Benthic community development in a new stream

Abstract

The development of the invertebrate fauna in a man-made, permanent stream which replaced a natural, temporary stream was observed over a year. Species colonized the new stream through drift, upstream migration, migration from a nearby underground field drainage system, and from neighbouring water bodies. Community development was examined in terms of the colonization and extinction rates proposed by MacArthur and Wilson (1963. Evolution, 17: 373–387) as part of their equilibrium model for island faunas. Although stability was possibly being approached after 109 days of flow, this equilibrium was disrupted by the introduction of a pollutant. Later, the colonization rate leveled out at about five times the value of the extinction rate. This is thought to reflect either continued instability or that the MacArthur–Wilson model does not apply as well to habitats that are seasonably invaded by recurring temporary inhabitants.