R/data_countryside.R

In txm676/mmSAR2: Fit and Compare Species-Area Relationship Models Using Multimodel Inference

#' A sar_countryside dataset describing vascular plants in a multi-habitat
#' landscape in Portugal
#'
#' A sample dataset in the correct sar_countryside format: for a set of sites,
#' contains the areas of different habitat types, and the numbers of species in
#' different habitat affinity groups. Data are nested.
#'
#' @usage data(countryside)
#' @format A data frame with 7 columns and 425 rows. Each row contains the area
#'   of three habitats in a site (first three columns: agricultural land - AG;
#'   shrubland - SH; oak forest - QF), and the number of species in the site in
#'   each of four habitat affinity groups (columns 4-7; names match habitats,
#'   except for UB which stands for ubiquitous species). Note that the area and
#'   species richness columns are in the same order (e.g., AG is first for
#'   both), with the UB richness column last.
#' @details Data are from Proença & Pereira (2013). The sampling design involved
#'   selecting five 512m×512m habitat mosaics with different land-cover
#'   composition. 64 sampling plots of 1m2 (1m×1m) were then set in each mosaic,
#'   and presence and percentage cover data of understory plant species
#'   (excluding adult trees) recorded. The disposition of sampling plots
#'   followed a nested design: 1m2 sampling plots were aggregated in groups of
#'   four, each plot placed on a corner of a 8m×8m square (64m2), then 8m×8m
#'   squares were aggregated in a similar way to form 64m×64m squares (4096m2)
#'   and these were finally aggregated in one square (habitat mosaic) measuring
#'   512m×512m (26.2 ha). Species–area relationships were then fitted to these
#'   data at the landscape level using nested species–area data at 1m2, 64m2,
#'   4096m2 and 26.2 ha. Fitted curves were thus similar to a Type IIIA curve
#'   (Scheiner, 2003).
#' @source Proença, V. & Pereira, H.M. (2013) Species–area models to assess
#'   biodiversity change in multi-habitat landscapes: the importance of species
#'   habitat affinity. Basic and Applied Ecology, 14, 102–114.
#'
#'   Scheiner, S.M. (2003) Six types of species-area curves. Global Ecology and
#'   Biogeography, 12, 441–447.
#' @examples
#' data(countryside)
"countryside"