In chhetrid/rangemapR: A Modular Platform for Reproducible Modeling of Species Niches and Distributions

Module: WorldClim

BACKGROUND

The WorldClim project provides bioclimatic variables for the Earth's land surfaces for all continents except Antarctica. Monthly data from weather stations were spatially extrapolated using elevation as a covariate and subsequently 19 bioclimatic variables were derived, reflecting various aspects of temperature and precipitation (Hijmans et al. 2005). The descriptions of each variable are listed below, taken from the WorldClim website, where more details can be found.

BIO1 = Annual Mean Temperature
BIO2 = Mean Diurnal Range (Mean of monthly (max temp - min temp))
BIO3 = Isothermality (BIO2/BIO7) ( 100)
BIO4 = Temperature Seasonality (standard deviation 100)
BIO5 = Max Temperature of Warmest Month
BIO6 = Min Temperature of Coldest Month
BIO7 = Temperature Annual Range (BIO5-BIO6)
BIO8 = Mean Temperature of Wettest Quarter
BIO9 = Mean Temperature of Driest Quarter
BIO10 = Mean Temperature of Warmest Quarter
BIO11 = Mean Temperature of Coldest Quarter
BIO12 = Annual Precipitation
BIO13 = Precipitation of Wettest Month
BIO14 = Precipitation of Driest Month
BIO15 = Precipitation Seasonality (Coefficient of Variation)
BIO16 = Precipitation of Wettest Quarter
BIO17 = Precipitation of Driest Quarter
BIO18 = Precipitation of Warmest Quarter
BIO19 = Precipitation of Coldest Quarter

IMPLEMENTATION

This module relies on the R package raster to download bioclimatic variables from the WorldClim server.

Wallace makes all four resolutions of the data available (10 arcmin ≈ 20 km, 5 arcmin ≈ 10 km, 2.5 arcmin ≈ 5 km, and 30 arcsec ≈ 1 km). The finest grain WorldClim dataset (30 arcsec) can only be downloaded by 30 x 30 degree tiles in the current implementation of dismo (1.1-1), and so Wallace uses the current center of the map display as the tile reference. This means that analyses with 30 arcsec climatic data using the current version of Wallace are restricted to the extent of a single tile. When running locally, the dataset is downloaded to the Wallace folder (which can take substantial time), but Wallace will use the downloaded data for later runs when the same resolution is selected.

REFERENCES

Hijmans, R. J., Cameron, S. E., Parra, J. L., Jones, P. G., Jarvis, A. 2005. Very high resolution interpolated climate surfaces for global land areas. International Journal of Climatology. 25: 1965-1978.

chhetrid/rangemapR documentation built on May 13, 2019, 11:09 a.m.