impacts of anthropocentric climate change on ecosystems

Question 1

what is phenotypic plasticity?

Answer 1

ability of a single genotype to produce alternate phenotypes in an environmentally dependent context

Question 2

what happens to fish when water becomes warmer?

Answer 2

1. warmer water contains less oxygen
2. fish require more oxygen at higher temperatures
3. larger fish cannot compensate with oxygen declines
4. increase in smaller fish

Question 3

what is the Gill-Oxygen Limitation Theory?

Answer 3

growth of gill surfaces cannot keep up with the oxygen demand of growing 3-dimensional bodies
-> gill surface area does not increase in constant proportion with fish body weight

Question 4

what is Allen’s rule?

Answer 4

appendages of endotherms will be larger in warmer climates because they need to do lots of dumping of heat loads

Question 5

what behavioral adaptation must reptiles adopt with climate change?

Answer 5

they must retreat to cool refuges, although this leads decreases their long term survival because they can’t reproduce or eat in refuges

Question 6

what is phenology?

Answer 6

study of recurring plant and animal life cycle stages that are influenced by environmental changes (especially seasonal variations in temperatures and precipitation)

Question 7

what is happening with life cycle stages with regards to climate change?

Answer 7

life events are happening earlier in the year

Question 8

what is the problem with changes in phenology?

Answer 8

not always adaptive! for example, birds have shfited their egg-laying date but not the date of their spring migration

Question 9

what are plant/animal species doing to adapt to rising temperatures?

Answer 9

• going north
• going up in altitude

Question 10

what are the limitations to shifting biome ranges?

Answer 10

• dispersal rates
• land-use change and fragmentation

Question 11

what issues are populations facing who are now isolated on “mountaintop islands”?

Answer 11

they face small island problems, less food, less genetic diversity

Question 12

what are the consequences of increased shrub growth due to climate change?

Answer 12

threatens caribou:
- shrubs crowd out lichens (caribou’s food)
- shrubs collect snow which makes it harder to reach lichens beneath
speads up rate of warming:
- snow trapped by shrubs insulates soil, keeping it warmer over winter -> arctic microbes increasing activity making soil better for shrubs (positive feedback loop)

Question 13

what is an example of the impacts of climate change on phenology and biotic interactions?

Answer 13

the nesting period of birds not coming up after the caterpillar stage (what they eat) which relies on the leafing stage

Question 14

what is the example of the effect of climate change on daphnia zooplankton?

Answer 14

as CO2 levels increase in the ocean, their predator perception is diminished so their defense expression decreases -> they can no longer properly defend themselves against predators

Question 15

how does climate change affect plants and herbivore interactions?

Answer 15

1. higher temperatures means that there will be higher insect growth rates causing more plant damage
2. warmer winter temperatures reduce overwinter mortality among herbivores and increase foraging
3. if there are more herbivores, the plants may have to invest more in defense which will have a negative effect on edible available biomass

Question 16

why are wildfires increasing in intensity?

Answer 16

• we stop little fires which leads to big fires (buildup of dead fuel)
• longer, more intense summer droughts are stressing out trees
• beetles attack stressed trees (more dead fuel)

Question 17

what types of plants are taking over the arctic with help from fires?

Answer 17

shrubs! fires are consuming lichens and giving soil nutrients and warmth to facilitate shrub growth

Question 18

why are mountain pine beetles thriving with climate change?

Answer 18

• they prefer lodgepole pine which is abundant because of fire surpression
• beetle larvae are killed by severe winter cold snaps which happen less and less with warmer winters
• positive feedback loop because the trees they kill are becoming sources of CO2

Question 19

what are some examples of population declines due to climate change?

Answer 19

• trees (species richness and density decreasing)
• butterflies due to early migration before milkweed is available
• seagrass meadows due to more seawater intrusions and increase saline conditions and depth
• birds due to phenology
• polar bears due to decrease in sea ice