Unified Life Models

Study a large panel of population dynamics models for research or teaching in the fields of ecology, conservation and management biology.

ULM (Unified Life Models, Legendre & Clobert 1995, Ferrière & al. 1996) is an open-source software enabling the simulation and analysis of deterministic and stochastic discrete time dynamical systems for population dynamics modeling. ULM works natively on Windows, Linux and macOS.

Download Ulm 6.0 - June 2017

GNU/Linux (deb)

Windows (zip)

MacOs (dmg)

Installation instructions and alternative architectures

Features

Models are described using a simple declaration language, close to the mathematical formulation. The system can be studied interactively by means of simple commands, producing convenient graphics and numerical results.

Read the documentation (pdf)

Model

A chaotic attractor (Cazelles & Ferrière 1992).

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

Stochastic models are handled via Monte Carlo simulation.

Compute

Computing Lyapunov exponents.

Population trajectories
Growth rate, population structure and reproductive values
Sensitivities and elasticities to changes in parameters
Generation time and net reproductive rate
Fitness landscapes
Probability of extinction or quasi-extinction, time of extinction
Lyapunov exponents and bifurcation diagrams

Quick Start

The ULM distribution includes the executable, example model files (in the models folder), and the documentation in a pdf format.

Start the ULM program.
Open a model file or create your own.
Click compile to process the file, and run to run the model.

Installation

Windows

Download ulm_6.0_win.zip.
Double click on the ulm_6.0_win.zip file and provide the path of installation (e.g. C:\Program Files\Ulm).
Start ULM by double clicking on ulm.exe.

Linux

For users of Debian-based distributions (such as Ubuntu):

Download the ULM package ulm_6.0_amd64.deb
Install it by running dkpg -i ulm.deb.
Start ULM by running the command ulm.

For other distributions:

Download the ULM package ulm_6.0_amd64.tar.gz
Extract the tarball and run the ulm executable.
From a terminal you can do:
tar xvz ulm_6.0_amd64.tar.gz cd ulm ./ulm

macOS

Download the ULM package ulm_6.0_macOs.dmg.
Drop the Ulm icon to Applications.
Start Ulm by running the program ulm.

Compiling from source

The source code can be downloaded from our git repository for both the stable version and the development version. Compilation instructions are in the README.md file.

References

Bienvenu F & S Legendre. 2015. A new approach to the generation time in matrix population models. American Naturalist 185:834-843.
Caswell H. 1989. Matrix Population Models. Sinauer, Sunderland, Massachussets, USA.
Caswell H. 2000. Matrix Population Models: Construction, Analysis, and Interpretation. 2nd edition. Sinauer, Sunderland, Massachussets, USA.
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.
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.
Schoener TW, J Clobert, S Legendre & DA Spiller. 2003. Life-history models of extinction: A test with island spiders. American Naturalist 162:558-573.
Tuljapurkar S. 1990. Population Dynamics in Variable Environments. Lecture Notes in Biomathematics, Springer Verlag, Germany.

People

Author

Stéphane Legendre Team of Eco-Evolutionary Mathematics Ecole normale supérieure 46 rue d'Ulm 75005 Paris France

ULM development team

François Bienvenu, Guilhem Doulcier, Hugo Gruson and Maxime Woringer.

Contributors

Jean Clobert, Régis Ferrière, Frédéric Gosselin, Jean-Dominique Lebreton, François Sarrazin, Karl-Michael Schindler, Alexis Simon.

Thanks

The developpers of Free Pascal and Lazarus.

All the people who used and supported ULM along the years.

Contact

Issues, feature requests and feedback can be reported on our issue tracker or by writing to Stéphane Legendre.

Links

last update: June 30th 2017