BIOCLIM – Bioclimatic prediction

BIOCLIM is a bioclimatic prediction system which uses surrogate terms (bioclimatic parameters) derived from mean monthly climate estimates, to approximate energy and water balances at a given location.1

Description

BIOCLIM can produce up to 35 bioclimatic parameters based on the climate variables maximum temperature, minimum temperature, rainfall, solar radiation and pan evaporation. If some of these climate variables are unavailable, fewer bioclimatic parameters are produced.2

Using BIOCLIM as a predictive system.3

BIOCLIM can either summarise the bioclimatic parameters for a list of sites to produce a species profile, or generate output consisting of the calculated parameters for each point in the input file. These points can be supplied either as a list of coordinates or as a regular grid.4

BIOCLIM has a number of advantages over most other models in cases where there is presence-only data (i.e. no absence data), and where the number of known records is extremely low. This makes it a particularly useful modelling system for use with threatened species. 5

The main drawbacks of BIOCLIM include:6

• A tendency to over-predict (i.e. predict larger areas than might otherwise be expected)
• A general restriction to climate-based environmental variables
• An unreliability at fine scales
• The model is sensitive to spatial inaccuracies in the data; a collection site which is in the wrong place can seriously affect the modelled distribution.
• There are many areas which may have climates similar to the species being modelled where the species does not occur. This is called the fundamental niche (Godown and Peterson 2000 (http://www.specifysoftware.org/Informatics/bios/biostownpeterson/GP_BC_2000.pdf). The areas where the species are actually found within the fundamental niche are called the realised niche.
• The fundamental and realised niches are different usually because of factors such as hard boundaries like major rivers and mountain ranges, clearing, land use change etc.
• BIOCLIM tends to overestimate the extent of modelled distributions. However because it is common to only have sampled a small subset of a species true range, models tend to be reasonable guesses at actual distributions.

Function

• Analysis tools
  • Simple – distribution
• Non-biological data
  • Environmental data
• User interface
  • Personal use
  • Raw data

Why use this tool?

The parameters derived by BIOCLIM (eg Mean Temperature of Warmest Period, Precipitation of Driest Quarter) are useful in determining the climatic envelope for plant and animal species. 7

Who will use this tool?

• Data users
  • Expert
• Special skills required

How will the tool be used?

When running BIOCLIM with the species data as input, the input file needs to contain the independent variables used in the creation of the surface coefficient files. For BIOCLIM, this is usually just the latitude (or northing), longitude (or easting) and elevation. This information is usually supplied in the form of a plain-text file.

Your input file of site data should contain lines only for known presences of the species. BIOCLIM is not designed to use known absences of a species, nor is it designed to use abundance information that you might have for your sites.8

• When using BIOCLIM as a predictive system a digital elevation model (DEM) is required.9
• A list of sites is required, each site accurately describing its position and elevation.
• Desktop application
• Windows, Unix (not Linux?)
• GIS may be required
• BIOCLIM is generally hosted inside another program such as ANUCLIM or BioMaps
• User input is required

Where in the data chain could this tool be used?

• User’s machine

When could this tool be used?

• As a post process, after data is with the user

Availability

• ANUCLIM: http://cres.anu.edu.au/outputs/anuclim.php
• ANU Centre for Resource and Environment Studies: http://cres.anu.edu.au
• Documentation: http://cres.anu.edu.au/outputs/anuclim/doc/bioclim.html
• ANUCLIM Version 5.1, December 2000 10
• Support: anuclim-support@cres.anu.edu.au
• Cost: (ANUCLIM) $1980 http://cres.anu.edu.au/outputs/orderform-aust.php

Comments

• BIOCLIM is a component of ANUCLIM, a software package of programs that enable the user to obtain estimates of monthly mean climate variables, bioclimatic parameters, and indices relating to crop growth. The main components of the package are ESOCLIM, BIOCLIM and GROCLIM. They use mathematical descriptions of the way a set of climate variables change across a region in order to estimate those climate variables, or parameters derived from them, at user specified points within the region.11
• BIOCLIM was developed in 1986 by Nix and is showing its age.
• There are newer methods that outperform BIOCLIM and other older modelling methods.12
• BIOCLIM is a component of BioMaps