Litter return nutrient cycling and ecosystem stability

In the previous chapter, we have seen that the mass balance of inputs and the outputs from an inorganic resource (typically a nutrient) at the base of a community or food web replaces the need for a phenomenologically defined carrying capacity to stabilize a system. But the mass balances of the Tilman and Armstrong and McGehee models considered in the previous chapter are incomplete. In particular, once the plant dies, its biomass and nutrient content are removed from the system and not...

Consumer regulation of nutrient cycling

Almost from the beginning of life on earth, organisms have evolved which consume primary producers. Modeling consumer regulation of nutrient cycling raises two major problems. First consumers have a very different chemical composition than primary producers. Many plant tissues are carbon rich because they have lignified cell walls, but consumers, having cell membranes rather than thick cell walls, are less carbon and consequently more nutrient rich. This difference in chemistry imposes a strong...

Stoichiometry and linked element cycles

Why stoichiometry is important and how it constrains allowable solutions of models The stuff of which organisms are made Wedin 1994 consists of abiotic materials which are combined only in certain ratios - indeed the ratios of different elements are almost an essential characteristic of each species Sterner and Elser 2002 . The characteristic elemental ratios of each species is called its stoichiometry. If we all were chemically identical if we were all green slime each species would have the...