Answer to Question #101136 in Ecology for Mike

Question

Why big ecosystems are more stable than smaller ones?

Answer 1

Both big and small ecosystems are associated with specific ecological relationships between organisms — there are producents, consuments and reducents in almost every ecosystem. The difference between the big and small ones lies in a number of species in every ecological group. For example, a group of producents in a big ecosystem is represented by several species while in a small ecosystem there might be only one producent.

Let's say we have a big and small ecosystem with identical structure in the same environmental conditions. Environmental factors aren't always stable and there are times when they change drastically. Serious perturbations in environment can lead to a massive loss of different organisms due to starvation, cold, toxic effect etc. When such a crisis happens a small ecosystem can lose the only producent species it has and the whole system will collapse without a stable source of carbohydrates. On the contrary, a big ecosystem is composed of different producent species and some of them will survive the crisis and adapt to new environment conditions keeping the balance between different ecological groups. At this point of view, a big ecosystem is always more stable than a small one.