Populations

Skylark

Metapopulations A metapopulation is a series of small, separate populations united together by dispersal

Metapopulation Dynamics Metapopulations are viewed as sets of populations persisting in a balance between local extinction and colonization

Metapopulations of Bay Checkerspot Butterfly

Bay Checkerspot Jasper Ridge

Aphids and Epilobium

Habitat fragmentation in Amazonia

Demography

Demography is the study of processes that influence population size - it is the way we study changes brought about by births, deaths and dispersal For Northwest Montana, Greater Yellowstone, Central Idaho

The Fundamental Equation of Ecology – Harper 1977 Δ N = B – D + I – E Change in Number = Births – Deaths + Immigration - Emigration John L. Harper –

Rearrange Fundamental Equation Δ N = B – D + I – E N future = N now + B – D + I – E Often we assume that I = E, so no net dispersal

Common Field Grasshopper

Grasshopper – development and incomplete metamorphosis

Red Deer – Stag, Hind, Fawn

Isle of Rhum, Scotland

Red deer fawn being tagged for study

Arithmetic scaleLogarithmic scale

General types of survivorship curves

Human management of species may change survivorship curves A – fish mortality in typical population B – fish taken by fishing

Population Pyramid For France Jan. 1, 1967

Changes in population of Japan over time

Changes in population of Canada from