Unified Life Models


Population Dynamics Modelling

Version 5 - January 2016

The ULM computer program (Legendre & Clobert 1995, Ferrière & al. 1996) has been designed to study a large panel of population dynamics models, for research or teaching purposes:

Computer / System



PC Windows

Self-extracting file


Double-click on autoulm.exe. It will expand in directory c:/ulm


PC Linux

Compressed file ulm.tar.gz

Linux version is identical to Windows version

Expand distribution file ulm.tar.gz using command tar -xzf ulm.tar.gz

For installation, consult file UlmLinuxInstall.txt




Compressed file


Console version, no graphics

Program file: ulmc


 After installation, the ULM directory should contain:

How to run ULM ?

How does ULM work ?

Models are described in a text file according to a reduced declaration language, close to the mathematical formulation. The program is run with the model file as input, and the system can be studied interactively by means of simple commands, producing convenient graphics and numerical results. The kernel of ULM is a symbolic evaluator. Stochastic models are handled via Monte Carlo simulation.

What can be modeled ?

Which results ?


Caswell H. 1989. Matrix Population Models. Sinauer Associates Inc., Sunderland, MA, USA.

Caswell H. 2001. Matrix Population Models. Second edition.

Ferrière R, F Sarrazin, S Legendre & J-P Baron. 1996. Matrix population models applied to viability analysis and conservation: Theory and practice with ULM software. Acta OEcologica 17:629-656.

Legendre S & J Clobert. 1995. ULM, a software for conservation and evolutionary biologists. Journal of Applied Statistics 22:817-834.

Legendre S, J Clobert, AP Møller & G Sorci. 1999. Demographic stochasticity and the social mating system in the process of extinction of small populations: The case of passerines introduced to New Zealand. American Naturalist 153:449-463.

Tuljapurkar S. 1990. Population Dynamics in Variable Environments. Lecture Notes in Biomathematics, Springer Verlag, Germany.

Schoener TW, J Clobert, S Legendre & DA Spiller. 2003. Life-history models of extinction: A test with island spiders. American Naturalist 162:558-573.

Legendre S. 2004. Influence of age structure and mating system on population viability. In Evolutionary Conservation Biology (Ferrière R, U Dieckmann & D Couvet eds.), Cambridge University Press, pp. 41-58.


Stéphane Legendre
Laboratoire d'Ecologie
Ecole Normale Supérieure
46 rue d'Ulm
75230 Paris Cedex 05

Web Site of Stéphane Legendre

Mail to Stéphane Legendre


Jean Clobert, Régis Ferrière, Frédéric Gosselin, Jean-Dominique Lebreton, François Sarrazin.