The Niche American oystercatcher prying limpet off a horseshoe crab

Hutchinson’s Niche Definitions The fundamental niche - the set of resources and conditions that permits the survival and reproduction of an organism - many resources and conditions interact to form the niche. The realized niche - the portion of the fundamental niche actually occupied by the species when restricted by other organisms - restricted by competition, predation, parasites, disease. - Hutchinson 1958

Fundamental vs. Realized Niche

Key point – two species cannot have identical niche

Populations

Populations Population - a group of organisms of the same species which have the potential to interbreed – or a population is a group of organisms of the same species occupying a particular place at a particular time Populations have a number of properties which are not possessed by individual organisms - this is because a population is the sum of many organisms interacting

Starling Murmuration http://vimeo.com/31158841

Population Dynamics Properties of populations Size Density Dispersal Emigration Immigration Births Deaths Survivorship

Population Boundaries

Density and Distribution

Prairie Dog Distributions

Prairie Dog Colonies

Cormorant Nesting - Patagonia

Properties dealing with changes in population size Natality - may think of this as births, but includes more than just birth - hatching, germination, fission Natality includes idea of fecundity - number of offspring produced per unit time - we are most concerned with realized fecundity - actual number of survivors Mortality - death rate - its converse is survivorship - mortality looks at how many die per unit time, survivorship at how many don't die per unit time Longevity examines life-span of individuals - again we are most interested in realized longevity, not potential longevity Immigration - individuals moving into a population Emigration - individuals leaving a population

Changes in human longevity - life expectancy at birth

Typical animal life spans

What is an individual? unitary organism - individuals are highly determinate in form and while growing pass through predictable (innately determined) sequences of life history stages modular organisms - zygote develops into unit, or module, which produces more modules asexually thus producing an organism with a variable number of modules, whose development is unpredictable and strongly influenced by environmental factors

A classic unitary organism

A classic modular organism Bryozoan colony

Freshwater Bryzoan

More classic modular organisms

Genets and Ramets ramet - a module with the potential for a separate existence genet - the "genetic individual"; the collection of all modules derived from a single zygote

A single Aspen clone

Posidonia oceanica – Neptune grass

Sampling to collect population data Census - most basic sampling - count and determine age of all individuals in population, count again later Several ways to subsample and estimate population size: 1. Determine total area in which population occurs, count all individuals in small plots, multiply average number in plots to get total, repeat at later dates - works best for sessile organisms 2. Mark-recapture methods 3. Catch per unit effort 4. Miscellaneous methods – traps, counts of fecal pellets, counts of vocalizations, feeding damage on plants, radar counts, roadside sightings, fur or pelt records, roadkill

Quadrat Sampling

Mark recapture of Cicadas

Catch per unit effort – Pacific Threadfin

Beetles feeding on Viburnum

Beetle damage on Viburnum

Bird migration data – typical altitude – from radar

Bird migration radar map

Skylark

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

Metapopulation Dynamics

Metapopulations of Bay Checkerspot Butterfly

Bay Checkerspot Jasper Ridge

Aphids and Epilobium

Habitat fragmentation in Amazonia