Abstract: Knowledge on environmental changes is of great value to environmental managers and scientists. Because of the special characteristics of environmental phenomena, the information needed to make an assessment of environmental changes over time cannot be derived from the usual sampling techniques: time series analysis is needed. A quick survey reviewing what time series methods in the literature fit well the needs of environmental data analysis is timely. Secondly, the gap between mathematically complicated materials in the literature and oversimplifications that exist in textbooks which are insufficient for practicing environmental scientists can perhaps be bridged. An outline of ideas, assumptions,…and limitations of some time series methods, supplemented by a Finnish case study on patterns and cyclicity in a microtine rodent population can be a useful quide for practical data analysis.