A dynamical systems model of the interaction of earthworms with plant litter quality and quantity

A rather unusual but realistic two-dimensional dynamical system is formulat ed, analysed, and interpreted for the interactions of earthworms and plant litter in soils. The model proposes the use of litter quality as an indepen dent variable as well as the elapsed time. The system is searched for thres holds beyond which the system is sustainable with an asymptotically stable steady state. Only one such state is possible. The outcome is that there is a threshold on the average quality value of the litter input which has to be above a certain value for the system to be sustainable. For special desc riptions of the litter input and palatability dependence on quality, explic it solutions are possible for the stability analysis. (C) 1999 Elsevier Sci ence Ltd. All rights reserved.