Biodiversity

species composition

species composition

a list of what species are in a community

species richness

number of species in a community

sample size effect

factor that can influence species richness?

more

The more individuals you look at, the _________ different kinds you find

increases steadily up until a point and then levels off

what would a species richness graph look like?

no

is species density the same as species richness?

species density is based on a sampling unit not entire community

species density difference from species richness

Relative abundance graph

drawn to illustrate evenness

log of abundance vs species rank

what is on the axises of a relative abundance graph?

high

Communities with high richness will have ______ evenness

richness and evenness

species diversity is a combination of ________ and _________

Shannon index

provides a measure of the uncertainty that exists concerning the identity of an individual selected at random from a community

no uncertainty

what does 0 indicate in a Shannon index?

uncertain

what does HI indicate in a Shannon index?

uncertainty

in the Shannon index, what is diversity related to?

uncertain

According to the Shannon index, The more diverse the system, the more ______________ you are about the identity of a randomly chosen individual

proportional abundance of species i

what is pi in the Shannon index?

H’ = -Sum( pi * ln pi)

Shannon index formula?

Ni/N

how do you find pi?

1

what should all the proportions (pis) in a sample set add to?

-Sum(pi*ln(pi))

how do you find Shannon index?

J

measure of evenness

H’/H’ max

how do. you find J?

by calculating H’ with even pi values

how is H’ max found?

1

pielou’s J value that indicates all species equally abundant

spatial heterogeneity, site productivity, disturbances

what factors set diversity?

coenocline

pattern of species abundance (community change) that occurs along an environmental gradient

spatial Heterogeneity

measure of the variation in some limiting factor from place to place in a community

higher

The more spatially heterogeneous the
environment, the __________ the species
diversity

pits an mounds, light vs shade

examples of heterogeneity in communities

R²

coefficient of determination, tells how strong relationship between variables is

in a correlation one thing is not dependent on the other, no independent or dependent variables

Difference between correlation and regression

no disturbance

major assumption of grimes’ models

disturbance

Event that causes mortality and frees up resources for surviving inviduals

intermediate disturbance hypothesis

huston and connells prediction about species richness

decrease phase

At the extreme right of graph, disturbances are either very intense or very frequent

increase phase

At the extreme left, disturbances are small and infrequent

intermediate

at what disturbance level can the most species survive?

richness, evenness

There is much evidence for the humped pattern for ___________, less for ___________

productive sites

where would disturbances have to be more frequent to prevent competitive exclusion?

low, high

Similar R* = _______ rate of competitive displacement

Very different R* = ______ rate of CD

low, high

High environmental variability = ___________ rate of competitive displacement
low variability = __________ rate of CD

increases

The amount of disturbance required to maximize diversity _________ as the rate
of competitive displacement increases

Huston

who modeled disturbance, productivity, and diversity together

no

should diversity be high where disturbance and productivity approach zero

no

should diversity be high where disturbance and productivity are both high?

evolutionary speed, geographic area, interspecific interactions, ambient energy, productivity, disturbance

what other factors influence S?

Harner and Harper Pinyon-Juniper Woodlands

Evidence for effect of spatial heterogeneity on S

grimes grassland plots

Evidence for effect of productivity on S (decrease phase)

henry and swan forensic study of the woods

Evidence for effect of disturbance on S (increase phase)

Howard and Lee shade tolerance

Evidence for effect of disturbance on S (decrease phase)