A REVIEW OF THE GENERIC COMPUTER-PROGRAMS ALEX, RAMAS SPACE AND VORTEX FOR MODELING THE VIABILITY OF WILDLIFE METAPOPULATIONS/

An assessment is presented of three computer packages, ALEX, RAMAS/spa ce and VORTEX, that have been developed for analyses of metapopulation viability. Their usefulness was assessed in the context of the need t o understand the assumptions and limitations of the programs. The stud y examined many attributes of these programs, ranging from availabilit y and ''user-friendliness'' to the mathematical structure and procedur es underpinning the sub-models. Key features and strengths of, and dif ferences between, the various programs were highlighted. They are stru ctured differently and vary in the way processes such as environmental and demographic variation are modelled. Many of these differences ref lect what the architects of the programs consider to be the most impor tant factors influencing the viability of metapopulations. These diffe rences mean that the programs may produce different results even for i nvestigations of the same populations. The selection of the most appro priate program should be based on a range of key criteria including: ( 1) the key question(s) and objectives of the study, and, (2) the stren gths, limitations and assumptions that underpin the program and how th ese match the attributes, life history parameters and available data f or the target species. The processes of data assembly, running the pro grams and reading the accompanying documentation give the user an impr oved understanding of population behaviour and dynamics. The wide vari ety of threatened taxa and diversity of conservation problems highligh t the value of a broad range of sound, well-developed and relatively e rror-free packages for simulating metapopulation viability. However, i n some cases it may be more appropriate to develop a new program that is tailored specifically to the requirements of a particular managemen t problem.