Understanding the Ecological Functions of Ephemeral and Intermittent Headwater Streams: Do Temporary Streams Support Native Fish Populations?

It is becoming increasingly imperative that we understand the roles and processes played by ephemeral and intermittent headwater streams.   As many cities are expanding into the headwater areas of their watersheds, both scientists and land use planners are becoming increasingly concerned that ephemeral and intermittent headwater streams are highly impacted by agricultural and urban land-use alterations and that these modifications will cause streams to lose their ability to perform critical ecological functions in the watershed before those functions can be appreciated or even understood.  One function that has been proposed is that ephemeral streams, which are known to transport large quantities of organic material, might act as important sources of food to downstream fish communities.  Several studies have recently demonstrated that large quantities of such organic materials are being exported from ephemeral and intermittent streams into permanent reaches; however this is the first study that empirically tests whether exports from temporary streams play a significant role in supplementing the diet of downstream fish populations.