POPULATION ECOLOGY: AN INTRODUCTION

I. CHARACTERISTICS OF POPULATIONS A. Density and Abundance – Abundance refers to the number of individuals, N.

I. CHARACTERISTICS OF POPULATIONS A. Density and Abundance – Abundance refers to the number of individuals, N. – Density refers to the number of individuals per unit area

I. CHARACTERISTICS OF POPULATIONS A. Density and Abundance – Relation to body size

I. CHARACTERISTICS OF POPULATIONS A. Density and Abundance l large species occur at lower densities l relationship exists with metabolic rate:

I. CHARACTERISTICS OF POPULATIONS A. Density and Abundance B. Vital Rates

I. CHARACTERISTICS OF POPULATIONS A. Density and Abundance B. Vital Rates – Fertility rate (# female live births/female/unit time) (also natality and fecundity)

I. CHARACTERISTICS OF POPULATIONS A. Density and Abundance B. Vital Rates – Fertility rate – Mortality rate (deaths/indiv/time)

I. CHARACTERISTICS OF POPULATIONS A. Density and Abundance B. Vital Rates – Fertility rate – Mortality rate – Immigration rate (in/indiv/time)

I. CHARACTERISTICS OF POPULATIONS A. Density and Abundance B. Vital Rates – Fertility rate – Mortality rate – Immigration rate – Emigration rate (out/indiv/time)

I. CHARACTERISTICS OF POPULATIONS A. Density and Abundance B. Vital Rates C. Age Structure – proportion of individuals of various ages

I. CHARACTERISTICS OF POPULATIONS A. Density and Abundance B. Vital Rates C. Age Structure D. Sex Ratio – ratio of males to females – example 60:40

II. DENSITY-INDEPENDENT POPULATION GROWTH A. Growth in a Constant Environment with Unlimited Resources – population doubles monthly – N after 4 months = ?

A. Growth in a Constant Environment with Unlimited Resources time N after 4 months

II. DENSITY-INDEPENDENT POPULATION GROWTH A. Growth in a Constant Environment with Unlimited Resources – finite rate of change ( ) = 6/3 = 12/6 = 24/12 = 48/24 = 2

II. DENSITY-INDEPENDENT POPULATION GROWTH Geometric model:

II. DENSITY-INDEPENDENT POPULATION GROWTH Exponential model:

II. DENSITY-INDEPENDENT POPULATION GROWTH Growth rate is independent of N

II. DENSITY-INDEPENDENT POPULATION GROWTH – Intrinsic rate of increase

II. DENSITY-INDEPENDENT POPULATION GROWTH B. The Importance of Considering Environmental Variation – Red deer and spring temperature

II. DENSITY-INDEPENDENT POPULATION GROWTH B. The Importance of Considering Environmental Variation – Cotton rats on the northern fringe

II. DENSITY-INDEPENDENT POPULATION GROWTH B. Importance of Environmental Variation SpeciesSpring Captures Cotton rats22% Prairie voles99% White-footed mice 83% Deer mice 80% Harvest mice 66%