Wednesday, October 3, 2012

Proposed Listing of the Spring Pygmy Sunfish as Threatened

The Spring Pygmy Sunfish Elassoma alabamae

The imperiled Spring Pygmy Sunfish (Elassoma alabamae), which is restricted to springs and spring-fed creeks along a five-mile length of Beaverdam Creek in northern Alabama, was proposed for federal listing as threatened by the U.S. Fish and Wildlife Service on 2 October 2012. Critical habitat for the species is also designated. This species was historically known from two other spring systems in the Tennessee River drainage in Alabama, but habitat destruction from dams, reservoirs, and herbicides caused these populations to disappear.

Beaverdam Spring, ideal habitat for the Spring Pygmy Sunfish
The Spring Pygmy Sunfish only reaches 1 inch, only lives for a year, and needs clear spring water and dense submerged vegetation.  They are reliant on their vision to find food and mates, so clear water is essential.  The dense submerged vegetation is needed for the eggs to be successfully laid, hatch, and for juveniles and adults to hide from predators. These life history traits make the species vulnerable to habitat disturbances that muddy the water, herbicides that reduce or kill aquatic vegetation, and groundwater withdrawals that lower water levels and together with drought conditions have caused springs in the system to go completely dry.

Spring Pygmy Sunfish habitat in the Beaverdam Creek system is highly imperiled due to the rapid growth of nearby Huntsville and an increase in agricultural and municipal groundwater pumping in the aquifer that feeds these springs. Construction projects with no or improperly installed silt fences and an increase in impervious surfaces that produces heavy stormwater runoff threaten water quality.

Ineffective silt fences along Beaverdam Creek that contribute to the siltation of critical habitat
Impervious surfaces also threaten water quantity by deflecting water that would normally recharge the underlying aquifer. These are just some of the escalating threats that Beaverdam Creek and the Spring Pygmy Sunfish are facing.

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