and methodology will not \ ield to con\ entional approaches. What can be achieved in 

 environmental protection will level off well beneath what is needed, and the stresses 

 and strains for re\ision will begin to set in. Second, the organism-environment 

 complex as an inseparable natural unit will gradually ascend in academic circles as 

 appreciation for the mutual interdependency of everything in a region becomes ever 

 more forcefulK demonstrated by ecologists. The "systems approach" will then begin 

 to be seen as the only way to achieve necessary refinements enabling precision and 

 deftness in the attack on environmental problems. 



Once system wholeness becomes widely perceived as the underlying reason for 

 ineffective solutions, a commitment to the development of an ecosystem based 

 science of environmental protection will develop. It is doubtful that this will happen 

 before the late 1980s. Here I would like to try to accelerate this evolution by 

 demonstrating in simple, but no uncertain terms, the central defect of any approach 

 based on direct, single factor causality as we tend to find it in the laboratory. 



ECOLOGICAL NETWORKS 



Ecology itself has been traditionally immune or resistant tothe idea of system. The 

 accepted concept of environment {see Notes, a) is one which specifically excludes 

 indirect causes, and the ecological niche (Notes, b) is a direct factor niche only. 

 Theories of limiting factors, tolerance, adaptation and natural selection are all 

 constructs that relate strictly to variables of direct experience by the organism. This 

 allows a quasi-rationality of the organism, or its population or even genome, to enter 

 the system of explanation in the form of "strategies" for adaptation, optimal fitness 

 or survival (Notes, c). The facts may be that in most ecosystems such strategies 

 probably could not be effective because the direct causes to which they are 

 supposedly responsive constitute only a small portion of the total influence which 

 reaches an organism from a gi\en source. If true, explanations would have to be 

 revised to include higher order influences. 



The conventional ecological focus on direct causes is anti-system, an outgrowth of 

 a deep philosophical separation of the organism from its environment (Notes, d). 

 Ecologists cannot yet admit co-implication and co-evolution of organism and 

 environment unitary wholes because the methodology required to treat such units is 

 not yet in place. However, food web elaboration by radiotracers, the on-again, 

 off-again romance with microcosms, and ecosystem modeling and systems analysis 

 all represent movement in the holistic direction. Some years ago, I participated in a 

 demonstration that as new biota were added to laboratory microcosms the 

 interactive networks changed both structurally and kinetically. '^ These changes were 

 manifested in coefficients for radiocesium transfers w ithin the experimental systems, 

 coefficients not of system level phenomena, but representing direct input-output 

 processes (feeding and excretion) of individual organisms. The message was: change 

 the network, change the organism. An organism and the system environing it were 

 closely linked as a functional unit, and both were altered by a change in either. 



Causal networks in nature are diverse and complicated so that the "network 

 variable" in ecology is in fact a variable to be contended with. It can be incorporated 

 into formal treatment of the propagation of cause in ecosystems. '^ It can be the basis 

 for a system theory of environment."' or niche,'-** in which indirect factors are 

 integral. And, it can be encompassed by an organism-environment whole in which 

 mutual consistency, co-adaptation and co-evolution of all the parts together are 

 inherent properties.'^ This paper will demonstrate how indirect causes can signifi- 

 cantly exceed direct causality in static networks by use of a partial ecosystem model. 



Development of a rich interactive biotic structure in an ecosystem is conditioned 

 by the physical environment. In severe environments, such as near the poles, in 

 extreme deserts, or hypersaline bodies of water, ecosystem development is fore- 

 shortened. The species list is short, food chains and webs are simple, and controls are 

 more physical than biological. In benign environments of temperate and tropical 



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