Abstract: In ecology,theory should be considered not only as a conceptual framework for research,but an ultimate preduct of ecological studies as well. Model may serve as the basic unit for many theoretical and applied studies. Theory and model can be used to generate new hypotheses,to clarify and test existing hypotheses,to identify key components in complex systems,to suggest critical experiments,to synthesize knowledge across disciplines and seales,and to make assesa,ment or optimization for decision-making processes.Models become indispensable when we deal with both spatial and temporal dynamics of systems simultaneously,and when the scales of the phenomenon become large. Ecologists should keep themselves up-to-date of the state-of-the-art in their field,and try to equip tbemselves with advanced methdsand approaches.Empirical and theoretical ecology are interdependent and interactive. Minimizing the gap between theoreticians and empiricists will certainly help promote the development of the science of ecology.

Key words: land consolidation, ecological effect, plain, hilly area, mountainous region.