ECEC - 9 Flashcards
what is a trend and some examples?
over long period of time working out a mean – gradual changes e.g CO2, temp , precipitation, N deposition
what is an extreme event and examples?
quick sudden changes with severe effects e.g. drough, heatwave, storms
why are extreme events becoming more frequent?
due to climate change -more changes in trends like increases in mean(e.g. overall warmer weather means very hot weather more likely) and variance
what is the return time for extreme hot summers?
5 years but used to be 52 - 10 fold increase in just a decade
why are extreme weather events a problem?
causing deaths and really expensive damage
is there evidence for links between trends and extreme events?
yes there is evidence for links between heat waves, droughts and precipitation
what are the ecological implications for extreme weather events?
its a problem for long living organisms not equipped for sudden change - Result in system with a new balance under new (trend) climatic conditions
the definition of extreme is abruptness, how do you measure abruptness?
magnitude/ duration - duration is relative to lifespan of organism
what affect does rain on snow have on reindeer populations?
as there is more rain on snow the reindeer population decreases due to increase in ground ice and warming means more rain on snow
what affect did the increase rain on snow have on arctic trophic interactions
close synchrony between all 3 herbivores and the consumer (arctic fox) - rain on snow causes increase in ground ice - less food
how are global extremes calculated?
Monthly mean temperatures: 17 stations around the world
Ratio = observed extremes vs extremes expected in a “businessas usual” (stationary) climate (=1)
what is ‘extreme’?
climatically - 95 percentile
ecological abruptness
The soil-water-bucket concept suggests that more extreme rainfall patterns (longer time between rainfall, with greater amounts falling in each rainfall event) will put most stress on which ecosystems?
mesic ecosystems
what did the Konza prarie field study manipulation show?
Lengthened inter-rainfall interval:
- more variable soil water content
- 10% reduction in productivity
Rain on snow events result in close synchrony in the population dynamics of reindeer, sibling voles and rock ptarmigan on Svalbard. what is the reason that synchrony of arctic fox populations is delayed by one year?
High mortality in prey from winter ground icing produces large quantities of carrion that increases success of spring breeding in arctic foxes
