combine one of those two with an interest in wetland ecosystems or in oceans. Despite the need for them, generalists in ecosystem studies are rare, just as are field botanists who can identify more than one group among the vascular plants, bryophytes, lichens, and algae. Given the rarity of generalists, team approaches are useful, although these have their own problems of interpersonal relations, differences in the scientific cultures (with their unfortunate ''pecking orders") from which team members spring, leadership, funding, etc.
One result of the lack of generalists is the infrequent occurrence of studies focusing on linkages among aquatic ecosystems. An examination of titles (and, in a few cases where the title was insufficient, abstracts) in recent issues of specialist journals revealed the following rations of linkage-oriented papers to the total number: Limnology and Oceanography (1 to 88), Journal of the North American Benthological Society (0 to 70), Wetlands (5 to 83), Journal of Marine Research (0 to 60), and Canadian Journal of Fisheries and Aquatic Sciences (4 to 99). In total, only 2.5 percent of the papers discussed interecosystem studies. This lack of examples means that the topic is seldom brought to the attention of either practicing scientists or students beginning to read technical literature. Indeed, the need for studies of functional couplings among streams, lakes, and wetlands is mentioned seldom, and without detailed consideration, in recent documents discussing the future of freshwater studies (Lewis et al., 1995; Naiman et al., 1995), although Lewis et al. do deplore the fragmentation of freshwater scientists into separate societies dealing with streams (North American Benthological Society), lakes and oceans (American Society of Limnology and Oceanography), and wetlands (Society of Wetland Scientists).
Because interecosystem studies are unusual, it may be difficult to attract research funds for them, as is sometimes the case with interdisciplinary studies. Members of review panels usually specialize in one of the major types of aquatic ecosystem, and some of them—consciously or unconsciously—may not be sympathetic to proposals to examine linkages among the various types. The reverse may of course be true of other reviewers; more needs to be known about such reviewer bias in order to find ways of countering it.
The nature and importance of interdisciplinary and interecosystem studies can be illustrated most clearly by a series of examples that demonstrate, first, the linkages among disciplines and, second, the functional couplings among different types of inland aquatic ecosystems.