Climate change - range shifts

Question 1

Greenhouse gases

Answer 1

•Last 400,000yrs - tight correlation of CO2 and mean global temp
•400ppm - above = irreversible damage
•Not only CO2 - 16 other GHGs contributing
•Lots of others are more powerful, just less abundant
•CO2 rising more than CH4 but could change
-high temps = melting of permafrost = release of CH4 peat stores

Question 2

Evidence that CC is human lead

Answer 2

Look at temp changes predicted from natural forcing only - doesn’t match what is observed
When take both natural and anthropogenic forcing - matches observed increase perfectly

Question 3

Abiotic impacts

Answer 3

1. Higher temps
2. Ocean acidification
3. Sea level rise - not primarily by melting of glaciers but thermal expansion
4. Change in precipitation - very hard to predict and is variable

Question 4

Precipitation across the globe

Answer 4

•Lots of Russia and other areas will experience more rainfall
•Rest of world will have much
•Lots will experience droughts - especially Amazon basin - major threat to rainforests
-increasing tree mortality, losing the C stores which will then be decomposed releasing more CO2

Question 5

Climate impacts on the UK

Answer 5

•UK for temperature - 2080 predictions both winter and summer warming
-worst case in S England highs of 8-9°C warmer in summer
•Rainfall will see more in winter and summer reduced (30-40% in S)
-some uncertainty, may increase

Question 6

IPCC 2018

Answer 6

Special report on warming at 1.5°C
Lots of cases will not be nearly as bad with only 1.5 than 2°C
Said we have 12yrs to make it happen

Question 7

Species distributions and climate examples

Answer 7

E.g. Ivy - strict climate area it occurs in, out of this it is absent
-Is infertile on its boundary of climates it occurs at - suggesting climate limits fertility
E.g. Small-leaved limes limits caused by winter and summer cold limits and summer moisture - boundaries associated with fertility
Pollen tubes cannot grow below certain tempeartures

Question 8

Latitudinal range shifts

Answer 8

•81% of spp moving to higher latitudes - towards poles
•71% moving their low latitude range edge
•Mean rate of change (Eu, America and Chile) 16.9km per decade
-found faster if warming more
-broadly speaking range shifts track CC - not always
•Looking at terrestrial inverts - lots of spp moving N but lots aren’t or are doing opposite - 22%

Question 9

Species traits explaining variation…

Answer 9

•Greater dispersal ability
•Reproductive rate or get time, or no. of young - can disperse and colonise
•Ecological generalists - cope with wider ranges of conditions
•Meta-analysis investigated this…
-Range size (generalist) negatively correlated…
-Diet breadth positively (generalist)
-Spp traits don’t really predict…

Question 10

Environmental quality explaining variation…

Answer 10

•Dartford warbler - expanded range in UK a lot Silver Spotted Skipper less so
-any new sites = PAs
-disproportionate colonising of these sites
•7 bird spp - range shift into PA use ratio of over 1 = shift into higher quality sites (same for inverts)

Question 11

Altitudinal range shifts…

Answer 11

•300m increase causes temp to fall by 1.5-3°C (due to water moisture in the air)
•As shorter distances than latitudinal, stronger response is expected
•Yosemite small mammals shifted upwards ~500m last 100yrs
•Mount Kinabalu - geometrid moth shifted 65m up in 40yrs
Elevational range far more limited than range shifts

Question 12

Species traits for altitudinal shifts…

Answer 12

Poor predictor
Due to aspect of mountains - N and S faces can differ by 2-3°C in temperature so spp may be moving around mountains instead of up
Or vegetation of such areas are having a delayed shift - may not be a sufficient habitat if animal moves up