Resources and Stability of The System
At any point in the system when organic material is added, it is used or stored, with a small proportion making its way further downstream. The existing energy is the limiting growth factor of the system, therefore the system is striving to be as efficient as possible. Free resources will enable new types of life in the community to establish, so that the excess resources are quickly exploited. This principle is not exclusively for river ecosystems but applies to most systems. Here, however, it plays a larger role, because resources are not spent in one place but are being constantly transported downstream. The temporal aspect of this continuity can be seen by its daily and seasonal changes. In the course of a day there are many changes in the structure of living communities, mainly due to increased resource pressure during the day (better rate of detection) and abiotic factors such as changes of temperature and light. The midreaches are the most affected by daily periodic changes, because here there is the greatest biodiversity, each with different ideal conditions. Because there is a uniform use of resources and high stability, disturbances and fluctuations are usually corrected relatively quickly. Inequalities in the use of resources will be quickly compensated for, creating a new equilibrium. Also, there is no ecological development of the system (succession) and changes in the system are a result of outside geological changes, such as a change in the level of water making its way into the system, change of organic inputs or earthquakes. Even after these changes, however, it returns to a steady and modified equilibrium. This ensures that the ecosystem stays as an optimal functioning river system.
Read more about this topic: River Continuum Concept
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