Wednesday, May 21, 2014

Streamside Salamander Larvae

Streamside Salamanders began hatching about three weeks ago.  Now I’m seeing the larvae in every part of the creek.  The cooler water temperature of the creek causes these larvae to develop more slowly than their relatives living in upland pools.  While the salamander larvae in the pond are nearly ready to leave the water, these creek dwelling larvae will remain in their aquatic environment for several more weeks.

Each year finds more Streamside Salamanders breeding in the creek and many have recently begun to utilize the smaller tributaries.  I am assuming that the salamander population has been increasing since stream disturbance, such as cattle access, stopped when I purchased the property.

Fish do not travel up these small tributaries, so the pool dwelling salamanders are not threatened by that voracious predator.  The down side is the fact that the smaller tributaries stop flowing earlier in the summer than the main creek.  Larvae in the tributaries are at a greater risk of losing their water supply before they have time enough to develop sufficiently to adopt a terrestrial lifestyle.

In the main creek, Streamside Salamanders are utilizing most of the prime breeding rocks.  Larvae hatching from beneath large flat rocks in the fast moving stream reaches are swept into the quiet waters of downstream pools.

Streamside Salamanders are now numerous enough that each set of riffles produces some larvae for the adjoining pool.

Larvae of this species develop a more streamlined shape than species living in quiet ponds.  Even in the pools, the water can sometimes move quite swiftly and the larvae need to keep from being swept away.  Their long, thin shape helps the larvae settle in and ride out times of storm runoff.

Even the gills appear to be stouter and more compact.  We’ve had plenty of rain this spring and the water table is high.  The creek should keep flowing well past the time that the salamanders lose their gills and move away into the surrounding woodland.

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