FLUVIAL ECOSYSTEM

Summary: The Fluvial ecosystems of Castilla y León (Spain).

Natural areas: Riberas de Castronuño y Arribes del Duero.

A main principle of ecology is that each living organism has an ongoing and continual relationship with every other element that makes up its environment. The sum total of interacting living organisms (the biocenosis) and their non-living environment (the biotope) in an area is termed an ecosystem.
In an ecosystem, the connections between species are generally related to their role in the food chain. There are three categories of organisms:
Producers or Autotrophs, usually plants that are capable of photosynthesis.
Consumers or Heterotrophs, animals which can be primary consumers (herbivorous), or secondary or tertiary consumers (carnivorous and omnivores)
Descomposers or Detritivores, bacteria, fungi and insects which degrade organic matter of all types and restore nutrients to the environment. The producers will then consume the nutrients, completing the cycle.
These relations form sequences, in which each individual consumes the preceding one and is consumed by the one following, which are called food chains or food networks. In food networks, there will be fewer organisms at each level as one follows the links of the network up the chain, forming an ecological pyramid.

Ecosystems can be roughly divided into terrestrial ecosystems (including forest ecosystems, bush ecosystems, steppes, meadows and so on) and freshwater ecosystems (lakes, ponds and rivers).

In this unit and the next units, our students will work on of the biocenosis or community (groups of populations of plants and animals) that make up the ecological pyramid of different ecosystems of Castilla y León.

This chapter provides an overview of the diversity of fauna and flora in the rivers and streams of Castilla y León. We will talk about the food chain in the rivers of Castilla y León, starting with the river flora, trees and plankton of the water and continue with the fish and the other animals ( birds and mammals) that eat them.