Behavioral Ecology: Movement

1
Behavioral EcologyMovement Orientation

• Why move?
• Types of movement
• Metapopulations
• Local Distribution
• Home Range
• Territoriality
• Migration - Mass movements
• Breeding
• Over-wintering
• Movements of juveniles - Dispersal
• Homing/Orientation

2
I. Why move?
Reasons to move

• Mortality can be high when individuals move from
  one habitat to another

3
A. General types of movement

• Herps are not distributed randomly! Some places
  are better than others
• Station keeping movements directly related to
  the acquisition of resources within a home range
• Ranging behavior exploring new habitats or
  resource patches
• Dispersal juveniles leaving their parents home
  range to find their own

4
B. Metapopulations populations of populations

• Spatially subdivided populations

5
II. Local distribution of individuals

• Home ranges area which individuals move within
  do not defend from conspecifics
• Association between body size home range
• Resources
• Food, shelter, thermoregulation sites, escape
  routes
• Social activities
• Finding mates
• Calculating home range minimum polygon method

6

• Minimum polygon method of calculating home ranges
  
• Measure the area that encompasses all of the
  outer points within which an individual occurs.
• Most widely used method
• Good for species living in 2D habitats
• Does not take into consideration amount of time
  or relative frequency with which an individual
  might use different parts of the home range

7
Anolis transversalis -
8
Home range can vary through time/space

• Terrestrial amphibians, during non-breeding
  season have small home ranges away from water
• Pond breeding species, home range breaks down
  during breeding events
• Microhabitat specificity a factor
• Vary w/sex reproductive state

9
Resource dispersion home range

• Habitat resource patches
• Depleted / not depleted
• How rapidly will resources be replenished?
• Abundant resources limited home range
• Resources renewed slowly wider home range

10
Herbivores wider food sources, but abundant
Masticophis (whiptail) has to go where the food
is
11
Iguana iguana
Dermochelys coriacea
Hoplocephalus bungaroides
12
B. Territoriality

• Territory area within the home range which is
  defended against conspecifics other species
• Usually has some sort of defendable resource
• Defense results in exclusivity
• Most often males defend territory
• Direct combat
• Threats
• Avoidance
• Selection favors those that control use
  resources in a way that positively influences
  their reproductive success

13
Amphibians exhibiting territoriality
Dendrobates pumilio
Plethodon cinereus
14
III. Migration - Mass movements

• A. Breeding migrations
• Amphibians - Triggered by rainfall temp,
  usually starting at night but continuing
  through day
• Mass movements explosive breeders, i.e.
  Ambystoma Bufo move en masse to and from
  breeding ponds
• Reptiles Vipera, Kinosternon, Chelydra,
  Crocodylus, Iguana, Sea turtles

15
Loggerhead turtle movement monitored via
satellite
16
(No Transcript)
17
B. Over-wintering movement

• Seeking more hospitable climate
• Flowing water of streams vs. frozen water of
  lakes/ponds

18
IV. Dispersal

• usually refers to juveniles leaving home ranges
  of parents to find a home of their own, reasons
  to disperse
• Costs

19
(No Transcript)
20
V. Homing Behavior

• Ability of displaced individuals to return to
  their original location animals must be able to
  sense the direction they are moving

21
ORIENTATION
Pilotage - orientation with respect to fixed
landmarks
home
22
Mechanisms of orientation

• Local environmental cues (landmarks)
• Smells, visual cues
• Compass orientation
• X-Y axis orientation
• Depends on sunny conditions
• Must have built in sense of daily changes in the
  suns position (internal clock)
• Celestial orientation
• Magnetic orientation

23
(No Transcript)
24
(No Transcript)
25
Navigation - orientation without fixed landmarks