ULM

Unified Life Models

Population Dynamics Modeling

Version 3.0 - nov 2000

The ULM computer program (Legendre & Clobert 1995; Ferrière et al. 1996) was designed to study population dynamics models, and, more generally, discrete dynamical systems.

Which platform ?

WINDOWS

Who's concerned, in which domains ?

Biologists, Ecologists, Mathematicians, either for research or teaching purposes in the following domains:

• management, conservation biology (Ferrière et al. 1996),
• evolutionary demography,
• general deterministic or stochastic dynamical systems.

How to get ULM ?

ULM is distributed free of charge. Users are under their own responsibility.
Click here to download autoulm.exe  self-extracting file

How to install ULM ?

• create directory c:\ulm in which you will install ULM,
• move autoulm.exe to the ULM directory,
• double-click on autoulm.exe .

ULM directory should now contain:

• the ULM program ulm.exe,
• example model files *.ulm,
• user's information readme.txt,
• reference manual ulmref.rtf.

The complete list of files contained in autoulm.exe may be found in readme.txt.

How to run ULM ?

• Double-click on any model file *.ulm, and select program c:\ulm\ulm.exe to open the file,
• ULM will then be run with files *.ulm as input.
• For detailed informations, consult readme.txt and ulmref.rtf.

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 ?

• any species life cycle graph (matrix models) (Caswell 1989, 2000),
• inter- and intra-specific competition, density dependence (non linear systems),
• environmental stochasticity (Tuljapurkar 1990) (random processes),
• demographic stochasticity (branching processes),
• metapopulations, migrations (coupled systems).

Which results ?

• population trajectories, distributions,
• growth rate, population structure, generation times,
• sensitivities to changes in parameters,
• fitness landscape,
• probability of extinction, of quasi-extinction, extinction times,
• statistics on population trajectories,
• lyapunov exponents, bifurcation diagrams.

References

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

Caswell, H. 2000. Matrix Population Models. Second edition.

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

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

Author

Stéphane Legendre
Laboratoire d'Ecologie, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France.
Tel: (33) 1 44 32 37 01 - Fax: (33) 1 44 32 38 85 - Email: legendre@ens.fr

Contributors

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