crabs {GAD}

Distribution patterns of the crab Ucides cordatus at different spatial scales

Description

Distribution patterns of the mangrove crab Ucides cordatus were assessed at four levels of spatial hierarchy (from meters to tens of km) using a nested ANOVA and variance components measures. The design included four spatial scales of variation: regions (10s km), locations (km), sites (10s m), and quadrats (m). Three regions tens of kilometers apart were sampled across the Paranagua Bay salinity-energy gradient. Within each region, three locations (1.5 - 3.5 km apart from each other) were randomly chosen. In each location, three sites of 10 x 10 m were randomized, and within these, five quadrats of 2 x 2 m were sampled (Sandrini-Neto and Lana, 2012).

Usage

data(crabs)

Format

A data frame with 135 rows and 6 variables

Details

• Region: a random factor with three levels (R1, R2, R3)

• Location: a random factor with three levels (L1, L2, L3) nested in Region

• Site: a random factor with three levels (S1, S2, S3) nested in Location

• Quadrat: sample size

• Crabs: response variable; number of crabs per quadrat

• Density: response variable; number of crabs per square meter

References

Sandrini-Neto, L., Lana, P.C. 2012. Distribution patterns of the crab Ucides cordatus (Brachyura, Ucididae) at different spatial scales in subtropical mangroves of Paranagua Bay (southern Brazil). Helgoland Marine Research 66, 167-174.

Examples

library(GAD)
data(crabs)
crabs