ECOSYSTEM RESPONSES TO STRESS 



111 



TABLE 3 



SUMMARY OF PREDICTED AND OBSERVED EFFECTS OF 



LARGE ABIOTIC NUTRIENT RESERVES ON 



ECOSYSTEM STABILITY* 



*Observations are based on the results of the nutrient — energy subsidy 

 experiment described in Table 2 and in text. 

 fNot discussed. 



OTHER INFLUENCES ON ECOSYSTEM STRESS RESPONSE 



Mass of the System 



Many other factors may influence an ecosystem's response to 

 stress. Data derived from the previously described experiments has 

 been used to evaluate some of these influences. GoUey (1974) and 

 Webster, Waide, and Patten (1975) related resistance and resiUence 

 of ecosystems to nutrient storages represented by standing-crop 

 biomass within the system. They proposed that a large biomass 

 v^^ould damp fluctuations induced by the external environment and, 

 thus, confer greater resistance to stresses impinging on the system, 

 Webster, Waide, and Patten also suggested that resilience has an 

 inverse relationship to resistance. The biomass-derived inertia that 

 increases a system's resistance to stress would also slow its recovery 

 from a stress, thereby decreasing its resilience. 



On the basis of these hypotheses, I would predict that 

 resistance and resilience rankings of treatments in the nutrient- 

 energy experiments would be correlated with the amount of 

 particulate matter in the microcosms of those treatments. The 

 stability rankings for each of the nine treatments were correlated 

 with the mean amount of particulate matter in the microcosms under 

 steady-state conditions by use of Kendall's rank correlation coeffi- 



