The concept of sustainability requires decisions which satisfy current needs without compromising the interests of future generation. It stipulates the necessity to predict the development of natural ecosystems with and without human impact. Simulation models and mathematical tools are widely used in environmental resource management and environmental assessment to generate required predictions. While short-term predictions provide particular estimates, in the long run, trends and patterns of ecosystems reactions to external perturbations are more informative. These patterns and trends are derived based on mathematical models and techniques and obviously reflect mathematical properties of the employed techniques. It is important to understand to what extent conclusions drawn from mathematical models and their properties reflect the behaviour of real world ecosystems and what theories and approaches are suitable for such analysis. Applied metho ds and tools including frameworks for mathematical analysis of the models are of great interest. The section invites contributions on application of quantitative approaches (models, methods, and frameworks) evaluating sustainability of environmental decisions.