Population Growth and Regulation

Ecological hierarchy

• Individual

• Population

• Metapopulation

• Community

• Ecosystem

Metapopulation

a group of populations linked by dispersal (gene flow)

BIDE

Births, Immigration, Deaths, Emigration

Standard nomenclature for BIDE

• Capital letters = number of individuals

• Lowercase letters = per capita rates

• Nt = population size

growth rate equation

Geometric growth (λ = Nt+1/Nt)

when a population reproduces in sync at regular time intervals and growth rates remain the same

Exponential growth (Nt + 1 = λNt)

when populations increase by a constant proportion

population growth (r)

b - d : instantaneous per capita rate of growth

population growth formula

dN/dt = rN

when λ=1 or r=0

pop size stays the same

when λ<1 or r<0

pop size will decrease

when λ>1 or r>0

pop size grows geometrically or exponentially

Life tables (age)

specific account of mortality and fecundity

Life tables (X)

cohort age class (years)

Life tables (n(sub x))

number of individuals in cohort

Life tables (Ix)

probability at birth of surviving to age class X

dispersal limited

species has not yet reached a suitable patch