Phenological shifts

Question 1

What are phenological shifts? Models? Example?

Answer 1

• Timing of events shifted
• Spring events getting earlier, and autumn events later in lots of spp
• Can be recorded for first event that occurs or mean of population
• Phenological models are robust - like leaf bud burst can be done for spring temp models, and spring & winter temp models (plants have certain amounts of chilling till bud burst)
• Winter temps predicted to increase in UK (problems for bud burst)

Question 2

Phenology at community level - trophic levels

Answer 2

Plants, inverts and verts…
•terrestrial ecosystems, plants responding most, inverts intermediate and verts less
•freshwater - opposite relationship
•different trophic levels are responding at different rates
-TROPHIC MISMATCH

Question 3

Times of breeding to match food abundance problems…

Answer 3

Results in verts breeding after food peaks have occurred
•Shown in caribou populations breeding at same time but spring green-up happening earlier
-mismatch correlated with less calf production and increased mortality

Question 4

Migrant bird problems

Answer 4

Found to be more vulnerable to trophic mismatch than non-migrant birds
-not exposed to changes in breeding ground climate
-don’t receive cues on when to start migrating to breed so young receive max food supplies
-clear relationship found when birds are migrating earlier trends are positive
•Spotted flycatcher = showed passage zones had impact on breeding rates as can pass quicker if weather good
-winter and passage conditions important = carry-over effects (arrive in better condition, can invest more in reproduction)

Question 5

Experiment to assess CC impacting populations

Answer 5

• Breeding phenology and performance - use observation data like that from BTO
• Climate predictors using their breeding grounds (look at bud burst, nesting temp and rainfall, chick-rearing temp and rainfall)
• Passage and wintering areas (mean temp and rainfall)
• Wintering and passage distributions data based on range maps and ringing recoveries

Question 6

Is trophic mismatch THAT important?

Answer 6

• climate impacts on food abundance will be more important
• pop size may not be regulated by breeding success - understand populations whole life cycle
• Behavioural flexibilities with diet, vegetation and nest site can change
• Maladaptive shifts though - Buzzard breeding earlier so chicks hatch in cooler summer, reduces survival - declining pop

Question 7

Multiple CC factors…

Answer 7

N deposition for example…
•development of countries causes increase
•impacts on Peak District in spp rich limestone and spp poor acidic
-dramatic impact of drought on plots receiving more N deposition
•in high N 1/3 vegetation died off - 3x more than control
•N deposition interacting with drought = negative
Human responses are important
Impacts not always predictable from 1 E change driver