A didactic approach to models of habitat suitability (HS) and the potential distribution of biological species

ABSTRACT

The aim of the present assay is to provide a simple algorithm as well as a didactic theoretical framework that may serve as an introduction to understanding modern habitat suitability (HS) modelling techniques in Ecology and Biogeography. The proposal is built on classical descriptive statistics and classical ecological theories. Shelford’s theory of a bell-shaped curve of tolerance is used to assign suitability values to individual sites, according to their deviations from the optimal requirements of a hypothetical biological species. Liebig’s law of the minimum is applied to assess the overall suitability given a multivariate set of environmental factors. To illustrate the algorithms, hypothetical examples are given with small sets of values simulating data extracted from maps with environmental information. The reader/lecturer is invited to reproduce these small-scale examples using common spreadsheet software or to apply them at a large scale using raster datasets in any advanced geographic information system. As didactical outcomes, this algorithm allows introducing students to the general form and applications of bell-shaped exponential equations (with mu and sigma parameters), understanding the convenience of the law of the minimum when analysing multivariate datasets and the philosophical understanding of certainty/uncertainty when working with the multidimensional niche theory.

KEYWORDS:

• Multivariate modelling
• Shelford’s law of tolerance
• Liebig’s law of minimum
• ecological niche
• geographic distribution

Acknowledgments

The author would like to thank the Escuela Nacional de Ciencias Biológicas of the Instituto Politécnico Nacional, Mexico, for hosting the course of General Ecology in which this topic was taught in 2015–2016. Special thanks to Prof. Jorge Carrillo Laguna and MSc Enrique Ramírez Barbán for their valuable input in the theoretical discussions. Also, Archaeologist Mercedes Jiménez del Arco, Director of the Museum of Natural History of Mexico City for her kind support to the development of this work. Special thanks to the Mexican Council of Science and Technology for the economic support through the programme: “Estímulo Económico por Distinción a Investigadores SNI”

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

This work was supported by the Consejo Nacional de Ciencia y Tecnología; This work was founded by Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional. Grant Number 2700716.