IntertidalAlgae {abd}

Intertidal Algae

Description

Area coverage of red algae (Mazzaella parksii) in two herbivore treatments (herbivores) at two tide levels (height).

Format

A data frame with 64 observations on the following 3 variables.

height

a factor with levels low and mid

herbivores

a factor with levels minus and plus

sqrt.area

a numeric vector

Source

Harley, C.D.G. 2003. Individualistic vertical responses of interacting species determine range limits across a horizontal gradient. Ecology 84: 1477-1488.

Examples

str(IntertidalAlgae)

# Using * includes the main effects and the interaction
aov.fit <- aov(sqrt.area ~ herbivores * height, data = IntertidalAlgae)
summary(aov.fit)
lm.fit <- lm(sqrt.area ~ herbivores * height, data = IntertidalAlgae)
anova(lm.fit)