The formal specification community has produced many languages but few structured design methods. Those which exist tend to be abstract, providing little guidance in tackling problems in particular domains. One way of devising domain-specific design methods is by reconstructing an example in the domain using the target method; then generalising the design structures to cover a class of designs in the domain and finally building an environment in which these structures may more easily by re-applied to new problems. We demonstrate this approach using animal population dynamics models as the domain and Prolog techniques as the target method. We have identified domain-specific techniques which use a parameterisation method from techniques editing but which contain information specific to the population dynamics domain; we define a problem description language which uses concepts from population dynamics; an interface which allows these concepts to be supplied; and provide an automated system which bridges between population dynamics problem description and the domain-specific techniques needed for model generation. TeMS - Techniques-based Model Synthesiser, is the system constructed as the main instrument of our research. Because it is an embodiment of our views on the issues addressed, we submitted TeMS to user evaluation by ecological modelling experts, which produced material for a broad discussion of the system itself, its approach to modelling and its potential uses on the ecological modelling scenario.