Migration and Movement Ecology

Question 1

As per Nathan et al (2008) what are the fundamental questions regarding the movement of organisms?

Answer 1

1.Why move - what motivates this movement; what are the internal goals (internal state)?

2. How to move - how is the movement performed (motion capacity)?
3. When and where to move - when and toward what target is this movement performed (navigation capacity)?
4. Which external factors affect this movement and how (external factors)?
5. How do all four components interact to produce this movement (movement path)?

Question 2

Movement Path

Answer 2

The final movement as a result of the four factors of the movement ecology framework.

A temporal sequence of locations of an individual.

(Nathan et al, 2008)

Question 3

In general, what does Nathan et al’s (2008) framework for movement ecology outline?

Answer 3

It’s a unifying framework for the study of movement ecology that can be used for generating hypotheses on movement.

It can be used at all scales and explores the causes, mechanisms, and patterns of movement, as well as the consequences of movement for the ecology and evolution of individuals, populations, and communities.

Question 4

Describe and draw the diagram for the movement ecology framework proposed by Nathan et al (2008).

Answer 4

Arrows show how the components relate to each other and the direction of impact.

Describe the 4 components.

All four components interact to produce the final movement path which feeds back to external factors and internal state.

The black arrow on internal state is reflecting its multidimensional nature as organisms can have multiple goals at the same time.

Blue arrows = motion process

Red arrows = navigation process

Green arrows = movement propagation process

Solid black arrows = internal state dynamics

Dashed black arrows = external factors dynamics

Question 5

Motion Process

Answer 5

The realized motion capacity given the impact of the current location, internal state, and external factors on the fundamental motion capacity of the focal individual.

(Nathan et al, 2008)

Question 6

Navigation Process

Answer 6

The realized navigation capacity given the impact of the current location, internal state, and external factors on the fundamental navigation capacity of the focal individual.

(Nathan et al, 2008)

Question 7

Movement Propagation Process

Answer 7

The realized movement produced by the motion process and (optionally affected by the navigation process).

(Nathan et al, 2008)

Question 8

How does the movement ecology framework relate to my work?

Answer 8

External factors mostly as I’m looking at how habitat variables impact movement.

Also internal state as I’ll be looking at specific behaviours for turtles e.g., nesting and hibernation.

A bit of navigation capacity - not so much the traits themselves but the results of them because I’ll be looking at the when and where of movement.

Question 9

What does Nathan et al’s (2008) framework for movement ecology characterize?

Answer 9

A focal individual.

Question 10

What is internal state in Nathan et al’s (2008) framework for movement ecology?

Answer 10

The physiological and/or psychological state of the individual that motivates it to pursue its goals.

Could have multiple goals at the same time so this component is multidimensional.

Question 11

What is motion capacity in Nathan et al’s (2008) framework for movement ecology?

Answer 11

The set of traits (e.g., biomechanical or morphological machineries) that enables the individual to move.

Question 12

What is navigation capacity in Nathan et al’s (2008) framework for movement ecology?

Answer 12

The set of traits (e.g., cognitive or sensory machineries to obtain and use information) that enable the focal individual to orient in space and/or time, selecting where (direction and position) and/or when (initiation and cessation) to move.

Question 13

What are external factors in Nathan et al’s (2008) framework for movement ecology?

Answer 13

The set of biotic and abiotic environmental factors that affect the movement of the focal individual.

Question 14

Why do animals move?

Answer 14

Changes in environment (e.g., flow, temperature, water quality)

Reproduction (spawning/nesting/mating)

Feeding

Escape from threat

Leave area of competition

Question 15

What is the difference between movement and migration?

Answer 15

Movement is simply a change in the spatial location of an individual in time.

Migration is an adaptive strategy that involves the cyclical movement of part or all of a population in time, between sites of different biotic and abiotic factors.

(Lucas et al, 2001; Nathan at al, 2008)

Question 16

What types of fish migrations are there?

Answer 16

Feeding
Refuge-seeking
Spawning
Post-displacement, recolonisation, and exploratory
Diel horizontal and vertical

(Lucas et al, 2001)

Question 17

Potomodromy

Answer 17

Migrations occurring entirely in freshwater.

(Lucas et al, 2001)

Question 18

What are the costs of migration?

Answer 18

Takes a lot of energy.
Requires more food.
Greater exposure to predators.

(Alcock, 2013)

Question 19

What are the benefits of migration?

Answer 19

Potentially more food available.
Being able to use optimal habitat for different life stages.

(Alcock, 2013)

Question 20

What are the strengths and limitations of the movement ecology framework?

Answer 20

S’s:
- unified basis for future studies
- helpful for applied studies since almost all environmental problems require needing to understand movement

L’s:
- difficult to quantify movement and its mechanisms
- focused on individual so hard to generalize to population

Question 21

Describe migration patterns in my fish species.

Answer 21

Suckers depend on riffle-pool sequences and migrate between the two. They move upstream in spring before spawning in gravelly riffles. Also display some diel migrations.

Northern pike and muskie migrate to to spawn as well (to heavily vegetated areas) though this is usually on a smaller scale.

Walleye go upstream into tributaries to spawn on coarse gravel and their larva passively drift back downstream on currents.

(Lucas et al, 2001)

Question 22

What is the ultimate reason for animal movement?

Answer 22

Irrespective of the proximate reason for moving, the ultimate reason is to increase individual fitness by increasing reproduction.

(Fahrig et al, 2021)

Question 23

When is movement successful?

Answer 23

Movement is successful when an individual who moves reaps the benefit of that movement, such that the benefit is higher than the cost, and the individual’s reproductive success is increased. As such, movement success is a per-individual concept.

(Fahrig et al, 2021)

Question 24

How does a fish move?

Answer 24

Brain signals muscle contractions that take place on alternate sides of the body.

This causes a propulsive wave that goes down the body to the tail.

Tail then transfers energy pushing the fishagainst the water moving the fish forward.

(BIOL 4503 Notes)

Question 25

How does a turtle move?

Answer 25

Brain signals muscle contractions that cause either hip flexion (pulling forward/in) or hip extension (pushing back/out).

Hip extensions cause limb to move either forward/in or backwards/out.

Force from limb on substrate results in walking or digging.

Force from limb on water results in swimming.

(Earhart & Stein, 2000)