Propagule Pressure

Tory White, Bri Habel, Sarah Ryan, Anna Sheinaus

Definitions

Propagule Pressure

Propagule Biases

Null Model

SummaryPropagule pressure...● Should be null model for

invasion studies● Is significantly associated with

invasiveness and invasibility● Can disconfirm interpretations

of invasion patterns

1- Invasion history/widespread2- Physiological tolerance3- Consumption efficiency4- Body size/ biomass5- Individual growth rate6- Life span/ generation time7- Generation success/ rate8- Seed Size

9- Reproductive output10- Length of growing/breeding season11- Hermaphroditic/ asexual reproduction12- Niche/ Habitat separation13- Effects of herbivores/ predators

0/1- Anthropogenic activity1- Disturbance2-Resource food availability or quality3- Light intensity4- Species richness or diversity5- Species abundance or density6- Effects of herbivores/ predators

:Contrasts that did not consider the potentiallyconfounding effects of propagule pressure

:Did measure propagule pressure

:Used propagule pressure as control

Example of Propagule BiasGlobally invasive birds tend to belong to just seven families

o ducks/geese, pheasants, other game species

Does this mean that those species have special characteristics that make them more successful for invasion?

Literature Review - Methods● Forward-tracing of our paper led to

441 papers

● We reviewed 20 papers

● Collected data: support/doesn’t support Colautti et al’s hypothesis; taxonomic group each paper focused on (if any)

Literature Review - Results

Agreeance: 19/20 Studies● -Aquatic/Terrestrial Plants, Freshwater Fish, Insects, Marine Fish,

Pathogens

Disagreeance: 1/20 Studies● -Birds● -Often due to lack of research or inconclusive results

Discussion

● Hypothesis well supported

● Applicable across almost all taxonomic groups; EXCEPT maybe birds

European StarlingSturnus vulgaris

An invasive bird in the US

http://ac.els-cdn.com/S0169534705000327/1-s2.0-S0169534705000327-main.pdf?_tid=1251fcce-5540-11e4-a2ee-00000aab0f6b&acdnat=1413469620_95a548b464d6743ba59391ebab738b8b http://www.esajournals.org/doi/abs/10.1890/05-0427http://www.annualreviews.org/doi/abs/10.1146/annurev.ecolsys.110308.120304http://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2009.01418.x/pdfhttp://onlinelibrary.wiley.com/doi/10.1046/j.1523-1739.2003.02365.x/full

http://onlinelibrary.wiley.com/doi/10.1111/j.1472-4642.2008.00521.x/pdf PAB