1 / 25

Behavioral Ecology: Movement & Orientation

Behavioral Ecology: Movement & Orientation. Why move? Types of movement Metapopulations Local Distribution Home Range Territoriality Migration - Mass movements Breeding Over-wintering Movements of juveniles - Dispersal Homing/Orientation. I. Why move?. Reasons to move:.

massimo
Télécharger la présentation

Behavioral Ecology: Movement & Orientation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Behavioral Ecology:Movement & 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 parent’s 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. B. Over-wintering movement Seeking more hospitable climate • Flowing water of streams vs. frozen water of lakes/ponds

  17. IV. Dispersal • usually refers to juveniles leaving home ranges of parents to find a home of their own, reasons to disperse: • Costs =

  18. V. Homing Behavior • Ability of displaced individuals to return to their original location – animals must be able to sense the direction they are moving

  19. ORIENTATION Pilotage - orientation with respect to fixed landmarks home

  20. 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 sun’s position (internal clock) • Celestial orientation • Magnetic orientation

  21. Navigation - orientation without fixed landmarks

More Related