Animal exchange ratios: an alternative point of view

An alternative interpretation is provided of the concepts of carrying capac ity and exchange ratios, particularly suitable for game animal species, bas ed on management models for a given area of rangeland or pasture. It involv es modelling animal population dynamics as discrete-time logistic equations . Carrying capacity is then generated endogenously using rainfall as a prox y. The model interaction parameters, also generated endogenously, represent the animal exchange ratios. Because these two parameters are generated end ogenously, this approach takes into account all the animals' habitat requir ements (food, cover, water and space) simultaneously, unlike other approach es that tend to consider food requirements only. This makes the approach am enable to multi-species situations. It also captures the ecological definit ion of population growth models where the realized rather than the theoreti cal carrying capacity is determined endogenously.