Tuesday, June 26, 2012

What's Left of the Creek

The adult of an aquatic insect sitting on vegetation along the creek is a normal sight for June.  Many species are in the process of mating and depositing their eggs into the creek water.  Unfortunately, there’s not much of a creek left for stoneflies such as this to use for their egg laying.

This has been a rough year for creek dependent creatures at Blue Jay Barrens.  The salamander larvae lost out to the fish and then the fish disappeared with the water.  Most of those little fish I posted about last week have now died. The shallow riffles have turned into dry gravel.

The creek has seen some extreme changes over the last six months.  A winter flood deposited most of this gravel.  A spring flood overtopped it all and began moving gravel farther downstream.  Now there’s no water and everything is drying out.

This stretch was running full just three months ago.  It’s not uncommon for the creek to stop flowing, but that is normally a late summer event.

There are about a half dozen of these larger pools surviving.  They are already providing water for a wide variety of wildlife and will become more attractive as the drought progresses.  A good measure of activity in the pool is the cloudiness of the water from suspended sediment.  The water becomes muddier with increasing animal visitations.

Water Striders have concentrated into the few remaining pools.  As they become more crowded, competition for food increases.  The Water Striders battle for each small insect that lands on the surface of the water.

Without substantial rain, all pools will eventually look like this.  The fact that the creek goes dry each year is not a problem.  The problem arises with the timing of that event.  Most of the organisms that live in these upper watershed tributaries are adapted to surviving in temporary water bodies.  The loss of water eliminates predators that would feed on the young and adults of the animals that breed here.  For many, a year of permanent water flow is just as disastrous as a year of early drought. 

Some animals are capable of leaving the doomed pools and others disappear beneath the stream bed.  As the last of the mud begins to dry in a lost pool, animals arrive to capture those creatures incapable of retreating.  We’re many months away from the time when drought relief is normally expected.  It’s hard to predict what the creek may endure during that time.

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