Since 2017 a group of citizen scientists have been monitoring roadkill mortality of two species of pacific newts: California Newt (Taricha torosa) and Rough-skinned Newt (Taricha granulosa) along a road near Lexington Reservoir, Los Gatos CA. The newts migrate from the hills to the reservoir and the creeks nearby in order to reproduce. They start migrating after the first substantial rains, and head back early spring (November-May). Many of them get hit by the busy traffic on the road surrounding the reservoir.
For the past three seasons we have been surveying a 4.2 miles section of the road, recording an average of about 5,000 dead newts per year. This is one of the highest rates of herpetofauna mortality on roads ever reported globally. We record each newt using a smartphone, and share our observations on iNaturalist (https://tinyurl.com/6csrsbf4). We also record other species, with over 800 individuals of 100 species documented so far.
Newt roadkill counts were affected by rainfall and frost. Although newts prefer to migrate on rainy nights, once they start migrating, they continue even during a long dry spell. In addition to our monitoring program, this year we also studied the impact of weather conditions on the persistence of dead newts on the road, in order to estimate how many newts are being missed by our teams.
We are highly concerned about the survival of the two newt populations. 5,000 dead newts a year are not sustainable. With climate change, fewer breeding ponds will be available for the newts to reproduce in. Plans to develop farther recreational activities along this road will attract even more traffic into the area. So far, different attempts by local environmental advocates have failed to engaged the different agencies in finding and funding solutions. We will discuss possible solutions.