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How does an animal choose where to live?. 5/29/08: Habitat Selection. Lecture objectives: Understand the adaptive value of: habitat selection, dispersal & migration, and territoriality Be able to distinguish between multiple adaptive hypotheses for a given behavior.
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5/29/08: Habitat Selection Lecture objectives: • Understand the adaptive value of: habitat selection, dispersal & migration, and territoriality • Be able to distinguish between multiple adaptive hypotheses for a given behavior
Where an animal chooses to live can greatly affect its fitness
Where an animal chooses to live can greatly affect its fitness Least tern& Habitat restoration
Since habitat selection is important, animals should have evolved the ability to evaluate habitat quality 30-60 LSmallentrance
So, where should an animal choose to live? But what happens to an animal’s fitness if all individuals choose the same spot? Animals must somehow distribute themselvesbetween patches that vary in resources
Animals must somehow distribute themselvesbetween patches that vary in resource # or quality
Why disperse? Costs Benefits
Migration is a special form of dispersal Migration – the regular (seasonal) movement back and forth between two relatively distant locations by animals
Animals have evolved behaviors that lower the costs of migration
To defend or not to defend? Home Range Territory
Why be territorial? Costs Benefits Bitterling (w/ mussel)
How does an animal establish/maintain territorial boundaries?
Example: Animals adjust territory size in relation to resource abundance
Example: Animals adjust territory size in relation to resource abundance
Example: well-defined boundaries reduce costs of territoriality “Good fences make good neighbors!!”
Example: Benefits of a dear neighbor Success in driving away intruder 88% 71% Crab + neighbor Crab (alone) Fiddler crab, Uca mjoebergi