USU 1350

The unit of management in outside world

a collection of individuals that are close enough geographically that they may find each other and reproduce

understand relationships between populations and their habitat

• food, water, and cover
• range of tolerance - dimensions
• conspecifics - others of own species
• other animals - predators, parasites

• abundance
• density
• age structure
• sex ratio
• birth rate
• death rate
• immigration
• emmigration
• growth rate

raw numbers

numbers per area

the number of animals in each cohort

age class

• number of males to females in population
• males:females
• can be combined with age structure

• MAKES GROWTH FLUCTUATE
• number of young born per female in population
• can be combined with age structure

• number dying per individual in population
• can be combined with age structure

Number joining a population

• number leaving a population
• 200 leave/1000 = 20%

• annual change in population
• can be positive (growing)
• can be negative (negative)
• can be zero

(birth rates + immigration) - (deaths+emigration) / total population size from previous year

• exponential
• logistic

• growth is independent of population density
• independent of resource availability
• Not REALISTIC

• dependent on population size
• dependent on resource availability

• exponential growth turns into logisitic growth
• always same 1/2 K (carrying capacity)

the growth rate is zero

• population density
• lower density equals higher quality
• higher density equals lower quality

• 1.)cannot have highest density and quality at same time
• 2.)focus on objective - quality or quantity
• 3.)density always relative to resource abundance
• 4.)resource abundance is low - must reduce population to help system recover