Lecture 18- Food Webs II

Question 1

What is environmental stability?

Answer 1

Interactions between species disrupted by environmental fluctuations

Question 2

A stable environment equals?

Answer 2

Diverse and interconnected food web

Question 3

Highly seasonal environments equals?

Answer 3

Less diverse and poorly interconnected food webs

Question 4

What is the match-mismatch hypothesis?

Answer 4

Central concept for understanding how climate and life history (events/stages) interact

Question 5

Match-mismatch hypothesis is based on _____

Answer 5

Phenology

Question 6

What is phenology?

Answer 6

Timing of life history events (like when the leaves emerge, flowers, when birds lay their eggs, when they leave the nest, when they migrate)

Question 7

Phenology is triggered by ____ and ____ environmental cues

Answer 7

• Temperature
• Photoperiod

Question 8

Phenology is also tied around ____

Answer 8

Resource availability

Question 9

How does resource availability interact with phenology?

Answer 9

Species matching their resources when its best when demand for resources and resource availability have a higher overlap

Question 10

Optimizing offspring fitness when ____ is high

Answer 10

Food abundance

Question 11

The match-mismatch hypothesis assumes ____

Answer 11

Seasonal timing of reproduction is fixed

Question 12

What happens when the timing of reproduction doesn’t match with the timing of resource availability?

Answer 12

• Not getting enough food availability and less survival
• Mismatch fo demand and supply

Question 13

What are the three main effects of climate change?

Answer 13

1. Changes in relative timing of prey (shift in timming of food availability = not much overlap)
2. Changes in level of prey abundance (Can have lots of overlaps with resources but there is less resources overall)
3. Changes in amplitude of annual variations (spaw worked out well, then the following year there was not enough resources, more population fluctuations)

Question 14

What is happening to great tits?

Answer 14

• Earlier selection on earlier breeding
• Later breeders are not selected for because the babies often dont survive because no resources
• Selection pressure on birds who breed earlier

Question 15

What are the effects of climate change on migratory birds?

Answer 15

• No change in timing of spring migration
• Earlier spring in breeding gorunds, plants green up earlier
• Increasing mismatch between arrival and development of high quality food.
• Decline in recruitment of juveniles leaving for fall migration

Question 16

What is happening to puffin due to climate change?

Answer 16

• Herring body size is related ti water temperature
• Warmr water = smaller herrings
• Success is higher when herrings are larger

Question 17

What are some implications of climate change on caribou?

Answer 17

• Ecosystem structure and trophic interactions may be changing
• Mismatch will have major implications
• Largely affects recruitment of juveniles