Ecological challenges for lake management

Abstract

The need for management, in natural systems, and possibly in all systems, reflects an inability of the systems to operate in self-sustaining ways, due to interference, or damage to an extent that is beyond the capacities of the system for self-repair. Management need is thus a symptom of failure of the system. The more management needed, the greater the failure and management is always costly. Most freshwater systems have been seriously altered by human activities. We may wish to restore them to self-sustaining systems which provide conservation or amenity values, or products such as potable water or fish, with minimal management, or preferably none at all. This may not be possible in many cases; it is completely impossible without profound understanding of their functioning. The ecological 'challenges' in lake management are thus to remove blocks which impede this understanding. There are at least three groups of blocks: fundamental; those of approach and method; and political. The latter is no less ecological than the others; human beings and their behaviour are ecological phenomena like those of any other animal. Fundamental blocks include the complexity and stochasticity of natural systems, which may change faster than they can be dissected and understood. They include also the scarcity of complete systems for investigation. Lakes are parts of greater systems in the landscape and if these systems are no longer intact, through insensitive land use, such as drainage, it is not possible to understand interactions and influences which were not confined to the lake basin. Examples are given concerning fish and bird movements. Methodological blocks concern the scale of investigations. The need for statistical rigour confines many investigations to small scale, easily replicable phenomena. Lake systems, however, are influenced by larger scale, lakewide or more extensive effects. An example is given concerning the effects of piscivorous birds. Unless whole lakes and their catchments are subject to experimentation, these influences will remain obscure, though they may be at least as important as within-lake effects. Replication is difficult and areas with large numbers of broadly similar lakes are needed. Such areas exist, but the costs of such large scale and long-term experimentation are rarely met. Political blocks are the ultimate blocks. A society which chooses to continue exploiting natural resources in an unsustainable way is not particularly interested in the fundamental understanding which underlies sustainability. There are many symptoms that we are choosing to follow the imperatives of our selfish genes, rather than make the ethical choices of which we are alternatively capable. They include the greatly reduced support for fundamental research in the U.K., the failure to use, in the spirit in which it was intended, existing European legislation for environmental protection, and the decreased strength of imperatives for conservation in the Environment Act 1995, compared with the Water Act 1989 and the Water Resources Act of 1991.