Indirect interrelations between ecosystem processes are often realised after a considerable time lag,and, therefore, are easily overlooked. The understanding of these relationships, however, is indispensable forsustainable development and ecomanagement. Investigation of mechanisms underpinning complex indirectdelayed relationships is greatly aided by advanced mathematical techniques, including correlation, multipleregression and factor analysis, simulation modelling, etc. This paper provides a brief review of the recentrelevant studies. These techniques may be especially useful if used in concert on a range of ecosystems, thusintegrating the information obtained in a comparative theoretical ecosystem analysis (CTEA). Amethodological framework for CTEA is given and possible implications discussed