Species Level Impacts Of CC Flashcards
What are the 6 types of response a species could do
- Behavioural
- Adaptive micro evolution
- Adaptive macro evolution
- Changes in geographical distribution
- Abundance changes
- Extinction
Wrong order
How much of the earths surface will have novel climates by 2100 with about 2 degree warming
20%
Thermophilisation
thermal migration (degree per year)
Thermophilisation of communities mainly driven by cold adapted spp mortality. Change in community composition- non analog.
Liana
Incr in liana in long term monitored plots in tropical rainforests eg amazon
abundance assoicated with low tree biomass. They put lots of leaves into canopy–> shade.
Thought to benefit from increased CO2 more so than trees. Proportionally greater leaf area –> greater C fixation channeled into growth than trees.
BUT experimental evidence suggests that temp is the influencing factor –> needs to be tested. lianas aren’t growing THAT much more than trees are therefore not co2
Spp level impacts
Behavioural
Include phenological shifts. No genetic adaptive component. Rapid, can be elicited even by seasonal climatic patterns or intra annual variability. Issues discussing this with cc that there are huge differences year on year
Spp level impacts
Adaptive microevolution
Predominant response to relatively slow to moderate rate of change at moderate magnitude. Results from selection amongst pre-existing genotypes
- variability generate by recombination of alleles resulting from sexual reproduction and crossing over of chromosomes during meiosis
- relatively rapid- not dependent on favourable new mutations
- limited in scope by pre-existing genetic variability
Selecting for what we already have
Spp level impacts
Adaptive macro- evolution
Elicited by relatively slow and especially larger magnitude changes. Depends upon chance acquisition of mutations favoured by new condition. Underlies evolution of major lineages over geological time scales eg forestation –> mammoths couldn’t survive
Spp level impacts
Changes in relative abundance
Rapid changes, small magnitude. Results from sensitivity of species key life-cycle stages to the environment. Changes not only in composition of communities but also the structural attributes of ecosystem. Lots of what we see now with CC in last few decades.
Spp level impacts
Spatial responses
Predominant response
Especially changes of relatively large magnitude occurring relatively rapidly. Linked to spp dispersal capabilities. rate at which spp can extend geographical distribution into newly suitable areas or its ability to colonise such areas when they are isolated from its current range, largely determined by diserpsal.
Spp level impacts
Extinction
Species unable to disperse rapidly enough or over such long distances, and or unable to evolve suitable enough adaptations to new conditions. Condition to which they are adapted for no longer available. Spp most at risk: spatially limited environments, small pops, long lifetimes, low reproductive output, relatively sedentary, prey not moving
Phenology
Timing of key events in organisms life cycle
Events usually triggered through mechanisms sensitive to day length or to seasonal climate- most often seasonal temps. Changes can affect organisms that rely on home. have record of eg daffodils way back so can see how they’ve changes
Phenocam
Can get shots across landscape about what’s happening daily, eg leaf colour, bud burst, can also link it up with CO2
Also get satellite access to assess greenness. Can see changes over the year. Good way of remotely getting data
Earth Observation data, time series of data provide a way to monitor global phenology in terms of greening
Multiyear data sets provide a basis for analysing the relationships between global and phenological patterns and climate. These data also highlight the phenology of the seasonal tropics where moisture availability, rather than temp, controls the pattern of greening (the ‘hydro period’)
Photoperiodic triggering
Higher plants- flowering. Both long day (respond to incr day length) and short day flowering responses
- leaf abscission
Animals- short day responses- insects enter diapause
- migratory bird changes
- long day reponses- insects break diapause, inception of antler growth
Seasonal climatic triggering and garden experiments
78 sites across europe established in 1957.
Series of clonal vegetatively propagated plant taxa grown in each garden, so phenological differences aren’t due to genetics. One or more annual phenological events recorded from each taxon in garden. Cover range of longitude and latitude.
Individually maintained records also valuable- eg Gilbert White ‘natures calendar’ citizen science
Mechanisms of triggering rarely known. Most info we have if from observation of interannual event timing and climate
evidence of timing changes
in Eu many plants have been flowering and leaf unfolding 1.4-3.1 days per decade earlier (over last 30-48 years)
18 butterfly spp in UK, 2.8-3.2 dvd earlier appearance (23 yrs)
Numerous bird spp, Eu and N USA, earlier spring migration 1.3-4.4 did earlier and breeding 1.9-4.8 did earlier (30-60 yrs)
Over long periods this data has been collected so not just inter annual variability
Evidence of phenological responses for 677 spp
Parmesan and Yohe 2003
Phenological records for 677 spp over a time period of 16-132 years.
62% showed advancement in date of spring phenological events
Overall mean trend about 3dpd advance
Differences between major taxonomic groups
- mammals about 10 dpd
- amphibians 8dpd
- herbaceous plants 1dpd
- shrubs 1 dpd
Northern hemisphere first leaf data also earlier Comparison of phenological and temp date indicate strong correlation. Given large number of spp responses
–> causal (v likely)
Decades worn change genotypes not long enough. particularly perennial plants that live for ages
Mismatching example
Spp A responds to photoperiod
Spp B responds to accumulated warmth
B feeds on A and its phenology was optimised to synchronise its emergence when A was most abundant/palatable/nutritious
following warming, B emerges too early and suffers food shortage - may delay development and incr exposure to predation
Growing degree days
Accumulated warmth
At day 0 is threshold day
If we know a plant strats growing at 5 degrees we take every days temp and all days over 5 degrees we take difference (10-5=5) Then sum
Thats the thermal sum when plants start to grow
Budburst of oak and moth hatching
Vissec and holleman 2001
incr asynchrony between bud burst of Pedunculate oak and egg hatching in winter moth
Synchronisation ensures larvae fed on newly expanding oak leaves. they are soft, highly nutritious, palatable (tannins and other phenolics that protect mature foliage haven’t accumulated yet)
There s been a series of warm winters since 1975 where egg hatching and bud burst were near synchronous in 80s, but by 99 the eggs were hatching about 20 days too early.
Newly hatched larvae survive about 2-3 days without food (max 10).
Asynchrony= deaths of large proportion of larvae
many small birds that eat the larvae- important for their young- effected too
Earlier spring greening consequences
If leaf fall is not advanced or even delayed, ought to have increased photosynthetic uptake and hence slow the rate of atmospheric co2 conc … if warmer winters do not compensate by increased respiration rates
during 70s and 80s seasonal amplitude of the Mauna Loa Co2 curve incr indicating both phot and respiration rates increased
Recent work has shown enhanced summer phot was principally in N uSA, enhanced winter resp principally in eurasia. Amplitude declined in 90s related to the effect of summer droughts on photosynthesis in N uSA
Then increase sharply after a return to more typical rainfall in 2004 - signal is confounded by changes in predominant circulation patterns. Reduced transport of air masses from eurasia to n hemisphere also contributed to reduction in amplitude seen in 90s.
Budburst in Fennoscandia
Bennie et al (2010)
Betula pubescens (downy birch) in Fennoscandia. They successfully modelled bud burst in relation to spring temps and frost incidence. But relationship varies systematically across spp ranges with a small heat sum needed for bb. Degree days changing in system
Black cap and plastic adaptation
Sylvia atriacapilla
Breeds widely throughout europe and exhibits a variety of migratory behaviours. Some populations migrate to subsaharan Africa for the n.b seasons, some only to iberian peninsula, or other to Eu, North Africa.
More recently numbers of some central eu pops that typically migrated SW to iberian peninsula are migrating W/NW and spending nb season in british isles
Plastic adaptation
Occasional overwintering from 50s onwards; ringing showed where they were from.
1965 some members of central EU pop regularly migrated to spend nb here. 1000-1500km north of other wintering areas around mediteranean. Berthold et al (1992) showed this to be an inherited trait
10% of breeding populations in Germany and Australia now migrate to british isles
Fossil record
As yet, ancient DNA records limited to non-coding regions so tells us nothing about potentially adaptive changes. Principally have evidence of morphological adaptation to quaternary climatic cycles- few examples
Bushytailed woodrat one
Bushy tailed woodrat
Neotama cinerea
Found across a range of latitudes in western north america. Exhibits a body size cline with latitude. Individuals north on average larger than those in south (Bergmans rule)
Body mass can be estimated from fossil remains
- series of fossil in central current range measured and C14 dated
- body mass greater than today during last glacial and showed a minimum corresponding to independently inferred maximum regional temps during early holocene
- inferred to an adaptive response to CC and probably a genetic determined response
- range of inferred body mass fall within range observed at present day along cline–> adaptive response limited by spp inherent genetic variability
Snail
Pupilla muscorum
Small snarled that exhibits a marked W-E cline in shell morphology across its Eu range. Shells from deposits in france representing full glacial, interglacial, and interstadial intervals examined
Interglacial shells match morphology of modern shells from France
Glacial morphology closest to modern shells near the spp present eastern range limit in Poland
Interstadial intermediate in form, closest to morphology from near the longitudinal centre of spp range
Likely shell morphology genetically determined range of forms once again encompassed by spp present variability
Indirect? but fits nicely with thesis that things change in response to climate
Adaptive vs spatial response
Observed adaptive genetic responses are the local expression of the spatial response. Possible that most species could not realise such adaptive responses without also a spatial response
- breadth of response in rat and snail probably made it possible only by movement of the spp range and of populations across that range and in response to climatic changes
pic on phone
Weight of evidence suggests adaptive genetic responses were a secondary response to quaternary climatic functions
- no examples to suggest a dominant evolutionary response
- Bennett (90,97) agued that the relatively rapid Quaternary climatic fluctuations led to frequency reversals in selective pressures with the result that, at least for higher organisms, evolving to adapt to these fluctuations is a viable option
- rapid fluctuations may have selected fro the ability to achieve rapid spatial responses –> perhaps also for rapid gene flow through spp that would facilitate local adaptive responses
(little genetic evidence from fossil evidence)
