America- if less than 15 individuals the species becomes extinct
what is the relationship between pop size and extinction risk in birds of Californian Channel Islands? and below what pop size is extinction rate accelerated?
strong non-linear relationship
below 100 extinction accelerated
what are the 4 reasons small populations are vulnerable?
- environmental stochasticity
- demographic stochasticity
- behavioural factors (Allee effects)
- genetic factors
what is environmental stochasticity?
chance events that disrupt populations/extrinsic
- often synchronised over large areas, especially climatic events
- deterioration in environmental conditions has big impact on populations
- even species with large ranges adversely affected
why are plants often more resistant than vertebrates?
seeds and tubers can buffer pop from environmental change due to dormant and stress tolerant life forms
in terms of environmental stochasticity what is the Montserrat oriole example?
- 4 major volcanic eruptions (1995, 2001, 2003, 2006)
- many died quickly
- direct impacts: volcanic dust and 75% habitat loss (density independent)
- indirect impacts: lower food abundance due to acid rain caused by volcanic dust interacting with rainfall which impacts food chains (density dependent )
in terms of environmental stochasticity describe the Coachella valley fringe toed lizard example
drought induced pop fluctuations with pop size decreasing with a decrease in rainfall
what is demographic stochasticity?
chance events that disrupt pop growth/intrinsic
what usually is there between pop size and demographic success and due to what?
negative density dependence due to intra-specific competition BUT: can be positive density dependence and Allee effect where population growth rate is reduced by under crowding
the Allee effect is often found in flowers pollinated by animals- explain the C.concinna plant example
- breeding success depends on external pollinators
- certain density needed for efficient pollen transfer
- probability of pollen transfer reduced the further apart plants are
- impacts breeding success of rainforest trees
- pollinators more likely to go to larger flower clumps
Allee effects can occur in social animals- give an example for each:
- foraging effectiveness
- willingness to mate
- colonial birds group for defence
- pack hunters such as wolves hunt better in larger groups
- flamingos more likely to mate in larger groups
give an example of a bird that the Allee effect applies to
lesser kestrel who has higher reproductive success and adult survival in large colonies
it can be hard to find mates if a population density is low- why?
- large home ranges
- competition for mates from other individuals
if population growth rate is below 1 what can occur?
Allee effects can drive species to extinction
what is allelic richness?
no. of alleles per locus
what does having a small population reduce?
what is population size?
- no. of individuals vs no. breeding individuals
- proportional contribution to gene pool that counts
- where individuals have an equal contribution to the next generation and no selection is occurring
what did wright discover in 1931?
the more individuals the lower the change in heterozygosity when studying a closed population without mutation for heterozygosity
what is the effective and census pop size and which is often lower?
effective pop size often lower
effective= prop. of contribution to gene pool
census= no. of individuals in pop
why is the H.amarus fish vulnerable to inbreeding?
lots of individuals but little contribution to gene pool
in detail in what 3 ways is the effective population size reduced?
1. not all individuals mate or some contribute more offspring than others
(uneven sex ratio- lek forming species may have a single male contributing more to next gen or non monogamous systems- females gain extra male pairs)
2. pop size fluctuates (years of low pop size means lots of genetic bottleneck)
3. generations overlap (small mammals)
what does genetic drift include?
stochastic events that determine which alleles are passed on to next generation
alleles can be lost through generations but what can drift be reduced by?
mutation and migration
in what 2 ways is a loss of genetic diversity bad?
- deleterious recessive alleles more likely to occur in combination leading to inbreeding depression
- natural selection acts on genetic diversity and reduced diversity can lead to reduced evolutionary potential
why may heritability remain high in a small pop?
alleles with high fitness usually dominate
what may a small pop with limited genetic diversity have and so what evidence is needed?
need evidence for impacts of low genetic diversity
what is the impact of genetic drift on new Zealand birds ?
pop size decreases, % hatching failure increases- impacts inbreeding depression
whats the impact of genetic drift on Atlantic salmon?
negative relationship between reproductive success and inbreeding depression
lower genetic diversity= lower reproductive success and more inbreeding
in a study on animals what % showed +ve correlation between fitness and genetic diversity
whats reduced for populations with limited genetic diversity?
reduced evolutionary potential
describe the example for reduced evolutionary potential for the panel 2008 study
- artificially selected for high and low pollen production levels
- lower genetic diversity the lower the trait divergence
- higher genetic diversity means can cope with more environmental conditions
-looked at closely related threatened species and unthreatened
- animals: 78% threatened had low genetic diversity
- plants: 75% threatened had low genetic diversity
what can genetic variation determine and example?
determine ecological processes and services
- primary production and energy flux for nutrient release and decomposition in aspen forests is higher when more genetic diversity
what 4 factors contribute to low effective population size which then leads to extinction?
- environmental variation
- more allee effects
- more genetic problems
- more demographic variation
explain in detial, with dates, the heath hen case study for an extinction vortex example and 4 potential reasons for its eventual extinction
abundant but confined to single small island
1870: 300 individuals
1900: 70 (conservation and management began- reserves and hunting ban)
1910: 2000 individuals
could be due to...
- environmental stochasticity: dry summers so fires and cold winters
- demographic stochasticity: sex ratio bias and severe fluctuations
- genetic effects: inbreeding occurred so low heterozygosity and genetic variation
- disease outbreaks
give an example of a bird with a small pop that doesn't have an increased risk of extinction
Socorro island hawk
- stable pop of 15- 20 pairs for several thousand years
- rare due to small pop, small range, habitat specialist
- can deal well with small pop size
whats the difference between small pop paradigm and declining pop paradigm?
pop decline is a continuum
declining- identifies and manages processes causing decline- often environmental degradation
give 2 points about the small pop paradigm
- rich in theory
- promotes local intensive management
explain the vaquita porpoise example as a firefighting approach
less than 30 individuals so likely extinct in next 20 years so action directed towards their conservation very last minute and desperate
give 4 points about the declining population paradigm
- less rich in theory
- aim to prevent a pop reaching a point where small population paradigm kicks in
- less intensive management over a larger area
- more proactive
declining population paradigm can apply to small populations - explain the spoon billed sandpiper example of this
- naturally rare species
- previously 3000 pairs, now <200
decline due to...
- low breeding success from disturbance and predation
- large scale winter habitat loss (east china sea where they travel has become more urbanised)
- low recruitment and hunting (often are caught when hunting for fish)
BUT: nit yet impacted by stochasticity, inbreeding, Allee effects
both small pop paradigm and declining can act together- describe the atitlan grebe example
initially DP then SP
- small pop experiencing decline in 1958 (DP)
- exotic fish introduced which were competitors for invertebrates
- human pop expansion led to reed cutting and loss of habitat
- conservation in 1960s where reed cutting banned in nature reserves and a net kept exotic fish out
- pied billed grebe arrives 1970s (SP) and hybridisation leading to pop decline
- 1970s earthquake (SP) which cracks lake basin, decreasing Leake size (environmental stochasticity)
- species driven to extinction
- multiple factors interacting so hard to diagnose the cause
why is it difficult to discover declining populations?
- geographic and taxonomic biases in monitoring
- many data deficient species so formal IUCN assessment can't be carried out
what 4 methods need to be exploited in order to discover declining populations?
- take advantage of hap hazarding recording by naturalists
- interview local people
- spatial variation in factors driving decline
- biological correlates of vulnerability
marine life is hard to monitor so what can help and where has a major population crash been revealed?
keep track of no. of sightings that occur in an hour
anecdotal data on sightings and captures reveal the pop crash in Adriatic and Canadas east coast shark populations
in Yangtze what does interviews with local fishers reveal?
accurate estimates for pop decline in dolphin and puffer fish
- but need to take into account shifting baselines
- if most of the decline occurred before younger generations born their report won't be accurate and the older generations may be
factors aren't evenly distributed across the globe so what can we use to highlight where decline most likely?
not all species decline- what is the theory behind this?
ecological and life history traits make population decline more likely for species in response to human activities
in terms of biological correlates of vulnerability
a) what does an increased body size mean for pop decline + 4 reasons
b) what does increased brain size mean for pop trend + 3 reasons
a) more -ve pop decline
- hunting pressure (Larger animals better food source and better indicator of hunting skill)
- larger animals have slower intrinsic rate of pop growth
- larger = longer lived
- raise fewer offspring
b) less rapid pop decline
- more behaviourally flexible
- can buffer more easily
- find food more easily
why are biological correlates of vulnerability limited?
geographic transferability limited (body size may be a better predictor in the tropics as more hunting there so the larger animals more vulnerable)
are species traits or environmental factors a less powerful predictor?
what 2 causes can lead to decline?
- demographic (reduced survival, breeding success)
what does a complete simulation model such as population viability analysis require knowledge of and what may be an issue of this?
- needs knowledge of relationship between demographic traits and external factors
- for nearly all species the knowledge barrier too great to implement solution with sufficient speed
what is the comparative approach and what are the 2 main ways it is carried out?
- list plausible candidate factors for decline
- identify populations that differ in exposure to environmental conditions
- environments associated with changes in pop status can be identified
a) compare timing of decline and environmental change
b) compare populations in areas with different environments
environmental change may be causing the decline such as the corncrake bird- explain
- now confined to a few small Scottish islands
- decline correlated with grassland management switching to machine cutting
- led to rapid decline
give 5 issues with comparing timing of decline and environmental change
- often several environmental factors change simultaneously
- more machinery, chemicals, hedge removal, higher stock densities
- monitoring too infrequent to identify precise timing of environmental change to a pop decline
- spatial scale of pop and environmental monitoring differ
- time lags can distort relationships
give an example of where spatial scale of pop and environmental monitoring differ
fish stocks and marine life
- sea bird colonies monitored on land but may be responding to changing fish stocks away from colony
- often to enough data on where birds foraging to know which fish stock data to analyse
when would you compare populations in areas with different environments as the comparative approach?
when not possible to compare pre and post decline situations
explain the Madagascan endemic of the radiated tortoise as an example of the comparative approach where populations in areas of different environments are compared
- harvest for food and pet trade
- pop decline
- trade bans put in place bu not evidence trade was causing decline
- compared densities in a real with commercial trade and remotes sites
- found densities increase with distance from urban areas
- commercial hunters travel increasing distances
does correlation prove causation?
what are the 4 methods available to prevent diagnosis errors?
1. check for individual movements
2. test for all possible causes of decline
3. check that the proposed cause alters demography
4. check using manipulative experiments
what is the buffer effect?
if habitat quality varies then the highest quality sites will be occupied first and abandoned last
describe the common great tit example for checking individual movements to prevent diagnosis errors
- decline in pop in hedgerows
- incorrect that hedgerow quality declined
- move to woodland areas that have become vacant due to cold winters
- if prefer wood and can move between woods and hedges then any factor driving pop decline will lead to greater decline in hedges
give 4 points about testing for all possible causes of decline
- often impossible due to lack of data
- often lack of information from non breeding grounds of migrants
- need to acknowledge bias
- many studies only test the favoured hypothesis which can lead to incorrect diagnosis
explain the 2 examples for why it is important to test all possible causes of decline
a) yellow nosed albatross
b) NZ native birds
a) thought threatened by long line fishing but more likely due to avian cholera
b) major declines due to introduced predators but disease ignored and avian malaria likely to be the causal agent
give an example of why when trying to prevent diagnosis errors you must check the proposed cause alters demography
- increase in number of breeders and fecundity
- 2000: insufficient food, more foraging
- 2001: less breeding success due to predation
explain the mangrove finch example for checking using manipulative experiments
- rat control decreased predation and increased fledging success
- but more eggs killed by parasites
- controlling flies as well as rat pop slightly increased persistence but not as much as the difference from increasing rate control
explain the recovery case study of line cratericola
- critically endangered plant
- 1966 discovered at 2 sites
- went extinct at 1 site when invaded by lantana camara, an exotic shrub
- large numbers of feral goats
- the hypothesis is that grazing and invasion causes the decline
- tested this in 1977
- put 2 groups of plants enclosed in goat proof fence and invasive shrubs cleared
- intensive goat control put in place
explain the skylark recovery case
1970-2008 was a 53% decline
- almost all decline farmland rather than moorland
- higher productivity on spring sown cereals than winter cereals due to reduced food availability in winter cereals
- recovery plots put in place
- increase breeding success by 50%
- decline reversed if 20% winter cereals had 2 plots per hectare
- economically profitable to farmer as is paid £500 to implement the plot
- but thought it can make their field look messy and indicate they are a poor farmer
when surveying you can conduct on a single site or compare multiple sites- describe each
single site: single point in time to discover, putting in place management plans and impacting assessments
multiple sites: survey biodiversity, habitat type/condition, status of key species to see if effective
what is surveying essential for and a benefit?
conservation planning- need fine scale distribution data
- cost effective
what is a downside to surveys and an example?
Ugandan forest is 15,000km2 and would take 100 years if 1 person surveyed it, costing $1 million
compare the complementarity survey approach with random site selection
complementarity selection more effective and rapid in reaching target number of species in network area
when can a survey be considered cost effective
if the cost of purchasing and managing extra land is more expensive than surveying
what is the Romeo error?
the rediscovering of new species
give an example of where the Romeo error has occurred?
Cebu flower pecker bird
1906: last seen
1959: declared extinct
surveyed the island after images from a plane crash showed forest still present so surveyed the island
what is monitoring and what 3 things does it involve?
regular repeat surveys to measure change
- quantify loss and impacts
- identify causal mechanisms
- devise strategies to reduce impacts
what are the 2 main monitoring targets?
1,. same as surveys: assess species richness, habitat condition etc. and how changed over time
2, additional reasons such as phenology and demography
there can be taxonomic biases in monitoring such as for UK breeding bird and plant success
birds: breeding success and pop size measured annually, distribution measured 3 times since 1960s
breeding success never measured, pop size measured annually for some rare species but otherwise haphazard, distribution measured 2 times since
there can be geographic biases in monitoring- give an example
North America and Europe have very good avian monitoring schemes but the rest of the world has little reliable data
in what 2 ways are the core principles of survey and monitoring the same?
- monitoring is a repeat survey
- if conducting a survey is best to use a design that can be repeated in the future
what is accuracy and give 3 points about it?
how close the estimate is to the true value
- inaccurate results biased
- difficult to directly assess but can if survey methods likely to create bias
- bias largely from inappropriate site selection or counting methods
what is precision and give 2 points about it
how close different estimates are to each other, unrelated to true value
- easy to access
- precision increases with sample size and reduced variation in sample
what do the 3 core principles of survey and monitoring require you to do?
1. define objectives (realism or ambition)
2. define study area (urban vs rural, habitat types, land use cover)
3. choose survey locations (must avoid bias)
what are the 3 main methods for choosing survey locations and what must be minimised and how?
- minimise all other sources of variation:
observer quality: must be clear guidelines and training
suitable weather conditions
constant time of day/season
what is systematic sampling? but how many bias occur?
sampling from a pre-specified pattern from a random starting point
- pre-specific pattern may match pattern of ecological variation creating bias
what is random sampling?
equal probability of selection
randomly choose grids of area but can be problematic
rare habitat types can be missed
what is random stratified sampling?
- used to increase sampling of rare habitats
- randomly select sites (within habitat type)
- can decrease sampling effort where variation will be low
give 6 points about territory mapping
- multiple visits where are territorial species
- record location and activity of all sightings including simultaneous ones
- defies clusters of sightings
- no. of clusters= no. of territories
- repeat survey maps over seasons and overlay and cluster
- if focal species chosen well can be good technique
give 4 downsides to territory mapping
- assumptions not always valid
- not ideal for Colonia, poly-territorial, cryptic species as hard to detect territories
- only good for more visually obvious species
- time consuming
what is the mark and recapture/re-sighting technique ?
estimate population size from % marked individuals recaptured/re-sighted in subsequent sample
- but some like being in the trap as provides protection from predators and food so if caught once likely to be caught again
what influences if a population is open or closed?
mortality, recruitment, immigration, emigration
if a population is completely open what method is used and what are the 3 assumptions of this method and what does it provide estimates for?
estimates of abundance, survival, capture rates from recapture experiments
- marks last during sample period
- capture probabilities constant across individuals
- emigration losses permanent
the two types of marks are natural and artificial- what is the difference between the two?
marks/cuts on fins from fights or fishing boat accidents and spot patterns considered unique
temporary- few months such as toe or fur clipping
permanent- pit tag: electronically injected under skin and a barcode reader is used (good for long term studies)
what is 1 +ve and 1 -ve of marking/recapturing?
good for elusive species
give 4 points about camera traps
- remotely activated camera with motion or infrared sensor
- only large animals trigger camera
- good for nocturnal, cryptic, rare animals
- small animals can cause false sightings by triggering leaves to fall in front of camera
what are pit fall traps?
used for reptiles, small mammals, insects etc. which enter the trap, usually in line with the surface level and can't escape
what is the appeal of transects and point counts and whats the difference between them?
appeal of simplicity- counting all individuals in an area
transect involves moving along whereas point count is at a single point in time- a transect of zero length
what are the 5 core assumptions of transects and point counts?
- all individuals exactly on the route are detected
- individuals do not move before detection
- individuals are not double counted
- individuals are detected independently
- distances measured accurately
why are transects preferable to point counts and in what 2 situations are they not?
more individuals counted per unit time as recorded constantly whilst moving
- habitats fragmented
- access difficulties create route diversions or makes It difficult to move and count simultaneously
for transects and point counts can we just 'count'?
yes if calculating index of population trends
but no when comparing densities between species/habitats or when calculating population size
what can distance sampling be applied to and what does it do?
applied to transect and point count data for more precise data
- corrects for variation in detectability by estimating number of undetected individuals
- allows for absolute density estimates
- rapid data collection especially for things easy to identify such as large plants (but need to take into account plant size as varies with age)
how does detectability of a species vary?
- declines with distance from transect
- varies between species and habitats
for small plants what would be the most common method for data collection?
for quadrants what size are they often? what is optimum size a trade off between? and what is usually recorded?
trade off between time taken per quadratic and sample size
record % cover
human fragmented landscapes typically have what 2 things?
- more fragmentation
- harsher, more homogenous matrix
are human dominated or natural habitats often more fragmented?
what is the fragmentation process?
1. initially gaps very small with little effect beyond reductions in habitat quantity
2. gaps become larger and dominate the landscape creating a matrix so increasing impacts of fragmentation
what is habitat fragmentation?
habitat loss results in the division of large continuous habitat into greater, smaller, isolated habitats with lower total area isolated from each other by a matrix of dissimilar habitats (but habitat loss alone is not fragmentation)
at what % of the original habitat left does habitat fragmentation kick in and at what % are the effects even stronger?
what 3 things does fragmentation consist of?
- habitat loss and gain
- smaller habitat patches
- isolated habitat patches
when a lower % of original habitat what is most of the habitat impacted by and what is is more impacted by at a lower %?
lower %: impacted by patch size and isolation
higher %: habitat loss
what are the main reasons for the break up of natural areas and the matrix of habitats in Britain and what is increase because of it?
roads, urbanisation, agriculture
edge effect increased
what are the 5 ecological principles relating to fragmentation?
1. species area relationship
2. island biogeography theory
3. extinction debate
4. small pop paradigm
5. edge effects
- what is the species are relationship?
- what is the equation?
- what does increasing area by factor of 10 do to species?
- what do larger fragments have?
- give an example that follows this relationship
- relationship between area of habitat and number of species found within
- S=CA^z (s= no. species, c= constant, varies with taxonomic groups, a= area, z= exponent)
- roughly doubles number
- more microhabitats and larger more viable populations
- rainforest butterflies fragmented by oil palm with an increased patch are leading to an increased species richness
what is the gene flow like on islands and what are they vulnerable to?
little/no and so diluting effects of selection and mutation
vulnerable to habitat change and extinction
for island biogeography theory why is it important to study relationship between area and species diversity?
to apply to fragments of habitats human activities protect
give 3 points about island biogeography theory
- developed to explain patterns of oceanic island species richness
- balance between colonisation and extinction
- relevant to habitat fragmentation if consider patches of islands in a sea of unsuitable habitat
what is species richness on islands a balance of?
colonisation and extinction rates
what 4 things do larger islands have?
more species, less isolated patches, lower extinction rates, colonisation more likely
who proposed the island biogeography theory, when and what were the 4 predictions?
MacArthur and Wilson 1976
- more species in large and less isolated patches
- continual turnover of species (some extinct and others colonise)
- number of species eventually becomes constant
- loss of species if relaxation and patched become smaller or more isolated)
what % of studies found evidence for extinction debt where future extinction will still occur even if no further change and give an example
e.g. sub saharan African countries already committed to loosing 1/3 forest primates due to previous habitat loss
in terms of populations what can fragmentation increase?
the number of small populations
where do edge effects have greater relative impact and what is the tree mortality example?
- higher rainforest tree mortality at patch edge as deforestation changes climate so is warmer and drier
- emergent trees particularly affected but these are important to ecosystems as store carbon and act as nesting sites
in a global study of vertebrate species...
- how may species were studied?
- what % were impacted by edge effect?
- how far away from the edge did red listed species peak abundance?
what does a species response to fragmentation depend on and is influenced by and what are the 5 potential outcomes?
- depends on quality of matrix surrounding patch
- influenced by matrix and species traits
1. do well in matrix
2. maintain viable populations in single fragments
3. be mobile and integrate multiple patches in single home range
4. be mobile and integrate multiple patches in metapopulation
5. go extinct
which is more robust to fragmentation, generalist or specialist species? and give an example
African forest birds- react worse to plantation matrix rather than agricultural matrix as agricultural one has isolated native trees
what does the species area relationship and island biogeography theory assume, is this true and what is crucial?
assumes species can't survive in the matrix but not true
- matrix quality control crucial and predictions improve when this is taken into account
when is maintaining viable populations in single fragments more likely and what is it qualified by?
- species with small home ranges
- tolerant of edge effects
qualified by area sensitivity
what is area sensitivity?
responses of species to different sized patches
a) what is a meta population?
b) what kind of dynamic can they have?
c) what must be considered when surveying data?
a) consists of several subpopulations linked together by recruitment of individuals into breeding programme - but not all fragmented populations are meta populations
b) source-sink : source= generates recruits, sink=receives recruits
c) can have habitat patches not constantly occupied but crucial in ensuring overall viability
what is the crowding effect?
abundance spike as individuals move into remaining patches (must be taken into account when assessing fragmentation impacts)
in terms of extinction what can fragmentation do?
cause extinction debt so extinction occurs decades after the fragmentation event
in fragmentation what 3 things is decline rate determined by?
- fragment area
- fragment isolation
- species life span
why may correlation with fragment size not imply causation?
fragment size may be confounded with other factors that influence pop responses
what 3 conservation strategies minimise impacts of fragmentation?
1. reserve design
3. assisted movement
what 3 factors are involved in reserve design?
a) size- larger fragments better
b) isolation- fragments closer to immigrant sources better
c) shape- shape minimising edge effects best, edge effects reduced in larger patches
a) what are the 2 types of corridors?
b) what do they result in?
c) what negative impacts may they have?
a) linear and stepping stone
b) result in gene flow and reduced risk of extinction
c) facilitate disease transmission
spread of exotic species
what is the assisted movement strategy to minimise impacts of fragmentation?
- many large bodied species confined to fragmented protected areas
- cost effective but not long term solutions
what are 2 land based human impacts on marine ecosystems?
- coastal development
- habitat destruction
what % world population lives within 100km of the coast ?
40% but is increasing
what do mangroves do?
- line the coast
- can absorb energy from tropical storms which is important for coastal protection and biodiversity
- 20% lost between 1980-2005 in an area more than 3X size Yorkshire
how much seagrass has been cleared and what is it useful for?
- 110km2 per year disappearing since 1980
- 29% decline since 1979
- 7% lost per year since 1990
- dissipates energy from storms
- nursery habitat for fish and C sink
what % of US shoreline is armoured and with what?
concrete structures: seawalls, jetties, groins
what are 2 kinds of commercial activities by humans in marine ecosystems?
- oil rigs, gas, communication pipelines
- shipping (collision, transport invasive species, noise oil and rubbish pollution)
what is acute pollution? what kind of pollution is it more now?
big disastrous event shooting pollution
- chronic pollution
what is the North Pacific Gyre?
huge current where lots of rubbish accumulates
give 3 points about the pacific garbage patch
- huge increases in concentration of plastic
- usually more microscopic plastic in ocean than plankton
- plastic found in 9% fish
what has increasing co2 driven and by how much in 2007?
increase in global ocean average temp by 0.74c
sea level rise by 17cm
depleted seawater carbonate concentration and seawater acidity by 0.1ph unit
on average where has sea surface temp increased and what 4 things has this led to?
- sea ice melting (less arctic sea ice extent)
- regime change in zoo plankton (species liking warmer water increased abundance but those that like colder over towards poles)
- north fish go deeper (to avoid increasing temp)
- coral bleaching occurs
what is coral bleaching?
healthy corals have algal symbiont that photosynthesise and provide energy but when stressed loose algae and their colour
what have oceans buffered us from and what would air temp be like if not?
buffered from huge temp rise by absorbing carbon otherwise air temp 60c hotter
in ocean acidification what is produced and what does it do?
carbonic acid as co2 reacts with seawater which lowers ph of sea and reduces available carbonate that would calcify marine organisms
what % annual anthropogenic co2 emissions absorbed into ocean?
since the industrial revolution how much co2 has been disposed of in seas?
530 billion tons co2
why is acidification leading to reduced rates of calcification bad?
important for corals, phytoplankton species and other organisms
what are policies that result in over 500 carbon ppm risky for?
coral reefs as fewer places they can survive, as well as the tens of millions of people who depend on them directly
give 5 points about fisheries
- industrial scale hunting of wild animals
- fish catching increased from 1950s peaking in 1980s and remaining more stable
- huge increase in effort for fishing
- produces about 1% global c emissions
- leads to decline in individual species
give 4 points on the blue fin tuna fishery example
- higher population means more mortality in tuna
- huge tuna caught for fun and sold for a lot
- now endangered
- early 1930s mr Mitchel Henry caught world record tuna of 387kg
which areas dominate the imports of fish?
NW Europe, N America, Japan
for fishing how have spatial subsidies been put in place ?
developing world subsidised overfishing in developed world
- fishers now travel further and fish deeper to meet demand
what is fishing down the food web?
when one fish supplies run out move to more low value fish
- krill harvesting in southern oceans but kill are vital in ocean ecosystems
when did fisheries records start and when did the exploitation of sea start?
fisheries: 20th century
sea exploitation: >1000ya
what did Pauly state 1995?
baselines shift with generations of scientists and fishers
what are shifting baselines of fishers?
older generations and those fishing for longer have noticed a large depletion and clear decline in cod stocks over the years as have been around to see it
there used to be a greater abundance of species in the ocean- give 4 points linked to this
- Jeremy Jackson noted green turtles used to be abundant in Caribbean
- marine mammals and large fish less abundant
- overfishing known about for >1000 years
- understanding this requires unorthodox eye witness data and archeological finds
what pattern such as that seen in the Canadian cod can be seen across all large taxa?
large decrease in abundance from historical baselines
what is the decline in Canadian cod?
- decreased from 1970s
- may seem like not too large of a decline from a biomass of about 100 to 25 in 2000 but is huge compared to historical baseline as historically used to be far more abundant
why are big fish too rare in the North Sea?
what % lower is current biomass of fishes than without fisheries exploitation?
by catch is a wider effect of overfishing- give 3 points about it, what it can exceed and an example
- no fishing gear perfectly selected
- many are more or less indiscriminate
- large numbers of non-target species routinely caught by mistake such as non target/undersized fish, marine invertebrates, sea birds, sea mammals, reptiles
- can exceed landings and is most common in shrimp, prawns and crabs
- albatross has been driven to endangered status by being caught in tuna long lining
what is the Steven campana study on sharks to do with by catch?
- 950 sharks caught in 1000 hooks set overnight by 1 fisherman targeting swordfish
- 20% sharks injured
- 44% dead
in North Sea trawling what is caught?
valuable fish but lots of other invertebrates
what can trawling, such as beam trawling lead to and give 5 points
- ruins sea beds and loss of structure
- less complex ecosystems
- some areas like the North Sea are trawled multiple times a year
- area of ocean trawled>area of all forests ever cut down
what are the 5 main threats to marine ecosystems?
- habitat destruction
- invasive species
- climate change
- over exploitation
what are examples of 2 universal solutions to threats to marine ecosystems and 2 more particular?
- reduce C emissions
- don't destroy habitats
- sustainable exploitation of fisheries
- balancing social economic, ecological needs
what are the 2 main specific barriers to marine conservation?
1. inexhaustible seas paradigm
2. perceptions of extinction risk in marine taxa
what is the inexhaustible seas paradigm, who prosed it and when?
thomas huxley 1883
- thought technology damaging to fish stocks
- but that nothing we do can seriously affect fish
what 11 reasons are there for why marine species have a low extinction risk?
- lower extinction of marine species in fossil record
- fish too fecund to go extinct
- fecundity poor predictor of response to fishery
- large geographic ranges and high dispersal
- many marine endemics and structured populations
- economic extinction precluded biological extinction
- value of rare species can increase so remains viable
- depleted populations will recover
- marine pop more variable and resilient than terrestrial
- most fish pop vary as much as birds and mammals
what is known about marine threatened species? - 3 points
- few recorded marine extinctions (IUCN lists <20 marine but >800 terrestrial)
- lots of recorded declines of magnitude to be listed under IUCN
- little evidence marine taxa intrinsically less vulnerable than terrestrial
what is the tragedy of the commons? example of where particularly occurs?
economic problem where every individual trie to reap the benefits from a given resource which harms others who can't benefit and the costs are shared y everyone
- common resource depleted by multiple individuals acting in rational self interest
- high sea fisheries as no ownership
what are the 2 solutions to tragedy of the commons and briefly explain each
1. international fisheries management - includes ICES (international council for exploration of seas)
2. fishery science - important role in development of populating ecology
what is the maximum sustainable yield for fisheries?
attained at intermediate fishing effort- around 50% virgin unexploited biomass
in what 3 main ways can rules be enforced for fisheries?
1. catch control- total allowable caches, individual quotas
2. effort control
3. technical measures
in terms of catch control what is total allowable catches? (3)
- set total limit on stock
- biologically good
- economically poor as fishers race to maximise their share of total allowable catch
in terms of catch control what are individual quotas? (5)
- limit catch for individual boats
- individual quotas will sum to total allowable catches
- transferable quotas traded to give fishers property rights
- initial allocations can be contentious
- can increase by catch/discards
what was the catch quota in 2012?
count whats caught no that's landed to reduced discard of North Sea cod and western channel sole from 30-40% to 0.2%
what could a ban on discarding healthy fish do?
give 3 points about effort control
- limit number of boats, fishers, gear
- reduce catching powers of fishers
- less effective than catch control
what are 3 restrictions involved in technical measures?
- restriction on size and /or sex of fished species
- restrictions of gear used
- restrictions on times and areas available for fishing
what are 3 problems with enforcing rules for fisheries?
- management is species specific but fishing affects who ecosystems
- organisations are data hungry such as for unexploited abundance
- enforcement is difficult
what is the common fisheries example of management?
- EU fisheries policy launched in 1970
- treats EU fish as common resource
- nationally managed through quotas and total allowable catches
- but historically largely ineffective at arresting decline in fish stocks
give 4 points about the science vs. politics debate
- politicians may ignore scientists advice even if correct
- quotas in EU typically 20% higher than recommended
- fishing mortality often increases even for declining stocks
- for European hake stock science may say don't fish at all but the total allowable catches allow fishing
what is the naive model for management of fisheries?
what is the reality?
fishers-> data -> scientists -> managers -> effective management
- fishers involve multiple species
- multiple stakeholders with conflicting goals
- no optimal solution
what are the 4 objectives of fishery management?
1. biological - protect habitat, rebuild stocks
2. economic- maximise income, keep prices low
3. social- maximise protein supply and employment
4. political- raise government revenue and reduce conflicts
what are the 3 management approaches?
1. top down enforcement where 1 large body makes the decision
2. community driven management
3. stop fishing
give 4 points on community led management?
- territorial user rights for fisheries established for fishers in Chile 1991
- fishers exploit and police own area
- increased target benthic species and reef squid
- solving people problems has positive biodiversity effects
give 3 points about ecosystem management
- acknowledgement that whole ecosystem is appropriate unit of conservation
- fisheries conserved as part of suite of ecosystem services from tourism to climate regulation
- include people as part of ecosystem
give 3 points about marine protected areas
- remote oceans preserved for marine conservation
- can have huge oceanic protected sanctuaries
- work well
what are 3 direct effects of marine protected areas?
- stopping fishing increases fish numbers
- biomass typically triples within reserves
- density increases by 40%
what are 4 spillover indirect effects of MPAs?
- export of mature individuals
- export of larvae to repopulate other areas
- significant for species with pelagic dispersal and high fecundity
- BOFFF- females fecundity increases exponentially with length so can restock whole fisheries
what are 6 issues with MPAs?
- positive effects vary in space and time
- spill over benefits unproven in many cases
- some systems easy to protect such as coral reefs but others harder such as open oceans and migratory species
- adaptive management important
- most are ineffective
- rare: cover 2.6km2 and 0.7% global ocean cover
what are NEOLI features and what does it mean if reserves have 4 or 5 compared to if they have 1 or 2 ?
N= No take
if 4 /5: reserve performs well with huge increases in fish biomass
if 1/2: reserve indistinguishable form non protected areas
give 5 points about aquaculture and what was found in a 2011 study?
- farming aquatic species
- in 2004 1/3 global supply were aquatic animals
- since 1970 has been 9% growth
- largely freshwater, has been recent growth in culture of marine fish
2011 study: seaweeds have large yield and produced a lot and shrimps, prawn, salmon have highest value
what are 6 costs of aquaculture?
- supply of feed
- nutrient/organic enrichment of waters
- pesticides enter water courses
- competition with other stakeholder for water resources
- habitat destruction
what are 4 possible solutions to the costs of aquaculture?
- top down regulations
- reduce reliance on wild fish derived feed
- community driven management
- ecosystem approach
what are 3 pieces of good news fo marine ecosystems?
- marine extinctions remain scare
- for most megafauna its not too late
- potential for large scale restoration
15 years after fishing ceased what happened to 25 overexploited fish pop?
3 fully revered, 10 show no recovery
what is the regime change in fish in the Baltic Sea?
from cod dominated to sprat dominated
for 5 reasons why has there been no revery of cod from fisheries?
- other fisheries still operate and will catch some cod
- behavioural: young fish unable to find spewing grounds
- predation by other species: capelin on cod larvae and seals on adults
- displacement by other species such as crabs and lobsters
- climate change because cod like cold water
what can maximise the chance of recovery?
reducing multiple impacts such as habitat destruction and overexploitation
for recovery of fish species what is the main problem?
what should sustainable managed fisheries be?
renewable and profitable
what proportion of amphibians are extinct or threatened with extinction?
1 in 3
what is the index of the IUCN red list index?
proportion species expected remain extant in near future without additional action
- when was conservation introduced to global bird species?
- in 2006 how many species were saved?
conservation management is essential but why is difficult?
- multi disciplinary
- rapid action needed
- limited evidence base
effective management involves many disciplines, what are 3 of these?
2. legal/regulatory framework
3. social sciences
economic driven drives can be long term or short term whats the difference?
long term: economic value usually maximised by sustainable management
short term: value increases with high demand and low supply
- as population size/supply increases what happens to the value?
- what does pop decline do to trade volume and export value?
- reduced trade volume by 50%
- export value increased by 10X
when is non sustainable management economically viable?
- when resource diminished by others so future economic gain not reliable
- pop growth rates lower than interest rates
what are slowly reproducing species like large whales population growth rates like?
lower than interest rates as sustainable harvest rates are low
what are the costs imposed on others not smoking and how can economics provide a solution?
- passive smoking
- cost of healthcare due to smoking related diseases
- massive tax put on cigarettes to internalise external costs to reduce damage
what are 3 benefits of forests and downside to intensive logging?
stabilise soils, regulate water flow, increase water quality
logging: reduces benefits and causes mud slides, fluctuating river levels and sedimentation
in what 3 ways are costs externalised for deforestation?
- logging company doesn't pay for costs imposed downstream it is the poor farmers and fishermen
- poorer people subsidising wealthier people
- costs externalised
in what 3 ways are costs internalised for deforestation?
- force logging companies to compensate downstream farmers and fishermen
- reduced logging profitability and deforestation rates
- working out details of compensatory scheme very difficult
how has the industry compensated for lost revenue?
by changing damaging practices to wildlife friendly ones such as agri-environment schemes
what are the 2 major approaches for legislation?
1. regulatory/control of trades in endangered species and persecution and pollution
2. facilitating legislation (ensure labels accurate to communicate labels to public)
what are the 3 categories of CITES for endangered species and what does it stand for?
convention on international trade in endangered species of wild fauna and flora
I: species threatened with extinction and international trade banned in most circumstances (800sp)
II: species threatened with extinction unless international trade controlled (32,500sp)
III: species included at request of party regulating trade and need cooperation (300sp)
what is an example where trade ban can be effective?
yellow crested cockatoo in Indonesia
- pop densities studied at 5 sites, 4 of which the densities have recovered
- 1981: CITES appendix 2
- 1981-99: heavy trade ban continues
- 1994: total trade ban
list the 4 main issues with trade bans
- trade spikes
- increased price
- decreased price
give 2 points about trade spikes
- can encourage spike in trading years after trade ban
- during implementation of trade ban trading spikes but after the ban was reduced
what % of mature pop size is traded for:
what is the issue of increased price due to trading bans and give and example
- price increases post listing
- leads to increase in poaching and trading
- high levels of rhino poaching in South Africa despite trade ban and price of rhino horns increased after listing
what is the argument for trophy hunting?
- farmers profits influenced by presence of large carnivores due to predation on livestock
- can gain money by allowing trophy hunters on land so if banned would loose +ve contribution to livelihood and conservation of livestock
what are 4 conflicts of trade bans?
- can drive trade underground and promote armed conflict
- difficult and expensive for conservation
- hinders monitoring and increases cost of conservation
- hard to combat organised crime gangs
what tends to be in areas of conservation importance and where is there an overlap?
overlap between human pop density and threatened bird species
what is an example of where historically people were kicked out of protected areas?
removed people from a game reserve area
- not sustainable
- leads to resentment of conservation
where is there often increased human pop growth and what does this cause?
near protected areas such as Latin America and sub sharan Africa
- in the buffer zone surrounding protected areas pop size almost doubles
- increases chance of conflict with people
what is the Kossi Tapu wildlife reserve example in Nepal?
65% people didn't like the protected area
- believe water buffalo damaged fences of reserve and ate crops
- restricted their resource use
BUT: research on the area showed...
- thatch collection economically viable
- fence damage by livestock entering reserve not buffalo
how has the siamese crocodiles population been able to recover?
- 250 mature individuals
- major pressures from hunting and deforestation
- doubled rice yields to reduce food insecurity
- increase in non timber forest product sales
( so no need to illegally log or hunt crocodile so these were reduced)
why is social science needed?
to understand how local people interact with ecosystem and how may need to intervene
what is the white deer hunting example?
conservationists shot mountain lions but this led to the deer population overloading and crashing
- management backfired
what may sometimes be the best option rather than management and why?
wrong decisions can be highly detrimental and so sometimes no management may be the best option
lack of action can be very damaging- how was that the case for the golden toad?
1966: species discovered
1966-87: 1,500 adults
1987: 43,500 eggs but 29 tadpoles
1988: 11 adults, 1 male
1989: 1 male
- small pop paradigm kicked in
- should have established captive breeding programme
- now extinct
lack of action can be very damaging- how was that the case for the slender billed curlew bird?
19th century: very common
20th century: rapid decline
1960-70s: >100 wintering in Morocco
1990s: max 19
1994: first conservation action
2001: last sighting
- action was too late
list the 5 general principles of management
1. critical biodiversity composition and ecological processes must be maintained
2. minimise external threats and maximise external benefits
3. capacity for evolutionary processes must be conserved
4. management should be minimally intrusive
5. management must be monitored and adaptive
in terms of critical biodiversity composition and ecological processes being maintained:
- what can't management plans do?
- what 2 solutions aren't mutually exclusive?
- what does ecosystem management encourage or mimic?
- what is it hindered by?
- area contains thousands of species and can't be written for all
- focus on species of special interest and focusing on ecosystems
- natural processes and disturbances which are key to maintaining biodiversity
- lack of data on natural disturbance regimes and small management area that limit development of large diverse habitats
what is an example of where maintenance of critical biodiversity composition and ecological processes worked and didn't work?
worked: fire regimes in North America
- encouraged regeneration and reduced major fire damage
- some trees need heat from fires to release seeds
- led to many different aged trees in ecosystems
didn't work:everglades and woodstorks
- restoring natural flows failed to prevent Woodstorck pop declines as specific habitat needs not met
explain the Ethiopian wolf and rabies control- give 5 points and then explain
a) the external threats, b) external benefits
c) primary management
d) secondary management
- wolf endangered and endemic to Ethiopian highlands
- lots of dogs transmit rabies
- 500 adults and sub adults in 7 isolate populations
- pop decline
- rabies outbreak 1990/91 and 2003/4 causing 76% decline
- canine distemper
- transmitted by dogs
- public health and ecotourism
- dog vaccination and sterilisation
- uptake rates less than ideal
- reduce livestock predation and perception of risk
- education regarding external benefits
- ensure external benefits realised
what does adaptive potential require and what does this conflict with?
requires natural secltiona dn individual death which conflicts with conservation goals
what is an example of where the capacity for evolutionary processes are conserved?
amakihi birds in Hawaii
- threatened by habitat loss and malaria
- recovering at low elevations despite high rates of malaria infection
- the exposure to malaria can evolve resistance
linking to regional levels of evolutionary processes:
- what is global species richness a balance of and what does most conservation focus on?
balance of speciation and extinction
most conservation cuses on extinction
management should be minimally intrusive- what is the black robin example of a success story but with major errors?
- chatham island
- tom tits were exterminated on island with robin as are competitors
- double clutching and cross fostering occurred (the first clutch removed and looked after separately)
- failed with first trial species
- only tom tits could rear the clutches
- had to transfer eggs to another island
what are the 6 stages of an adaptive management framework?
1. conceptualise (define initial team, vision, targets, threats)
2. plan actions and monitoring (goals, strategies, monitoring plan)
3. implement actions and monitoring (work plan, timeline, budget)
4. analyse, use, adapt
5. capture and share learning
why is adaptive management needed?
due to possible unintended consequences
what is an example where management has cause unintended consequences?
island fox U.littoralis
- only occur on island
- critically endangered
- feral pigs cause habitat destruction and attract golden eagles that predate foxes
- removed pigs but increased eagle predation on foxes
a) what does CEBC stand for?
b) why do conservation managers have limited access to data on management effectiveness?
c) how does CEBC aim to deal with this?
a) centre for evidence based on conservation
b) -poorly connected with each other and scientific community
- much data in grey literature or not written down
- time and financial constraints on data access
c) conducting systematic reviews and freely publishing results
why can't the impact of CO2 today be predicted by historical CO2?
unknown rate of climate change for at least 500,000 years
in 2016 what was CO2 conc and what will happen if this is crossed?
400ppm- if crossed will be irreversible damage
- roughly how many greenhouse gases
- which is especially more powerful than CO2?
- CO2 is currently rising more rapidly than methane but how may this change in the future?
- feedback loop where warmer temp leads to melting of permafrost which can release methane and lead to more warming
for IPCC climate change in 2007:
a) is natural forcing a good predictor for climate change?
b) what happens/what is revealed when climate change is predicted with natural and anthropogenic forcing?
b) predictions closer to observed values
- predict differences between observed temp and temp in 1900 better
- human influence on climate change system clear
what is the biggest single contribution to radiative forcing?
what are 4 major abiotic impacts on climate?
- higher temp
- changes in rainfall
- ocean acidification where carbonic acid produced affects marine species
- sea valorise primarily due to thermal expansion
where has had increased rainfall and where has had decreased?
most of Russia and Asia increased
rest of world decreased
specifically where has there been predicted drought?
amazon basin- impacts amazon rainforest, increased tree mortality and more CO2 released into atmosphere
under medium emission scenario what were the UK 2080 predictions for temp and rainfall?
- 50% temp rise
- winter and summer warming
- likely 3c warmer summer but could be 8-9c warmer
- winter will experience higher rainfall so more flooding
- summer rainfall likely reduced by 30-40%
what the the IPCC 2018 report of global warming sase and how did they say global warming could be coped with?
big difference in global warming between 1.5c-2c mean surface temp (small increase has a massive impact)
- can cope if limit global temp change to 1.5c
describe the distribution of Ivy (H.ilex)
- looked where ivy present and found won't occur where warm summer and winter temps
- climate limits their fertility which limits distribution
where are the limits for the small leaved lime T.cordata?
east- winter cold limit
north- summer cold limit
south- summer moisture limit
for both high and low latitudinal range edges what % changed as predicted?
- what is the mean rate of latitudinal range shift per decade?
- where do Northern distributions shift?
- 6.1km per decade
- shift closer to pole
- what has mean rate of latitudinal range shift accelerated from and to?
- where is it faster?
- what can range shifts sometimes track?
- 6.1km per decade to 16.9km per decade
- faster in areas with rapid warming
- track climate change
in terms of UK invertebrates give 4 points about their latitudinal range shift
- most species moving north
- fastest rate 120km per decade
- some aren't shifting
- 22% shifting in opposite direction
what do species traits not predict?
shifts in distribution
how may species traits explain variation?
- if greater dispersal ability
- reproductive rate
- ecological generalisation
in UK what % are shifting ranges and why?
protected areas use ratios above 1
what is the variation in range shifts for Dartford warbler and silver spotted skipper in UK?
- dartford expanded range a lot
- silver spotted have more limited species distributions shift
- the newly colonised sites match the protected areas
- protected areas are of the highest quality
- environmental quality is limiting range shifts in distributions
for the silver spotted skipper range expansion what model was used, what did it explain?
- metapopulation model- looked at patch occupancy and area and connectivity
- explains 85-90% variation
- explains limiting northwards range spread and expansion due to habitat fragmentation
what does a 300m increase in altitude cause temp to do?
falls by 1.5-3c
do you expect a stronger response in latitudinal or elevational range shifts and why?
elevational as a shorter distance
in Yosemite (national park) what has happened to small mammal range shifts?
shifted upwards 500m over last 100 years
over the last 40 years on mount Kinabalu where have geometrid moths shifted?
what kind of shift is more limited?
what is a poor predictor of altitudinal shifts?
roughly what is the temp difference between the sides of the mountains?
why may vegetation shifts on mountains be delayed?
trees long lived and there may not be sufficient habitat to support communities
what are the 2 principles of bioclimatic envelope models?
- principle is to record relationship between current species distribution and current climate
- feed predictions of future climate into this relationship to predict future distributions
what is the predicted range loss in % of Appalachian mountain salamanders (southern, mid latitude, northern)
southern species: 85-100%
what was the range shift for dartford warbler?
- occurs across Europe
- northwards shift by late 21st century
- decrease in overall range size
what are 4 general findings of bioclimatic envelope models?
- NE shift in range boundary: typically several hundred km
- average future range 80% current range
- average overlap of current and future range 38-53%
- mean for endemics for Europe is 14-34%
what are the 4 main problems with the bioclimatic envelope model?
1. not based on global ranges: climatic distribution association may not be reliable
2. spatial scale is based on average conditions in a large grid cell which can have a lot of variation
3. ignores local adaptation: assumes all individuals have identical response to climate
4. assumes that climate regulates range limits
what is an example of where bioclimatic envelope models not being based on a global scale is an issue?
- predicted to lose 75% existing range
- new range 65% size of former range
- actually occurs in Africa so bioclimatic approach may be overestimating impacts of climate change
- species can cope with much drier and warmer climates
for the silene ciliate plant was is the difference in temp in the seeds at high and low sites?
1.8c cooler higher up mountain
low site seeds from the low site have higher survival than if from higher elevation site and vice versa
- evidence of local adaptation and home advantage
what are 2 examples of where the bioclimatic envelope model assumes that climate regulates range limits?
dispersal (azure winged magpies have limited dispersal capacity to move into environments outside of range
competitive interactions (thrush distributions are limited by competition not climate)
human factors may be more important than climate- give an example of where this may be true
red backed shrike
- common in England in 1970s
- BEMs predicted expansion in range by 1990s
- but range contracted sue to changes in the farming landscape
- habitat specialist whose requirements weren't met
- human induced habitat loss
on Kilimanjaro what happened to the upper tree line 1976-2000 and why?
shifted down slope by 800m
- changes in human activity and drought and deforestation higher up mountain
what was the British birds study in 2008 for bioclimatic envelope models?
1 group represented fire crest- north UK distribution limit
1 group represented red wing- southern UK distribution limit
- models predicted species population trends and that warm adapted species increase
what were the 2 types of UK butterflies with range limits introduced into sites north of their range and what happened?
marbled and small skipper
- population increased steadily following introductions
what can improve predicting capacity for species responding to climate change?
when you add other factors into the model
what are the explanatory capacity powers of distribution models for grasshoppers and butterflies in Belgium for each of these:
b) climate and land cover
c)climate and soil
d) climate, land cover and soil
a) B: 47% G:31%
b) B:57% G:44%
c) B: 59% G:40%
d) B: 68% G:50%
what are many species predicted to have in terms of their ranges?
limited overlap between current and future ranges
why are many species not currently tracking climatic shifts?
have to facilitate dispersal
what are the 2 white paper recommendations for making space for nature and who proposed them?
- enhance connections between/join up sites either through physical corridors or stepping stones
- create new sites
how many nature improvement areas were identified in 2012?
what is an example of a new site for colonists ?
ham wall RSPB reserve
- wetland complexes delivering success for breeding herons and other birds to improve breeding
- allows species to shift distributions
not all species can shift distributions accordingly so what is needed?
- move species outside of native ranges to combat problems of climate change
- but non native species can have detrimental impacts in ecosystem introduced to
if low risk of decline/extinction due to climate change what is the approach?
if moderate risk of decline/extinction due to climate change what is the approach?
improve connectivity and traditional conservation
if high risk of decline/extinction due to climate change and translocation not feasible and habitat can't be created what is the approach?
ex situ conservation (captive breeding)
if high risk of decline/extinction due to climate change and translocation not feasible and habitat can be created with individuals arriving unaided what is the approach?
wait and protect colonisers
if high risk of decline/extinction due to climate change and translocation not feasible and habitat can be created with individuals arriving aided and translocation benefits outweigh costs what is the approach?
in mammals what kind of impact do intracontinental introductions have?
what 4 species are argued should be introduced into UK due to threat of climate change?
- pyrenean desman
- iberian lynx
- Spanish imperial eagle
- caucasian wing nut tree
what 2 things are combined for range shift?
local extinction and local colonisation
extinction is a gradual process- so what is needed to understand mechanisms of range change?
understand mechanisms of pop growth and demographic traits
for what two reasons do mechanisms matter ?
- incorporates co-occurence of plants
- improves fit of models to actual data
in the eastern fence lizard of North America what are the 3 different mechanistic models and what do they differ in?
differ in prediction of how species range and species distribution
1. biophysical threshold: foraging duration and how temp influences ectotherm foraging capacity
2. life history: winter survival, summer recruitment
3. recruitment and foraging energetics
what are the 3 broad types of mechanisms?
1. direct impacts: physiology
2. indirect impacts: altered species interactions
3. indirect impacts: habitat changes and human responses
describe the mechanism of direct impacts such as drought and heat stress on Australian small birds
- stress due to arid conditions
- peak water requirements increase by 150-200% so risk of massive die offs
- crowd into shaded areas and small pools of water but can't meet requirements
explain in detail (points) the direct impacts mechanisms for trees in SW USA 2012
- 355 data sets
- 13,100 trees
- 3 different conifer: pinon, ponderosa pine, Douglas fir
- forests die back
- tree ring analysis (narrow rings when drought and measures drought stress index)
- drought stress increased in recent decades
- less green vegetation
- increased no. dead trees so more flammable so wildfires more likely
- more pests of bark beetles
- by end of century drought stress index increased dramatically, wiping out forests
what can tree ring analysis be used for?
- to see how well tree growing by width of rings each year
- narrow rings= drought
- can be used to measure forest drought stress index
what are suitability maps based on?
what is the 'suitability' change of UK pedunculate oak and sitka spruce ?
- growth rate suitability will drastically change by 2050 in low and high emission scenarios
- parts of UK less suitable for tree types
- impacts ecosystems and species whose habitats UK forest
- decreased tree growth impacts forest dynamics
what are the French bird monitoring data sets for heatwaves?
- 2003 French heatwave
- rook bird decreased pop size due to heatwave
- negative impact
- impacts predictable based on mean thermal conditions of species range
- species from warmer areas of Europe less impacted by heatwave
- species traits influence response to climate change
what is the strong spatial pattern in temp between the northern and southern hemisphere?
larger increases in temp in northern
what is the thermal safety margin?
max increase in temp that species can withstand before lethal impact on individuals
where is the thermal safety margin found to be lower ?
tropical regions as are more vulnerable- temperate species can cope better with impacts of climate change
anolis cristatellus lizard:
- what impacts populations and how and what is it mediated by?
- in 1973 what was the daytime temp?
- what was the temp rise in 2008?
- what is the warming doing?
- what is caused?
- summaries the result of the interaction
- temp change impacts pops by altering how they use their environment- sun rises body temp increases- mediated by changes in body temp
- 1973 daytime temp within optimal body temp
- 3c rise so body temp above optimal conditions impacting performance to be 50% of 1973
- forcing lizards into shaded cooer area where other lizard specie are
- interspecific competition, shift in habitat use and species distribution
- interaction between direct thermal impacts of climate change on body temp influencing lizards performance leading to shifts in habitat use and one species outcompeting another and local extinction
some species benefit from the cod and are heat and drought stress winners - give an example
- birds are limited by winter cold as it reduced access to food resources and reduced survival such as the wren
- pop increases when warmer winter
what is the population size of passerines limited by in temperate regions?
overwinter survival due to harsh winters
some communities are resilient to impacts- explain the 2008 peak district limestone grassland study
- plots exposed to heat, drought, extra water
- includes Forbes, shrubs, grasses, sedges
- no long term change in vegetation community
- species composition resilient
- community reorganisation at small size as variable habitat
- variation in soil depth buffering plant community from impacts of climate change
- increased soil depth allows for access to water
what is phenology?
timing of biological events such as flowerings and breedings
what is an example of a phenological shift in the northern hemisphere?
spring events getting earlier as an adaptive response to phenotypic plasticity
in what 2 ways would you measure phenotypic plasticity?
- first events: date when leaves produced
- mean timing (across population of many trees)
what is the phenological shift for leaf bud bursts affected by winter and summer temp?
- vegetation adapted for chilling in winter before adapted to spring
- warmer winters can impact the bursts and the wintering chilling and flowering development not met
what is the phenological shift in long tailed tits?
warmer march temp leads to earlier breeding
phenological shifts can occur at the community level- give an example
2010 UK ecosystems study on marine, terrestrial, freshwater ecosystems
- looked at response of plants, invertebrates, vertebrates
- difference in response of groups at different rates for terrestrial ecosystem with plants shifting for the most days per year
- marine and freshwater show opposite pattern with different trophic levels responding at different rates
what can phenological shifts at the community level lead to?
what is the timing of breeding adapted to suit?
seasonal peaks of food abundance
what is the shifting of timing of breeding divergent to and why may this be a problem?
divergent to peak food abundance but different trophic levels respond at different rates so may breed after the food supply
give 5 points about the 2003 caribou trophic mismatch example
- timing of breeding the same- timing of plant development much earlier
- trophic mismatch correlated with date of emerge of key species that caribou forage on
- plant species emerging earlier so stronger mismatch
- leads to earlier calf mortality and calf production declining
describe the trophic mismatch for the pied flycatcher
- breed in broad leaved woodland in UK and Europe
- feeds on flies and caterpillars
- peak abundance of insects early spring, especially caterpillars as indicated by pitfall traps
- food abundance hits peak after timing of breeding in pied flycatchers so pop declining
what will species in different habitats with different patterns of seasonality have?
different levels of vulnerability to trophic mismatch
are migratory species or resident species declining more rapidly and what may be the general mechanisms behind the decline? why?
due to trophic mismatches
- different climate in winter to breeding grounds so aren't exposed to cues for indicating spring on breeding grounds so don't know when to migrate
what was shown when the 200 population trends of migratory bird species was studied?
- looked at change in spring migration date
- populations of migratory bird species didn't show phenological response to climate change so are declining
in the uni of Sheffield bird study 2014 what was the aim, what was assessed/tested for and what were the 3 species?
- aim: test for carry over effects and trophic mismatch
- testing: for trophic mismatches to assess importance of climatic impacts, influence of winter, passage and breeding climate on breeding programme
- species: spotted flycatcher, wood warbler, redstart
in the uni of Sheffield bird study what were the 4 annual means taken for the nest record scheme?
- first egg date
- clutch size
- brood size
- fledglings per breeding attempt
in the uni of Sheffield bird study what were the 2 phenology results?
- big influence during Mediterranean passage zone rather than wintering zone
- conditions in spring passage enable birds to migrate more rapidly if conditions favourable- shifting breeding dates early
in the uni of Sheffield bird study what were the 3 performance results?
- little impact of breeding climatic conditions on breeding performance
- winter and passage area impacted breeding success more
- due to carry over effects favourable conditions during migrations enable birds to arrive in better body condition on breeding grounds so can invest more in reproduction
in the uni of Sheffield bird study what was the impact of breeding conditions?
in opposite direction to what would be expected from trophic mismatch hypothesis as warmer conditions benefiting breeding success
for what 4 reasons may trophic mismatch not be as important as earlier literature suggests ?
1. climate change can reduce abundance of food
2. population size may not be regulated by breeding success - need to understand whole annual cycle to know impact of climate change
3. diet swaps can occur
4. climate change could be leading to longer vegetation growing seasons changing suitability of nest sites
where is spring warming more rapid?
northern rather than southern hemisphere
what happens If breeding times are shifted for large bodies birds such as the buzzard?
long incubation periods so chicks will hatch in cool summer conditions which are less suitable so have reduced survival rates
what does rapid increase in industry lead to ?
increase in N deposition
in terms of N deposition what was the study in the Peak District example?
1995-2006 quadratic treated
2006 onwards half treated half in recovery
- limestone grasslands: species rich
- acidic grasslands: fewer species
- high N deposition plot had 1/3 vegetation die off during drought conditions
- N deposition has negative impacts on species survival rate
in what case may impacts not always be predictable?
from studies of single environmental change
what is the resource conservation ethic advocated by John mill described as?
aligned with an ecosystem service approach to nature conservation
The IUCN red list of threatened species uses population size as one criterion for
listing species. What is the correct definition of population size for assigning
mammals to IUCN red list categories?
the total number of sexually reproducing individuals
Conservation biologists often attempt to diagnose the cause of a population
decline by comparing the timing of the decline with the timing of environmental
change what are 2 problems with this approach?
- time lags
- multiple environmental factors may change at the same time
what can the demand for rapid knowledge lead to ?
poor science and advocacy
what are the 3 ethical approaches to discipline origins?
- romantic transcendental ethic
- resource conservation ethic
- evolutionary ecological land ethic
in conservation biology was was the focus in 1960s/70s
broader concerns such as pollution and population growth
what disciplines does conservation biology interact with?
social sciences and economics
for what 2 reasons why may we select conservation units?
- essential for effective and efficient planning given limited resources
- aim to protect biodiversity