Newt Migration at Lexington Reservoir - Roadkill Stats

I went back to Lexington Reservoir to do a more extensive count of newts killed along Alma Bridge Road from the St. Joseph Hill parking lot to Soda Springs Road (1.8 miles total).

I found a total of 457 newt carcasses on the road in various stages of decomposition. There weren't as many "fresh" carcasses as last week. This count may be inclusive of the 42 carcasses I recorded last week between Limekiln and Priest Rock trailheads (0.5 mile).

Since I don't know how long it takes a newt carcass to decompose, I don't know the timeframe for these deaths (a few weeks? a few months?), but I would guess they all happened this season.

Things I noticed:
• There were clusters of carcasses around drainages from the hillside.
• Most carcasses were found on the left side of the road (uphill side).
• Not surprisingly, there were also clusters of carcasses near the trailheads and parking lots, where the traffic is heaviest.
• There were many fewer carcasses after the Boat Club entrance (traveling south), when traffic thins out.

I have photos of these 457 newt carcasses if anyone needs them for proof. (I'll probably have newt zombie nightmares after seeing all these dead bodies.)

P.S. I didn't see a single live newt on my 4.5 hour hike this morning.

References:
Best management practices for mitigating the effects of roads on amphibian and reptile populations:
https://postbox.box.com/s/bierhcr5fs25l583qavqvornkfaancnx

Posted on January 22, 2018 01:29 AM by truthseqr truthseqr

Comments

Posted by truthseqr over 6 years ago

Great work. Were they all California newts or mixed with Rough-skin?

Posted by biohexx1 over 6 years ago

The ones I was able to identify were Rough-Skinned Newts. Most were too squished & decomposed to tell one way or the other.

Do you happen to know how I can find out how long it takes for a newt body to decompose? So we can get some kind of time frame on this.

Posted by truthseqr over 6 years ago

I would imagine it primarily depends on temperature. The higher the temperature, the more microbes like bacteria and fungi can begin to decompose. The second factor would be moistness. How much rain is available. If it is too dry, bacteria and fungi take longer to decompose. The third factor here is how much they are being trampled on or run over. This obviously pulverizes them.

Posted by biohexx1 over 6 years ago

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